Setting up on Compute Engine

You can send errors from your Compute Engine applications to Error Reporting in one of two ways:

• By logging to Cloud Logging. If you're already using Cloud Logging, the only additional requirement is that your log entries be recognizable by Error Reporting. For more information on error formatting requirements, read Formatting errors in Cloud Logging.

• Using the Error Reporting API. Your application can send HTTP requests using the REST API, or can make use of experimental libraries in several languages.

Using Logging to report errors

To connect your Compute Engine applications to Error Reporting, send your exceptions or other errors to Logging.

For example:

1. Install the Logging google-fluentd agent as is appropriate for your environment. For instructions, see Installing the Logging agent.

2. Modify your application so that it logs exceptions and their stack traces to Logging.

   You must include all the information for a single error or exception in the same log entry, including all the frames of any stack trace. If all the information isn't together, then Error Reporting might not detect the error. You can use the structured JSON format for your log entry payloads to include different kinds of information for each error.

Java

Add the following to your pom.xml file:

<dependency>
  <groupId>org.fluentd</groupId>
  <artifactId>fluent-logger</artifactId>
  <version>0.3.4</version>
</dependency>

Then use code like the following to send the exception data:

public class ExceptionUtil {
  private static FluentLogger ERRORS = FluentLogger.getLogger("myapp");

  public static void main(String[] args) {
    try {
      throw new Exception("Generic exception for testing Stackdriver");
    } catch (Exception e) {
      report(e);
    }
  }

  public static void report(Throwable ex) {
    StringWriter exceptionWriter = new StringWriter();
    ex.printStackTrace(new PrintWriter(exceptionWriter));
    Map<String, Object> data = new HashMap<>();
    data.put("message", exceptionWriter.toString());
    Map<String, String> serviceContextData = new HashMap<>();
    serviceContextData.put("service", "myapp");
    data.put("serviceContext", serviceContextData);
    // ... add more metadata
    ERRORS.log("errors", data);
  }
}

Python

First, install the fluent-logger-python library:

sudo pip install fluent-logger

Then use code like the following to send the exception data:

import traceback

import fluent.event
import fluent.sender


def simulate_error():
    fluent.sender.setup("myapp", host="localhost", port=24224)

    def report(ex):
        data = {}
        data["message"] = "{0}".format(ex)
        data["serviceContext"] = {"service": "myapp"}
        # ... add more metadata
        fluent.event.Event("errors", data)

    # report exception data using:
    try:
        # simulate calling a method that's not defined
        raise NameError
    except Exception:
        report(traceback.format_exc())

Node.js

First, install the fluent-logger-node library:

npm install --save fluent-logger

Then use code like the following to send the exception data:

const structuredLogger = require('fluent-logger').createFluentSender('myapp', {
  host: 'localhost',
  port: 24224,
  timeout: 3.0,
});

const report = (err, req) => {
  const payload = {
    serviceContext: {
      service: 'myapp',
    },
    message: err.stack,
    context: {
      httpRequest: {
        url: req.originalUrl,
        method: req.method,
        referrer: req.header('Referer'),
        userAgent: req.header('User-Agent'),
        remoteIp: req.ip,
        responseStatusCode: 500,
      },
    },
  };
  structuredLogger.emit('errors', payload);
};

// Handle errors (the following uses the Express framework)
// eslint-disable-next-line no-unused-vars
app.use((err, req, res, next) => {
  report(err, req);
  res.status(500).send(err.response || 'Something broke!');
});

Go

First, install the fluent-logger-golang package:

go get github.com/fluent/fluent-logger-golang/

Then use code like the following to send error data:

package main

import (
	"log"
	"net/http"
	"os"
	"runtime"

	"github.com/fluent/fluent-logger-golang/fluent"
)

var logger *fluent.Fluent

func main() {
	var err error
	logger, err = fluent.New(fluent.Config{
		FluentHost: "localhost",
		FluentPort: 24224,
	})
	if err != nil {
		log.Fatal(err)
	}

	http.HandleFunc("/demo", demoHandler)

	port := os.Getenv("PORT")
	if port == "" {
		port = "8080"
	}
	log.Printf("Listening on port %s", port)
	if err := http.ListenAndServe(":"+port, nil); err != nil {
		log.Fatal(err)
	}
}

func report(stackTrace string, r *http.Request) {
	payload := map[string]interface{}{
		"serviceContext": map[string]interface{}{
			"service": "myapp",
		},
		"message": stackTrace,
		"context": map[string]interface{}{
			"httpRequest": map[string]interface{}{
				"method":    r.Method,
				"url":       r.URL.String(),
				"userAgent": r.UserAgent(),
				"referrer":  r.Referer(),
				"remoteIp":  r.RemoteAddr,
			},
		},
	}
	if err := logger.Post("myapp.errors", payload); err != nil {
		log.Print(err)
	}
}

// Handler for the incoming requests.
func demoHandler(w http.ResponseWriter, r *http.Request) {
	// How to handle a panic.
	defer func() {
		if e := recover(); e != nil {
			stack := make([]byte, 1<<16)
			stackSize := runtime.Stack(stack, true)
			report(string(stack[:stackSize]), r)
		}
	}()

	// Panic is triggered.
	x := 0
	log.Println(100500 / x)
}

Using the Error Reporting API to write errors

The Error Reporting API provides a report endpoint for writing error information to the service.

