Testing Event-Driven Functions

There are two distinct types of Cloud Functions: HTTP functions and event-driven functions. Each type has its own testing requirements.

A function's test structure depends on which Google Cloud resources that function uses. In turn, a function's resource use depends on how that function is triggered.

This document describes how to test event-driven Cloud Functions. See Testing HTTP Functions for information on how to test HTTP functions.

Pub/Sub-triggered functions

Pub/Sub-triggered function tests are structured differently depending on where the tested function is running.

Here is an example of a Pub/Sub-triggered function that prints "Hello, World":

Node.js

functions/helloworld/helloPubSub/index.js

View on GitHub Feedback

/**
 * Background Cloud Function to be triggered by Pub/Sub.
 * This function is exported by index.js, and executed when
 * the trigger topic receives a message.
 *
 * @param {object} message The Pub/Sub message.
 * @param {object} context The event metadata.
 */
exports.helloPubSub = (message, context) => {
  const name = message.data
    ? Buffer.from(message.data, 'base64').toString()
    : 'World';

  console.log(`Hello, ${name}!`);
};

Python

functions/helloworld/main.py

View on GitHub Feedback

def hello_pubsub(event, context):
    """Background Cloud Function to be triggered by Pub/Sub.
    Args:
         event (dict):  The dictionary with data specific to this type of
                        event. The `@type` field maps to
                         `type.googleapis.com/google.pubsub.v1.PubsubMessage`.
                        The `data` field maps to the PubsubMessage data
                        in a base64-encoded string. The `attributes` field maps
                        to the PubsubMessage attributes if any is present.
         context (google.cloud.functions.Context): Metadata of triggering event
                        including `event_id` which maps to the PubsubMessage
                        messageId, `timestamp` which maps to the PubsubMessage
                        publishTime, `event_type` which maps to
                        `google.pubsub.topic.publish`, and `resource` which is
                        a dictionary that describes the service API endpoint
                        pubsub.googleapis.com, the triggering topic's name, and
                        the triggering event type
                        `type.googleapis.com/google.pubsub.v1.PubsubMessage`.
    Returns:
        None. The output is written to Cloud Logging.
    """
    import base64

    print("""This Function was triggered by messageId {} published at {} to {}
    """.format(context.event_id, context.timestamp, context.resource["name"]))

    if 'data' in event:
        name = base64.b64decode(event['data']).decode('utf-8')
    else:
        name = 'World'
    print(f'Hello {name}!')

Go

functions/helloworld/hello_pubsub.go

View on GitHub Feedback


// Package helloworld provides a set of Cloud Functions samples.
package helloworld

import (
	"context"
	"log"
)

// PubSubMessage is the payload of a Pub/Sub event.
// See the documentation for more details:
// https://cloud.google.com/pubsub/docs/reference/rest/v1/PubsubMessage
type PubSubMessage struct {
	Data []byte `json:"data"`
}

// HelloPubSub consumes a Pub/Sub message.
func HelloPubSub(ctx context.Context, m PubSubMessage) error {
	name := string(m.Data) // Automatically decoded from base64.
	if name == "" {
		name = "World"
	}
	log.Printf("Hello, %s!", name)
	return nil
}

Java

functions/helloworld/hello-pubsub/src/main/java/functions/HelloPubSub.java

View on GitHub Feedback


import com.google.cloud.functions.BackgroundFunction;
import com.google.cloud.functions.Context;
import functions.eventpojos.PubsubMessage;
import java.nio.charset.StandardCharsets;
import java.util.Base64;
import java.util.logging.Level;
import java.util.logging.Logger;

public class HelloPubSub implements BackgroundFunction<PubsubMessage> {
  private static final Logger logger = Logger.getLogger(HelloPubSub.class.getName());

  @Override
  public void accept(PubsubMessage message, Context context) {
    String name = "world";
    if (message != null && message.getData() != null) {
      name = new String(
          Base64.getDecoder().decode(message.getData().getBytes(StandardCharsets.UTF_8)),
          StandardCharsets.UTF_8);
    }
    logger.info(String.format("Hello %s!", name));
    return;
  }
}

C#

functions/helloworld/HelloPubSub/Function.cs

View on GitHub Feedback

using CloudNative.CloudEvents;
using Google.Cloud.Functions.Framework;
using Google.Events.Protobuf.Cloud.PubSub.V1;
using Microsoft.Extensions.Logging;
using System.Threading;
using System.Threading.Tasks;

namespace HelloPubSub;

public class Function : ICloudEventFunction<MessagePublishedData>
{
    private readonly ILogger _logger;

    public Function(ILogger<Function> logger) =>
        _logger = logger;

    public Task HandleAsync(CloudEvent cloudEvent, MessagePublishedData data, CancellationToken cancellationToken)
    {
        string nameFromMessage = data.Message?.TextData;
        string name = string.IsNullOrEmpty(nameFromMessage) ? "world" : nameFromMessage;
        _logger.LogInformation("Hello {name}", name);
        return Task.CompletedTask;
    }
}

Ruby

functions/helloworld/pubsub/app.rb

View on GitHub Feedback

require "functions_framework"
require "base64"

FunctionsFramework.cloud_event "hello_pubsub" do |event|
  # The event parameter is a CloudEvents::Event::V1 object.
  # See https://cloudevents.github.io/sdk-ruby/latest/CloudEvents/Event/V1.html
  name = Base64.decode64 event.data["message"]["data"] rescue "World"

  # A cloud_event function does not return a response, but you can log messages
  # or cause side effects such as sending additional events.
  logger.info "Hello, #{name}!"
end

PHP

functions/helloworld_pubsub/index.php

View on GitHub Feedback


use CloudEvents\V1\CloudEventInterface;
use Google\CloudFunctions\FunctionsFramework;

// Register the function with Functions Framework.
// This enables omitting the `FUNCTIONS_SIGNATURE_TYPE=cloudevent` environment
// variable when deploying. The `FUNCTION_TARGET` environment variable should
// match the first parameter.
FunctionsFramework::cloudEvent('helloworldPubsub', 'helloworldPubsub');

function helloworldPubsub(CloudEventInterface $event): void
{
    $log = fopen(getenv('LOGGER_OUTPUT') ?: 'php://stderr', 'wb');

    $cloudEventData = $event->getData();
    $pubSubData = base64_decode($cloudEventData['message']['data']);

    $name = $pubSubData ? htmlspecialchars($pubSubData) : 'World';
    fwrite($log, "Hello, $name!" . PHP_EOL);
}

Unit tests

Here are unit tests for the Pub/Sub-triggered function above:

Node.js

functions/helloworld/helloPubSub/test/sample.unit.pubsub.test.js

View on GitHub Feedback

const assert = require('assert');
const uuid = require('uuid');
const sinon = require('sinon');

const {helloPubSub} = require('..');

const stubConsole = function () {
  sinon.stub(console, 'error');
  sinon.stub(console, 'log');
};

const restoreConsole = function () {
  console.log.restore();
  console.error.restore();
};

beforeEach(stubConsole);
afterEach(restoreConsole);

it('helloPubSub: should print a name', () => {
  // Create mock Pub/Sub event
  const name = uuid.v4();
  const event = {
    data: Buffer.from(name).toString('base64'),
  };

  // Call tested function and verify its behavior
  helloPubSub(event);
  assert.ok(console.log.calledWith(`Hello, ${name}!`));
});

Python

functions/helloworld/sample_pubsub_test.py

View on GitHub Feedback

import base64

from unittest import mock

import main


mock_context = mock.Mock()
mock_context.event_id = '617187464135194'
mock_context.timestamp = '2019-07-15T22:09:03.761Z'
mock_context.resource = {
    'name': 'projects/my-project/topics/my-topic',
    'service': 'pubsub.googleapis.com',
    'type': 'type.googleapis.com/google.pubsub.v1.PubsubMessage',
}


def test_print_hello_world(capsys):
    data = {}

    # Call tested function
    main.hello_pubsub(data, mock_context)
    out, err = capsys.readouterr()
    assert 'Hello World!' in out


def test_print_name(capsys):
    name = 'test'
    data = {'data': base64.b64encode(name.encode())}

    # Call tested function
    main.hello_pubsub(data, mock_context)
    out, err = capsys.readouterr()
    assert f'Hello {name}!\n' in out

Go

functions/helloworld/hello_pubsub_test.go

View on GitHub Feedback


package helloworld

import (
	"context"
	"io/ioutil"
	"log"
	"os"
	"testing"
)

func TestHelloPubSub(t *testing.T) {
	tests := []struct {
		data string
		want string
	}{
		{want: "Hello, World!\n"},
		{data: "Go", want: "Hello, Go!\n"},
	}
	for _, test := range tests {
		r, w, _ := os.Pipe()
		log.SetOutput(w)
		originalFlags := log.Flags()
		log.SetFlags(log.Flags() &^ (log.Ldate | log.Ltime))

		m := PubSubMessage{
			Data: []byte(test.data),
		}
		HelloPubSub(context.Background(), m)

		w.Close()
		log.SetOutput(os.Stderr)
		log.SetFlags(originalFlags)

		out, err := ioutil.ReadAll(r)
		if err != nil {
			t.Fatalf("ReadAll: %v", err)
		}
		if got := string(out); got != test.want {
			t.Errorf("HelloPubSub(%q) = %q, want %q", test.data, got, test.want)
		}
	}
}

Java

functions/helloworld/hello-pubsub/src/test/java/functions/HelloPubSubTest.java

View on GitHub Feedback


import static com.google.common.truth.Truth.assertThat;

import com.google.common.testing.TestLogHandler;
import functions.eventpojos.PubsubMessage;
import java.nio.charset.StandardCharsets;
import java.util.Base64;
import java.util.logging.Logger;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.JUnit4;

