Use Pub/Sub with Cloud Run tutorial

Set up gcloud defaults

To configure gcloud with defaults for your Cloud Run service:

1. Set your default project:

   gcloud config set project PROJECT_ID

   Replace PROJECT_ID with the name of the project you created for this tutorial.

2. Configure gcloud for your chosen region:

   gcloud config set run/region REGION

   Replace REGION with the supported Cloud Run region of your choice.

Create an Artifact Registry standard repository

Create an Artifact Registry standard repository to store your container image:

gcloud artifacts repositories create REPOSITORY \
    --repository-format=docker \
    --location=REGION

Replace:

• REPOSITORY with a unique name for the repository.
• REGION with the Google Cloud region to be used for the Artifact Registry repository.

Create a Pub/Sub topic

The sample service is triggered by messages published to a Pub/Sub topic, so you'll need to create a topic in Pub/Sub.

gcloud pubsub topics create myRunTopic

resource "google_pubsub_topic" "default" {
  name = "pubsub_topic"
}

Retrieve the code sample

To retrieve the code sample for use:

1. Clone the sample app repository to your local machine:

   Node.js

   git clone https://github.com/GoogleCloudPlatform/nodejs-docs-samples.git

   Alternatively, you can download the sample as a zip file and extract it.

   Python

   git clone https://github.com/GoogleCloudPlatform/python-docs-samples.git

   Alternatively, you can download the sample as a zip file and extract it.

   Go

   git clone https://github.com/GoogleCloudPlatform/golang-samples.git

   Alternatively, you can download the sample as a zip file and extract it.

   Java

   git clone https://github.com/GoogleCloudPlatform/java-docs-samples.git

   Alternatively, you can download the sample as a zip file and extract it.

   C#

   git clone https://github.com/GoogleCloudPlatform/dotnet-docs-samples.git

   Alternatively, you can download the sample as a zip file and extract it.

2. Change to the directory that contains the Cloud Run sample code:

   Node.js

   cd nodejs-docs-samples/run/pubsub/

   Python

   cd python-docs-samples/run/pubsub/

   Go

   cd golang-samples/run/pubsub/

   Java

   cd java-docs-samples/run/pubsub/

   C#

   cd dotnet-docs-samples/run/Run.Samples.Pubsub.MinimalApi/

Review the code

The code for this tutorial consists of the following:

• A server that handles incoming requests.

  Node.js

  To keep the Node.js service easy to test, the server configuration is separate from the server startup.

  The Node.js web server is set up in app.js.

  const express = require('express');
  const app = express();
  
  // This middleware is available in Express v4.16.0 onwards
  app.use(express.json());

  The web server is started in index.js:

  const app = require('./app.js');
  const PORT = parseInt(parseInt(process.env.PORT)) || 8080;
  
  app.listen(PORT, () =>
    console.log(`nodejs-pubsub-tutorial listening on port ${PORT}`)
  );

  Python

  import base64
  
  from flask import Flask, request
  
  
  app = Flask(__name__)
  

  Go

  
  // Sample run-pubsub is a Cloud Run service which handles Pub/Sub messages.
  package main
  
  import (
  	"encoding/json"
  	"io"
  	"log"
  	"net/http"
  	"os"
  )
  
  func main() {
  	http.HandleFunc("/", HelloPubSub)
  	// Determine port for HTTP service.
  	port := os.Getenv("PORT")
  	if port == "" {
  		port = "8080"
  		log.Printf("Defaulting to port %s", port)
  	}
  	// Start HTTP server.
  	log.Printf("Listening on port %s", port)
  	if err := http.ListenAndServe(":"+port, nil); err != nil {
  		log.Fatal(err)
  	}
  }
  

  Java

  import org.springframework.boot.SpringApplication;
  import org.springframework.boot.autoconfigure.SpringBootApplication;
  
  @SpringBootApplication
  public class PubSubApplication {
    public static void main(String[] args) {
      SpringApplication.run(PubSubApplication.class, args);
    }
  }

  C#

  var builder = WebApplication.CreateBuilder(args);
  var app = builder.Build();
  
  var port = Environment.GetEnvironmentVariable("PORT");
  if (port != null)
  {
      app.Urls.Add($"http://0.0.0.0:{port}");
  }
  

• A handler that processes the Pub/Sub message and logs a greeting.

