/opt/bin/d - docker management script for CoreOS/systemd

d

#!/usr/bin/env bash

command -v systemd-cat &>/dev/null && exec 2> >(systemd-cat -t d)

source /etc/environment

run() {
  shift
  $docker run --cidfile "$pid_file" $@
}

create() {
  shift
  $docker create --cidfile "$pid_file" $@
}

stop() {
  __execute_if_running 'stop'
}

kill() {
  __execute_if_running 'kill'
}

rm() {
  __exists || return 0
  __is_running && args='--force'

  $docker rm $args $(name) && command rm -f "$pid_file" && curl -X DELETE $kv_url/$kv_path/cid
}

enrol() {
  __wait_for_active_registry

  curl -X PUT -d "$(__container_pidfile_contents)" $kv_url/$kv_path/cid
  command rm -f "$pid_file"
}

name() {
  __enroled || return 1

  [ -z "$name" ] && name=$(__container_id | xargs docker inspect --format '{{.Name}}')

  # See: https://github.com/docker/docker/issues/6705
  [ "${name::1}" = "/" ] && name=${name:1}

  echo $name
}

other() {
  $docker $@
}

main() {
  local readonly subcommand=$1
  [[ -z "$subcommand" ]] && help
  shift

  case "$subcommand" in
    run)      run "$@";;
    create)   create "$@";;
    stop)     stop "$@";;
    kill)     kill "$@";;
    rm)       rm "$@";;
    enrol)    enrol "$@";;
    name)     name "$@";;
    *)        other "$subcommand $@";;
  esac
}

__container_id() {
  __wait_for_active_registry

  [ -z "$cid" ] && cid=$(/usr/bin/curl -s $kv_url/$kv_path/cid | \
    /opt/bin/jq '.[] | .Value' | xargs echo | base64 --decode 2>/dev/null)

  echo $cid
}

__wait_for_started_registry() {
  until echo 'dummy-value' | ncat $COREOS_PRIVATE_IPV4 8400 >/dev/null 2>&1; do
    sleep 3
  done
}

__wait_for_active_registry() {
  __wait_for_started_registry

  if [ -f /opt/bin/consul ]; then
    until command /opt/bin/consul info -rpc-addr $COREOS_PRIVATE_IPV4:8400 | grep 'last_log_index' | grep -qv '= 0'; do
      sleep 3
    done
  else
    until curl "$kv_url/?recurse" 2>&1 | grep -qv "No cluster leader"; do
      sleep 3
    done
  fi
}

__container_pidfile_contents() {
  local contents=""

  until [ -f "$pid_file" ]; do
    sleep 1
  done

  while [ -z "$contents" ]; do
    contents=$(cat $pid_file)
    sleep 1
  done

  echo $contents
}

__inspect() {
  [ -z "$(name)" ] && return 1
  [ -n "$1" ] && local readonly args="--format {{$1}}"

  $docker inspect $args $(name) 2>/dev/null
}

__enroled() {
  [ -n "$(__container_id)" ]
}

__exists() {
  [ -z "$(name)" ] && return 1
  [ "$(__inspect)" != "[]" ]
}

__is_running() {
  [ "$(__inspect '.State.Running')" = "true" ]
}

__execute_if_running() {
  __is_running || return 0
  $docker $1 $(name)
}

readonly ARGS="$@"
readonly cmd="$1"
readonly kv_name="$2"
readonly pid_file="/tmp/${kv_name/\//_}.cid"
readonly kv_url="http://${COREOS_PRIVATE_IPV4}:8500/v1/kv"
readonly kv_path="$(hostname)/${kv_name}"
readonly docker=$(which docker)

name=""
cid=""

main $ARGS