ExDockerCompose

ExDockerCompose is a simple library to for interacting with docker-compose. It’s a wrapper for the docker-compose binary and running the actuall commands by using Porcelain.

It works by spawning a GenServer that’s using Porcelain.spawn_shell/2 and handles the messages coming from the process.

Usage

TL;DR: ExDockerCompose.<subcommand>(<compose_opts>, <subcommand_opts>), where:

• subcommand is one of the available docker-compose subcommands.
• compose_opts is a List of parameters to the docker-compose binary (not for the subcommand), type docker-comose --help to see those.
• subcommand_opts is a List of parameters to the specific subcommand, for example; docker-compose up -t 10

Since the library simply takes those and translates the command, subcommand and the opts to a docker-compose binary execution, usage is similar to the regular usage of docker-compose.

Example

Consider the following docker-compose definition and assume that the yaml file is located at /tmp/docker-compose.yml. The content of the file is:

version: '3'
services:
  redis:
    image: "redis:alpine"

$ iex -S mix

iex(1)> ExDockerCompose.up([{:f, "/tmp/docker-compose.yml"}], [])
:ok
iex(2)> Creating network "tmp_default" with the default driver
Creating tmp_redis_1 ... done

Attaching to tmp_redis_1
redis_1  | 1:C 21 Jan 17:16:28.737 # oO0OoO0OoO0Oo Redis is starting oO0OoO0OoO0Oo
redis_1  | 1:C 21 Jan 17:16:28.737 # Redis version=4.0.6, bits=64, commit=00000000, modified=0, pid=1, just started
redis_1  | 1:C 21 Jan 17:16:28.737 # Warning: no config file specified, using the default config. In order to specify a config file use redis-server /path/to/redis.conf
redis_1  | 1:M 21 Jan 17:16:28.739 * Running mode=standalone, port=6379.
redis_1  | 1:M 21 Jan 17:16:28.739 # WARNING: The TCP backlog setting of 511 cannot be enforced because /proc/sys/net/core/somaxconn is set to the lower value of 128.
redis_1  | 1:M 21 Jan 17:16:28.739 # Server initialized
redis_1  | 1:M 21 Jan 17:16:28.739 # WARNING you have Transparent Huge Pages (THP) support enabled in your kernel. This will create latency and memory usage issues with Redis. To fix this issue run the command 'echo never > /sys/kernel/mm/transparent_hugepage/enabled' as root, and add it to your /etc/rc.local in order to retain the setting after a reboot. Redis must be restarted after THP is disabled.
redis_1  | 1:M 21 Jan 17:16:28.739 * Ready to accept connections

nil
iex(3)> ExDockerCompose.stop([{:f, "/tmp/docker-compose.yml"}], [])
:ok
iex(4)> Stopping tmp_redis_1 ...
redis_1  | 1:signal-handler (1516554998) Received SIGTERM scheduling shutdown...
redis_1  | 1:M 21 Jan 17:16:38.442 # User requested shutdown...
redis_1  | 1:M 21 Jan 17:16:38.442 * Saving the final RDB snapshot before exiting.
redis_1  | 1:M 21 Jan 17:16:38.449 * DB saved on disk
Stopping tmp_redis_1 ... done

tmp_redis_1 exited with code 0

pid #PID<0.168.0> exited with exit code 0 (command /usr/local/bin/docker-compose -f /tmp/docker-compose.yml stop)
pid #PID<0.163.0> exited with exit code 0 (command /usr/local/bin/docker-compose -f /tmp/docker-compose.yml up)

nil

Testing locally

$ mix do deps.get, deps.compile
$ mix test

Tests are incomplete at the moment.

Configuration

docker-compose executable path is configurable by either using Application config, or by using an environment varibale. Note that the Application config has the precedence.

config :ex_docker_compose, :bin_file, "/path/to/docker-compose"

As an environment variable, ExDockerCompose will look for DOCKER_COMPOSE_BIN. If non of them are found, ExDockerCompose will get the docker-compose executable by using System.find_executable("docker-compose")

Config Porcelain

Porcelain can be configured to use the goon driver. ExDockerCompose configured to use :goon_warn_if_missing = true to deprecate the warnings, however, one can configure Porcelain to use the goon driver locally by adding the same configuration that’s described on Porcelain docs:

config :porcelain, :goon_driver_path, <path>