Pub/Sub integration tests

Demonstrates how to integration test a function triggered by Pub/Sub.

Code sample

Java

To authenticate to Cloud Run functions, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

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));
  }
}

Node.js

To authenticate to Cloud Run functions, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

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();
      }
    }
  });
});

PHP

To authenticate to Cloud Run functions, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

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);
    }
}

Python

To authenticate to Cloud Run functions, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

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)

What's next

To search and filter code samples for other Google Cloud products, see the Google Cloud sample browser.