Nicolas De Loof
76df8709cc
Lifecycle hooks are execs: their output only existed for the attached listener, and post-hoc inspection was impossible — the engine's logging driver never sees exec output. With CaptureLogs, hook execs now tee their output into the container's logging driver, stamped with the compose identity labels (project, service, and the new com.docker.compose.hook label carrying post_start or pre_stop). compose logs gains a --hooks flag: it requests the log details, tells hook-stamped lines apart from the container's own output, and labels them with the hook type (e.g. "db [post_start] | ..."). No client-side state is involved: the log stream itself carries the attribution, so any client can retrieve hook output for a project it did not create. Daemons whose API predates CaptureLogs ignore the capture fields, and without --hooks the logs output is unchanged: the PoC degrades gracefully in both directions.
Table of Contents
Docker Compose
Docker Compose is a tool for running multi-container applications on Docker
defined using the Compose file format.
A Compose file is used to define how one or more containers that make up
your application are configured.
Once you have a Compose file, you can create and start your application with a
single command: docker compose up.
Note
: About Docker Swarm Docker Swarm used to rely on the legacy compose file format but did not adopt the compose specification so is missing some of the recent enhancements in the compose syntax. After acquisition by Mirantis swarm isn't maintained by Docker Inc, and as such some Docker Compose features aren't accessible to swarm users.
Where to get Docker Compose
Windows and macOS
Docker Compose is included in Docker Desktop for Windows and macOS.
Linux
You can download Docker Compose binaries from the release page on this repository.
Rename the relevant binary for your OS to docker-compose and copy it to $HOME/.docker/cli-plugins
Or copy it into one of these folders to install it system-wide:
/usr/local/lib/docker/cli-pluginsOR/usr/local/libexec/docker/cli-plugins/usr/lib/docker/cli-pluginsOR/usr/libexec/docker/cli-plugins
(might require making the downloaded file executable with chmod +x)
Quick Start
Using Docker Compose is a three-step process:
- Define your app's environment with a
Dockerfileso it can be reproduced anywhere. - Define the services that make up your app in
compose.yamlso they can be run together in an isolated environment. - Lastly, run
docker compose upand Compose will start and run your entire app.
A Compose file looks like this:
services:
web:
build: .
ports:
- "5000:5000"
volumes:
- .:/code
redis:
image: redis
Contributing
Want to help develop Docker Compose? Check out our contributing documentation.
If you find an issue, please report it on the issue tracker.
Legacy
The Python version of Compose is available under the v1 branch.