Logging client libraries

This page shows how to get started with the Cloud Client Libraries for the Cloud Logging API. Client libraries make it easier to access Google Cloud APIs from a supported language. Although you can use Google Cloud APIs directly by making raw requests to the server, client libraries provide simplifications that significantly reduce the amount of code you need to write.

Read more about the Cloud Client Libraries and the older Google API Client Libraries in Client libraries explained.

Cloud Logging client libraries are idiomatic interfaces around the API. Client libraries provide an integration option with Logging. You can use client libraries in addition to using an agent. Some Google Cloud services, such as Google Kubernetes Engine, contain an integrated logging agent that sends the data written to stdout or stderr as logs to Cloud Logging.

• For App Engine flexible environment and Cloud Run functions, you can use the integrated agent.

• For Compute Engine, you can install an agent that collects both logs and metrics.

• For Android, we recommend that you use Firebase for logging. For more information, see Write and view logs.

To learn more about setting up Logging using a language runtime, see Setting up Language Runtimes.

Incoming log entries with timestamps that are more than the logs retention period in the past or that are more than 24 hours in the future are discarded.

Install the client library

C++

See Setting up a C++ development environment for details about this client library's requirements and install dependencies.

C#

dotnet add package Google.Cloud.Logging.V2

For more information, see Setting Up a C# Development Environment.

Go

go get cloud.google.com/go/logging

For more information, see Setting Up a Go Development Environment.

Java

If you are using Maven with a BOM, add the following to your pom.xml file:

<dependencyManagement>
  <dependencies>
    <dependency>
      <groupId>com.google.cloud</groupId>
      <artifactId>libraries-bom</artifactId>
      <version>26.51.0</version>
      <type>pom</type>
      <scope>import</scope>
    </dependency>
  </dependencies>
</dependencyManagement>

<dependencies>
  <dependency>
    <groupId>com.google.cloud</groupId>
    <artifactId>google-cloud-logging</artifactId>
  </dependency>

  <!-- ...
</dependencies>

If you are using Maven without a BOM, add this to your dependencies:

<dependency>
  <groupId>com.google.cloud</groupId>
  <artifactId>google-cloud-logging</artifactId>
  <version>3.20.7</version>
</dependency>

If you are using Gradle, add the following to your dependencies:

implementation platform('com.google.cloud:libraries-bom:26.51.0')

implementation 'com.google.cloud:google-cloud-logging'

If you are using sbt, add the following to your dependencies:

libraryDependencies += "com.google.cloud" % "google-cloud-logging" % "3.21.0"

If you're using Visual Studio Code, IntelliJ, or Eclipse, you can add client libraries to your project using the following IDE plugins:

• Cloud Code for VS Code
• Cloud Code for IntelliJ
• Cloud Tools for Eclipse

The plugins provide additional functionality, such as key management for service accounts. Refer to each plugin's documentation for details.

Note: Cloud Java client libraries do not currently support Android.

For more information, see Setting Up a Java Development Environment.

Node.js

npm install --save @google-cloud/logging

For more information, see Setting Up a Node.js Development Environment.

PHP

composer require google/cloud-logging

For more information, see Using PHP on Google Cloud.

Python

pip install --upgrade google-cloud-logging

Install the google-cloud-logging library, not an explicitly versioned library.

For more information, see Setting Up a Python Development Environment.

Ruby

gem install google-cloud-logging

For more information, see Setting Up a Ruby Development Environment.

Set up authentication

To authenticate calls to Google Cloud APIs, client libraries support Application Default Credentials (ADC); the libraries look for credentials in a set of defined locations and use those credentials to authenticate requests to the API. With ADC, you can make credentials available to your application in a variety of environments, such as local development or production, without needing to modify your application code.

For production environments, the way you set up ADC depends on the service and context. For more information, see Set up Application Default Credentials.

For a local development environment, you can set up ADC with the credentials that are associated with your Google Account:

1. Install the Google Cloud CLI, then initialize it by running the following command:

   gcloud init

2. If you're using a local shell, then create local authentication credentials for your user account:

   gcloud auth application-default login

   You don't need to do this if you're using Cloud Shell.

   A sign-in screen appears. After you sign in, your credentials are stored in the local credential file used by ADC.

Use the client library

The following example shows how to use the client library.

