ruamel.dc2service 0.3.1

generate init configuration file (systemd/Upstart) from docker-compose.yml

The dc2service utility generates configuration files for systemd/Upstart based on a single docker-compose YAML input file.

The init type is autodetected, but can be overruled from the command-line.

The service name is determinted by the container_name entries for all the services in the YAML file. Each service has to have a container_name specified.

As docker-compose YAML file format doesn’t allow for extra metadata fields, two comment entries at the beginning of the YAML file are parsed for a description and author.

If the version 2 YAML file format is used you should consider using ruamel.dcw as wrapper for docker-compose, if you do the comments are not necessary and you can specify author and description under the top level user-data key.

If external ports are specified (i.e. of the form “ip:ip”) then the external port numbers are extended to the description.

The file generation is template based and can easily be adjusted to your needs. Their location can be viewed by doing dc2service templates

Example version 2 input YAML file for Mongo DB

In a version 1 docker-compose.yml and using ruamel.dcw you can set the author and description conveniently as normal key-value pairs, and also specify a default for environment variables:

version: "2"
user-data:
  author: Anthon van der Neut <[e-mail]>
  description: mongo container
  env-variables:
    DOCKER_MONGO_PORT: 27017
    DOCKER_MONGO_BASE_DIR: /data1/DB/mongo
services:
  mongodb:
    container_name: mongo
    image: mongo:2.4
    volumes:
      - ${DOCKER_MONGO_BASE_DIR}:/data/db
      ports:
        - ${DOCKER_MONGO_PORT}:27017

Example version 1 input YAML file for Mongo DB

As version 1 docker-compose.yml file for single service running Mongo DB with an external (i.e. host oriented) port:

# author: Anthon van der Neut <[e-mail]>
# description: mongo container
mongodb:
  container_name: mongo
  image: mongo:2.4
  volumes:
   - /data1/DB/mongo:/data/db
  ports:
  - 27017:27017

systemd

The command dc2service --systemd generate /opt/docker/mongo/docker-compose.yml will generate the file /etc/systemd/system/mongo-docker.service:

[Unit]
Description=mongo container on port 27017
# Author = Anthon van der Neut <[e-mail]> (dc2service 0.1.0.dev)
Requires=docker.service
After=docker.service

[Service]
Restart=always
ExecStart=/opt/util/docker-compose/bin/docker-compose -f /opt/docker/mongo/docker-compose.yml up --no-recreate
ExecStop=/opt/util/docker-compose/bin/docker-compose -f /opt/docker/mongo/docker-compose.yml stop

[Install]
WantedBy=multi-user.target

If you have ruamel.dcw installed .../bin/docker-compose will be .../bin/dcw

Upstart

The command dc2service --upstart generate /opt/docker/mongo/docker-compose.yml will generate the file /etc/init/mongo-docker.conf:

description "mongo container on port 27017"
author "Anthon van der Neut <[e-mail]> (dc2service 0.1.0.dev)"
start on filesystem and started docker
stop on runlevel [!2345]
respawn

pre-start script
  /opt/util/docker-compose/bin/docker-compose -f /opt/docker/mongo/docker-compose.yml up -d --no-recreate
end script

script
  sleepWhileAppIsUp(){
    while docker ps --filter=name=mongo | grep -qF mongo ; do
      sleep 2
    done
  }

  sleepWhileAppIsUp
end script

post-stop script
  if docker ps --filter=name=mongo | grep -qF mongo; then
    /opt/util/docker-compose/bin/docker-compose -f /opt/docker/mongo/docker-compose.yml stop
  fi
end script

If you have ruamel.dcw installed .../bin/docker-compose will be .../bin/dcw

Expanding environment variables

If you use environment variables in a version 1 docker-compose.yml file in your YAML file they will be expanded if the are of the form ${XYZ}. The other form $XYZ is not expanded. You should however consider installing ruamel.dcw and using the version 2 format as that can handle the expansion dynamically and allow defaults to be specified in the YAML file, as well as storing the environment variables for the Dockerfile to use.

Expansion is only relevant for the parts that are copied (external port numbers, name of container).

If you use this feature make sure that the environment variables are set in the conf file. In systemd with:

[Service]
Environment=DOCKERIMAPPORT=143

and in Upstart:

env DOCKERIMAPPORT=143

dc2service will try to insert the right definitions for you.

For version 2 files and when using ``ruamel.dcw`` this is not necessary and therefore not done

Finding docker-compose

As the full path to docker-compose or dcw will be inserted in the configuration file, this path needs to be available. dc2service will search /opt/util/docker-compose/bin/ and the PATH environement variable for the locations of dcw and docker-compose. If your docker-compose is not in your path you can hand the full path in with the option --docker-compose or specify this in the file ~/.config/ruamel_dc2service/ruamel_dc2service.pon:

dict(
    glbl={'docker-compose': '/opt/util/docker-compose/bin/docker-compose'},
)