Integrate on Google Cloud Functions GoLang

The dynatrace-oss/opentelemetry-exporter-go package provides an API for tracing Go code on Google Cloud Functions. This package provides a way to instrument your code with Dynatrace-enhanced OpenTelemetry traces.

Prerequisites

Ensure that you have followed the initial configuration steps described in Set up OpenTelemetry monitoring for Google Cloud Functions before using the packages below.

Installation

Run the following command in the root directory of your Google Cloud Function project to install the latest version of the dynatrace-oss/opentelemetry-exporter-go package from GitHub.

go get github.com/dynatrace-oss/opentelemetry-exporter-go/core

Note that this package by itself is not enough to get Dynatrace-enhanced traces. Further initialization code and dependencies need to be added, as described below.

Usage

Follow the steps below to instrument your Google Cloud Functions.

Install dependencies

Set up OpenTelemetry

Instrument the function entry point

Instrument outgoing requests

Install dependencies

Use the following commands to add the required OpenTelemetry and Google Cloud dependencies to your function. If your project already contains any of these dependencies, you might want to skip the corresponding go get call, otherwise, it will upgrade you to the latest version of the dependency.

go get go.opentelemetry.io/otel
go get go.opentelemetry.io/otel/sdk
go get github.com/GoogleCloudPlatform/functions-framework-go
go get cloud.google.com/go/compute

Set up OpenTelemetry

Some initialization code is required to set up OpenTelemetry before you can start instrumenting your Cloud Function. The following code snippet will initialize the required DtTracerProvider and DtTextMapPropagator instances, and register them via the OpenTelemetry API.

package otelsetup

import (
    "go.opentelemetry.io/otel"
    "go.opentelemetry.io/otel/attribute"
    "go.opentelemetry.io/otel/sdk/resource"
    sdk "go.opentelemetry.io/otel/sdk/trace"
    semconv "go.opentelemetry.io/otel/semconv/v1.10.0"

    dtTrace "github.com/dynatrace-oss/opentelemetry-exporter-go/core/trace"
)

func InitializeTracing() (*dtTrace.DtTracerProvider, error) {
    r, err := resource.Merge(
        resource.Default(),
        resource.NewWithAttributes(
            semconv.SchemaURL,
            attribute.String("my.resource.attribute", "My Resource"),
        ),
    )

    tracerProvider, err := dtTrace.NewTracerProvider(
        sdk.WithResource(r),
    )
    if err != nil {
        // handle error
        return nil, err
    }
    otel.SetTracerProvider(tracerProvider)

    propagator, err := dtTrace.NewTextMapPropagator()
    if err != nil {
        // handle error
        return nil, err
    }
    otel.SetTextMapPropagator(propagator)

    return tracerProvider, nil
}

Instrument the function entry point

There are several trigger types for Google Cloud Functions. See below how to instrument Cloud Functions with HTTP triggers and Pub/Sub triggers.

For instructions on how to deploy your Cloud Function, see Create and deploy a Cloud Function by using the Google Cloud CLI.

Instrument outgoing requests

If you have any outgoing requests in your Cloud Function, you can instrument them as well to achieve full end-to-end tracing. Your requests can be instrumented by using instrumentation libraries provided by OpenTelemetry.

Instrumenting outgoing requests works equivalently with the Dynatrace-enhanced tracing package and plain OpenTelemetry. For instructions on how to instrument outgoing requests, see Trace Google Cloud Functions in Go with OpenTelemetry.

Span flush

In the code snippets above, ForceFlush is explicitly called after every function invocation to ensure that spans are exported properly.

Because flushing spans becomes part of the function's execution logic, it results in longer execution times. To avoid this, you can omit the call to ForceFlush. Spans will still be periodically exported in the background.

Dynatrace overhead