C++

#include "google/cloud/logging/v2/logging_service_v2_client.h"
#include "google/cloud/project.h"
#include <iostream>

int main(int argc, char* argv[]) try {
  if (argc != 2) {
    std::cerr << "Usage: " << argv[0] << " project-id\n";
    return 1;
  }

  namespace logging = ::google::cloud::logging_v2;
  auto client = logging::LoggingServiceV2Client(
      logging::MakeLoggingServiceV2Connection());
  auto const project = google::cloud::Project(argv[1]);
  for (auto l : client.ListLogs(project.FullName())) {
    if (!l) throw std::move(l).status();
    std::cout << *l << "\n";
  }

  return 0;
} catch (google::cloud::Status const& status) {
  std::cerr << "google::cloud::Status thrown: " << status << "\n";
  return 1;
}

C#

using System;
// Imports the Google Cloud Logging client library
using Google.Cloud.Logging.V2;
using Google.Cloud.Logging.Type;
using System.Collections.Generic;
using Google.Api;

namespace GoogleCloudSamples
{
    public class QuickStart
    {
        public static void Main(string[] args)
        {
            // Your Google Cloud Platform project ID.
            string projectId = "YOUR-PROJECT-ID";

            // Instantiates a client.
            var client = LoggingServiceV2Client.Create();

            // Prepare new log entry.
            LogEntry logEntry = new LogEntry();
            string logId = "my-log";
            LogName logName = new LogName(projectId, logId);
            logEntry.LogNameAsLogName = logName;
            logEntry.Severity = LogSeverity.Info;

            // Create log entry message.
            string message = "Hello World!";
            string messageId = DateTime.Now.Millisecond.ToString();
            Type myType = typeof(QuickStart);
            string entrySeverity = logEntry.Severity.ToString().ToUpper();
            logEntry.TextPayload =
                $"{messageId} {entrySeverity} {myType.Namespace}.LoggingSample - {message}";

            // Set the resource type to control which GCP resource the log entry belongs to.
            // See the list of resource types at:
            // https://cloud.google.com/logging/docs/api/v2/resource-list
            // This sample uses resource type 'global' causing log entries to appear in the 
            // "Global" resource list of the Developers Console Logs Viewer:
            //  https://console.cloud.google.com/logs/viewer
            MonitoredResource resource = new MonitoredResource
            {
                Type = "global"
            };

            // Create dictionary object to add custom labels to the log entry.
            IDictionary<string, string> entryLabels = new Dictionary<string, string>();
            entryLabels.Add("size", "large");
            entryLabels.Add("color", "red");

            // Add log entry to collection for writing. Multiple log entries can be added.
            IEnumerable<LogEntry> logEntries = new LogEntry[] { logEntry };

            // Write new log entry.
            client.WriteLogEntries(logName, resource, entryLabels, logEntries);

            Console.WriteLine("Log Entry created.");
        }
    }
}

Go

// Sample logging-quickstart writes a log entry to Cloud Logging.
package main

import (
	"context"
	"fmt"
	"log"

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

func main() {
	ctx := context.Background()

	// Sets your Google Cloud Platform project ID.
	projectID := "YOUR_PROJECT_ID"

	// Creates a client.
	client, err := logging.NewClient(ctx, projectID)
	if err != nil {
		log.Fatalf("Failed to create client: %v", err)
	}

	// Sets the name of the log to write to.
	logName := "my-log"

	// Selects the log to write to.
	logger := client.Logger(logName)

	// Sets the data to log.
	text := "Hello, world!"

	// Adds an entry to the log buffer.
	logger.Log(logging.Entry{Payload: text})

	// Closes the client and flushes the buffer to the Cloud Logging
	// service.
	if err := client.Close(); err != nil {
		log.Fatalf("Failed to close client: %v", err)
	}

	fmt.Printf("Logged: %v\n", text)
}

Java

import com.google.cloud.MonitoredResource;
import com.google.cloud.logging.LogEntry;
import com.google.cloud.logging.Logging;
import com.google.cloud.logging.LoggingOptions;
import com.google.cloud.logging.Payload.StringPayload;
import com.google.cloud.logging.Severity;
import java.util.Collections;

/**
 * This sample demonstrates writing logs using the Cloud Logging API. The library also offers a
 * java.util.logging Handler `com.google.cloud.logging.LoggingHandler` Logback integration is also
 * available :
 * https://github.com/googleapis/google-cloud-java/tree/master/google-cloud-clients/google-cloud-contrib/google-cloud-logging-logback
 * Using the java.util.logging handler / Logback appender should be preferred to using the API
 * directly.
 */
public class QuickstartSample {

  /** Expects a new or existing Cloud log name as the first argument. */
  public static void main(String... args) throws Exception {
    // The name of the log to write to
    String logName = args[0]; // "my-log";
    String textPayload = "Hello, world!";

    // Instantiates a client
    try (Logging logging = LoggingOptions.getDefaultInstance().getService()) {

      LogEntry entry =
          LogEntry.newBuilder(StringPayload.of(textPayload))
              .setSeverity(Severity.ERROR)
              .setLogName(logName)
              .setResource(MonitoredResource.newBuilder("global").build())
              .build();

      // Writes the log entry asynchronously
      logging.write(Collections.singleton(entry));

      // Optional - flush any pending log entries just before Logging is closed
      logging.flush();
    }
    System.out.printf("Logged: %s%n", textPayload);
  }
}