1. Enable the Error Reporting API.

   Enable the API

2. Report errors to the API using either the REST API or a client library.

   • REST API

     See the reference documentation for information about the API.

   • Using client libraries

     Libraries exist in a limited number of languages to help you call the Error Reporting API from your application:

     • ASP.NET
     • Go
     • Java
     • Node.js
     • Ruby
     • Python
     • PHP

Samples

ASP.NET

The ASP.NET NuGet package reports uncaught exceptions from ASP.NET web applications to Error Reporting.

Install the NuGet package

To install the Stackdriver ASP.NET NuGet package in Visual Studio:

1. Right-click your solution and select Manage NuGet packages for solution.
2. Select the Include prerelease checkbox.
3. Search for and install the package named Google.Cloud.Diagnostics.AspNet.

Usage

Once you've installed the Stackdriver ASP.NET NuGet package, add the following statement to your application code to start sending errors to Stackdriver:

using Google.Cloud.Diagnostics.AspNet;

Add the following HttpConfiguration code to the Register method of your .NET web app (replacing your-project-id with your actual project ID to enable the reporting of exceptions:

public static void Register(HttpConfiguration config)
{
    string projectId = "YOUR-PROJECT-ID";
    string serviceName = "NAME-OF-YOUR-SERVICE";
    string version = "VERSION-OF-YOUR-SERVCICE";
    // ...
    // Add a catch all for the uncaught exceptions.
    config.Services.Add(typeof(IExceptionLogger),
        ErrorReportingExceptionLogger.Create(projectId, serviceName, version));
    // ...
}

Once you've added this method to your ASP.NET application, you can view any uncaught exceptions that occur as they get reported to Google Cloud in the Error Reporting section of the Google Cloud console.

C#

The following example can be found in the GoogleCloudPlatform/dotnet-docs-samples repo. To use it, after building the project, specify your project ID:

C:\...\bin\Debug> set GOOGLE_PROJECT_ID=[YOUR_PROJECT_ID]

Make sure to replace [YOUR_PROJECT_ID] with the correct value from the Google Cloud console.

Then, send exception data with code similar to the following:

public class ErrorReportingSample
{
    public static void Main(string[] args)
    {
        try
        {
            throw new Exception("Generic exception for testing Stackdriver Error Reporting");
        }
        catch (Exception e)
        {
            report(e);
            Console.WriteLine("Stackdriver Error Report Sent");
        }
    }

    /// <summary>
    /// Create the Error Reporting service (<seealso cref="ClouderrorreportingService"/>)
    /// with the Application Default Credentials and the proper scopes.
    /// See: https://developers.google.com/identity/protocols/application-default-credentials.
    /// </summary>
    private static ClouderrorreportingService CreateErrorReportingClient()
    {
        // Get the Application Default Credentials.
        GoogleCredential credential = GoogleCredential.GetApplicationDefaultAsync().Result;

        // Add the needed scope to the credentials.
        credential.CreateScoped(ClouderrorreportingService.Scope.CloudPlatform);

        // Create the Error Reporting Service.
        ClouderrorreportingService service = new ClouderrorreportingService(new BaseClientService.Initializer
        {
            HttpClientInitializer = credential,
        });
        return service;
    }

    /// <summary>
    /// Creates a <seealso cref="ReportRequest"/> from a given exception.
    /// </summary>
    private static ReportRequest CreateReportRequest(Exception e)
    {
        // Create the service.
        ClouderrorreportingService service = CreateErrorReportingClient();

        // Get the project ID from the environement variables.
        string projectId = Environment.GetEnvironmentVariable("GOOGLE_PROJECT_ID");

        // Format the project id to the format Error Reporting expects. See:
        // https://cloud.google.com/error-reporting/reference/rest/v1beta1/projects.events/report
        string formattedProjectId = string.Format("projects/{0}", projectId);

        // Add a service context to the report.  For more details see:
        // https://cloud.google.com/error-reporting/reference/rest/v1beta1/projects.events#ServiceContext
        ServiceContext serviceContext = new ServiceContext()
        {
            Service = "myapp",
            Version = "8c1917a9eca3475b5a3686d1d44b52908463b989",
        };
        ReportedErrorEvent errorEvent = new ReportedErrorEvent()
        {
            Message = e.ToString(),
            ServiceContext = serviceContext,
        };
        return new ReportRequest(service, errorEvent, formattedProjectId);
    }

    /// <summary>
    /// Report an exception to the Error Reporting service.
    /// </summary>
    private static void report(Exception e)
    {
        // Create the report and execute the request.
        ReportRequest request = CreateReportRequest(e);
        request.Execute();
    }
}

Go

See Setting up Error Reporting for Go.

Java

See Setting up Error Reporting for Java.

Node.js

See Setting up Error Reporting for Node.js.

Ruby

See Setting up Error Reporting for Ruby.

Python

See Setting up Error Reporting for Python.

PHP

See Setting up Error Reporting for PHP.

View error groups

In the Google Cloud console, go to the Error Reporting page:

Go to Error Reporting

You can also find this page by using the search bar.

Note: If you see the message "Set up Error Reporting" on the Error Reporting page, then your Google Cloud project has no error groups to display.