Buildpacks for source-based deployment in GCP - Commands & Configuration

Introduction

Buildpacks let you turn your app's source code into a runnable container automatically. This solves the problem of manually writing container files and managing dependencies.

When you want to deploy your app to Google Cloud Run without writing a Dockerfile.

When you have source code in languages like Python, Node.js, or Go and want an easy build process.

When you want Google Cloud Build to create a container image from your source code automatically.

When you want to focus on writing code and let the platform handle container setup.

When you want consistent builds that follow best practices without manual configuration.

Commands

This command uploads your source code to Google Cloud Build and uses Buildpacks to create a container image named 'my-app-image' in your Google Container Registry.

Terminal

gcloud builds submit --pack image=gcr.io/my-project/my-app-image

Expected Output

Starting build...

Step 1/5 : FROM gcr.io/buildpacks/builder:v1

 ---> abcdef123456

Step 2/5 : COPY . /workspace

 ---> Using cache

Step 3/5 : RUN /cnb/lifecycle/detector

 ---> Running buildpacks...

Step 4/5 : RUN /cnb/lifecycle/builder

 ---> Building image...

Step 5/5 : COMMIT

 ---> Image built successfully

Build completed successfully

→

--pack - Specifies to use Buildpacks for building the container image.

This command deploys the container image built by Buildpacks to Cloud Run, making your app available on the internet.

Terminal

gcloud run deploy my-app --image gcr.io/my-project/my-app-image --platform managed --region us-central1 --allow-unauthenticated

Expected Output

Deploying container to Cloud Run service [my-app] in project [my-project] region [us-central1]

Service [my-app] revision [my-app-00001] has been deployed and is serving 100 percent of traffic.

Service URL: https://my-app-abcdefg-uc.a.run.app

→

--platform - Deploys to fully managed Cloud Run.

→

--allow-unauthenticated - Allows public access to the service.

This command shows details about your deployed Cloud Run service, including URL, traffic, and revisions.

Terminal

gcloud run services describe my-app --platform managed --region us-central1

Expected Output

apiVersion: serving.knative.dev/v1

kind: Service

metadata:

  name: my-app

  namespace: my-project

spec:

  template:

    spec:

      containers:

      - image: gcr.io/my-project/my-app-image

status:

  url: https://my-app-abcdefg-uc.a.run.app

→

--platform managed - Specifies the managed Cloud Run platform.

Key Concept

Buildpacks automatically create container images from your source code without needing a Dockerfile.

Common Mistakes

Not specifying the --pack flag when running gcloud builds submit.

Without --pack, Cloud Build expects a Dockerfile and will fail if none exists.

Always include --pack to use Buildpacks for source-based builds.

Deploying to Cloud Run with an incorrect image name or missing image.

Cloud Run cannot deploy if the container image does not exist or is misnamed.

Ensure the image name matches exactly the one built and pushed to Container Registry.

Not allowing unauthenticated access when you want a public app.

The app will require authentication and block public users.

Use --allow-unauthenticated flag during deployment for public access.

Summary

Use 'gcloud builds submit --pack' to build a container image from source code using Buildpacks.

Deploy the built image to Cloud Run with 'gcloud run deploy' to make your app live.

Check your deployed service details with 'gcloud run services describe' to verify deployment.