Add the dd-trace-js library to your application.

app.js

// The tracer includes a dogstatsd client. The tracer is actually started with `NODE_OPTIONS`
// so that we can take advantage of startup tracing.
// The tracer will inject the current trace ID into logs with `DD_LOGS_INJECTION`.
// The tracer will send profiling information with `DD_PROFILING_ENABLED`.
const tracer = require('dd-trace').init();

const express = require("express");
const app = express();

const { createLogger, format, transports } = require('winston');

// We can use the DD_SERVERLESS_LOG_PATH environment variable if it is available.
// While this is not necessary, it the log forwarding configuration centralized
// in the cloud run configuration.
const logFilename = process.env.DD_SERVERLESS_LOG_PATH?.replace("*.log", "app.log") || "/shared-logs/logs/app.log";
console.log(`writing logs to ${logFilename}`);

const logger = createLogger({
	level: 'info',
	exitOnError: false,
	format: format.json(),
	transports: [new transports.File({ filename: logFilename })],
});

app.get("/", (_, res) => {
	logger.info("Hello!");
	tracer.dogstatsd.distribution("our-sample-app.sample-metric", 1);

	res.status(200).json({ msg: "A traced endpoint with custom metrics" });
});

const port = process.env.PORT || 8080;
app.listen(port);

You can use npm install dd-trace to add the tracer to your package.

Dockerfile

Your Dockerfile can look something like this. This will create a minmimal application container with metrics, traces, logs, and profiling. Note that the dockerfile needs to be built for the the x86_64 architecture (use the --platform linux/arm64 parameter for docker build).

FROM node:22-slim

COPY app.js package.json package-lock.json .
RUN npm ci --only=production

# Initialize the tracer
ENV NODE_OPTIONS="--require dd-trace/init"

EXPOSE 8080

CMD ["node", "app.js"]

Details

The dd-trace-js library provides support for Tracing, Metrics, and Profiling.

Set the NODE_OPTIONS="--require dd-trace/init" environment variable in your docker container to include the dd-trace/init module when the Node.js process starts.

Application Logs need to be sent to a file that the sidecar container can access. The container setup is detailed below. Log and Trace Correlation possible when logging is combined with the dd-trace-js library. The sidecar finds log files based on the DD_SERVERLESS_LOG_PATH environment variable, usually /shared-volume/logs/*.log which will forward all of files ending in .log in the /shared-volume/logs directory. The application container needs the DD_LOGS_INJECTION environment variable to be set since we are using NODE_OPTIONS to actually start our tracer. If you do not use NODE_OPTIONS, call the dd-trace init method with the logInjection: true configuration parameter:

const tracer = require('dd-trace').init({
	logInjection: true,
});

Set DD_PROFILING_ENABLED to enable Profiling.

Example Code

# add the example code here, with traces, custom metrics, profiling, and logs

Details

Tracing

Profiling

Metrics

Logs

Example Code

// add the example code here, with traces, custom metrics, profiling, and logs

Details

Tracing

Profiling

Metrics

Logs

Example Code

// add the example code here, with traces, custom metrics, profiling, and logs

Details

Tracing

Profiling

Metrics

Logs

Example Code

// add the example code here, with traces, custom metrics, profiling, and logs

Details

Tracing

Profiling

Metrics

Logs

Example Code

// add the example code here, with traces, custom metrics, profiling, and logs

Details

Tracing

Profiling

Metrics

Logs

1. On the Cloud Run service page, select Edit & Deploy New Revision.
2. Open the Volumes main tab and create a new volume for log forwarding.
   1. Make an In-Memory volume called shared-logs.
   2. You may set a size limit if necessary.
3. Open the Containers main tab and click Add Container to add a new gcr.io/datadoghq/serverless-init:latest sidecar container.
4. Click Add health check to add a Startup check for the container.
   1. Select the TCP probe type.
   2. Choose any free port (9999, for example). We will need this port number shortly for the DD_HEALTH_PORT variable.
5. Click the Variables & Secrets tab and add the required environment variables.
   • The DD_HEALTH_PORT variable should be the port for the TCP health check you configured.
   • The DD_SERVERLESS_LOG_PATH variable should be set to /shared-logs/logs/*.log where /shared-logs is the volume mount point we will use in the next step.
   • See the table above for the other required and suggested Environment Variables.
6. Click the Volume Mounts tab and add the logs volume mount.
   • Mount it at the location that matches the prefix of DD_SERVERLESS_LOG_PATH, for example /shared-logs for a /shared-logs/logs/*.log log path.
7. Edit the application container.
8. Click the Volume Mounts tab and add the logs volume mount.
   • Mount it to the same location that you did for the sidecar container, for example /shared-logs.
9. Click the Variables & Secrets tab and set the DD_SERVICE and DD_LOGS_INJECTION environment variables as you did for the sidecar.
10. Click the Settings tab and set the Container start up order to Depends on the sidecar container.
11. Deploy the application.

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1. Step
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