笔记：Docker命令自动补全

一 背景

作为一名 Linux 重度用户，每次敲命令总会情不自禁地按下 Tab 键。在键入 Docker 命令时也会出现类似的习惯性动作。那么是否 Docker 相关命令也能自动补全呢？

二 操作步骤

2.1 安装 bash-completion

sudo yum install -y bash-completion

安装完成之后重启系统或者重新登录 shell。如果安装成功。键入 docker p 后，再 Tab 键，系统显示如下：

pause   plugin  port    ps      pull    push

此时，我们运行例如 docker run 之类的命令，键入镜像的首字母，镜像名称依然无法自动补全。

2.2 根据 Docker 官方文档进一步配置

sudo curl -L https://raw.githubusercontent.com/docker/compose/1.24.1/contrib/completion/bash/docker-compose -o /etc/bash_completion.d/docker-compose
source /etc/bash_completion.d/docker-compose

/etc/bash_completion.d/docker-compose内容如下：

#!/bin/bash
#
# bash completion for docker-compose
#
# This work is based on the completion for the docker command.
#
# This script provides completion of:
#  - commands and their options
#  - service names
#  - filepaths
#
# To enable the completions either:
#  - place this file in /etc/bash_completion.d
#  or
#  - copy this file to e.g. ~/.docker-compose-completion.sh and add the line
#    below to your .bashrc after bash completion features are loaded
#    . ~/.docker-compose-completion.sh

__docker_compose_previous_extglob_setting=$(shopt -p extglob)
shopt -s extglob

__docker_compose_q() {
        docker-compose 2>/dev/null "${top_level_options[@]}" "$@"
}

# Transforms a multiline list of strings into a single line string
# with the words separated by "|".
__docker_compose_to_alternatives() {
        local parts=( $1 )
        local IFS='|'
        echo "${parts[*]}"
}

# Transforms a multiline list of options into an extglob pattern
# suitable for use in case statements.
__docker_compose_to_extglob() {
        local extglob=$( __docker_compose_to_alternatives "$1" )
        echo "@($extglob)"
}

# Determines whether the option passed as the first argument exist on
# the commandline. The option may be a pattern, e.g. `--force|-f`.
__docker_compose_has_option() {
        local pattern="$1"
        for (( i=2; i < $cword; ++i)); do
                if [[ ${words[$i]} =~ ^($pattern)$ ]] ; then
                        return 0
                fi
        done
        return 1
}

# Returns `key` if we are currently completing the value of a map option (`key=value`)
# which matches the extglob passed in as an argument.
# This function is needed for key-specific completions.
__docker_compose_map_key_of_current_option() {
        local glob="$1"

        local key glob_pos
        if [ "$cur" = "=" ] ; then        # key= case
                key="$prev"
                glob_pos=$((cword - 2))
        elif [[ $cur == *=* ]] ; then     # key=value case (OSX)
                key=${cur%=*}
                glob_pos=$((cword - 1))
        elif [ "$prev" = "=" ] ; then
                key=${words[$cword - 2]}  # key=value case
                glob_pos=$((cword - 3))
        else
                return
        fi

        [ "${words[$glob_pos]}" = "=" ] && ((glob_pos--))  # --option=key=value syntax

        [[ ${words[$glob_pos]} == @($glob) ]] && echo "$key"
}

# suppress trailing whitespace
__docker_compose_nospace() {
        # compopt is not available in ancient bash versions
        type compopt &>/dev/null && compopt -o nospace
}


# Outputs a list of all defined services, regardless of their running state.
# Arguments for `docker-compose ps` may be passed in order to filter the service list,
# e.g. `status=running`.
__docker_compose_services() {
        __docker_compose_q ps --services "$@"
}

# Applies completion of services based on the current value of `$cur`.
# Arguments for `docker-compose ps` may be passed in order to filter the service list,
# see `__docker_compose_services`.
__docker_compose_complete_services() {
        COMPREPLY=( $(compgen -W "$(__docker_compose_services "$@")" -- "$cur") )
}

# The services for which at least one running container exists
__docker_compose_complete_running_services() {
        local names=$(__docker_compose_services --filter status=running)
        COMPREPLY=( $(compgen -W "$names" -- "$cur") )
}


