github.com/GoogleCloudPlatform/opentelemetry-operations-go/exporter/trace

OpenTelemetry Google Cloud Trace Exporter

OpenTelemetry Google Cloud Trace Exporter allows the user to send collected traces and spans to Google Cloud.

Google Cloud Trace is a distributed tracing backend system. It helps developers to gather timing data needed to troubleshoot latency problems in microservice & monolithic architectures. It manages both the collection and lookup of gathered trace data.

This exporter package assumes your application is already instrumented with the OpenTelemetry SDK. Once you get ready to export OpenTelemetry data, you can add this exporter to your application.

Setup

Google Cloud Trace is a managed service provided by Google Cloud Platform. The end-to-end set up guide with OpenTelemetry is available on the official GCP docs, so this document goes through the exporter set up.

Usage

Once you import the trace exporter package, create and install a new export pipeline, then you can start tracing. If you are running in a GCP environment, the exporter will automatically authenticate using the environment's service account. If not, you will need to follow the instruction in Authentication.

package main

import (
	"context"
	"log"

	texporter "github.com/GoogleCloudPlatform/opentelemetry-operations-go/exporter/trace"

	"go.opentelemetry.io/otel"
	sdktrace "go.opentelemetry.io/otel/sdk/trace"
)

func main() {
	exporter, err := texporter.New()
	if err != nil {
		log.Fatalf("unable to set up tracing: %v", err)
	}
	tp := sdktrace.NewTracerProvider(sdktrace.WithBatcher(exporter))
	defer tp.Shutdown(context.Background())

	otel.SetTracerProvider(tp)

	tracer := tp.Tracer("example.com/trace")
	ctx := context.TODO()
	ctx, span := tracer.Start(ctx, "foo")
	defer span.End()

	// Do some work.
}

Authentication

The Google Cloud Trace exporter depends upon google.FindDefaultCredentials, so the service account is automatically detected by default, but also the custom credential file (so called service_account_key.json) can be detected with specific conditions. Quoting from the document of google.FindDefaultCredentials:

• A JSON file whose path is specified by the GOOGLE_APPLICATION_CREDENTIALS environment variable.
• A JSON file in a location known to the gcloud command-line tool. On Windows, this is %APPDATA%/gcloud/application_default_credentials.json. On other systems, $HOME/.config/gcloud/application_default_credentials.json.

When running code locally, you may need to specify a Google Project ID in addition to GOOGLE_APPLICATION_CREDENTIALS. This is best done using an environment variable (e.g. GOOGLE_CLOUD_PROJECT) and the WithProjectID method, e.g.:

projectID := os.Getenv("GOOGLE_CLOUD_PROJECT")
exporter, err := texporter.New(texporter.WithProjectID(projectID))
...

Useful links

• For more information on OpenTelemetry, visit: https://opentelemetry.io/
• For more about OpenTelemetry Go, visit: https://github.com/open-telemetry/opentelemetry-go
• Learn more about Google Cloud Trace at https://cloud.google.com/trace