Go Docker Service Clone (aka GDSC)

Clone docker services in a easy way.

Usage

$ go get github.com/herlon214/gdsc
$ gdsc -h
Utilities to deal with services in docker.

Usage:
  gdsc [command]

Available Commands:
  export      Export a service to a json file
  help        Help about any command
  import      Import a JSON file and create a service using it
  upsert      Copy a service and create a new one overriding some props

Flags:
      --api-url string   Docker api url (default "http://127.0.0.1:2375")
  -h, --help             help for gdsc

Use "gdsc [command] --help" for more information about a command.

Create / Update behaviors

There are two behaviors when executed: create / update.

Create

This behavior will be triggered if there's no service created with name --name. If triggered, it will copy the whole --copy-from service, secrets, hosts, mounts, environment vars, labels, creating a new one with name --name and the given --image.

It will change the traefik.frontend.rule label in the new service setting a new host to the service. The new host will be http://new_service_name.domain_from_arg. The new service name is cleaned replacing all non-words (/\W/) with "_" to be a bit web friendly.

In other words: if you specify --name my_service_feature/1 --domain mycompany.org, the service name will be set to my_service_feature_1 and the host will be http://my_service_feature_1.mycompany.org.

Update

This behavior will be triggered if there is a service with the name given (--name), it will only update the docker image of this service with the given one (--image).

How to build

If you have docker installed you can type make build and the binary output will appear in dist/ folder.

Published Ports issue

This project doesn't copy the published ports because Traefik will connect to container port. The published port may cause a already in use error.

How it works in a CI stack

Think about the scenario below and you can understand what's the purpose of this project.

Your stack:

Your services (based on git flow branches):

Name	Type	Branch	URI
website_master	production	master	http://mycompany.org/
website_develop	stagging	develop	http://beta.mycompany.org/

Developer A (aka D.A) is working on feature/a in the website project.

Developer B (aka D.B) is working on feature/b in the website project.

D.A just merged his feature to stagging environment (website_develop) because it's done.

D.B wants to test his feature in the stagging environment. But he can't merge to website_develop because it would be merged to master without being done and cause errors (D.B will merge develop to master soon).

GDSC will clone the service website_develop with a new name based on the branch's name with the new docker image URL and a new Traefik host.

D.B publishes his feature/a to the repository (git flow feature publish).

Git repository (gitlab, github) will trigger Jenkins with the update.

Jenkins will build the Dockerfile and then call GDSC to create a new service or update a created service.

gdsc --copy-from voting_example_develop --name voting_example_feature/a --image registry.gitlab.com/mycompany/website:feature_a --domain mycompany.org

Here is a Jenkinsfile example:

pipeline {
  stages {
    stage ("Clone") {
      steps {
        checkout scm
      }
    }
    stage ("Build") {
      steps {
        sh "docker build --no-cache -t REGISTRY_URL:${env.BRANCH_NAME} ."
        sh "docker push REGISTRY_URL:${env.BRANCH_NAME}"
      }
    }
    stage ("Deploy") {
      steps {
        sh "gdsc --copy-from ${env.JOB_NAME} --name ${env.JOB_NAME}${env.BRANCH_NAME} --image REGISTRY_URL:${env.BRANCH_NAME} --domain mycompany.org"
      }
    }
  }
}

Lastly, your services will look like:

Name	Type	Branch	URI
website_master	production	master	http://mycompany.org/
website_develop	stagging	develop	http://beta.mycompany.org/
website_feature_a	testing	feature/a	http://feature_a.mycompany.org/