_docker_compose_build() {
        case "$prev" in
                --build-arg)
                        COMPREPLY=( $( compgen -e -- "$cur" ) )
                        __docker_compose_nospace
                        return
                        ;;
        esac

        case "$cur" in
                -*)
                        COMPREPLY=( $( compgen -W "--build-arg --compress --force-rm --help --memory --no-cache --pull --parallel" -- "$cur" ) )
                        ;;
                *)
                        __docker_compose_complete_services --filter source=build
                        ;;
        esac
}


_docker_compose_bundle() {
        case "$prev" in
                --output|-o)
                        _filedir
                        return
                        ;;
        esac

        COMPREPLY=( $( compgen -W "--push-images --help --output -o" -- "$cur" ) )
}


_docker_compose_config() {
        case "$prev" in
                --hash)
                        if [[ $cur == \\* ]] ; then
                                COMPREPLY=( '\*' )
                        else
                                COMPREPLY=( $(compgen -W "$(__docker_compose_services) \\\* " -- "$cur") )
                        fi
                        return
                        ;;
        esac

        COMPREPLY=( $( compgen -W "--hash --help --quiet -q --resolve-image-digests --services --volumes" -- "$cur" ) )
}


_docker_compose_create() {
        case "$cur" in
                -*)
                        COMPREPLY=( $( compgen -W "--build --force-recreate --help --no-build --no-recreate" -- "$cur" ) )
                        ;;
                *)
                        __docker_compose_complete_services
                        ;;
        esac
}


_docker_compose_docker_compose() {
        case "$prev" in
                --tlscacert|--tlscert|--tlskey)
                        _filedir
                        return
                        ;;
                --file|-f)
                        _filedir "y?(a)ml"
                        return
                        ;;
                --log-level)
                        COMPREPLY=( $( compgen -W "debug info warning error critical" -- "$cur" ) )
                        return
                        ;;
                --project-directory)
                        _filedir -d
                        return
                        ;;
                $(__docker_compose_to_extglob "$daemon_options_with_args") )
                        return
                        ;;
        esac

        case "$cur" in
                -*)
                        COMPREPLY=( $( compgen -W "$daemon_boolean_options $daemon_options_with_args $top_level_options_with_args --help -h --no-ansi --verbose --version -v" -- "$cur" ) )
                        ;;
                *)
                        COMPREPLY=( $( compgen -W "${commands[*]}" -- "$cur" ) )
                        ;;
        esac
}


_docker_compose_down() {
        case "$prev" in
                --rmi)
                        COMPREPLY=( $( compgen -W "all local" -- "$cur" ) )
                        return
                        ;;
                --timeout|-t)
                        return
                        ;;
        esac

        case "$cur" in
                -*)
                        COMPREPLY=( $( compgen -W "--help --rmi --timeout -t --volumes -v --remove-orphans" -- "$cur" ) )
                        ;;
        esac
}


_docker_compose_events() {
        case "$prev" in
                --json)
                        return
                        ;;
        esac

        case "$cur" in
                -*)
                        COMPREPLY=( $( compgen -W "--help --json" -- "$cur" ) )
                        ;;
                *)
                        __docker_compose_complete_services
                        ;;
        esac
}


_docker_compose_exec() {
        case "$prev" in
                --index|--user|-u|--workdir|-w)
                        return
                        ;;
        esac

        case "$cur" in
                -*)
                        COMPREPLY=( $( compgen -W "-d --detach --help --index --privileged -T --user -u --workdir -w" -- "$cur" ) )
                        ;;
                *)
                        __docker_compose_complete_running_services
                        ;;
        esac
}


_docker_compose_help() {
        COMPREPLY=( $( compgen -W "${commands[*]}" -- "$cur" ) )
}

_docker_compose_images() {
        case "$cur" in
                -*)
                        COMPREPLY=( $( compgen -W "--help --quiet -q" -- "$cur" ) )
                        ;;
                *)
                        __docker_compose_complete_services
                        ;;
        esac
}

_docker_compose_kill() {
        case "$prev" in
                -s)
                        COMPREPLY=( $( compgen -W "SIGHUP SIGINT SIGKILL SIGUSR1 SIGUSR2" -- "$(echo $cur | tr '[:lower:]' '[:upper:]')" ) )
                        return
                        ;;
        esac

        case "$cur" in
                -*)
                        COMPREPLY=( $( compgen -W "--help -s" -- "$cur" ) )
                        ;;
                *)
                        __docker_compose_complete_running_services
                        ;;
        esac
}


