Pin docker-compose versions to the time of release

- Otherwise the docker-compose version is the latest available at time of build, which may not be compatible or expected
  - The latest `COMPOSE_VERSION` can be taken by setting the argument blank (or leaving it as is in the case of `latest`)
  - pip requires the `.*` to denote that we want the latest patch level, eg. just putting `docker-compose==1.11` installs `1.11.0` instead of `1.11.2`
- The extra `${COMPOSE_VERSION:+==}` is because pip errors out with `docker-compose==`

Fixes #4

1.12/Dockerfile

@@ -1,5 +1,7 @@
+ARG COMPOSE_VERSION=1.8.*
+
 FROM docker:1.12
 MAINTAINER Tobias Maier <tobias.maier@baucloud.com>
 
 RUN apk add --no-cache py-pip
-RUN pip install docker-compose
+RUN pip install "docker-compose${COMPOSE_VERSION:+==}${COMPOSE_VERSION}"

1.13/Dockerfile

@@ -1,5 +1,7 @@
+ARG COMPOSE_VERSION=1.10.*
+
 FROM docker:1.13
 MAINTAINER Tobias Maier <tobias.maier@baucloud.com>
 
 RUN apk add --no-cache py-pip
-RUN pip install docker-compose
+RUN pip install "docker-compose${COMPOSE_VERSION:+==}${COMPOSE_VERSION}"

17.03/Dockerfile

@@ -1,5 +1,7 @@
+ARG COMPOSE_VERSION=1.11.*
+
 FROM docker:17.03
 MAINTAINER Tobias Maier <tobias.maier@baucloud.com>
 
 RUN apk add --no-cache py-pip
-RUN pip install docker-compose
+RUN pip install "docker-compose${COMPOSE_VERSION:+==}${COMPOSE_VERSION}"

17.06/Dockerfile

@@ -1,5 +1,7 @@
+ARG COMPOSE_VERSION=1.15.*
+
 FROM docker:17.06
 MAINTAINER Tobias Maier <tobias.maier@baucloud.com>
 
 RUN apk add --no-cache py-pip
-RUN pip install docker-compose
+RUN pip install "docker-compose${COMPOSE_VERSION:+==}${COMPOSE_VERSION}"

17.09/Dockerfile

@@ -1,5 +1,7 @@
+ARG COMPOSE_VERSION=1.16.*
+
 FROM docker:17.09
 MAINTAINER Tobias Maier <tobias.maier@baucloud.com>
 
 RUN apk add --no-cache py-pip
-RUN pip install docker-compose
+RUN pip install "docker-compose${COMPOSE_VERSION:+==}${COMPOSE_VERSION}"

17.12/Dockerfile

@@ -1,5 +1,7 @@
+ARG COMPOSE_VERSION=1.18.*
+
 FROM docker:17.12
 MAINTAINER Tobias Maier <tobias.maier@baucloud.com>
 
 RUN apk add --no-cache py-pip
-RUN pip install docker-compose
+RUN pip install "docker-compose${COMPOSE_VERSION:+==}${COMPOSE_VERSION}"

17/Dockerfile

@@ -1,5 +1,7 @@
+ARG COMPOSE_VERSION=1.18.*
+
 FROM docker:17
 MAINTAINER Tobias Maier <tobias.maier@baucloud.com>
 
 RUN apk add --no-cache py-pip
-RUN pip install docker-compose
+RUN pip install "docker-compose${COMPOSE_VERSION:+==}${COMPOSE_VERSION}"

18.02/Dockerfile

@@ -1,5 +1,7 @@
+ARG COMPOSE_VERSION=1.19.*
+
 FROM docker:18.02
 MAINTAINER Tobias Maier <tobias.maier@baucloud.com>
 
 RUN apk add --no-cache py-pip
-RUN pip install docker-compose
+RUN pip install "docker-compose${COMPOSE_VERSION:+==}${COMPOSE_VERSION}"

18/Dockerfile

@@ -1,5 +1,7 @@
+ARG COMPOSE_VERSION=1.19.*
+
 FROM docker:18
 MAINTAINER Tobias Maier <tobias.maier@baucloud.com>
 
 RUN apk add --no-cache py-pip
-RUN pip install docker-compose
+RUN pip install "docker-compose${COMPOSE_VERSION:+==}${COMPOSE_VERSION}"

README.md

@@ -6,12 +6,14 @@
 [![GitHub stars](https://img.shields.io/github/stars/tmaier/docker-compose.svg?style=social&label=Star)](https://github.com/tmaier/docker-compose)
 
 This docker image installs docker-compose on top of the `docker` image.
-This is very usefull for CI pipelines, which leverage "Docker in Docker".
+This is very useful for CI pipelines, which leverage "Docker in Docker".
 
 ## Docker versions supported
 
 There are versions based on different docker versions, e.g. `latest`, `17.06`, `17.03` and `1.13`.
 
+docker-compose matches the latest minor version available when the docker release was made. Eg, `17.06` includes docker-compose 1.15.0. The `latest` tag always includes the latest docker-compose build.
+
 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

latest/Dockerfile

@@ -1,5 +1,7 @@
+ARG COMPOSE_VERSION=
+
 FROM docker:latest
 MAINTAINER Tobias Maier <tobias.maier@baucloud.com>
 
 RUN apk add --no-cache py-pip
-RUN pip install docker-compose
+RUN pip install "docker-compose${COMPOSE_VERSION:+==}${COMPOSE_VERSION}"