/**
 * Unit tests for main.java.com.example.functions.helloworld.HelloPubSub.
 */
@RunWith(JUnit4.class)
public class HelloPubSubTest {

  private HelloPubSub sampleUnderTest;
  private static final Logger logger = Logger.getLogger(HelloPubSub.class.getName());

  private static final TestLogHandler LOG_HANDLER = new TestLogHandler();

  @Before
  public void setUp() {
    sampleUnderTest = new HelloPubSub();
    logger.addHandler(LOG_HANDLER);
    LOG_HANDLER.clear();
  }

  @Test
  public void helloPubSub_shouldPrintName() {
    PubsubMessage pubSubMessage = new PubsubMessage();
    pubSubMessage.setData(Base64.getEncoder().encodeToString(
        "John".getBytes(StandardCharsets.UTF_8)));
    sampleUnderTest.accept(pubSubMessage, null);

    String logMessage = LOG_HANDLER.getStoredLogRecords().get(0).getMessage();
    assertThat("Hello John!").isEqualTo(logMessage);
  }

  @Test
  public void helloPubSub_shouldPrintHelloWorld() {
    PubsubMessage pubSubMessage = new PubsubMessage();
    sampleUnderTest.accept(pubSubMessage, null);

    String logMessage = LOG_HANDLER.getStoredLogRecords().get(0).getMessage();
    assertThat("Hello world!").isEqualTo(logMessage);
  }
}

C#

functions/helloworld/HelloWorld.Tests/HelloPubSubUnitTest.cs

View on GitHub Feedback

using CloudNative.CloudEvents;
using Google.Cloud.Functions.Testing;
using Google.Events.Protobuf.Cloud.PubSub.V1;
using Microsoft.Extensions.Logging;
using System;
using System.Threading;
using System.Threading.Tasks;
using Xunit;

namespace HelloWorld.Tests;

public class HelloPubSubUnitTest
{
    [Fact]
    public async Task MessageWithTextData()
    {
        var data = new MessagePublishedData { Message = new PubsubMessage { TextData = "PubSub user" } };
        var cloudEvent = new CloudEvent
        {
            Type = MessagePublishedData.MessagePublishedCloudEventType,
            Source = new Uri("//pubsub.googleapis.com", UriKind.RelativeOrAbsolute),
            Id = Guid.NewGuid().ToString(),
            Time = DateTimeOffset.UtcNow,
            Data = data
        };

        var logger = new MemoryLogger<HelloPubSub.Function>();
        var function = new HelloPubSub.Function(logger);
        await function.HandleAsync(cloudEvent, data, CancellationToken.None);

        var logEntry = Assert.Single(logger.ListLogEntries());
        Assert.Equal("Hello PubSub user", logEntry.Message);
        Assert.Equal(LogLevel.Information, logEntry.Level);
    }

    [Fact]
    public async Task MessageWithoutTextData()
    {
        var data = new MessagePublishedData
        {
            Message = new PubsubMessage { Attributes = { { "key", "value" } } }
        };
        var cloudEvent = new CloudEvent
        {
            Type = MessagePublishedData.MessagePublishedCloudEventType,
            Source = new Uri("//pubsub.googleapis.com", UriKind.RelativeOrAbsolute),
            Id = Guid.NewGuid().ToString(),
            Time = DateTimeOffset.UtcNow
        };

        var logger = new MemoryLogger<HelloPubSub.Function>();
        var function = new HelloPubSub.Function(logger);
        await function.HandleAsync(cloudEvent, data, CancellationToken.None);

        var logEntry = Assert.Single(logger.ListLogEntries());
        Assert.Equal("Hello world", logEntry.Message);
        Assert.Equal(LogLevel.Information, logEntry.Level);
    }
}

Ruby

functions/test/helloworld/pubsub_test.rb

View on GitHub Feedback

require "minitest/autorun"
require "functions_framework/testing"
require "base64"

describe "functions_helloworld_pubsub" do
  include FunctionsFramework::Testing

  let(:resource_type) { "type.googleapis.com/google.pubsub.v1.PubsubMessage" }
  let(:source) { "//pubsub.googleapis.com/projects/sample-project/topics/gcf-test" }
  let(:type) { "google.cloud.pubsub.topic.v1.messagePublished" }

  it "prints a name" do
    load_temporary "helloworld/pubsub/app.rb" do
      payload = { "@type" => resource_type, "message" => { "data" => Base64.encode64("Ruby") } }
      event = make_cloud_event payload, source: source, type: type
      _out, err = capture_subprocess_io do
        # Call tested function
        call_event "hello_pubsub", event
      end
      assert_match(/Hello, Ruby!/, err)
    end
  end

  it "prints hello world" do
    load_temporary "helloworld/pubsub/app.rb" do
      payload = { "@type" => resource_type, "message" => { "data" => nil } }
      event = make_cloud_event payload, source: source, type: type
      _out, err = capture_subprocess_io do
        # Call tested function
        call_event "hello_pubsub", event
      end
      assert_match(/Hello, World!/, err)
    end
  end
end

PHP

functions/helloworld_pubsub/SampleUnitTest.php

View on GitHub Feedback


namespace Google\Cloud\Samples\Functions\HelloworldPubsub\Test;

use CloudEvents\V1\CloudEventImmutable;
use CloudEvents\V1\CloudEventInterface;
use PHPUnit\Framework\TestCase;

/**
 * Class SampleUnitTest.
 *
 * Unit test for 'Helloworld Pub/Sub' Cloud Function.
 */
class SampleUnitTest extends TestCase
{
    /**
     * Include the Cloud Function code before running any tests.
     *
     * @see https://phpunit.readthedocs.io/en/latest/fixtures.html
     */
    public static function setUpBeforeClass(): void
    {
        require_once __DIR__ . '/index.php';
    }

    public function dataProvider()
    {
        return [
            [
                'cloudevent' => new CloudEventImmutable(
                    uniqId(), // id
                    'pubsub.googleapis.com', // source
                    'google.cloud.pubsub.topic.v1.messagePublished', // type
                    [
                        'data' => base64_encode('John')
                    ]
                ),
                'expected' => 'Hello, John!'
            ],
        ];
    }

    /**
     * @dataProvider dataProvider
     */
    public function testFunction(
        CloudEventInterface $cloudevent,
        string $expected
    ): void {
        // Capture function output by overriding the function's logging behavior.
        // The 'LOGGER_OUTPUT' environment variable must be used in your function:
        //
        // $log = fopen(getenv('LOGGER_OUTPUT') ?: 'php://stderr', 'wb');
        // fwrite($log, 'Log Entry');
        putenv('LOGGER_OUTPUT=php://output');
        helloworldPubsub($cloudevent);
        // Provided by PHPUnit\Framework\TestCase.
        $actual = $this->getActualOutput();

        // Test that output includes the expected value.
        $this->assertStringContainsString($expected, $actual);
    }
}

Run the unit tests with the following command:

Node.js

mocha test/sample.unit.pubsub.test.js --exit

Python

pytest sample_pubsub_test.py

Go

go test -v ./hello_pubsub_test.go

Java

Maven uses mvn test to run unit tests.

mvn test

C#

dotnet test

PHP

To run the unit tests, use PHPUnit.

Integration tests

Here are integration tests for the Pub/Sub-triggered function above:

Node.js

functions/helloworld/helloPubSub/test/sample.integration.pubsub.test.js

View on GitHub Feedback

const assert = require('assert');
const {spawn} = require('child_process');
const {request} = require('gaxios');
const uuid = require('uuid');
const waitPort = require('wait-port');

  it('helloPubSub: should print a name', async () => {
    const name = uuid.v4();
    const PORT = 8088; // Each running framework instance needs a unique port

    const encodedName = Buffer.from(name).toString('base64');
    const pubsubMessage = {data: {data: encodedName}};
    const ffProc = spawn('npx', [
      'functions-framework',
      '--target',
      'helloPubSub',
      '--signature-type',
      'event',
      '--port',
      PORT,
    ]);

    try {
      const ffProcHandler = new Promise((resolve, reject) => {
        let stdout = '';
        let stderr = '';
        ffProc.stdout.on('data', data => (stdout += data));
        ffProc.stderr.on('data', data => (stderr += data));
        ffProc.on('exit', code => {
          if (code === 0 || code === null) {
            // code === null corresponds to a signal-kill
            // (which doesn't necessarily indicate a test failure)
            resolve(stdout);
          } else {
            stderr = `Error code: ${code}\n${stderr}`;
            reject(new Error(stderr));
          }
        });
      });
      await waitPort({host: 'localhost', port: PORT});

      // Send HTTP request simulating Pub/Sub message
      // (GCF translates Pub/Sub messages to HTTP requests internally)
      const response = await request({
        url: `http://localhost:${PORT}/`,
        method: 'POST',
        data: pubsubMessage,
      });
      ffProc.kill();

      assert.strictEqual(response.status, 204);

      // Wait for the functions framework to stop
      const stdout = await ffProcHandler;
      assert.match(stdout, new RegExp(`Hello, ${name}!`));
    } catch {
      if (ffProc) {
        // Make sure the functions framework is stopped
        ffProc.kill();
      }
    }
  });
});

Python

functions/helloworld/sample_pubsub_test_integration.py

View on GitHub Feedback

import base64
import os
import subprocess
import uuid

import requests
from requests.packages.urllib3.util.retry import Retry


def test_print_name():
    name = str(uuid.uuid4())
    port = 8088  # Each running framework instance needs a unique port

    encoded_name = base64.b64encode(name.encode('utf-8')).decode('utf-8')
    pubsub_message = {
        'data': {'data': encoded_name}
    }

    process = subprocess.Popen(
      [
        'functions-framework',
        '--target', 'hello_pubsub',
        '--signature-type', 'event',
        '--port', str(port)
      ],
      cwd=os.path.dirname(__file__),
      stdout=subprocess.PIPE
    )