_docker_compose_logs() {
        case "$prev" in
                --tail)
                        return
                        ;;
        esac

        case "$cur" in
                -*)
                        COMPREPLY=( $( compgen -W "--follow -f --help --no-color --tail --timestamps -t" -- "$cur" ) )
                        ;;
                *)
                        __docker_compose_complete_services
                        ;;
        esac
}


_docker_compose_pause() {
        case "$cur" in
                -*)
                        COMPREPLY=( $( compgen -W "--help" -- "$cur" ) )
                        ;;
                *)
                        __docker_compose_complete_running_services
                        ;;
        esac
}


_docker_compose_port() {
        case "$prev" in
                --protocol)
                        COMPREPLY=( $( compgen -W "tcp udp" -- "$cur" ) )
                        return;
                        ;;
                --index)
                        return;
                        ;;
        esac

        case "$cur" in
                -*)
                        COMPREPLY=( $( compgen -W "--help --index --protocol" -- "$cur" ) )
                        ;;
                *)
                        __docker_compose_complete_services
                        ;;
        esac
}


_docker_compose_ps() {
        local key=$(__docker_compose_map_key_of_current_option '--filter')
        case "$key" in
                source)
                        COMPREPLY=( $( compgen -W "build image" -- "${cur##*=}" ) )
                        return
                        ;;
                status)
                        COMPREPLY=( $( compgen -W "paused restarting running stopped" -- "${cur##*=}" ) )
                        return
                        ;;
        esac

        case "$prev" in
                --filter)
                        COMPREPLY=( $( compgen -W "source status" -S "=" -- "$cur" ) )
                        __docker_compose_nospace
                        return;
                        ;;
        esac

        case "$cur" in
                -*)
                        COMPREPLY=( $( compgen -W "--all -a --filter --help --quiet -q --services" -- "$cur" ) )
                        ;;
                *)
                        __docker_compose_complete_services
                        ;;
        esac
}


_docker_compose_pull() {
        case "$cur" in
                -*)
                        COMPREPLY=( $( compgen -W "--help --ignore-pull-failures --include-deps --no-parallel --quiet -q" -- "$cur" ) )
                        ;;
                *)
                        __docker_compose_complete_services --filter source=image
                        ;;
        esac
}


_docker_compose_push() {
        case "$cur" in
                -*)
                        COMPREPLY=( $( compgen -W "--help --ignore-push-failures" -- "$cur" ) )
                        ;;
                *)
                        __docker_compose_complete_services
                        ;;
        esac
}


_docker_compose_restart() {
        case "$prev" in
                --timeout|-t)
                        return
                        ;;
        esac

        case "$cur" in
                -*)
                        COMPREPLY=( $( compgen -W "--help --timeout -t" -- "$cur" ) )
                        ;;
                *)
                        __docker_compose_complete_running_services
                        ;;
        esac
}


_docker_compose_rm() {
        case "$cur" in
                -*)
                        COMPREPLY=( $( compgen -W "--force -f --help --stop -s -v" -- "$cur" ) )
                        ;;
                *)
                        if __docker_compose_has_option "--stop|-s" ; then
                                __docker_compose_complete_services
                        else
                                __docker_compose_complete_services --filter status=stopped
                        fi
                        ;;
        esac
}


_docker_compose_run() {
        case "$prev" in
                -e)
                        COMPREPLY=( $( compgen -e -- "$cur" ) )
                        __docker_compose_nospace
                        return
                        ;;
                --entrypoint|--label|-l|--name|--user|-u|--volume|-v|--workdir|-w)
                        return
                        ;;
        esac

        case "$cur" in
                -*)
                        COMPREPLY=( $( compgen -W "--detach -d --entrypoint -e --help --label -l --name --no-deps --publish -p --rm --service-ports -T --use-aliases --user -u --volume -v --workdir -w" -- "$cur" ) )
                        ;;
                *)
                        __docker_compose_complete_services
                        ;;
        esac
}


_docker_compose_scale() {
        case "$prev" in
                =)
                        COMPREPLY=("$cur")
                        return
                        ;;
                --timeout|-t)
                        return
                        ;;
        esac

        case "$cur" in
                -*)
                        COMPREPLY=( $( compgen -W "--help --timeout -t" -- "$cur" ) )
                        ;;
                *)
                        COMPREPLY=( $(compgen -S "=" -W "$(__docker_compose_services)" -- "$cur") )
                        __docker_compose_nospace
                        ;;
        esac
}


