# Docker Compose

[![Docker Automated build](https://img.shields.io/docker/automated/tmaier/docker-compose.svg)](https://hub.docker.com/r/tmaier/docker-compose/)
[![Docker Pulls](https://img.shields.io/docker/pulls/tmaier/docker-compose.svg)](https://hub.docker.com/r/tmaier/docker-compose/)
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This docker image installs docker-compose on top of the `docker` image.
This is very useful for CI pipelines, which leverage "Docker in Docker".

## Docker versions supported

Note: In the past. this docker image (tags) focused on the docker version (e.g. `latest`, `20.10`, `19.03` and `19`).
But as the docker releases got less disruptive, the approach changes to use the docker compose version as tags.

The Docker Compose versions supported here use the most recent docker version compatible with it.

All available Docker Engine versions and the respective Docker Compose versions are defined in [`DOCKER_AND_COMPOSE_VERSION_MATRIX`](./DOCKER_AND_COMPOSE_VERSION_MATRIX).

Please open an issue or a pull request (preferred) [at GitHub](https://github.com/tmaier/docker-compose), if a version is missing.

## Usage instructions for GitLab CI

You may use it like this in your `.gitlab-ci.yml` file.

```yaml
image: tmaier/docker-compose:latest

services:
  - docker:dind

before_script:
  - docker info
  - docker-compose --version

build image:
  stage: build
  script:
    - docker-compose build
```

## How to add support for a new docker version to this repository?

You must only provide a Pull Request for the file [`DOCKER_AND_COMPOSE_VERSION_MATRIX`](./DOCKER_AND_COMPOSE_VERSION_MATRIX).

`DOCKER_AND_COMPOSE_VERSION_MATRIX` specifies in the first column the docker version.
The second column states the most recent release of docker-compose when the docker version has been released.

You can see the latest matching versions of both by checking their release notes:

- https://github.com/docker/docker-ce/releases or https://hub.docker.com/_/docker
- https://github.com/docker/compose/releases

## Common issues and possible fixes

### `ERROR: error during connect: Get http://docker:2375/v1.40/info: dial tcp: ...`

> As of version 19.03, docker:dind will automatically generate TLS certificates and require using them for communication.

See <https://github.com/tmaier/docker-compose/issues/21#issuecomment-578780163>

## Author

[Tobias L. Maier](http://tobiasmaier.info) for [BauCloud GmbH](https://www.baucloud.com)