executable_dshell

#!/usr/bin/env bash
set -euo pipefail

CONTAINER=""
USER="root"
LOGIN=0

usage() {
  cat << EOF
Usage: dshell CONTAINER [OPTIONS]

Open an interactive shell in a Docker container easily.

Arguments:
  CONTAINER         Docker container name 

Options:
  -h, --help        Display this help message
  -l, --login       Use login shell (default: false)
  -u, --user USER   User to run the shell as (default: root)

Examples:
  dshell c1
  dshell c1 --user myuser
  dshell c1 --login --user myuser

EOF
}

generate_shell_command() {
    local user=$1
    local container=$2
    local login_flag=""

    if [[ "${LOGIN}" -eq 1 ]]; then
        if login_path=$(docker exec "${container}" which login 2>/dev/null); then
            echo "docker exec -ti -u root ${container} ${login_path} -f ${user}"
            return
        fi
        login_flag="-l"
    fi

    if bash_path=$(docker exec "${container}" which bash 2>/dev/null); then
        echo "docker exec -ti -u ${user} ${container} ${bash_path} ${login_flag}"
    else
        echo "docker exec -ti -u ${user} ${container} sh ${login_flag}"
    fi
}

while [[ $# -gt 0 ]]; do
  case $1 in
    -h|--help) 
      usage ; exit 0 ;;
    -l|--login)
      LOGIN=1 ; shift ;;
    -u|--user)
      USER="$2"; shift 2 ;;
    -*) 
      echo -e "Error: Unknown option: $1\n"; usage ; exit 1 ;;
    *)
      if [[ -n "$CONTAINER" ]]; then
        echo -e "Error: Too many arguments\n"; usage ; exit 1
      fi
      CONTAINER="$1"; shift ;;
  esac
done

if [[ -z "${CONTAINER}" ]]; then
  echo -e "Error: CONTAINER argument is required\n"; usage; exit 1
fi

echo -e "Opening shell in container '${CONTAINER}' as user '${USER}'\n"
exec $(generate_shell_command "${USER}" "${CONTAINER}")