Improve bash completion of containers

Signed-off-by: Harald Albers <github@albersweb.de>

contrib/completion/bash/docker

@@ -20,6 +20,7 @@
 # For several commands, the amount of completions can be configured by
 # setting environment variables.
 #
+# DOCKER_COMPLETION_SHOW_CONTAINER_IDS
 # DOCKER_COMPLETION_SHOW_NETWORK_IDS
 # DOCKER_COMPLETION_SHOW_NODE_IDS
 # DOCKER_COMPLETION_SHOW_SERVICE_IDS
@@ -58,32 +59,56 @@ __docker_q() {
 	docker ${host:+-H "$host"} ${config:+--config "$config"} 2>/dev/null "$@"
 }
 
-__docker_complete_containers_all() {
-	local IFS=$'\n'
-	local containers=( $(__docker_q ps -aq --no-trunc) )
-	if [ "$1" ]; then
-		containers=( $(__docker_q inspect --format "{{if $1}}{{.Id}}{{end}}" "${containers[@]}") )
+# Returns a list of containers. Additional arguments to `docker ps`
+# may be specified in order to filter the list, e.g.
+# `__docker_containers --filter status=running`
+# By default, only names are returned.
+# Set DOCKER_COMPLETION_SHOW_CONTAINER_IDS=yes to also complete IDs.
+# An optional first option `--id|--name` may be used to limit the
+# output to the IDs or names of matching items. This setting takes
+# precedence over the environment setting.
+__docker_containers() {
+	local format
+	if [ "$1" = "--id" ] ; then
+		format='{{.ID}}'
+		shift
+	elif [ "$1" = "--name" ] ; then
+		format='{{.Names}}'
+		shift
+	elif [ "${DOCKER_COMPLETION_SHOW_CONTAINER_IDS}" = yes ] ; then
+		format='{{.ID}} {{.Names}}'
+	else
+		format='{{.Names}}'
 	fi
-	local names=( $(__docker_q inspect --format '{{.Name}}' "${containers[@]}") )
-	names=( "${names[@]#/}" ) # trim off the leading "/" from the container names
-	unset IFS
-	COMPREPLY=( $(compgen -W "${names[*]} ${containers[*]}" -- "$cur") )
+	__docker_q ps --format "$format" "$@"
 }
 
-__docker_complete_containers_running() {
-	__docker_complete_containers_all '.State.Running'
+# Applies completion of containers based on the current value of `$cur` or
+# the value of the optional first option `--cur`, if given.
+# Additional filters may be appended, see `__docker_containers`.
+__docker_complete_containers() {
+	local current="$cur"
+	if [ "$1" = "--cur" ] ; then
+		current="$2"
+		shift 2
+	fi
+	COMPREPLY=( $(compgen -W "$(__docker_containers "$@")" -- "$current") )
 }
 
-__docker_complete_containers_stopped() {
-	__docker_complete_containers_all 'not .State.Running'
+__docker_complete_containers_all() {
+	__docker_complete_containers "$@" --all
 }
 
-__docker_complete_containers_pauseable() {
-	__docker_complete_containers_all 'and .State.Running (not .State.Paused)'
+__docker_complete_containers_running() {
+	__docker_complete_containers "$@" --filter status=running
+}
+
+__docker_complete_containers_stopped() {
+	__docker_complete_containers "$@" --filter status=exited
 }
 
 __docker_complete_containers_unpauseable() {
-	__docker_complete_containers_all '.State.Paused'
+	__docker_complete_containers "$@" --filter status=paused
 }
 
 __docker_complete_container_names() {
@@ -1080,8 +1105,7 @@ _docker_events() {
 	local key=$(__docker_map_key_of_current_option '-f|--filter')
 	case "$key" in
 		container)
-			cur="${cur##*=}"
-			__docker_complete_containers_all
+			__docker_complete_containers_all --cur "${cur##*=}"
 			return
 			;;
 		daemon)
@@ -2142,7 +2166,7 @@ _docker_pause() {
 		*)
 			local counter=$(__docker_pos_first_nonflag)
 			if [ $cword -eq $counter ]; then
-				__docker_complete_containers_pauseable
+				__docker_complete_containers_running
 			fi
 			;;
 	esac
@@ -2171,13 +2195,11 @@ _docker_ps() {
 			return
 			;;
 		before)
-			cur="${cur##*=}"
-			__docker_complete_containers_all
+			__docker_complete_containers_all --cur "${cur##*=}"
 			return
 			;;
 		id)
-			cur="${cur##*=}"
-			__docker_complete_container_ids
+			__docker_complete_containers_all --cur "${cur##*=}" --id
 			return
 			;;
 		is-task)
@@ -2185,8 +2207,7 @@ _docker_ps() {
 			return
 			;;
 		name)
-			cur="${cur##*=}"
-			__docker_complete_container_names
+			__docker_complete_containers_all --cur "${cur##*=}" --name
 			return
 			;;
 		network)
@@ -2195,8 +2216,7 @@ _docker_ps() {
 			return
 			;;
 		since)
-			cur="${cur##*=}"
-			__docker_complete_containers_all
+			__docker_complete_containers_all --cur "${cur##*=}"
 			return
 			;;
 		status)
@@ -2532,8 +2552,7 @@ _docker_run() {
 		--network)
 			case "$cur" in
 				container:*)
-					local cur=${cur#*:}
-					__docker_complete_containers_all
+					__docker_complete_containers_all --cur "${cur#*:}"
 					;;
 				*)
 					COMPREPLY=( $( compgen -W "$(__docker_plugins Network) $(__docker_networks) container:" -- "$cur") )
@@ -2547,8 +2566,7 @@ _docker_run() {
 		--pid)
 			case "$cur" in
 				*:*)
-					cur="${cur#*:}"
-					__docker_complete_containers_running
+					__docker_complete_containers_running --cur "${cur#*:}"
 					;;
 				*)
 					COMPREPLY=( $( compgen -W 'host container:' -- "$cur" ) )