_docker_compose_start() {
        case "$cur" in
                -*)
                        COMPREPLY=( $( compgen -W "--help" -- "$cur" ) )
                        ;;
                *)
                        __docker_compose_complete_services --filter status=stopped
                        ;;
        esac
}


_docker_compose_stop() {
        case "$prev" in
                --timeout|-t)
                        return
                        ;;
        esac

        case "$cur" in
                -*)
                        COMPREPLY=( $( compgen -W "--help --timeout -t" -- "$cur" ) )
                        ;;
                *)
                        __docker_compose_complete_running_services
                        ;;
        esac
}


_docker_compose_top() {
        case "$cur" in
                -*)
                        COMPREPLY=( $( compgen -W "--help" -- "$cur" ) )
                        ;;
                *)
                        __docker_compose_complete_running_services
                        ;;
        esac
}


_docker_compose_unpause() {
        case "$cur" in
                -*)
                        COMPREPLY=( $( compgen -W "--help" -- "$cur" ) )
                        ;;
                *)
                        __docker_compose_complete_services --filter status=paused
                        ;;
        esac
}


_docker_compose_up() {
        case "$prev" in
                =)
                        COMPREPLY=("$cur")
                        return
                        ;;
                --exit-code-from)
                        __docker_compose_complete_services
                        return
                        ;;
                --scale)
                        COMPREPLY=( $(compgen -S "=" -W "$(__docker_compose_services)" -- "$cur") )
                        __docker_compose_nospace
                        return
                        ;;
                --timeout|-t)
                        return
                        ;;
        esac

        case "$cur" in
                -*)
                        COMPREPLY=( $( compgen -W "--abort-on-container-exit --always-recreate-deps --build -d --detach --exit-code-from --force-recreate --help --no-build --no-color --no-deps --no-recreate --no-start --renew-anon-volumes -V --remove-orphans --scale --timeout -t" -- "$cur" ) )
                        ;;
                *)
                        __docker_compose_complete_services
                        ;;
        esac
}


_docker_compose_version() {
        case "$cur" in
                -*)
                        COMPREPLY=( $( compgen -W "--short" -- "$cur" ) )
                        ;;
        esac
}


_docker_compose() {
        local previous_extglob_setting=$(shopt -p extglob)
        shopt -s extglob

        local commands=(
                build
                bundle
                config
                create
                down
                events
                exec
                help
                images
                kill
                logs
                pause
                port
                ps
                pull
                push
                restart
                rm
                run
                scale
                start
                stop
                top
                unpause
                up
                version
        )

        # Options for the docker daemon that have to be passed to secondary calls to
        # docker-compose executed by this script.
        local daemon_boolean_options="
                --skip-hostname-check
                --tls
                --tlsverify
        "
        local daemon_options_with_args="
                --file -f
                --host -H
                --project-directory
                --project-name -p
                --tlscacert
                --tlscert
                --tlskey
        "

        # These options are require special treatment when searching the command.
        local top_level_options_with_args="
                --log-level
        "

        COMPREPLY=()
        local cur prev words cword
        _get_comp_words_by_ref -n : cur prev words cword

        # search subcommand and invoke its handler.
        # special treatment of some top-level options
        local command='docker_compose'
        local top_level_options=()
        local counter=1

        while [ $counter -lt $cword ]; do
                case "${words[$counter]}" in
                        $(__docker_compose_to_extglob "$daemon_boolean_options") )
                                local opt=${words[counter]}
                                top_level_options+=($opt)
                                ;;
                        $(__docker_compose_to_extglob "$daemon_options_with_args") )
                                local opt=${words[counter]}
                                local arg=${words[++counter]}
                                top_level_options+=($opt $arg)
                                ;;
                        $(__docker_compose_to_extglob "$top_level_options_with_args") )
                                (( counter++ ))
                                ;;
                        -*)
                                ;;
                        *)
                                command="${words[$counter]}"
                                break
                                ;;
                esac
                (( counter++ ))
        done

        local completions_func=_docker_compose_${command//-/_}
        declare -F $completions_func >/dev/null && $completions_func

        eval "$previous_extglob_setting"
        return 0
}

eval "$__docker_compose_previous_extglob_setting"
unset __docker_compose_previous_extglob_setting

complete -F _docker_compose docker-compose docker-compose.exe

至此，所有补全功能相关的准备工作完成！执行 docker run 类似的命令时，镜像名称及 tag 均能自动补全了。