    # Send HTTP request simulating Pub/Sub message
    # (GCF translates Pub/Sub messages to HTTP requests internally)
    url = f'http://localhost:{port}/'

    retry_policy = Retry(total=6, backoff_factor=1)
    retry_adapter = requests.adapters.HTTPAdapter(
      max_retries=retry_policy)

    session = requests.Session()
    session.mount(url, retry_adapter)

    response = session.post(url, json=pubsub_message)

    assert response.status_code == 200

    # Stop the functions framework process
    process.kill()
    process.wait()
    out, err = process.communicate()

    print(out, err, response.content)

    assert f'Hello {name}!' in str(out)

Java

functions/helloworld/hello-pubsub/src/test/java/functions/ExampleIT.java

View on GitHub Feedback


import static com.google.common.truth.Truth.assertThat;

import com.google.gson.Gson;
import io.github.resilience4j.core.IntervalFunction;
import io.github.resilience4j.retry.Retry;
import io.github.resilience4j.retry.RetryConfig;
import io.github.resilience4j.retry.RetryRegistry;
import io.vavr.CheckedRunnable;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.net.URI;
import java.nio.charset.StandardCharsets;
import java.util.Base64;
import java.util.Map;
import java.util.UUID;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.conn.HttpHostConnectException;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.HttpClientBuilder;
import org.junit.AfterClass;
import org.junit.BeforeClass;
import org.junit.Test;

public class ExampleIT {
  // Each function must be assigned a unique port to run on.
  // Otherwise, tests can flake when 2+ functions run simultaneously.
  // This is also specified in the `function-maven-plugin` config in `pom.xml`.
  private static final int PORT = 8083;

  // Root URL pointing to the locally hosted function
  // The Functions Framework Maven plugin lets us run a function locally
  private static final String BASE_URL = "http://localhost:" + PORT;

  private static Process emulatorProcess = null;
  private static HttpClient client = HttpClientBuilder.create().build();
  private static final Gson gson = new Gson();

  @BeforeClass
  public static void setUp() throws IOException {
    // Get the sample's base directory (the one containing a pom.xml file)
    String baseDir = System.getProperty("user.dir");

    // Emulate the function locally by running the Functions Framework Maven plugin
    emulatorProcess = new ProcessBuilder()
        .command("bash", "-c", "mvn function:run")
        .directory(new File(baseDir))
        .start();
  }

  @AfterClass
  public static void tearDown() throws IOException {
    // Display the output of the plugin process
    InputStream stdoutStream = emulatorProcess.getInputStream();
    ByteArrayOutputStream stdoutBytes = new ByteArrayOutputStream();
    stdoutBytes.write(stdoutStream.readNBytes(stdoutStream.available()));
    System.err.println(stdoutBytes.toString(StandardCharsets.UTF_8));

    // Terminate the running Functions Framework Maven plugin process (if it's still running)
    if (emulatorProcess.isAlive()) {
      emulatorProcess.destroy();
    }
  }

  @Test
  public void helloPubSub_shouldRunWithFunctionsFramework() throws Throwable {
    String functionUrl = BASE_URL + "/helloPubsub"; // URL to your locally-running function

    // Initialize constants
    String name = UUID.randomUUID().toString();
    String nameBase64 = Base64.getEncoder().encodeToString(name.getBytes(StandardCharsets.UTF_8));

    String jsonStr = gson.toJson(Map.of("data", Map.of("data", nameBase64)));

    HttpPost postRequest =  new HttpPost(URI.create(functionUrl));
    postRequest.setEntity(new StringEntity(jsonStr));

    // The Functions Framework Maven plugin process takes time to start up
    // Use resilience4j to retry the test HTTP request until the plugin responds
    RetryRegistry registry = RetryRegistry.of(RetryConfig.custom()
        .maxAttempts(12)
        .retryExceptions(HttpHostConnectException.class)
        .retryOnResult(u -> {
          // Retry if the Functions Framework process has no stdout content
          // See `retryOnResultPredicate` here: https://resilience4j.readme.io/docs/retry
          try {
            return emulatorProcess.getErrorStream().available() == 0;
          } catch (IOException e) {
            return true;
          }
        })
        .intervalFunction(IntervalFunction.ofExponentialBackoff(200, 2))
        .build());
    Retry retry = registry.retry("my");

    // Perform the request-retry process
    CheckedRunnable retriableFunc = Retry.decorateCheckedRunnable(
        retry, () -> client.execute(postRequest));
    retriableFunc.run();

    // Get Functions Framework plugin process' stdout
    InputStream stdoutStream = emulatorProcess.getErrorStream();
    ByteArrayOutputStream stdoutBytes = new ByteArrayOutputStream();
    stdoutBytes.write(stdoutStream.readNBytes(stdoutStream.available()));

    // Verify desired name value is present
    assertThat(stdoutBytes.toString(StandardCharsets.UTF_8)).contains(
        String.format("Hello %s!", name));
  }
}

PHP

functions/helloworld_pubsub/SampleIntegrationTest.php

View on GitHub Feedback


namespace Google\Cloud\Samples\Functions\HelloworldPubsub;

use Google\CloudFunctions\CloudEvent;
use GuzzleHttp\Client;
use PHPUnit\Framework\TestCase;
use Symfony\Component\Process\Process;
use Symfony\Component\Process\PhpExecutableFinder;

/**
 * Class SampleIntegrationTest.
 *
 * Integration tests for the 'Helloworld Pubsub' Cloud Function.
 */
class SampleIntegrationTest extends TestCase
{
    /** @var Process */
    private static $process;

    /** @var Client */
    private static $client;

    public function dataProvider()
    {
        return [
            [
                'cloudevent' => CloudEvent::fromArray([
                    'id' => uniqid(),
                    'source' => 'pubsub.googleapis.com',
                    'specversion' => '1.0',
                    'type' => 'google.cloud.pubsub.topic.v1.messagePublished',
                ]),
                'data' => [
                    'data' => base64_encode('John')
                ],
                'expected' => 'Hello, John!'
            ],
        ];
    }

    /**
     * Start a local PHP server running the Functions Framework.
     *
     * @beforeClass
     */
    public static function startFunctionFramework(): void
    {
        $port = getenv('PORT') ?: '8080';
        $php = (new PhpExecutableFinder())->find();
        $uri = 'localhost:' . $port;

        // https://symfony.com/doc/current/components/process.html#usage
        self::$process = new Process([$php, '-S', $uri, 'vendor/bin/router.php'], null, [
            'FUNCTION_SIGNATURE_TYPE' => 'cloudevent',
            'FUNCTION_TARGET' => 'helloworldPubsub',
        ]);
        self::$process->start();

        // Initialize an HTTP client to drive requests.
        self::$client = new Client(['base_uri' => 'http://' . $uri]);

        // Short delay to ensure PHP server is ready.
        sleep(1);
    }

    /**
     * Stop the local PHP server.
     *
     * @afterClass
     */
    public static function stopFunctionFramework(): void
    {
        if (!self::$process->isRunning()) {
            echo self::$process->getErrorOutput();
            throw new RuntimeException('Function Framework PHP process not running by end of test');
        }
        self::$process->stop(3, SIGTERM);
    }

    /**
     * @dataProvider dataProvider
     */
    public function testHelloPubsub(
        CloudEvent $cloudevent,
        array $data,
        string $expected
    ): void {
        // Send an HTTP request using CloudEvent metadata.
        $resp = self::$client->post('/', [
            'body' => json_encode($data),
            'headers' => [
                // Instruct the function framework to parse the body as JSON.
                'content-type' => 'application/json',

                // Prepare the HTTP headers for a CloudEvent.
                'ce-id' => $cloudevent->getId(),
                'ce-source' => $cloudevent->getSource(),
                'ce-specversion' => $cloudevent->getSpecVersion(),
                'ce-type' => $cloudevent->getType()
            ],
        ]);

        // The Cloud Function logs all data to stderr.
        $actual = self::$process->getIncrementalErrorOutput();

        // Verify the function's results are correctly logged.
        $this->assertStringContainsString($expected, $actual);
    }
}

You can run the integration tests for this function as follows:

Node.js

mocha test/sample.integration.pubsub.test.js --exit

Python

pytest sample_pubsub_test_integration.py

Java

Maven uses mvn verify to run integration tests.

mvn verify -Dit.test=ExampleIT

PHP

To run the integration tests, use PHPUnit.

System tests

Here are system tests for this function:

Node.js

functions/helloworld/helloPubSub/test/sample.system.pubsub.test.js

View on GitHub Feedback

const childProcess = require('child_process');
const assert = require('assert');
const uuid = require('uuid');
const {PubSub} = require('@google-cloud/pubsub');
const moment = require('moment');
const promiseRetry = require('promise-retry');

const pubsub = new PubSub();
const topicName = process.env.FUNCTIONS_TOPIC;
if (!topicName) throw new Error('"FUNCTIONS_TOPIC" env var must be set.');
if (!process.env.GCF_REGION) {
  throw new Error('"GCF_REGION" env var must be set.');
}
const baseCmd = 'gcloud functions';

describe('system tests', () => {
  it('helloPubSub: should print a name', async () => {
    const name = uuid.v4();

    // Subtract time to work-around local-GCF clock difference
    const startTime = moment().subtract(4, 'minutes').toISOString();

    // Publish to pub/sub topic
    const topic = pubsub.topic(topicName);
    const data = Buffer.from(name);
    await topic.publishMessage({data});

    console.log(`published topic ${topicName}, ${name}`);

    // Wait for logs to become consistent
    await promiseRetry(retry => {
      const logs = childProcess
        .execSync(`${baseCmd} logs read helloPubSub --start-time ${startTime}`)
        .toString();

      try {
        assert.ok(logs.includes(`Hello, ${name}!`));
      } catch (err) {
        console.log('An error occurred, retrying:', err);
        retry(err);
      }
    });
  });