Node.js

// Imports the Google Cloud client library
const {Logging} = require('@google-cloud/logging');

async function quickstart(
  projectId = 'YOUR_PROJECT_ID', // Your Google Cloud Platform project ID
  logName = 'my-log' // The name of the log to write to
) {
  // Creates a client
  const logging = new Logging({projectId});

  // Selects the log to write to
  const log = logging.log(logName);

  // The data to write to the log
  const text = 'Hello, world!';

  // The metadata associated with the entry
  const metadata = {
    resource: {type: 'global'},
    // See: https://cloud.google.com/logging/docs/reference/v2/rest/v2/LogEntry#logseverity
    severity: 'INFO',
  };

  // Prepares a log entry
  const entry = log.entry(metadata, text);

  async function writeLog() {
    // Writes the log entry
    await log.write(entry);
    console.log(`Logged: ${text}`);
  }
  writeLog();
}

PHP

# Includes the autoloader for libraries installed with composer
require __DIR__ . '/vendor/autoload.php';

# Imports the Google Cloud client library
use Google\Cloud\Logging\LoggingClient;

# Your Google Cloud Platform project ID
$projectId = 'YOUR_PROJECT_ID';

# Instantiates a client
$logging = new LoggingClient([
    'projectId' => $projectId
]);

# The name of the log to write to
$logName = 'my-log';

# Selects the log to write to
$logger = $logging->logger($logName);

# The data to log
$text = 'Hello, world!';

# Creates the log entry
$entry = $logger->entry($text);

# Writes the log entry
$logger->write($entry);

echo 'Logged ' . $text;

Python

# Imports the Google Cloud client library
from google.cloud import logging

# Instantiates a client
logging_client = logging.Client()

# The name of the log to write to
log_name = "my-log"
# Selects the log to write to
logger = logging_client.logger(log_name)

# The data to log
text = "Hello, world!"

# Writes the log entry
logger.log_text(text)

print("Logged: {}".format(text))

Ruby

# Imports the Google Cloud client library
require "google/cloud/logging"

# Instantiates a client
logging = Google::Cloud::Logging.new

# Prepares a log entry
entry = logging.entry
# payload = "The data you want to log"
entry.payload = payload
# log_name = "The name of the log to write to"
entry.log_name = log_name
# The resource associated with the data
entry.resource.type = "global"

# Writes the log entry
logging.write_entries entry

puts "Logged #{entry.payload}"

Code samples

For all code samples, see All logging samples.

For Cloud Shell tutorials that illustrate how to write structured logs, see the following:

Go

For step-by-step guidance on running a client library in Cloud Shell Editor:

1. Click Guide me.

2. You see a panel Learn. Click Start to follow the tutorial.

Guide me

Java

For step-by-step guidance on running a client library in Cloud Shell Editor:

1. Click Guide me.

2. You see a panel Learn. Click Start to follow the tutorial.

Guide me

Node.js

For step-by-step guidance on running a client library in Cloud Shell Editor:

1. Click Guide me.

2. You see a panel Learn. Click Start to follow the tutorial.

Guide me

Python

For step-by-step guidance on running a client library in Cloud Shell Editor:

1. Click Guide me.

2. You see a panel Learn. Click Start to follow the tutorial.

Guide me

Additional resources

C++

The following list contains links to more resources related to the client library for C++:

• API reference
• Client libraries best practices
• Issue tracker
• google-cloud-logging on Stack Overflow
• Source code

C#

The following list contains links to more resources related to the client library for C#:

• API reference
• Client libraries best practices
• Issue tracker
• google-cloud-logging on Stack Overflow
• Source code

Go

The following list contains links to more resources related to the client library for Go:

• API reference
• Client libraries best practices
• Issue tracker
• google-cloud-logging on Stack Overflow
• Source code

Java

The following list contains links to more resources related to the client library for Java:

• API reference
• Client libraries best practices
• Issue tracker
• google-cloud-logging on Stack Overflow
• Source code

Node.js

The following list contains links to more resources related to the client library for Node.js:

• API reference
• Client libraries best practices
• Issue tracker
• google-cloud-logging on Stack Overflow
• Source code

PHP

The following list contains links to more resources related to the client library for PHP:

• API reference
• Client libraries best practices
• Issue tracker
• google-cloud-logging on Stack Overflow
• Source code

Python

The following list contains links to more resources related to the client library for Python:

• API reference
• Client libraries best practices
• Issue tracker
• google-cloud-logging on Stack Overflow
• Source code

Ruby

The following list contains links to more resources related to the client library for Ruby:

• API reference
• Client libraries best practices
• Issue tracker
• google-cloud-logging on Stack Overflow
• Source code

Additional client libraries

In addition to the libraries previously listed, a set of integration libraries are available to support using popular third-party logging libraries with Cloud Logging.

Language	Library
C#	ASP.NET
C#	log4Net
Java	logback
Node	bunyan
Node	winston
PHP	PSR-3