Dockerfile using golang:onbuild

[mikljohansson]

Added Dockerfile that uses golang:onbuild to automatically build and package the app binary. This enables very simple deployment and usage e.g.

alias marathonctl='docker run --rm --net=host shoenig/marathonctl:latest'
marathonctl -h http://hostname:8080 marathon ping

If this PR be merged then an automatic build with a webhook should be setup on https://registry.hub.docker.com/u/shoenig to automatically build the Docker image whenever the github repo is modified.

[mikljohansson]

Ping? We really like your utility, it's by far the best console client for Marathon we've found. The marathonctl tool would really help our dev and ops teams when they interact with Marathon in the console environment they're normally in. Having an easy way to run the tool, e.g. alias to "docker run .." would go a long ways in getting the tool used by people, as building from source or redistributing a binary is an issue.

Thanks, Mikael

[shoenig]

Thanks! And sorry for the delay. I setup automated builds for this on the docker hub, but as of right now the status is still "pending". Will check back later to see if it worked

[shoenig]

This appears to be working with docker hub now

$ sudo docker run --rm --net=host shoenig/marathonctl:latest
config error: no host info provided

marathonctl <flags...> [action] <args...>
 Actions
    app
       list                      - list all apps
       versions [id]             - list all versions of apps of id
       show [id]                 - show config and status of app of id (latest version)
       show [id] [version]       - show config and status of app of id and version
       create [jsonfile]         - deploy application defined in jsonfile
       update [id] [jsonfile]    - update application id as defined in jsonfile
       update cpu [id] [cpu%]    - update application id to have cpu% of cpu share
       update memory [id] [MB]   - update application id to have MB of memory
       update instances [id] [N] - update application id to have N instances
       restart [id]              - restart app of id
       destroy [id]              - destroy and remove all instances of id

    task
       list               - list all tasks
       list [id]          - list tasks of app of id
       kill [id]          - kill all tasks of app id
       kill [id] [taskid] - kill task taskid of app id
       queue              - list all queued tasks

    group
       list                        - list all groups
       list [groupid]              - list groups in groupid
       create [jsonfile]           - create a group defined in jsonfile
       update [groupid] [jsonfile] - update group groupid as defined in jsonfile
       destroy [groupid]           - destroy group of groupid

    deploy
       list               - list all active deploys
       destroy [deployid] - cancel deployment of [deployid]

    marathon
       leader   - get the current Marathon leader
       abdicate - force the current leader to relinquish control
       ping     - ping Marathon master host[s]

 Flags
  -c [config file]
  -h [host]
  -u [user:password] (separated by colon)
  -f [format]
       human  (simplified columns, default)
       json   (json on one line)
       jsonpp (json pretty printed)
       raw    (the exact response from Marathon