Python

functions/helloworld/sample_pubsub_test_system.py

View on GitHub Feedback

from datetime import datetime
from os import getenv
import subprocess
import time
import uuid

from google.cloud import pubsub_v1
import pytest

PROJECT = getenv('GCP_PROJECT')
TOPIC = getenv('FUNCTIONS_TOPIC')

assert PROJECT is not None
assert TOPIC is not None


@pytest.fixture(scope='module')
def publisher_client():
    yield pubsub_v1.PublisherClient()


def test_print_name(publisher_client):
    start_time = datetime.utcnow().isoformat()
    topic_path = publisher_client.topic_path(PROJECT, TOPIC)

    # Publish the message
    name = uuid.uuid4()
    data = str(name).encode('utf-8')
    publisher_client.publish(topic_path, data=data).result()

    # Wait for logs to become consistent
    time.sleep(15)

    # Check logs after a delay
    log_process = subprocess.Popen([
        'gcloud',
        'alpha',
        'functions',
        'logs',
        'read',
        'hello_pubsub',
        '--start-time',
        start_time
    ], stdout=subprocess.PIPE)
    logs = str(log_process.communicate()[0])
    assert f'Hello {name}!' in logs

Go

functions/helloworld/hello_pubsub_system_test.go

View on GitHub Feedback


package helloworld

import (
	"context"
	"log"
	"os"
	"os/exec"
	"strings"
	"testing"
	"time"

	"cloud.google.com/go/pubsub"
	"github.com/gobuffalo/uuid"
)

func TestHelloPubSubSystem(t *testing.T) {
	ctx := context.Background()

	topicName := os.Getenv("FUNCTIONS_TOPIC")
	projectID := os.Getenv("GCP_PROJECT")

	startTime := time.Now().UTC().Format(time.RFC3339)

	// Create the Pub/Sub client and topic.
	client, err := pubsub.NewClient(ctx, projectID)
	if err != nil {
		log.Fatal(err)
	}
	topic := client.Topic(topicName)

	// Publish a message with a random string to verify.
	// We use a random string to make sure the function is logging the correct
	// message for this test invocation.
	u := uuid.Must(uuid.NewV4())
	msg := &pubsub.Message{
		Data: []byte(u.String()),
	}
	topic.Publish(ctx, msg).Get(ctx)

	// Wait for logs to be consistent.
	time.Sleep(20 * time.Second)

	// Check logs after a delay.
	cmd := exec.Command("gcloud", "alpha", "functions", "logs", "read", "HelloPubSub", "--start-time", startTime)
	out, err := cmd.CombinedOutput()
	if err != nil {
		t.Fatalf("exec.Command: %v", err)
	}
	if got := string(out); !strings.Contains(got, u.String()) {
		t.Errorf("HelloPubSub got %q, want to contain %q", got, u.String())
	}
}

Java

functions/helloworld/hello-pubsub/src/test/java/functions/ExampleSystemIT.java

View on GitHub Feedback

import static com.google.common.truth.Truth.assertThat;

import com.google.api.gax.paging.Page;
import com.google.cloud.logging.LogEntry;
import com.google.cloud.logging.Logging;
import com.google.cloud.logging.LoggingOptions;
import com.google.cloud.pubsub.v1.Publisher;
import com.google.protobuf.ByteString;
import com.google.pubsub.v1.ProjectTopicName;
import com.google.pubsub.v1.PubsubMessage;
import io.github.resilience4j.core.IntervalFunction;
import io.github.resilience4j.retry.Retry;
import io.github.resilience4j.retry.RetryConfig;
import io.github.resilience4j.retry.RetryRegistry;
import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.time.Duration;
import java.time.Instant;
import java.time.format.DateTimeFormatter;
import java.util.UUID;
import java.util.stream.Collectors;
import java.util.stream.StreamSupport;
import org.junit.BeforeClass;
import org.junit.Test;

public class ExampleSystemIT {

  // TODO<developer>: set these values (as environment variables)
  private static final String PROJECT_ID = System.getenv("GCP_PROJECT");
  private static final String TOPIC_NAME = System.getenv("FUNCTIONS_SYSTEM_TEST_TOPIC");

  // TODO<developer>: set this value (as an environment variable) to HelloPubSub
  private static final String FUNCTION_DEPLOYED_NAME = System.getenv("FUNCTIONS_PUBSUB_FN_NAME");

  private static Logging loggingClient;

  private static Publisher publisher;

  private HelloPubSub sampleUnderTest;

  @BeforeClass
  public static void setUp() throws IOException {
    loggingClient = LoggingOptions.getDefaultInstance().getService();
    publisher = Publisher.newBuilder(
        ProjectTopicName.of(PROJECT_ID, TOPIC_NAME)).build();
  }

  private static String getLogEntriesAsString(String startTimestamp) {
    // Construct Stackdriver logging filter
    // See this page for more info: https://cloud.google.com/logging/docs/view/advanced-queries
    String filter = "resource.type=\"cloud_function\""
        + " AND severity=INFO"
        + " AND resource.labels.function_name=" + FUNCTION_DEPLOYED_NAME
        + String.format(" AND timestamp>=\"%s\"", startTimestamp);

    // Get Stackdriver logging entries
    Page<LogEntry> logEntries =
        loggingClient.listLogEntries(
            Logging.EntryListOption.filter(filter),
            Logging.EntryListOption.sortOrder(
                Logging.SortingField.TIMESTAMP, Logging.SortingOrder.DESCENDING)
        );

    // Serialize Stackdriver logging entries + collect them into a single string
    String logsConcat = StreamSupport.stream(logEntries.getValues().spliterator(), false)
        .map((x) -> x.toString())
        .collect(Collectors.joining("%n"));

    return logsConcat;
  }

  @Test
  public void helloPubSub_shouldRunOnGcf() throws Exception {
    String name = UUID.randomUUID().toString();

    // Subtract time to work-around local-GCF clock difference
    Instant startInstant = Instant.now().minus(Duration.ofMinutes(4));
    String startTimestamp = DateTimeFormatter.ISO_INSTANT.format(startInstant);

    // Publish to pub/sub topic
    ByteString byteStr = ByteString.copyFrom(name, StandardCharsets.UTF_8);
    PubsubMessage pubsubApiMessage = PubsubMessage.newBuilder().setData(byteStr).build();
    publisher.publish(pubsubApiMessage).get();

    // Keep retrying until the logs contain the desired invocation's log entry
    // (If the invocation failed, the retry process will eventually time out)
    RetryRegistry registry = RetryRegistry.of(RetryConfig.custom()
        .maxAttempts(8)
        .intervalFunction(IntervalFunction.ofExponentialBackoff(1000, 2))
        .retryOnResult(s -> !s.toString().contains(name))
        .build());
    Retry retry = registry.retry(name);
    String logEntry = Retry
        .decorateFunction(retry, ExampleSystemIT::getLogEntriesAsString)
        .apply(startTimestamp);

    // Perform final assertion (to make sure we fail on timeout)
    assertThat(logEntry).contains(name);
  }
}

Run the system tests by following these instructions:

In your Google Cloud project, select a Pub/Sub topic to subscribe to. If you provide the name of a Pub/Sub topic that does not exist, it is created automatically.
Next, deploy your functions using the following command:
Node.js
```
gcloud functions deploy helloPubSub \
--runtime nodejs18 \
--trigger-topic YOUR_PUBSUB_TOPIC
```
You can use the following values for the --runtime flag to specify your preferred Node.js version:
- nodejs18 (recommended)
- nodejs20 (preview)
- nodejs16
- nodejs14
- nodejs12
- nodejs10
Python
```
gcloud functions deploy hello_pubsub \
--runtime python311 \
--trigger-topic YOUR_PUBSUB_TOPIC
```
You can use the following values for the --runtime flag to specify your preferred Python version:
- python311 (recommended)
- python310
- python39
- python38
- python37
Go
```
gcloud functions deploy HelloPubSub \
--runtime go120 \
--trigger-topic YOUR_PUBSUB_TOPIC
```
You can use the following values for the --runtime flag to specify your preferred Go version:
- go120 (recommended)
- go119
- go118
- go116
- go113
Java
```
gcloud functions deploy java-hello-pubsub \
--entry-point functions.HelloPubSub \
--runtime java17 \
--memory 512MB \
--trigger-topic YOUR_PUBSUB_TOPIC
```
You can use the following values for the --runtime flag to specify your preferred Java version:
- java17 (recommended)
- java11
where YOUR_PUBSUB_TOPIC is the name of the Pub/Sub topic you want your functions to subscribe to.

Run the system tests with the following command:

Node.js

export FUNCTIONS_TOPIC=YOUR_PUBSUB_TOPIC
mocha test/sample.system.pubsub.test.js --exit

Python

export FUNCTIONS_TOPIC=YOUR_PUBSUB_TOPIC
pytest sample_pubsub_test_system.py

Go

export FUNCTIONS_TOPIC=YOUR_PUBSUB_TOPIC
go test -v ./hello_pubsub_system_test.go

Java

export FUNCTIONS_TOPIC=YOUR_PUBSUB_TOPIC
mvn verify -Dit.test=ExampleSystemIT

where YOUR_PUBSUB_TOPIC is the name of the Pub/Sub topic you want your functions to subscribe to.

Storage-triggered functions

Tests for storage-triggered functions are similar in structure to their Pub/Sub-triggered counterparts. Like Pub/Sub-triggered function tests, storage-triggered function tests are structured differently depending on where the tested function is hosted.

