feat: implement the scheduler plugin

This also performs a one-time migration of the DOKKU_SCHEDULER values the scheduler plugin properties.

Closes #4739

plugins/common/common.go

@@ -101,7 +101,7 @@ func GetAppScheduler(appName string) string {
 }
 
 func getAppScheduler(appName string) string {
-	b, _ := PlugnTriggerOutput("config-get", []string{appName, "DOKKU_SCHEDULER"}...)
+	b, _ := PlugnTriggerOutput("scheduler-detect", []string{appName}...)
 	value := strings.TrimSpace(string(b[:]))
 	if value != "" {
 		return value
@@ -111,7 +111,7 @@ func getAppScheduler(appName string) string {
 
 // GetGlobalScheduler fetchs the global scheduler
 func GetGlobalScheduler() string {
-	b, _ := PlugnTriggerOutput("config-get-global", []string{"DOKKU_SCHEDULER"}...)
+	b, _ := PlugnTriggerOutput("scheduler-detect", []string{"--global"}...)
 	value := strings.TrimSpace(string(b[:]))
 	if value != "" {
 		return value

plugins/common/functions

@@ -324,22 +324,8 @@ get_app_image_name() {
 get_app_scheduler() {
   declare desc="fetch the scheduler for a given application"
   declare APP="$1"
-  local DOKKU_APP_SCHEDULER DOKKU_GLOBAL_SCHEDULER DOKKU_SCHEDULER
 
-  if [[ "$APP" == "--global" ]]; then
-    APP=""
-  fi
-
-  source "$PLUGIN_AVAILABLE_PATH/config/functions"
-  [[ -n "$APP" ]] && DOKKU_APP_SCHEDULER="$(config_get "$APP" DOKKU_SCHEDULER || true)"
-  DOKKU_GLOBAL_SCHEDULER="$(config_get --global DOKKU_SCHEDULER || true)"
-
-  DOKKU_SCHEDULER=${DOKKU_APP_SCHEDULER:="$DOKKU_GLOBAL_SCHEDULER"}
-  if [[ -z "$DOKKU_SCHEDULER" ]]; then
-    DOKKU_SCHEDULER="docker-local"
-  fi
-
-  echo "$DOKKU_SCHEDULER"
+  "$PLUGIN_CORE_AVAILABLE_PATH/common/common" --quiet scheduler-detect "$APP"
 }
 
 get_running_image_tag() {
@@ -690,7 +676,8 @@ release_and_deploy() {
     dokku_release "$APP" "$IMAGE_SOURCE_TYPE" "$IMAGE_TAG"
 
     if [[ "$DOKKU_SKIP_DEPLOY" != "true" ]]; then
-      dokku_log_info1 "Deploying $APP..."
+      local DOKKU_SCHEDULER=$(get_app_scheduler "$APP")
+      dokku_log_info1 "Deploying $APP via the $DOKKU_SCHEDULER scheduler..."
       cmd-deploy "$APP" "$IMAGE_TAG"
       dokku_log_info2 "Application deployed:"
       get_app_urls urls "$APP" | sed "s/^/       /"

plugins/common/src/common/common.go

@@ -32,6 +32,12 @@ func main() {
 		if !common.IsDeployed(appName) {
 			err = fmt.Errorf("App %v not deployed", appName)
 		}
+	case "scheduler-detect":
+		appName := flag.Arg(1)
+		if *global {
+			appName = "--global"
+		}
+		fmt.Print(common.GetAppScheduler(appName))
 	default:
 		err = fmt.Errorf("Invalid common command call: %v", cmd)
 	}