Building Containers

Cloud Run accepts container images built with any tool capable of building container images, as long as they respect the container contract. In particular, your code must listen for HTTP requests on the port defined by the PORT environment variable. This PORT environment variable is automatically injected by Cloud Run into your container.

This page describes several ways to build container images:

Using a Dockerfile
Using Google Cloud's buildpacks

Before you begin

You need the Google Cloud CLI to run some of the commands in this page.

Create a repository at a supported container registry. To create an Artifact Registry repository, run:

    gcloud artifacts repositories create REPOSITORY \
        --repository-format=docker \
        --location=LOCATION \
        --description="DESCRIPTION" \
        --immutable-tags \
        --async

You can configure Docker to get access to Artifact Registry using the gcloud CLI credential helper
```
gcloud auth configure-docker LOCATION-docker.pkg.dev
```

Building using a Dockerfile

Before building your sources into a container image ("containerizing") locally using Docker or using Cloud Build, you need a Dockerfile to be present along with your sources. The Hello World samples contain sample applications and Dockerfiles in many popular languages.

If you use Dockerfiles, you can use either of the following methods to build:

Build using Cloud Build
Build locally using Docker

Building using Cloud Build

You can build your image on Google Cloud by using Cloud Build:

Navigate to the folder containing your sources and Dockerfile.
Run the command:
```
gcloud builds submit --tag IMAGE_URL
```
Replace IMAGE_URL with a reference to the container image, for example, us-docker.pkg.dev/cloudrun/container/hello:latest. If you use Artifact Registry, the repository REPO_NAME must already be created. The URL has the shape LOCATION-docker.pkg.dev/PROJECT_ID/REPO_NAME/PATH:TAG .

For tips on improving build performance, see Speeding up your builds

Building locally and pushing using Docker

If you have Docker installed locally, you can use docker build instead of using Cloud Build or Google Cloud's buildpacks.

To build your container image using Docker:

Navigate to the folder containing your sources and Dockerfile.
Run the command:
```
docker build . --tag IMAGE_URL
```
Replace IMAGE_URL with a reference to the container image, for example, us-docker.pkg.dev/cloudrun/container/hello:latest. If you use Artifact Registry, the repository REPO_NAME must already be created. The URL has the shape LOCATION-docker.pkg.dev/PROJECT_ID/REPO_NAME/PATH:TAG .

Note that if you are using a Mac with Apple silicon, you must specify --platform linux/amd64 in the command line.
Push the container image to a supported container registry:
```
docker push IMAGE_URL
```
Replace IMAGE_URL with a reference to the container image, for example, us-docker.pkg.dev/cloudrun/container/hello:latest. If you use Artifact Registry, the repository REPO_NAME must already be created. The URL has the shape LOCATION-docker.pkg.dev/PROJECT_ID/REPO_NAME/PATH:TAG .

To exclude local files from this process, follow the .dockerignore configuration file instructions.

Building using Google Cloud's buildpacks

Google Cloud's buildpacks is a set of CNCF-compatible Buildpacks that build source code into container images designed to run on Google Cloud container platforms, including Cloud Run.

For a list of supported languages, refer to the Google Cloud's buildpacks documentation

Building with Google Cloud's buildpacks using Cloud Build

To build with a Google Cloud's buildpacks:

Navigate to the folder containing your sources.
Run the command:
```
gcloud builds submit --pack image=IMAGE_URL
```
Replace IMAGE_URL with a reference to the container image, for example, us-docker.pkg.dev/cloudrun/container/hello:latest. If you use Artifact Registry, the repository REPO_NAME must already be created. The URL has the shape LOCATION-docker.pkg.dev/PROJECT_ID/REPO_NAME/PATH:TAG .
Wait for the build to complete.

Building with Google Cloud's buildpacks using the `pack` command line

To build using the pack command:

If you haven't already done so, install Docker.
If you haven't already done so, install pack.
Navigate to the folder containing your sources.
Run the following command to build and push to your supported container registry:
```
pack build --publish IMAGE_URL
```
Replace IMAGE_URL with a reference to the container image, for example, us-docker.pkg.dev/cloudrun/container/hello:latest. If you use Artifact Registry, the repository REPO_NAME must already be created. The URL has the shape LOCATION-docker.pkg.dev/PROJECT_ID/REPO_NAME/PATH:TAG .
Wait for pack to finish.

For more information, read the instructions under Building an Application.

What's next

After your container has been built, you can test locally before deploying to Cloud Run; see Testing a Cloud Run service locally to learn more.
To learn more about the contract your containers must respect to be deployed to Cloud Run, see Container contract.
To deploy your built containers to Cloud Run, follow Deploying services.
To automate the builds and deployments of your Cloud Run services using Cloud Build Triggers, set up continuous deployment.
To perform optimal container builds for Java application, see Building Java containers with Jib.