Here is an example of a storage-triggered function:

Node.js

functions/helloworld/helloGCS/index.js

View on GitHub Feedback

/**
 * Generic background Cloud Function to be triggered by Cloud Storage.
 * This sample works for all Cloud Storage CRUD operations.
 *
 * @param {object} file The Cloud Storage file metadata.
 * @param {object} context The event metadata.
 */
exports.helloGCS = (file, context) => {
  console.log(`  Event: ${context.eventId}`);
  console.log(`  Event Type: ${context.eventType}`);
  console.log(`  Bucket: ${file.bucket}`);
  console.log(`  File: ${file.name}`);
  console.log(`  Metageneration: ${file.metageneration}`);
  console.log(`  Created: ${file.timeCreated}`);
  console.log(`  Updated: ${file.updated}`);
};

Python

functions/helloworld/main.py

View on GitHub Feedback

def hello_gcs(event, context):
    """Background Cloud Function to be triggered by Cloud Storage.
       This generic function logs relevant data when a file is changed,
       and works for all Cloud Storage CRUD operations.
    Args:
        event (dict):  The dictionary with data specific to this type of event.
                       The `data` field contains a description of the event in
                       the Cloud Storage `object` format described here:
                       https://cloud.google.com/storage/docs/json_api/v1/objects#resource
        context (google.cloud.functions.Context): Metadata of triggering event.
    Returns:
        None; the output is written to Cloud Logging
    """

    print(f'Event ID: {context.event_id}')
    print(f'Event type: {context.event_type}')
    print('Bucket: {}'.format(event['bucket']))
    print('File: {}'.format(event['name']))
    print('Metageneration: {}'.format(event['metageneration']))
    print('Created: {}'.format(event['timeCreated']))
    print('Updated: {}'.format(event['updated']))

Go

functions/helloworld/hello_cloud_storage.go

View on GitHub Feedback


// Package helloworld provides a set of Cloud Functions samples.
package helloworld

import (
	"context"
	"fmt"
	"log"
	"time"

	"cloud.google.com/go/functions/metadata"
)

// GCSEvent is the payload of a GCS event.
type GCSEvent struct {
	Kind                    string                 `json:"kind"`
	ID                      string                 `json:"id"`
	SelfLink                string                 `json:"selfLink"`
	Name                    string                 `json:"name"`
	Bucket                  string                 `json:"bucket"`
	Generation              string                 `json:"generation"`
	Metageneration          string                 `json:"metageneration"`
	ContentType             string                 `json:"contentType"`
	TimeCreated             time.Time              `json:"timeCreated"`
	Updated                 time.Time              `json:"updated"`
	TemporaryHold           bool                   `json:"temporaryHold"`
	EventBasedHold          bool                   `json:"eventBasedHold"`
	RetentionExpirationTime time.Time              `json:"retentionExpirationTime"`
	StorageClass            string                 `json:"storageClass"`
	TimeStorageClassUpdated time.Time              `json:"timeStorageClassUpdated"`
	Size                    string                 `json:"size"`
	MD5Hash                 string                 `json:"md5Hash"`
	MediaLink               string                 `json:"mediaLink"`
	ContentEncoding         string                 `json:"contentEncoding"`
	ContentDisposition      string                 `json:"contentDisposition"`
	CacheControl            string                 `json:"cacheControl"`
	Metadata                map[string]interface{} `json:"metadata"`
	CRC32C                  string                 `json:"crc32c"`
	ComponentCount          int                    `json:"componentCount"`
	Etag                    string                 `json:"etag"`
	CustomerEncryption      struct {
		EncryptionAlgorithm string `json:"encryptionAlgorithm"`
		KeySha256           string `json:"keySha256"`
	}
	KMSKeyName    string `json:"kmsKeyName"`
	ResourceState string `json:"resourceState"`
}

// HelloGCS consumes a(ny) GCS event.
func HelloGCS(ctx context.Context, e GCSEvent) error {
	meta, err := metadata.FromContext(ctx)
	if err != nil {
		return fmt.Errorf("metadata.FromContext: %w", err)
	}
	log.Printf("Event ID: %v\n", meta.EventID)
	log.Printf("Event type: %v\n", meta.EventType)
	log.Printf("Bucket: %v\n", e.Bucket)
	log.Printf("File: %v\n", e.Name)
	log.Printf("Metageneration: %v\n", e.Metageneration)
	log.Printf("Created: %v\n", e.TimeCreated)
	log.Printf("Updated: %v\n", e.Updated)
	return nil
}

Java

functions/helloworld/hello-gcs/src/main/java/functions/HelloGcs.java

View on GitHub Feedback

import com.google.cloud.functions.BackgroundFunction;
import com.google.cloud.functions.Context;
import functions.eventpojos.GcsEvent;
import java.util.logging.Logger;

/**
 * Example Cloud Storage-triggered function.
 * This function can process any event from Cloud Storage.
 */
public class HelloGcs implements BackgroundFunction<GcsEvent> {
  private static final Logger logger = Logger.getLogger(HelloGcs.class.getName());

  @Override
  public void accept(GcsEvent event, Context context) {
    logger.info("Event: " + context.eventId());
    logger.info("Event Type: " + context.eventType());
    logger.info("Bucket: " + event.getBucket());
    logger.info("File: " + event.getName());
    logger.info("Metageneration: " + event.getMetageneration());
    logger.info("Created: " + event.getTimeCreated());
    logger.info("Updated: " + event.getUpdated());
  }
}

C#

functions/helloworld/HelloGcs/Function.cs

View on GitHub Feedback

using CloudNative.CloudEvents;
using Google.Cloud.Functions.Framework;
using Google.Events.Protobuf.Cloud.Storage.V1;
using Microsoft.Extensions.Logging;
using System.Threading;
using System.Threading.Tasks;

namespace HelloGcs;

 /// <summary>
 /// Example Cloud Storage-triggered function.
 /// This function can process any event from Cloud Storage.
 /// </summary>
public class Function : ICloudEventFunction<StorageObjectData>
{
    private readonly ILogger _logger;

    public Function(ILogger<Function> logger) =>
        _logger = logger;

    public Task HandleAsync(CloudEvent cloudEvent, StorageObjectData data, CancellationToken cancellationToken)
    {
        _logger.LogInformation("Event: {event}", cloudEvent.Id);
        _logger.LogInformation("Event Type: {type}", cloudEvent.Type);
        _logger.LogInformation("Bucket: {bucket}", data.Bucket);
        _logger.LogInformation("File: {file}", data.Name);
        _logger.LogInformation("Metageneration: {metageneration}", data.Metageneration);
        _logger.LogInformation("Created: {created:s}", data.TimeCreated?.ToDateTimeOffset());
        _logger.LogInformation("Updated: {updated:s}", data.Updated?.ToDateTimeOffset());
        return Task.CompletedTask;
    }
}

Ruby

functions/helloworld/storage/app.rb

View on GitHub Feedback

require "functions_framework"

FunctionsFramework.cloud_event "hello_gcs" do |event|
  # This function supports all Cloud Storage events.
  # The `event` parameter is a CloudEvents::Event::V1 object.
  # See https://cloudevents.github.io/sdk-ruby/latest/CloudEvents/Event/V1.html
  payload = event.data

  logger.info "Event: #{event.id}"
  logger.info "Event Type: #{event.type}"
  logger.info "Bucket: #{payload['bucket']}"
  logger.info "File: #{payload['name']}"
  logger.info "Metageneration: #{payload['metageneration']}"
  logger.info "Created: #{payload['timeCreated']}"
  logger.info "Updated: #{payload['updated']}"
end

PHP

functions/helloworld_storage/index.php

View on GitHub Feedback


use CloudEvents\V1\CloudEventInterface;
use Google\CloudFunctions\FunctionsFramework;

// Register the function with Functions Framework.
// This enables omitting the `FUNCTIONS_SIGNATURE_TYPE=cloudevent` environment
// variable when deploying. The `FUNCTION_TARGET` environment variable should
// match the first parameter.
FunctionsFramework::cloudEvent('helloGCS', 'helloGCS');

function helloGCS(CloudEventInterface $cloudevent)
{
    // This function supports all Cloud Storage event types.
    $log = fopen(getenv('LOGGER_OUTPUT') ?: 'php://stderr', 'wb');
    $data = $cloudevent->getData();
    fwrite($log, 'Event: ' . $cloudevent->getId() . PHP_EOL);
    fwrite($log, 'Event Type: ' . $cloudevent->getType() . PHP_EOL);
    fwrite($log, 'Bucket: ' . $data['bucket'] . PHP_EOL);
    fwrite($log, 'File: ' . $data['name'] . PHP_EOL);
    fwrite($log, 'Metageneration: ' . $data['metageneration'] . PHP_EOL);
    fwrite($log, 'Created: ' . $data['timeCreated'] . PHP_EOL);
    fwrite($log, 'Updated: ' . $data['updated'] . PHP_EOL);
}

Unit tests

Here are unit tests for the storage-triggered function above:

Node.js

functions/helloworld/helloGCS/test/sample.unit.storage.test.js

View on GitHub Feedback

const assert = require('assert');
const uuid = require('uuid');
const sinon = require('sinon');

const {helloGCS} = require('..');

const stubConsole = function () {
  sinon.stub(console, 'error');
  sinon.stub(console, 'log');
};

const restoreConsole = function () {
  console.log.restore();
  console.error.restore();
};

beforeEach(stubConsole);
afterEach(restoreConsole);

it('helloGCS: should print out event', () => {
  // Initialize mocks
  const filename = uuid.v4();
  const eventType = 'google.storage.object.finalize';
  const event = {
    name: filename,
    resourceState: 'exists',
    metageneration: '1',
  };
  const context = {
    eventId: 'g1bb3r1sh',
    eventType: eventType,
  };

  // Call tested function and verify its behavior
  helloGCS(event, context);
  assert.ok(console.log.calledWith(`  File: ${filename}`));
  assert.ok(console.log.calledWith(`  Event Type: ${eventType}`));
});

Python

functions/helloworld/sample_storage_test.py

View on GitHub Feedback

from unittest import mock

import main


def test_print(capsys):
    name = 'test'
    event = {
        'bucket': 'some-bucket',
        'name': name,
        'metageneration': 'some-metageneration',
        'timeCreated': '0',
        'updated': '0'
    }

    context = mock.MagicMock()
    context.event_id = 'some-id'
    context.event_type = 'gcs-event'

