figexec - Bash script to add docker exec support for fig orchestrations

gistfile1.txt

#!/bin/bash

######################################################################
#
# figexec
#
# Author: Rion Dooley <[email protected]>
# Description:
# This script emulates the functionality one would expect if `docker exec`
# functionality were supported in fig. Simply run this from your project
# folder and you will be able to exec commands by specifying just the
# service name. If multiple services are scaled up, you can use the
# --scalar argument to specify a particular container.
#
# By default this script will run
#
# docker exec -it <projectname>_web_1 /bin/bash
#
# giving you an interactive shell inside the web container. No particular
# reason for this as the default other than it's what I use most.
#
######################################################################
scalar=1
tty="true"
interactive="true"

out() {
  local message="$@"
  printf '%b\n' "$message";
}

die() { out "$@"; exit 1; } >&2

# Set a trap for cleaning up in case of errors or when script exits.
rollback() {
	stty echo
	die
}

# A non-destructive exit for when the script exits naturally.
safe_exit() {
  trap - INT TERM EXIT
  exit
}

# Set our rollback function for unexpected exits.
#trap rollback INT TERM EXIT


# Print usage
usage() {
  echo -n "$(basename $0) [OPTIONS]...
$(basename $0) [OPTIONS]... [SERVICE]
$(basename $0) [OPTIONS]... [SERVICE] [COMMAND]

Runs docker exec on a fig service. This command should be run within the
same directory as the fig file that started the services. It will ignore
the project portion of the service names and just focus on the component
and scalar values. The default command is '/bin/bash'. The default service
name is 'web'. If you have scaled a particular service that you want to
exec, use the scalar option to select the scaled instance of that service.

 Options:
  -s, --scalar=1          Selects the service with the given scalar in case
                          multiple services of a given type have been started
                          using 'fig scale'. ex. project_web_1 has scalar=1,
                          project_web_5 has scalar=5.
  -i, --interactive=true  Run 'docker exec' in interactive mode
  -t, --tty=true          Add a tty to the interactive session
  -h, --help              Display this help and exit

"
}

main() {

  if [[ "$#" -eq 0 ]]; then
    SERVICE_NAME=web
    CMD=/bin/bash

  elif [[ "$#" -eq 1 ]]; then
    SERVICE_NAME=$1
    CMD=/bin/bash

  elif [[ "$#" -eq 2 ]]; then
    SERVICE_NAME=$1
    CMD=$2

  else

    out "Invalid number of arguments"

    usage

    die

  fi

  if [[ -z "$SERVICE_NAME" ]]; then
    SERVICE_NAME=web
  fi

  if [[ -z "$CMD" ]]; then
    CMD=/bin/bash
  fi


  matches=($(fig ps | grep -v "Exit " | awk '{print $1}' | grep "${SERVICE_NAME}_${scalar}"))

  if [[ "${#matches[@]}" -eq 0 ]]; then

    die "No service named \"$SERVICE_NAME\" is currently running"

  elif [[ "${#matches[@]}" -eq 1 ]]; then

    SERVICE=$matches[0]

  else

    die "Multiple instances of the \"$SERVICE_NAME\" service with scalar $scalar are currently running. Please use docker exec manually"

  fi

  args=''

  execcmd="docker exec --interactive=$interactive --tty=$tty $matches $CMD"
  echo "Running $execcmd"
  sh -c "$execcmd"

}

# Read the options and set stuff
while [[ $1 = -?* ]]; do
  case $1 in
    -h|--help) usage >&2; safe_exit ;;
    -s|--scaler) shift; scaler=$1 ;;
    -t|--tty) shift; tty=$1 ;;
    -i|--interactive) shift; interactive=$1 ;;
    --endopts) shift; break ;;
    *) die "invalid option: $1" ;;
  esac
  shift
done

main $@

# This has to be run last not to rollback changes we've made.
safe_exit