refactor: use a single implementation for checking cnb/herokuish images

Also use a plugin trigger for testing whether an image is herokuish or not rather than trying to mess around with sourced files.

plugins/20_events/builder-image-is-cnb

@@ -0,0 +1 @@
+hook

plugins/20_events/builder-image-is-herokuish

@@ -0,0 +1 @@
+hook

plugins/builder/.gitignore

@@ -7,4 +7,4 @@
 /install
 /post-*
 /report
-/builder-detect
+/builder-*

plugins/builder/Makefile

@@ -1,5 +1,5 @@
 SUBCOMMANDS = subcommands/report subcommands/set
-TRIGGERS = triggers/builder-detect triggers/core-post-extract triggers/install triggers/post-app-clone-setup triggers/post-app-rename-setup triggers/post-delete triggers/report
+TRIGGERS = triggers/builder-detect triggers/builder-image-is-cnb triggers/builder-image-is-herokuish triggers/core-post-extract triggers/install triggers/post-app-clone-setup triggers/post-app-rename-setup triggers/post-delete triggers/report
 BUILD = commands subcommands triggers
 PLUGIN_NAME = builder
 

plugins/builder/src/triggers/triggers.go

@@ -21,6 +21,14 @@ func main() {
 	case "builder-detect":
 		appName := flag.Arg(0)
 		err = builder.TriggerBuilderDetect(appName)
+	case "builder-image-is-cnb":
+		appName := flag.Arg(0)
+		image := flag.Arg(1)
+		err = builder.TriggerBuilderImageIsCNB(appName, image)
+	case "builder-image-is-herokuish":
+		appName := flag.Arg(0)
+		image := flag.Arg(1)
+		err = builder.TriggerBuilderImageIsHerokuish(appName, image)
 	case "core-post-extract":
 		appName := flag.Arg(0)
 		sourceWorkDir := flag.Arg(1)

plugins/builder/triggers.go

@@ -26,6 +26,28 @@ func TriggerBuilderDetect(appName string) error {
 	return nil
 }
 
+// TriggerBuilderImageIsCNB prints true if an image is cnb based, false otherwise
+func TriggerBuilderImageIsCNB(appName string, image string) error {
+	if common.IsImageCnbBased(image) {
+		fmt.Println("true")
+	} else {
+		fmt.Println("false")
+	}
+
+	return nil
+}
+
+// TriggerBuilderImageIsHerokuish prints true if an image is herokuish based, false otherwise
+func TriggerBuilderImageIsHerokuish(appName string, image string) error {
+	if common.IsImageHerokuishBased(image, appName) {
+		fmt.Println("true")
+	} else {
+		fmt.Println("false")
+	}
+
+	return nil
+}
+
 // TriggerCorePostExtract moves a configured build-dir to be in the app root dir
 func TriggerCorePostExtract(appName string, sourceWorkDir string) error {
 	buildDir := strings.Trim(reportComputedBuildDir(appName), "/")

plugins/common/functions

@@ -357,41 +357,19 @@ is_image_cnb_based() {
   declare desc="returns true if app image is based on cnb"
   declare IMAGE="$1"
 
-  if [[ -z "$IMAGE" ]]; then
+
+  if [[ "$("$PLUGIN_CORE_AVAILABLE_PATH/common/common" --quiet image-is-cnb-based "$IMAGE")" != "true" ]]; then
     return 1
   fi
-
-  CNB_STACK_ID="$("$DOCKER_BIN" image inspect --format '{{ index .Config.Labels "io.buildpacks.stack.id" }}' "$IMAGE")"
-  if [[ -n "$CNB_STACK_ID" ]]; then
-    return 0
-  fi
-
-  return 1
 }
 
 is_image_herokuish_based() {
   declare desc="returns true if app image is based on herokuish or a buildpack-like env"
   declare IMAGE="$1" APP="$2"
-  local DOKKU_APP_USER
-  local USER_VALUE
 
-  if [[ -z "$IMAGE" ]]; then
+  if [[ "$("$PLUGIN_CORE_AVAILABLE_PATH/common/common" --quiet image-is-herokuish-based "$IMAGE" "$APP")" != "true" ]]; then
     return 1
   fi
-
-  if is_image_cnb_based "$IMAGE"; then
-    return 0
-  fi
-
-  if [[ -n "$APP" ]]; then
-    DOKKU_APP_USER=$(plugn trigger config-get "$APP" DOKKU_APP_USER || true)
-  fi
-  DOKKU_APP_USER=${DOKKU_APP_USER:="herokuishuser"}
-
-  # due to how the build process works, all herokuish images have the Environment variable USER=$DOKKU_APP_USER
-  USER_VALUE="$("$DOCKER_BIN" image inspect --format '{{range .Config.Env}}{{if eq . "USER='"$DOKKU_APP_USER"'"}}{{println .}}{{end}}{{end}}' "$IMAGE")"
-  [[ "$USER_VALUE" == "" ]] && return 1
-  return 0
 }
 
 get_docker_version() {

plugins/common/src/common/common.go

@@ -32,6 +32,21 @@ func main() {
 		if !common.IsDeployed(appName) {
 			err = fmt.Errorf("App %v not deployed", appName)
 		}
+	case "image-is-cnb-based":
+		image := flag.Arg(1)
+		if common.IsImageCnbBased(image) {
+			fmt.Print("true")
+		} else {
+			fmt.Print("false")
+		}
+	case "image-is-herokuish-based":
+		image := flag.Arg(1)
+		appName := flag.Arg(2)
+		if common.IsImageHerokuishBased(image, appName) {
+			fmt.Print("true")
+		} else {
+			fmt.Print("false")
+		}
 	case "scheduler-detect":
 		appName := flag.Arg(1)
 		if *global {