    # Call tested function
    main.hello_gcs(event, context)
    out, err = capsys.readouterr()
    assert f'File: {name}\n' in out

Go

functions/helloworld/hello_cloud_storage_test.go

View on GitHub Feedback

package helloworld

import (
	"context"
	"io/ioutil"
	"log"
	"os"
	"strings"
	"testing"

	"cloud.google.com/go/functions/metadata"
)

func TestHelloGCS(t *testing.T) {
	r, w, _ := os.Pipe()
	log.SetOutput(w)
	originalFlags := log.Flags()
	log.SetFlags(log.Flags() &^ (log.Ldate | log.Ltime))

	name := "hello_gcs.txt"
	e := GCSEvent{
		Name: name,
	}
	meta := &metadata.Metadata{
		EventID: "event ID",
	}
	ctx := metadata.NewContext(context.Background(), meta)

	HelloGCS(ctx, e)

	w.Close()
	log.SetOutput(os.Stderr)
	log.SetFlags(originalFlags)

	out, err := ioutil.ReadAll(r)
	if err != nil {
		t.Fatalf("ReadAll: %v", err)
	}

	got := string(out)
	wants := []string{
		"File: " + name,
		"Event ID: " + meta.EventID,
	}
	for _, want := range wants {
		if !strings.Contains(got, want) {
			t.Errorf("HelloGCS(%v) = %q, want to contain %q", e, got, want)
		}
	}
}

Java

functions/helloworld/hello-gcs/src/test/java/functions/HelloGcsTest.java

View on GitHub Feedback


import static com.google.common.truth.Truth.assertThat;

import com.google.common.testing.TestLogHandler;
import functions.eventpojos.GcsEvent;
import functions.eventpojos.MockContext;
import java.util.logging.Logger;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;

/**
 * Unit tests for main.java.com.example.functions.helloworld.HelloGcs.
 */
public class HelloGcsTest {
  private static final TestLogHandler LOG_HANDLER = new TestLogHandler();
  private static final Logger logger = Logger.getLogger(HelloGcs.class.getName());

  @Before
  public void beforeTest() throws Exception {
    logger.addHandler(LOG_HANDLER);
  }

  @After
  public void afterTest() {
    LOG_HANDLER.clear();
  }

  @Test
  public void helloGcs_shouldPrintFileName() {
    GcsEvent event = new GcsEvent();
    event.setName("foo.txt");

    MockContext context = new MockContext();
    context.eventType = "google.storage.object.finalize";

    new HelloGcs().accept(event, context);

    String message = LOG_HANDLER.getStoredLogRecords().get(3).getMessage();
    assertThat(message).contains("File: foo.txt");
  }
}

C#

functions/helloworld/HelloWorld.Tests/HelloGcsUnitTest.cs

View on GitHub Feedback

using CloudNative.CloudEvents;
using Google.Cloud.Functions.Testing;
using Google.Events;
using Google.Events.Protobuf.Cloud.Storage.V1;
using Microsoft.Extensions.Logging;
using System;
using System.Threading;
using System.Threading.Tasks;
using Xunit;

namespace HelloWorld.Tests;

public class HelloGcsUnitTest
{
    [Fact]
    public async Task FileNameIsLogged()
    {
        // Prepare the inputs
        var data = new StorageObjectData { Name = "new-file.txt" };
        var cloudEvent = new CloudEvent
        {
            Type = StorageObjectData.FinalizedCloudEventType,
            Source = new Uri("//storage.googleapis.com", UriKind.RelativeOrAbsolute),
            Id = "1234",
            Data = data
        };
        var logger = new MemoryLogger<HelloGcs.Function>();

        // Execute the function
        var function = new HelloGcs.Function(logger);
        await function.HandleAsync(cloudEvent, data, CancellationToken.None);

        // Check the log results - just the entry starting with "File:".
        var logEntry = Assert.Single(logger.ListLogEntries(), entry => entry.Message.StartsWith("File:"));
        Assert.Equal("File: new-file.txt", logEntry.Message);
        Assert.Equal(LogLevel.Information, logEntry.Level);
    }
}

Ruby

functions/test/helloworld/storage_test.rb

View on GitHub Feedback

require "minitest/autorun"
require "functions_framework/testing"
require "date"

describe "functions_helloworld_storage" do
  include FunctionsFramework::Testing

  let(:source) { "//storage.googleapis.com/projects/sample-project/buckets/sample-bucket/objects/ruby-rocks.rb" }
  let(:type) { "google.cloud.storage.object.v1.finalized" }

  it "responds to generic event" do
    load_temporary "helloworld/storage/app.rb" do
      timestamp = DateTime.new(2020, 2, 3, 4, 5, 6).rfc3339
      payload = {
        "bucket"         => "sample-bucket",
        "name"           => "ruby-rocks.rb",
        "metageneration" => "1",
        "timeCreated"    => timestamp,
        "updated"        => timestamp
      }
      event = make_cloud_event payload, source: source, type: type
      _out, err = capture_subprocess_io do
        call_event "hello_gcs", event
      end

      assert_match(/Event: /, err)
      assert_match(/Event Type: google.cloud.storage.object.v1.finalized/, err)
      assert_match(/Bucket: sample-bucket/, err)
      assert_match(/File: ruby-rocks.rb/, err)
      assert_match(/Metageneration: 1/, err)
      assert_match(/Created: 2020-02-03T04:05:06\+00:00/, err)
      assert_match(/Updated: 2020-02-03T04:05:06\+00:00/, err)
    end
  end
end

PHP

functions/helloworld_storage/SampleUnitTest.php

View on GitHub Feedback


namespace Google\Cloud\Samples\Functions\HelloworldStorage\Test;

use CloudEvents\V1\CloudEventImmutable;
use CloudEvents\V1\CloudEventInterface;

use PHPUnit\Framework\TestCase;

/**
 * Class SampleUnitTest.
 *
 * Unit test for 'Helloworld Storage' Cloud Function.
 */
class SampleUnitTest extends TestCase
{
    /**
     * Include the Cloud Function code before running any tests.
     *
     * @see https://phpunit.readthedocs.io/en/latest/fixtures.html
     */
    public static function setUpBeforeClass(): void
    {
        require_once __DIR__ . '/index.php';
    }

    public function dataProvider()
    {
        return [
            [
                'cloudevent' => new CloudEventImmutable(
                    uniqId(), // id
                    'storage.googleapis.com', // source
                    'google.cloud.storage.object.v1.finalized', // type
                    [
                        'bucket' => 'some-bucket',
                        'metageneration' => '1',
                        'name' => 'folder/friendly.txt',
                        'timeCreated' => '2020-04-23T07:38:57.230Z',
                        'updated' => '2020-04-23T07:38:57.230Z',
                    ] // data
                ),
                'statusCode' => '200',
            ],
        ];
    }

    /**
     * @dataProvider dataProvider
     */
    public function testFunction(CloudEventInterface $cloudevent): void
    {
        // Capture function output by overriding the function's logging behavior.
        // The 'LOGGER_OUTPUT' environment variable must be used in your function:
        //
        // $log = fopen(getenv('LOGGER_OUTPUT') ?: 'php://stderr', 'wb');
        // fwrite($log, 'Log Entry');
        putenv('LOGGER_OUTPUT=php://output');
        helloGCS($cloudevent);
        // Provided by PHPUnit\Framework\TestCase.
        $actual = $this->getActualOutput();

        // Test output includes the properties provided in the CloudEvent.
        foreach ($cloudevent->getData() as $property => $value) {
            $this->assertStringContainsString($value, $actual);
        }
        $this->assertStringContainsString($cloudevent->getId(), $actual);
        $this->assertStringContainsString($cloudevent->getType(), $actual);
    }
}

Run the unit tests with the following command:

Node.js

mocha test/sample.unit.storage.test.js --exit

Python

pytest sample_storage_test.py

Go

go test -v ./hello_cloud_storage_test.go

Java

Maven uses mvn test to run unit tests.

mvn test

C#

dotnet test

PHP

To run the unit tests, use PHPUnit.

Integration tests

Here are integration tests for the storage-triggered function above:

Node.js

functions/helloworld/helloGCS/test/sample.integration.storage.test.js

View on GitHub Feedback

const assert = require('assert');
const {spawn} = require('child_process');
const uuid = require('uuid');
const {request} = require('gaxios');
const waitPort = require('wait-port');

  it('helloGCSGeneric: should print GCS event', async () => {
    const filename = uuid.v4(); // Use a unique filename to avoid conflicts
    const PORT = 9009; // Each running framework instance needs a unique port

    const eventType = 'google.storage.object.finalize';

    const data = {
      data: {
        name: filename,
        resourceState: 'exists',
        metageneration: '1',
      },
      context: {
        eventType: eventType,
      },
    };
    const ffProc = spawn('npx', [
      'functions-framework',
      '--target',
      'helloGCS',
      '--signature-type',
      'event',
      '--port',
      PORT,
    ]);
    const ffProcHandler = new Promise((resolve, reject) => {
      let stdout = '';
      let stderr = '';
      ffProc.stdout.on('data', data => (stdout += data));
      ffProc.stderr.on('data', data => (stderr += data));
      ffProc.on('exit', code => {
        if (code === 0 || code === null) {
          // code === null corresponds to a signal-kill
          // (which doesn't necessarily indicate a test failure)
          resolve(stdout);
        } else {
          stderr = `Error code: ${code}\n${stderr}`;
          reject(new Error(stderr));
        }
      });
    });
    await waitPort({host: 'localhost', port: PORT});

    // Send HTTP request simulating GCS change notification
    // (GCF translates GCS notifications to HTTP requests internally)
    const response = await request({
      url: `http://localhost:${PORT}/`,
      method: 'POST',
      data,
    });
    assert.strictEqual(response.status, 204);

    ffProc.kill();
    const stdout = await ffProcHandler;
    assert.ok(stdout.includes(`File: ${filename}`));
    assert.ok(stdout.includes(`Event Type: ${eventType}`));
  });
});

