feat: add ability to upgrade service image and image-version

subcommands/upgrade

@@ -0,0 +1,42 @@
+#!/usr/bin/env bash
+source "$(dirname "$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)")/config"
+set -eo pipefail; [[ $DOKKU_TRACE ]] && set -x
+source "$PLUGIN_BASE_PATH/common/functions"
+source "$(dirname "$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)")/functions"
+
+service-upgrade-cmd() {
+  #E you can upgrade an existing service to a new image or image-version
+  #E dokku $PLUGIN_COMMAND_PREFIX:upgrade lolipop
+  #A service, service to run command against
+  #F -c|--custom-env "USER=alpha;HOST=beta", semi-colon delimited environment variables to start the service with
+  #F -i|--image IMAGE, the image name to start the service with
+  #F -i|--image-version IMAGE_VERSION, the image version to start the service with
+  declare desc="upgrade service <service> to the specified versions"
+  local cmd="$PLUGIN_COMMAND_PREFIX:upgrade" argv=("$@"); [[ ${argv[0]} == "$cmd" ]] && shift 1
+  declare SERVICE="$1" CLONE_FLAGS_LIST="${@:2}"
+  is_implemented_command "$cmd" || dokku_log_fail "Not yet implemented"
+
+  [[ -z "$SERVICE" ]] && dokku_log_fail "Please specify a name for the service"
+  verify_service_name "$SERVICE"
+
+  local SERVICE_ROOT="$PLUGIN_DATA_ROOT/$SERVICE"
+  local ID="$(cat "$SERVICE_ROOT/ID")"
+  is_container_status "$ID" "Running" || dokku_log_fail "Service ${SERVICE} container is not running"
+
+  PLUGIN_IMAGE=$(service_version "$SERVICE" |  grep -o "^.*:" | sed -r "s/://g")
+  PLUGIN_IMAGE_VERSION=$(service_version "$SERVICE" |  grep -o ":.*$" | sed -r "s/://g")
+
+  service_parse_args "${@:2}"
+
+  if ! service_image_exists "$SERVICE"; then
+    dokku_log_fail "Unable to proceed with upgrade, image ${PLUGIN_IMAGE}:${PLUGIN_IMAGE_VERSION} does not exist"
+  fi
+
+  dokku_log_info2 "Stopping $SERVICE"
+  service_container_rm "$NEW_SERVICE"
+  dokku_log_info2 "Upgrading $SERVICE @ $PLUGIN_IMAGE:$PLUGIN_IMAGE_VERSION"
+  service_start "$NEW_SERVICE" "${@:2}"
+  dokku_log_info2 "Done"
+}
+
+service-upgrade-cmd "$@"