  Node.js

  app.post('/', (req, res) => {
    if (!req.body) {
      const msg = 'no Pub/Sub message received';
      console.error(`error: ${msg}`);
      res.status(400).send(`Bad Request: ${msg}`);
      return;
    }
    if (!req.body.message) {
      const msg = 'invalid Pub/Sub message format';
      console.error(`error: ${msg}`);
      res.status(400).send(`Bad Request: ${msg}`);
      return;
    }
  
    const pubSubMessage = req.body.message;
    const name = pubSubMessage.data
      ? Buffer.from(pubSubMessage.data, 'base64').toString().trim()
      : 'World';
  
    console.log(`Hello ${name}!`);
    res.status(204).send();
  });

  Python

  @app.route("/", methods=["POST"])
  def index():
      """Receive and parse Pub/Sub messages."""
      envelope = request.get_json()
      if not envelope:
          msg = "no Pub/Sub message received"
          print(f"error: {msg}")
          return f"Bad Request: {msg}", 400
  
      if not isinstance(envelope, dict) or "message" not in envelope:
          msg = "invalid Pub/Sub message format"
          print(f"error: {msg}")
          return f"Bad Request: {msg}", 400
  
      pubsub_message = envelope["message"]
  
      name = "World"
      if isinstance(pubsub_message, dict) and "data" in pubsub_message:
          name = base64.b64decode(pubsub_message["data"]).decode("utf-8").strip()
  
      print(f"Hello {name}!")
  
      return ("", 204)
  
  

  Go

  
  // PubSubMessage is the payload of a Pub/Sub event.
  // See the documentation for more details:
  // https://cloud.google.com/pubsub/docs/reference/rest/v1/PubsubMessage
  type PubSubMessage struct {
  	Message struct {
  		Data []byte `json:"data,omitempty"`
  		ID   string `json:"id"`
  	} `json:"message"`
  	Subscription string `json:"subscription"`
  }
  
  // HelloPubSub receives and processes a Pub/Sub push message.
  func HelloPubSub(w http.ResponseWriter, r *http.Request) {
  	var m PubSubMessage
  	body, err := io.ReadAll(r.Body)
  	defer r.Body.Close()
  	if err != nil {
  		log.Printf("io.ReadAll: %v", err)
  		http.Error(w, "Bad Request", http.StatusBadRequest)
  		return
  	}
  	// byte slice unmarshalling handles base64 decoding.
  	if err := json.Unmarshal(body, &m); err != nil {
  		log.Printf("json.Unmarshal: %v", err)
  		http.Error(w, "Bad Request", http.StatusBadRequest)
  		return
  	}
  
  	name := string(m.Message.Data)
  	if name == "" {
  		name = "World"
  	}
  	log.Printf("Hello %s!", name)
  }
  

  Java

  import com.example.cloudrun.Body;
  import java.util.Base64;
  import org.apache.commons.lang3.StringUtils;
  import org.springframework.http.HttpStatus;
  import org.springframework.http.ResponseEntity;
  import org.springframework.web.bind.annotation.RequestBody;
  import org.springframework.web.bind.annotation.RequestMapping;
  import org.springframework.web.bind.annotation.RequestMethod;
  import org.springframework.web.bind.annotation.RestController;
  
  // PubsubController consumes a Pub/Sub message.
  @RestController
  public class PubSubController {
    @RequestMapping(value = "/", method = RequestMethod.POST)
    public ResponseEntity<String> receiveMessage(@RequestBody Body body) {
      // Get PubSub message from request body.
      Body.Message message = body.getMessage();
      if (message == null) {
        String msg = "Bad Request: invalid Pub/Sub message format";
        System.out.println(msg);
        return new ResponseEntity<>(msg, HttpStatus.BAD_REQUEST);
      }
  
      String data = message.getData();
      String target =
          !StringUtils.isEmpty(data) ? new String(Base64.getDecoder().decode(data)) : "World";
      String msg = "Hello " + target + "!";
  
      System.out.println(msg);
      return new ResponseEntity<>(msg, HttpStatus.OK);
    }
  }

  C#

  app.MapPost("/", (Envelope envelope) =>
  {
      if (envelope?.Message?.Data == null)
      {
          app.Logger.LogWarning("Bad Request: Invalid Pub/Sub message format.");
          return Results.BadRequest();
      }
  
      var data = Convert.FromBase64String(envelope.Message.Data);
      var target = System.Text.Encoding.UTF8.GetString(data);
  
      app.Logger.LogInformation($"Hello {target}!");
  
      return Results.NoContent();
  });
  

  You must code the service to return an accurate HTTP response code. Success codes, such as HTTP 200 or 204, acknowledge complete processing of the Pub/Sub message. Error codes, such as HTTP 400 or 500, indicate the message will be retried, as described in Receiving messages using Push guide.

• A Dockerfile that defines the operating environment for the service. The contents of the Dockerfile vary by language.