Java

functions/helloworld/hello-gcs/src/test/java/functions/ExampleIT.java

View on GitHub Feedback


import static com.google.common.truth.Truth.assertThat;

import com.google.gson.Gson;
import io.github.resilience4j.core.IntervalFunction;
import io.github.resilience4j.retry.Retry;
import io.github.resilience4j.retry.RetryConfig;
import io.github.resilience4j.retry.RetryRegistry;
import io.vavr.CheckedRunnable;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.net.URI;
import java.nio.charset.StandardCharsets;
import java.util.Map;
import java.util.UUID;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.conn.HttpHostConnectException;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.HttpClientBuilder;
import org.junit.AfterClass;
import org.junit.BeforeClass;
import org.junit.Test;

public class ExampleIT {
  // Each function must be assigned a unique port to run on.
  // Otherwise, tests can flake when 2+ functions run simultaneously.
  // This is also specified in the `function-maven-plugin` config in `pom.xml`.
  private static final int PORT = 8082;

  // Root URL pointing to the locally hosted function
  // The Functions Framework Maven plugin lets us run a function locally
  private static final String BASE_URL = "http://localhost:" + PORT;

  private static Process emulatorProcess = null;
  private static final HttpClient client = HttpClientBuilder.create().build();
  private static final Gson gson = new Gson();

  @BeforeClass
  public static void setUp() throws IOException {
    // Get the sample's base directory (the one containing a pom.xml file)
    String baseDir = System.getProperty("user.dir");

    // Emulate the function locally by running the Functions Framework Maven plugin
    emulatorProcess = new ProcessBuilder()
        .command("mvn", "function:run")
        .directory(new File(baseDir))
        .start();
  }

  @AfterClass
  public static void tearDown() throws IOException {
    // Display the output of the plugin process
    InputStream stdoutStream = emulatorProcess.getInputStream();
    ByteArrayOutputStream stdoutBytes = new ByteArrayOutputStream();
    stdoutBytes.write(stdoutStream.readNBytes(stdoutStream.available()));
    System.out.println(stdoutBytes.toString(StandardCharsets.UTF_8));

    // Terminate the running Functions Framework Maven plugin process (if it's still running)
    if (emulatorProcess.isAlive()) {
      emulatorProcess.destroy();
    }
  }

  @Test
  public void helloGcs_shouldRunWithFunctionsFramework() throws Throwable {
    String functionUrl = BASE_URL + "/helloGcs"; // URL to your locally-running function

    // Initialize constants
    String name = UUID.randomUUID().toString();
    String jsonStr = gson.toJson(Map.of(
        "data", Map.of(
            "name", name, "resourceState", "exists", "metageneration", 1),
        "context", Map.of(
            "eventType", "google.storage.object.finalize")
    ));

    HttpPost postRequest =  new HttpPost(URI.create(functionUrl));
    postRequest.setEntity(new StringEntity(jsonStr));

    // The Functions Framework Maven plugin process takes time to start up
    // Use resilience4j to retry the test HTTP request until the plugin responds
    RetryRegistry registry = RetryRegistry.of(RetryConfig.custom()
        .maxAttempts(12)
        .retryExceptions(HttpHostConnectException.class)
        .retryOnResult(u -> {
          // Retry if the Functions Framework process has no stdout content
          // See `retryOnResultPredicate` here: https://resilience4j.readme.io/docs/retry
          try {
            return emulatorProcess.getErrorStream().available() == 0;
          } catch (IOException e) {
            return true;
          }
        })
        .intervalFunction(IntervalFunction.ofExponentialBackoff(200, 2))
        .build());
    Retry retry = registry.retry("my");

    // Perform the request-retry process
    CheckedRunnable retriableFunc = Retry.decorateCheckedRunnable(
        retry, () -> client.execute(postRequest));
    retriableFunc.run();

    // Get Functions Framework plugin process' stdout
    InputStream stdoutStream = emulatorProcess.getErrorStream();
    ByteArrayOutputStream stdoutBytes = new ByteArrayOutputStream();
    stdoutBytes.write(stdoutStream.readNBytes(stdoutStream.available()));

    // Verify desired name value is present
    assertThat(stdoutBytes.toString(StandardCharsets.UTF_8)).contains(
        String.format("File: %s", name));
  }
}

PHP

functions/helloworld_storage/SampleIntegrationTest.php

View on GitHub Feedback


namespace Google\Cloud\Samples\Functions\HelloworldStorage;

use Google\CloudFunctions\CloudEvent;
use GuzzleHttp\Client;
use PHPUnit\Framework\TestCase;
use Symfony\Component\Process\Process;
use Symfony\Component\Process\PhpExecutableFinder;

/**
 * Class SampleIntegrationTest.
 *
 * Integration tests for the 'Helloworld Storage' Cloud Function.
 */
class SampleIntegrationTest extends TestCase
{
    /** @var Process */
    private static $process;

    /** @var Client */
    private static $client;

    public function dataProvider()
    {
        return [
            [
                'cloudevent' => [
                    'id' => uniqid(),
                    'source' => 'storage.googleapis.com',
                    'specversion' => '1.0',
                    'type' => 'google.cloud.storage.object.v1.finalized',
                ],
                'data' => [
                    'bucket' => 'some-bucket',
                    'metageneration' => '1',
                    'name' => 'folder/friendly.txt',
                    'timeCreated' => '2020-04-23T07:38:57.230Z',
                    'updated' => '2020-04-23T07:38:57.230Z',
                ],
                'statusCode' => '200',
            ],
        ];
    }

    /**
     * @dataProvider dataProvider
     */
    public function testHelloGCS(array $cloudevent, array $data, string $statusCode): void
    {
        // Prepare the HTTP headers for a CloudEvent.
        $cloudEventHeaders = [];
        foreach ($cloudevent as $key => $value) {
            $cloudEventHeaders['ce-' . $key] = $value;
        }

        // Send an HTTP request using CloudEvent metadata.
        $resp = self::$client->post('/', [
            'body' => json_encode($data),
            'headers' => $cloudEventHeaders + [
                // Instruct the function framework to parse the body as JSON.
                'content-type' => 'application/json'
            ],
        ]);

        // The Cloud Function logs all data to stderr.
        $actual = self::$process->getIncrementalErrorOutput();

        // Confirm the status code.
        $this->assertEquals($statusCode, $resp->getStatusCode());

        // Verify the CloudEvent and data properties are logged by the function.
        foreach ($data as $property => $value) {
            $this->assertStringContainsString($value, $actual);
        }
        $this->assertStringContainsString($cloudevent['id'], $actual);
        $this->assertStringContainsString($cloudevent['type'], $actual);
    }

    /**
     * Start a local PHP server running the Functions Framework.
     *
     * @beforeClass
     */
    public static function startFunctionFramework(): void
    {
        $port = getenv('PORT') ?: '8080';
        $php = (new PhpExecutableFinder())->find();
        $uri = 'localhost:' . $port;

        // https://symfony.com/doc/current/components/process.html#usage
        self::$process = new Process([$php, '-S', $uri, 'vendor/bin/router.php'], null, [
            'FUNCTION_SIGNATURE_TYPE' => 'cloudevent',
            'FUNCTION_TARGET' => 'helloGCS',
        ]);
        self::$process->start();

        // Initialize an HTTP client to drive requests.
        self::$client = new Client(['base_uri' => 'http://' . $uri]);

        // Short delay to ensure PHP server is ready.
        sleep(1);
    }

    /**
     * Stop the local PHP server.
     *
     * @afterClass
     */
    public static function stopFunctionFramework(): void
    {
        if (!self::$process->isRunning()) {
            echo self::$process->getErrorOutput();
            throw new RuntimeException('Function Framework PHP process not running by end of test');
        }
        self::$process->stop(3, SIGTERM);
    }
}

You can run the integration tests for this function as follows:

Node.js

mocha test/sample.integration.storage.test.js --exit

Java

Maven uses mvn verify to run integration tests:

mvn verify -Dit.test=ExampleIT

System tests

These are the system tests for the storage-triggered function above:

Node.js

functions/helloworld/helloGCS/test/sample.system.storage.test.js

View on GitHub Feedback

const {Storage} = require('@google-cloud/storage');
const storage = new Storage();
const uuid = require('uuid');
const assert = require('assert');
const path = require('path');
const childProcess = require('child_process');
const moment = require('moment');
const promiseRetry = require('promise-retry');

// Use unique GCS filename to avoid conflicts between concurrent test runs
const gcsFileName = `test-${uuid.v4()}.txt`;

const localFileName = 'test.txt';
const bucketName = process.env.FUNCTIONS_DELETABLE_BUCKET;
if (!bucketName) {
  throw new Error('"FUNCTIONS_DELETABLE_BUCKET" env var must be set.');
}
if (!process.env.GCF_REGION) {
  throw new Error('"GCF_REGION" env var must be set.');
}
const bucket = storage.bucket(bucketName);
const baseCmd = 'gcloud functions';

describe('system tests', () => {
  it('helloGCS: should print event', async () => {
    // Subtract time to work-around local-GCF clock difference
    const startTime = moment().subtract(2, 'minutes').toISOString();

    // Upload file
    const filepath = path.join(__dirname, localFileName);
    await bucket.upload(filepath, {
      destination: gcsFileName,
    });

    // Wait for logs to become consistent
    await promiseRetry(retry => {
      const logs = childProcess
        .execSync(`${baseCmd} logs read helloGCS --start-time ${startTime}`)
        .toString();

      try {
        assert.ok(logs.includes(`File: ${gcsFileName}`));
        assert.ok(logs.includes('Event Type: google.storage.object.finalize'));
      } catch (err) {
        console.log('An error occurred, retrying:', err);
        retry(err);
      }
    });
  });

