This guide shows how to prepare a web service to run in a container on Cloud Run. It does not cover data migration.
Identify the port your code is listening on
Your service should listen for requests on a specific port. You must identify this port and configure Cloud Run to send requests to the same port.
This is the same port you would use when invoking your service on your local
machine. For example, if to test your code you open localhost:3000, then set
the container port to
3000 in Cloud Run.
Cloud Run defaults to sending requests to 8080.
The value of the port to which requests are sent is always available in the
PORT environment variable. It is a best practice for your code to listen on
the value defined by the PORT environment variable if possible.
Remove reliance on local filesystem for persistent storage
Check your application code for reliance on local filesystems, and replace it with file storage on Cloud Storage or data storage such as Firestore or Cloud SQL.
Add a Dockerfile
In order to wrap your service in a container, you should use a Dockerfile to define the operating environment. The build and deploy quickstart shows some basic Dockerfiles you can use to get started.
Read more about customizing your Dockerfile on the Developing your service
page.
Tune for concurrency and memory limits
Learn more about how concurrency works then optimize your service concurrency support in development tips for tuning concurrency
Make sure your memory limit is high enough for your application to run, including capacity for any temporary file storage your service requires.
Send logs to stdout, stderr, or /var/log
Cloud Run automatically uses Google Cloud Observability to aggregate and review your logs, as described in the logging page.