Cloud Debugger

Cloud Debugger lets you inspect the state of an application, at any code location, without stopping or slowing down the running application.

Cloud Debugger is supported in all Google Cloud runtime environments (except for Cloud Functions) and can also be used when running applications in non-Google Cloud environments (on-premises, other clouds).

Enable API

gcloud services enable


A Snapshot can introspect the context information on a given line of code as user go through the code flow.


A Logpoint can add additional log messages to a running application without modifying the code nor redeploying the code.


In both Snapshot and Logpoint, you can specify conditionals so you can capture specific information for a specific request (e.g., match against a session ID, or request ID).

Java Agent

Cloud Debugger works by adding a Java agent to your JVM startup argument, and the agent can communicate with the Cloud Debugger service in the Cloud. Through the Cloud Console, you can then instruct your JVM instances to take a Snapshot of the application state at a specific line of code, or to add an additional log message on a specific line.

Agent Files

There are 2 types of Cloud Debugger Java agents that authenticates with Cloud Debugger service differently:


When to use?

Latest Version

Versioned URL

Machine Credentials

Google Cloud runtime environments${VERSION}/cdbg_java_agent_gce.tar.gz

Service Account Key

Non-Google Cloud environments${VERSION}/cdbg_java_agent_service_account.tar.gz

You can find all the versions in the cloud-debug-java GitHub repository. For example, Cloud Debugger agent version 2.25 using Machine Credentials can be downloaded with URL:

Agent Configurations

Agent Path

To use the agent, you'll need to configure the JVM command line using the standard -agentpath , e.g.:

java -agentpath:/opt/cdbg/ \
  -jar ...

Rather than hard coding the startup command line, you can also configure it with the JAVA_TOOL_OPTIONS environmental variable:

java -jar ...

System Properties

There are additional flags you can pass to the Java agent using Java's system properties.

System Properties




The name of your application.

Not required for Cloud Run or App Engine.


The version of your application.

Not required for Cloud Run or App Engine.



true or false.Whether to turn on debugger for a subset of the running instances. See Canary snapshots and logpoints documentation.

Not required and defaults to false.


true or false. Whether to authenticate with a Service Account key file.

Required when running outside of Google Cloud.


File path to the Service Account key file.

Required when running outside of Google Cloud.

For example, you can enable the snapshot using the system property:

JAVA_TOOL_OPTIONS="-agentpath:/opt/cdbg/ \"


By default the Cloud Debugger agent writes its logs to cdbg_java_agent.INFO file in the default logging directory. You can overwrite the log file path:

java -agentpath:/opt/cdbg/ \
  -jar ...

Alternatively you can make the Java Cloud Debugger log to stderr:

java -agentpath:/opt/cdbg/ \
  -jar ...

See Setting Up Cloud Debugger for Java documentation for more information.

Runtime Configuration

Follow App Engine Hello World! instructions to deploy an application to App Engine.

Cloud Debugger agent is automatically added to your App Engine application.

In Cloud Debugger console, you can see the Default service in the drop down:

Source Code

Cloud Debugger needs to have access to the application's source code in order for you to add a Snapshot or Logpoint from the Cloud Debugger console. There are severals ways to associating the source code:

  • Existing Git Repository

  • Source code capture / upload

  • Git repository reference from

  • IntelliJ Cloud Code plugin

Git Repository

From Cloud Debugger console, navigate to Deployed Files > Add source code.

Choose an Alternative source code.

For example, using an existing GitHub repository:

Once selected, the contents of the Git repository will be available to navigate.


Upload from Browser

From Cloud Debugger console, navigate to Deployed Files > Add source code.

Choose an Alternative source code.

Click on Local files's Select Source, then simply select the folder/directory that contains the source code.

Upload from Command Line

You can use gcloud CLI to upload the source code into a Source Captures repository.

Create a Source Captures repository:

# Enable API
gcloud services enable

# Create a source capture repository
gcloud source repos create google-source-captures

In the Alternative source code choices, scroll to the very bottom is Upload a source code capture to Google servers.

Do not click on Select source yet.

Use the command line to upload the source code (for example, if you deployed the Helloworld Application):

# Clone the sample repository manually
git clone
cd java-docs-samples/appengine-java11/springboot-helloworld

# Upload just the `src/` directory.
# Note that the `branch` value is important and you must use the same value
# that's shown in the UI
gcloud beta debug source upload \
  --project=<FROM THE UI> \
  --branch=<FROM THE UI> \

Once uploaded, click Select source.


You can associate a Git repository using the git-commit-plugin that generates a file, which contains the information to the Git repository. This only works if the repository is publicly accessible.


Cloud Debugger service will automatically examine this file, and clone the code, and checkout the corresponding revision.

IntelliJ with Cloud Code

You can use the Cloud Code plugin to directly add a Snapshot point without using the Cloud Debugger console.

Navigate to Tools > Cloud Code > Attach Cloud Debugger.

Once configured the IntelliJ profile, you can add Snapshot to source code directly from the IDE.

Learn More

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