How to Run Your Docker App in the Background with uvicorn

Описание: Discover how to run your Dockerized FastAPI application in the background, effortlessly managing logs and performance.
---
This video is based on the question https://stackoverflow.com/q/66957040/ asked by the user 'Jenia Ivanov' ( https://stackoverflow.com/u/963319/ ) and on the answer https://stackoverflow.com/a/66957479/ provided by the user 'Vitor Bertulucci Borges' ( https://stackoverflow.com/u/13750582/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: How to run Docker app in background instead of output to terminal

Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l...
The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license.

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
Run Your Docker App in the Background with uvicorn

If you're developing applications using Docker and FastAPI, you might encounter a situation where running your app outputs logs directly to the terminal rather than keeping them contained within the Docker environment. This can be a bit of a nuisance, especially when you want a cleaner output and to run your app in the background. Let's explore how to achieve just that.

The Problem

When you run a FastAPI app with uvicorn inside Docker, you may notice the logs appear directly on your terminal, which isn’t ideal if you’re trying to manage your application effectively. For instance, you might see output like this:

[[See Video to Reveal this Text or Code Snippet]]

This output suggests that while you’ve initiated your app, it’s not running as you would expect in a containerized environment. Let’s look at the steps you need to take to resolve this.

Solution Steps

Here’s how you can efficiently run your Dockerized FastAPI app in the background while ensuring that logs are managed better.

1. Update the Docker Run Command

To run your Docker container in the background, you should use the -d option with docker run. This option is also known as "detached mode". Here’s the modified command:

[[See Video to Reveal this Text or Code Snippet]]

-d or --detach: This flag tells Docker to run the container in the background, returning the container ID without cluttering your terminal with logs.

2. Monitor Container Logs

Once your container is running in the background, you’ll want to check the logs to ensure everything is functioning correctly. You can do this by using the container ID (obtained from running the Docker command with -d). Execute the following command:

[[See Video to Reveal this Text or Code Snippet]]

-f or --follow: This flag will allow you to follow the log output, so you’ll be able to see real-time updates just as if you were outputting to the terminal.

3. Stopping the Container

If you want to stop your running container, instead of using CTRL+ C, which only cancels the logs command (not the application), you should use the following command:

[[See Video to Reveal this Text or Code Snippet]]

This approach properly shuts down your FastAPI application that is running inside the Docker container.

Summary

Running your FastAPI application inside Docker in the background is as simple as adding a flag to your run command. Remember to check your logs using the docker logs -f command for real-time updates. Here’s a quick recap:

Build your Docker image: docker build -t example00 .

Run in the background: docker run -d -p 5000:5000 example00

Check logs: docker logs -f <container-ID>

Stop the container: docker stop <container-ID>

By following these steps, you can effectively manage your FastAPI application running in a Docker container, keeping your terminal clear and monitoring logs as needed. Happy coding!