  Node.js

  
  # Use the official lightweight Node.js image.
  # https://hub.docker.com/_/node
  FROM node:20-slim
  # Create and change to the app directory.
  WORKDIR /usr/src/app
  
  # Copy application dependency manifests to the container image.
  # A wildcard is used to ensure both package.json AND package-lock.json are copied.
  # Copying this separately prevents re-running npm install on every code change.
  COPY package*.json ./
  
  # Install dependencies.
  # if you need a deterministic and repeatable build create a
  # package-lock.json file and use npm ci:
  # RUN npm ci --omit=dev
  # if you need to include development dependencies during development
  # of your application, use:
  # RUN npm install --dev
  
  RUN npm install --omit=dev
  
  # Copy local code to the container image.
  COPY . .
  
  # Run the web service on container startup.
  CMD [ "npm", "start" ]
  

  Python

  
  # Use the official Python image.
  # https://hub.docker.com/_/python
  FROM python:3.11
  
  # Allow statements and log messages to immediately appear in the Cloud Run logs
  ENV PYTHONUNBUFFERED True
  
  # Copy application dependency manifests to the container image.
  # Copying this separately prevents re-running pip install on every code change.
  COPY requirements.txt ./
  
  # Install production dependencies.
  RUN pip install -r requirements.txt
  
  # Copy local code to the container image.
  ENV APP_HOME /app
  WORKDIR $APP_HOME
  COPY . ./
  
  # Run the web service on container startup.
  # Use gunicorn webserver with one worker process and 8 threads.
  # For environments with multiple CPU cores, increase the number of workers
  # to be equal to the cores available.
  # Timeout is set to 0 to disable the timeouts of the workers to allow Cloud Run to handle instance scaling.
  CMD exec gunicorn --bind :$PORT --workers 1 --threads 8 --timeout 0 main:app
  

  Go

  
  # Use the offical golang image to create a binary.
  # This is based on Debian and sets the GOPATH to /go.
  # https://hub.docker.com/_/golang
  FROM golang:1.21-bookworm as builder
  
  # Create and change to the app directory.
  WORKDIR /app
  
  # Retrieve application dependencies.
  # This allows the container build to reuse cached dependencies.
  # Expecting to copy go.mod and if present go.sum.
  COPY go.* ./
  RUN go mod download
  
  # Copy local code to the container image.
  COPY . ./
  
  # Build the binary.
  RUN go build -v -o server
  
  # Use the official Debian slim image for a lean production container.
  # https://hub.docker.com/_/debian
  # https://docs.docker.com/develop/develop-images/multistage-build/#use-multi-stage-builds
  FROM debian:bookworm-slim
  RUN set -x && apt-get update && DEBIAN_FRONTEND=noninteractive apt-get install -y \
      ca-certificates && \
      rm -rf /var/lib/apt/lists/*
  
  # Copy the binary to the production image from the builder stage.
  COPY --from=builder /app/server /server
  
  # Run the web service on container startup.
  CMD ["/server"]
  

  Java

  This sample uses Jib to build Docker images using common Java tools. Jib optimizes container builds without the need for a Dockerfile or having Docker installed. Learn more about building Java containers with Jib.

  <plugin>
    <groupId>com.google.cloud.tools</groupId>
    <artifactId>jib-maven-plugin</artifactId>
    <version>3.4.0</version>
    <configuration>
      <to>
        <image>gcr.io/PROJECT_ID/pubsub</image>
      </to>
    </configuration>
  </plugin>
  

  C#

  # Build in SDK base image
  FROM mcr.microsoft.com/dotnet/sdk:6.0 AS build-env
  WORKDIR /app
  
  COPY *.csproj ./
  RUN dotnet restore
  
  COPY . ./
  RUN dotnet publish -r linux-x64 --no-self-contained -p:PublishReadyToRun=true -c Release -o out
  
  # Copy to runtime image
  FROM mcr.microsoft.com/dotnet/aspnet:6.0
  WORKDIR /app
  COPY --from=build-env /app/out .
  
  # Port passed in by Cloud Run via environment variable PORT.  Default 8080.
  ENV PORT=8080
  
  ENTRYPOINT ["dotnet", "Run.Samples.Pubsub.MinimalApi.dll"]

For details on how to authenticate the origin of Pub/Sub requests, see Integrate with Pub/Sub.

Ship the code

Shipping code consists of three steps: building a container image with Cloud Build, uploading the container image to Artifact Registry, and deploying the container image to Cloud Run.

To ship your code:

1. Build your container and publish on Artifact Registry:

   Node.js

   gcloud builds submit --tag REGION-docker.pkg.dev/PROJECT_ID/REPOSITORY/pubsub

   Replace:

   • PROJECT_ID with your Google Cloud project ID.
   • REPOSITORY with the name of the Artifact Registry repository.
   • REGION with the Google Cloud region to be used for the Artifact Registry repository.

   pubsub is the image name.

   Upon success, you should see a SUCCESS message containing the ID, creation time, and image name. The image is stored in Artifact Registry and can be re-used if required.