Python

functions/helloworld/sample_storage_test_system.py

View on GitHub Feedback

from datetime import datetime
from os import getenv, path
import subprocess
import time
import uuid

from google.cloud import storage
import pytest

PROJECT = getenv('GCP_PROJECT')
BUCKET = getenv('BUCKET')

assert PROJECT is not None
assert BUCKET is not None


@pytest.fixture(scope='module')
def storage_client():
    yield storage.Client()


@pytest.fixture(scope='module')
def bucket_object(storage_client):
    bucket_object = storage_client.get_bucket(BUCKET)
    yield bucket_object


@pytest.fixture(scope='module')
def uploaded_file(bucket_object):
    name = f'test-{str(uuid.uuid4())}.txt'
    blob = bucket_object.blob(name)

    test_dir = path.dirname(path.abspath(__file__))
    blob.upload_from_filename(path.join(test_dir, 'test.txt'))
    yield name
    blob.delete()


def test_hello_gcs(uploaded_file):
    start_time = datetime.utcnow().isoformat()
    time.sleep(10)  # Wait for logs to become consistent

    log_process = subprocess.Popen([
        'gcloud',
        'alpha',
        'functions',
        'logs',
        'read',
        'hello_gcs_generic',
        '--start-time',
        start_time
    ], stdout=subprocess.PIPE)
    logs = str(log_process.communicate()[0])
    assert uploaded_file in logs

Go

functions/helloworld/hello_cloud_storage_system_test.go

View on GitHub Feedback


package helloworld

import (
	"context"
	"fmt"
	"os"
	"os/exec"
	"strings"
	"testing"
	"time"

	"cloud.google.com/go/storage"
)

func TestHelloGCSSystem(t *testing.T) {
	ctx := context.Background()
	bucketName := os.Getenv("BUCKET_NAME")

	client, err := storage.NewClient(ctx)
	if err != nil {
		t.Fatalf("storage.NewClient: %v", err)
	}

	// Create a file.
	startTime := time.Now().UTC().Format(time.RFC3339)
	oh := client.Bucket(bucketName).Object("TestHelloGCSSystem")
	w := oh.NewWriter(ctx)
	fmt.Fprintf(w, "Content of the file")
	w.Close()

	// Wait for logs to be consistent.
	time.Sleep(20 * time.Second)

	// Check logs.
	want := "created"
	if got := readLogs(t, startTime); !strings.Contains(got, want) {
		t.Errorf("HelloGCS logged %q, want to contain %q", got, want)
	}

	// Modify the file.
	startTime = time.Now().UTC().Format(time.RFC3339)
	_, err = oh.Update(ctx, storage.ObjectAttrsToUpdate{
		Metadata: map[string]string{"Content-Type": "text/html"},
	})
	if err != nil {
		t.Errorf("Update: %v", err)
	}

	// Wait for logs to be consistent.
	time.Sleep(20 * time.Second)

	// Check logs.
	want = "updated"
	if got := readLogs(t, startTime); !strings.Contains(got, want) {
		t.Errorf("HelloGCS logged %q, want to contain %q", got, want)
	}

	// Delete the file.
	startTime = time.Now().UTC().Format(time.RFC3339)
	if err := oh.Delete(ctx); err != nil {
		t.Errorf("Delete: %v", err)
	}

	// Wait for logs to be consistent.
	time.Sleep(20 * time.Second)

	// Check logs.
	want = "deleted"
	if got := readLogs(t, startTime); !strings.Contains(got, want) {
		t.Errorf("HelloGCS logged %q, want to contain %q", got, want)
	}
}

func readLogs(t *testing.T, startTime string) string {
	t.Helper()
	cmd := exec.Command("gcloud", "alpha", "functions", "logs", "read", "HelloGCS", "--start-time", startTime)
	got, err := cmd.CombinedOutput()
	if err != nil {
		t.Fatalf("exec.Command: %v", err)
	}
	return string(got)
}

Java

functions/helloworld/hello-gcs/src/test/java/functions/ExampleSystemIT.java

View on GitHub Feedback

import static com.google.common.truth.Truth.assertThat;

import com.google.api.gax.paging.Page;
import com.google.cloud.logging.LogEntry;
import com.google.cloud.logging.Logging;
import com.google.cloud.logging.LoggingOptions;
import com.google.cloud.storage.BlobId;
import com.google.cloud.storage.BlobInfo;
import com.google.cloud.storage.Storage;
import com.google.cloud.storage.StorageOptions;
import io.github.resilience4j.core.IntervalFunction;
import io.github.resilience4j.retry.Retry;
import io.github.resilience4j.retry.RetryConfig;
import io.github.resilience4j.retry.RetryRegistry;
import java.io.IOException;
import java.time.Duration;
import java.time.Instant;
import java.time.format.DateTimeFormatter;
import java.util.UUID;
import java.util.stream.Collectors;
import java.util.stream.StreamSupport;
import org.junit.BeforeClass;
import org.junit.Test;

public class ExampleSystemIT {

  // TODO<developer>: set these values (as environment variables)
  private static final String PROJECT_ID = System.getenv("GCP_PROJECT");
  private static final String FUNCTIONS_BUCKET = System.getenv("FUNCTIONS_BUCKET");

  // TODO<developer>: set this value (as an environment variable) to HelloGcs
  private static final String FUNCTION_DEPLOYED_NAME = System.getenv("FUNCTIONS_GCS_FN_NAME");
  private static final Storage STORAGE = StorageOptions.getDefaultInstance().getService();

  private static Logging loggingClient;

  private HelloGcs sampleUnderTest;

  @BeforeClass
  public static void setUp() throws IOException {
    loggingClient = LoggingOptions.getDefaultInstance().getService();
  }

  private static String getLogEntriesAsString(String startTimestamp) {
    // Construct Stackdriver logging filter
    // See this page for more info: https://cloud.google.com/logging/docs/view/advanced-queries
    String filter = "resource.type=\"cloud_function\""
        + " AND severity=INFO"
        + " AND resource.labels.function_name=" + FUNCTION_DEPLOYED_NAME
        + String.format(" AND timestamp>=\"%s\"", startTimestamp);

    // Get Stackdriver logging entries
    Page<LogEntry> logEntries =
        loggingClient.listLogEntries(
            Logging.EntryListOption.filter(filter),
            Logging.EntryListOption.sortOrder(
                Logging.SortingField.TIMESTAMP, Logging.SortingOrder.DESCENDING)
        );

    // Serialize Stackdriver logging entries + collect them into a single string
    String logsConcat = StreamSupport.stream(logEntries.getValues().spliterator(), false)
        .map((x) -> x.toString())
        .collect(Collectors.joining("%n"));

    return logsConcat;
  }

  @Test
  public void helloGcs_shouldRunOnGcf() {
    String filename = String.format("test-%s.txt", UUID.randomUUID());

    // Subtract time to work-around local-GCF clock difference
    Instant startInstant = Instant.now().minus(Duration.ofMinutes(4));
    String startTimestamp = DateTimeFormatter.ISO_INSTANT.format(startInstant);

    // Upload a file to Cloud Storage
    BlobInfo blobInfo = BlobInfo.newBuilder(BlobId.of(FUNCTIONS_BUCKET, filename)).build();
    STORAGE.create(blobInfo);

    // Keep retrying until the logs contain the desired invocation's log entry
    // (If the invocation failed, the retry process will eventually time out)
    String expected = String.format("File: %s", filename);
    RetryRegistry registry = RetryRegistry.of(RetryConfig.custom()
        .maxAttempts(8)
        .intervalFunction(IntervalFunction.ofExponentialBackoff(1000, 2))
        .retryOnResult(s -> !s.toString().contains(expected))
        .build());
    Retry retry = registry.retry(filename);
    String logEntry = Retry
        .decorateFunction(retry, ExampleSystemIT::getLogEntriesAsString)
        .apply(startTimestamp);

    // Perform final assertion (to make sure we fail on timeout)
    assertThat(logEntry).contains(filename);
  }
}

Deploy your function with the following command:

Node.js

gcloud functions deploy helloGCS \
--runtime nodejs18 \
--trigger-bucket YOUR_GCS_BUCKET_NAME

You can use the following values for the --runtime flag to specify your preferred Node.js version:

nodejs18 (recommended)
nodejs20 (preview)
nodejs16
nodejs14
nodejs12
nodejs10

Python

gcloud functions deploy hello_gcs \
--runtime python311 \
--trigger-bucket YOUR_GCS_BUCKET_NAME

You can use the following values for the --runtime flag to specify your preferred Python version:

python311 (recommended)
python310
python39
python38
python37

Go

gcloud functions deploy HelloGCS \
--runtime go120 \
--trigger-bucket YOUR_GCS_BUCKET_NAME

You can use the following values for the --runtime flag to specify your preferred Go version:

go120 (recommended)
go119
go118
go116
go113

Java

gcloud functions deploy java-hello-gcs \
--entry-point functions.HelloGcs \
--runtime java17 \
--memory 512MB \
--trigger-bucket YOUR_GCS_BUCKET_NAME

You can use the following values for the --runtime flag to specify your preferred Java version:

java17 (recommended)
java11

where YOUR_GCS_BUCKET_NAME is the Cloud Storage bucket you want to monitor. Note that this must reference a bucket that exists in the same Google Cloud project that the function is deployed to.

Run system tests with the following commands:

Node.js

export BUCKET_NAME=YOUR_GCS_BUCKET_NAME
mocha test/sample.system.storage.test.js --exit

Python

export BUCKET_NAME=YOUR_GCS_BUCKET_NAME
pytest sample_storage_test_system.py

Go

export BUCKET_NAME=YOUR_GCS_BUCKET_NAME
go test -v ./hello_cloud_storage_system_test.go

Java

Maven uses mvn verify to run system tests:

mvn verify -Dit.test=ExampleSystemIT