LocalCloud Cloud Logging Local Emulator
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Cloud Logging

Cloud Logging collects and queries structured application logs. It helps developers investigate requests, errors, and resource activity.

When to use Cloud Logging

Typical uses

Use when you need searchable records of individual application events, including severity, structured fields, and request IDs for investigating failures.

Examples

  • Application log ingestion
  • Request tracing and audit inspection

Explore another service

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Example usage

Service ID: logging. Starts by default. Use an already running LocalCloud runtime for the examples below.

Export the local project and mapped endpoints in your client process, then use the client settings below. First-time setup 

# Export GOOGLE_CLOUD_PROJECT and CLOUD_LOGGING_EMULATOR_HOST
eval "$(localcloud env)"

REST gateway examples use the generated HTTP address in SERVICE_USAGE_EMULATOR_HOST; native SDKs can use a different protocol.

Java · REST

Read structured log entries

Read structured log entries; Cloud Logging helps trace application requests and diagnose failures.

Call the Google Cloud REST API with the JDK HTTP client. Requires JDK 17+. Results reflect resources already created in your local project.

Discovery check · reads existing local state.

Save as Hello.java

import java.net.URI;
import java.net.http.*;
import java.time.Duration;
import java.util.Objects;

public class Hello {
  public static void main(String[] args) throws Exception {
    var project = Objects.requireNonNull(System.getenv("GOOGLE_CLOUD_PROJECT"));
    var endpoint = Objects.requireNonNull(System.getenv("SERVICE_USAGE_EMULATOR_HOST"));
    var url = URI.create(endpoint.replaceAll("/+$", "") + "/v2/entries:list");
    var request = HttpRequest.newBuilder(url).timeout(Duration.ofSeconds(30))
        .header("Content-Type", "application/json")
        .POST(HttpRequest.BodyPublishers.ofString("{\"resourceNames\":[\"projects/" + project + "\"],\"pageSize\":10}")).build();
    var client = HttpClient.newBuilder().connectTimeout(Duration.ofSeconds(10)).build();
    var response = client.send(request, HttpResponse.BodyHandlers.ofString());
    if (response.statusCode() >= 400) {
      throw new IllegalStateException(response.statusCode() + ": " + response.body());
    }
    System.out.println(response.body());
  }
}

Run the example

java Hello.java

Verify the result

The request succeeds. An empty list or no printed rows is valid before matching resources exist. Continue with the documented workflows for a resource test.

Verify a resource workflow by creating isolated state, performing the operation, and reading the result back. Run cleanup even after a failure; delete only test-owned resources.

Connection failed? Check localcloud status --verbose, enabled services, and client exports. Stop accidental Google Cloud calls; correct local routing before retrying.

Documented workflows

  • Log ingestion, listing, and local filtering

    Write structured entries with project, resource, and label fields, then list them using the supported local filter subset. Assert the entries needed to diagnose a test request.

  • Sink configuration and runtime/KMS audit events

    Create a sink configuration and inspect runtime or KMS audit entries. Test configuration readback independently of any external sink delivery.

  • Logs-based metric definition create/get/list/update/delete APIs

    Create a logs-based metric definition, update its filter, and read it back. This checks metric configuration; log entries do not generate metric values locally.

Service boundaries

  • Local filters cover a subset of Google syntax; metric definitions do not derive values
  • Validate exclusions and sink delivery in Google Cloud

Code examples and integrations

Integration

Build an integration test loop

Start the runtime, verify readiness, exercise your SDK, and clean up test state.

Open guide
Agent testing

Use Cloud Logging with an AI agent

Before the agent changes application logic, have it create local Cloud Logging state, read it back with the project SDK, and note which feature the check covered. That first local call catches accidental production routing and needs no GCP account, service-account key, or billing project.

Configure this repo

Set up this repository to use LocalCloud for local GCP development. First read https://local.cloud/ai/agents.md, then inspect this repo, identify the GCP services and SDK language, configure emulator environment variables, and run the narrowest integration test against localhost. Do not use real GCP credentials or production endpoints.

Production endpoints, auth, IAM, quotas, regional behavior, and final release validation still need the target Google Cloud project.

Agent resources has more prompts and the AGENTS.md template.

Related guides

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