   Python

   gcloud builds submit --tag REGION-docker.pkg.dev/PROJECT_ID/REPOSITORY/pubsub

   Replace:

   • PROJECT_ID with your Google Cloud project ID.
   • REPOSITORY with the name of the Artifact Registry repository.
   • REGION with the Google Cloud region to be used for the Artifact Registry repository.

   pubsub is the image name.

   Upon success, you should see a SUCCESS message containing the ID, creation time, and image name. The image is stored in Artifact Registry and can be re-used if required.

   Go

   gcloud builds submit --tag REGION-docker.pkg.dev/PROJECT_ID/REPOSITORY/pubsub

   Replace:

   • PROJECT_ID with your Google Cloud project ID.
   • REPOSITORY with the name of the Artifact Registry repository.
   • REGION with the Google Cloud region to be used for the Artifact Registry repository.

   pubsub is the image name.

   Upon success, you should see a SUCCESS message containing the ID, creation time, and image name. The image is stored in Artifact Registry and can be re-used if required.

   Java

   • Use the gcloud CLI credential helper to authorize Docker to push to your Artifact Registry.

     gcloud auth configure-docker

   • Use the Jib Maven Plugin to build and push the container to Artifact Registry.

     mvn compile jib:build -D image=REGION-docker.pkg.dev/PROJECT_ID/REPOSITORY/pubsub

     Replace:
     • PROJECT_ID with your Google Cloud project ID.
     • REPOSITORY with the name of the Artifact Registry repository.
     • REGION with the Google Cloud region to be used for the Artifact Registry repository.

     pubsub is the image name.

     Upon success, you should see a BUILD SUCCESS message. The image is stored in Artifact Registry and can be re-used if required.

   C#

   gcloud builds submit --tag REGION-docker.pkg.dev/PROJECT_ID/REPOSITORY/pubsub

   Replace:

   • PROJECT_ID with your Google Cloud project ID.
   • REPOSITORY with the name of the Artifact Registry repository.
   • REGION with the Google Cloud region to be used for the Artifact Registry repository.

   pubsub is the image name.

   Upon success, you should see a SUCCESS message containing the ID, creation time, and image name. The image is stored in Artifact Registry and can be re-used if required.

2. Deploy your application:

   Command line

   1. Run the following command to deploy your app:

      gcloud run deploy pubsub-tutorial --image REGION-docker.pkg.dev/PROJECT_ID/REPOSITORY/pubsub  --no-allow-unauthenticated

      Replace:
      • PROJECT_ID with your Google Cloud project ID.
      • REPOSITORY with the name of the Artifact Registry repository.
      • REGION with the Google Cloud region to be used for the Artifact Registry repository.

      pubsub is the image name and pubsub-tutorial is the name of the service. Notice that the container image is deployed to the service and region that you configured previously under Setting up gcloud

      The --no-allow-unauthenticated flag restricts unauthenticated access to the service. By keeping the service private you can rely on Cloud Run's automatic Pub/Sub integration to authenticate requests. See Integrate with Pub/Sub for more details on how this is configured. For more details about authentication that is based on Identity and Access Management (IAM), see Managing access using IAM.

      Wait until the deployment is complete: this can take about half a minute. On success, the command line displays the service URL. This URL is used to configure a Pub/Sub subscription.

   2. If you want to deploy a code update to the service, repeat the previous steps. Each deployment to a service creates a new revision and automatically starts serving traffic when ready.

   Terraform

   To create a Cloud Run service, add the following to your existing .tf file.

   Replace the value for image with your image URL: REGION-docker.pkg.dev/PROJECT_ID/REPOSITORY/pubsub.

   resource "google_cloud_run_v2_service" "default" {
     name     = "pubsub-tutorial"
     location = "us-central1"
   
     deletion_protection = false # set to true to prevent destruction of the resource
   
     template {
       containers {
         image = "us-docker.pkg.dev/cloudrun/container/hello" # Replace with newly created image gcr.io/<project_id>/pubsub
       }
     }
     depends_on = [google_project_service.cloudrun_api]
   }

Integrate with Pub/Sub

To integrate the service with Pub/Sub:

Try it out

To test the end-to-end solution:

1. Send a Pub/Sub message to the topic:

   gcloud pubsub topics publish myRunTopic --message "Runner"

   You can also publish messages programmatically instead of using the command-line as shown in this tutorial. For more information, see Publishing messages.

2. Navigate to the service logs:

   1. Navigate to the Google Cloud console
   2. Click the pubsub-tutorial service.

   3. Select the Logs tab.

      Logs might take a few moments to appear. If you don't see them immediately, check again after a few moments.

3. Look for the "Hello Runner!" message.