dokku · josegonzalez · Aug 22, 2025 · Aug 22, 2025
diff --git a/docs/configuration/environment-variables.md b/docs/configuration/environment-variables.md
@@ -101,7 +101,6 @@ The following config variables have special meanings and can be set in a variety
 | `DOKKU_APP_PROXY_TYPE`         | `nginx`                         | `dokku proxy:set`                                                                                                                                | |
 | `DOKKU_APP_RESTORE`            | `1`                             | `dokku config:set` <br /> `dokku ps:stop`                                                                                                        | |
 | `DOKKU_APP_SHELL`              | `/bin/bash`                     | `dokku config:set`                                                                                                                               | Allows users to change the default shell used by Dokku for `dokku enter` and execution of deployment tasks. |
-| `DOKKU_APP_TYPE`               | `herokuish`                     |  Auto-detected by using buildpacks or dockerfile                                                                                                 | |
 | `DOKKU_CHECKS_DISABLED`        | none                            | `dokku checks:disable`                                                                                                                           | |
 | `DOKKU_CHECKS_ENABLED`         | none                            | `dokku checks:enable`                                                                                                                            | |
 | `DOKKU_CHECKS_SKIPPED`         | none                            | `dokku checks:skip`                                                                                                                              | |

diff --git a/plugins/builder-herokuish/docker-args-build b/plugins/builder-herokuish/docker-args-build
@@ -10,9 +10,9 @@ trigger-builder-herokuish-docker-args() {
   local STDIN DOKKU_APP_TYPE DOKKU_APP_USER
 
   STDIN=$(cat)
-  DOKKU_APP_TYPE=$(config_get "$APP" DOKKU_APP_TYPE || true)
-  DOKKU_APP_USER=$(config_get "$APP" DOKKU_APP_USER || true)
-  DOKKU_APP_USER=${DOKKU_APP_USER:="herokuishuser"}
+  DOKKU_APP_TYPE="$(plugn trigger builder-get-property "$APP" "detected" || true)"
+  DOKKU_APP_USER="$(config_get "$APP" DOKKU_APP_USER || true)"
+  DOKKU_APP_USER="${DOKKU_APP_USER:="herokuishuser"}"
 
   if [[ "$DOKKU_APP_TYPE" == "herokuish" ]]; then
     local docker_args="$STDIN --env=USER=${DOKKU_APP_USER}"

diff --git a/plugins/builder/Makefile b/plugins/builder/Makefile
@@ -1,5 +1,5 @@
 SUBCOMMANDS = subcommands/report subcommands/set
-TRIGGERS = triggers/builder-detect triggers/builder-get-property 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
+TRIGGERS = triggers/builder-detect triggers/builder-get-property triggers/builder-image-is-cnb triggers/builder-image-is-herokuish triggers/builder-set-property 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
 

diff --git a/plugins/builder/builder.go b/plugins/builder/builder.go
@@ -4,6 +4,7 @@ var (
 	// DefaultProperties is a map of all valid builder properties with corresponding default property values
 	DefaultProperties = map[string]string{
 		"selected":  "",
+		"detected":  "",
 		"build-dir": "",
 	}
 

diff --git a/plugins/builder/report.go b/plugins/builder/report.go
@@ -14,6 +14,7 @@ func ReportSingleApp(appName string, format string, infoFlag string) error {
 		"--builder-computed-selected":  reportComputedSelected,
 		"--builder-global-selected":    reportGlobalSelected,
 		"--builder-selected":           reportSelected,
+		"--builder-detected":           reportDetected,
 		"--builder-computed-build-dir": reportComputedBuildDir,
 		"--builder-global-build-dir":   reportGlobalBuildDir,
 		"--builder-build-dir":          reportBuildDir,
@@ -43,6 +44,10 @@ func reportGlobalSelected(appName string) string {
 	return common.PropertyGet("builder", "--global", "selected")
 }
 
+func reportDetected(appName string) string {
+	return common.PropertyGet("builder", appName, "detected")
+}
+
 func reportSelected(appName string) string {
 	return common.PropertyGet("builder", appName, "selected")
 }

diff --git a/plugins/builder/src/triggers/triggers.go b/plugins/builder/src/triggers/triggers.go
@@ -33,6 +33,11 @@ func main() {
 		appName := flag.Arg(0)
 		image := flag.Arg(1)
 		err = builder.TriggerBuilderImageIsHerokuish(appName, image)
+	case "builder-set-property":
+		appName := flag.Arg(0)
+		property := flag.Arg(1)
+		value := flag.Arg(2)
+		err = builder.TriggerBuilderSetProperty(appName, property, value)
 	case "core-post-extract":
 		appName := flag.Arg(0)
 		sourceWorkDir := flag.Arg(1)

diff --git a/plugins/builder/subcommands.go b/plugins/builder/subcommands.go
@@ -30,6 +30,11 @@ func CommandReport(appName string, format string, infoFlag string) error {
 
 // CommandSet set or clear a builder property for an app
 func CommandSet(appName string, property string, value string) error {
+	if property == "detected" {
+		common.LogWarn("detected is a read-only property")
+		return nil
+	}
+
 	common.CommandPropertySet("builder", appName, property, value, DefaultProperties, GlobalProperties)
 	return nil
 }
diff --git a/plugins/builder/triggers.go b/plugins/builder/triggers.go
@@ -27,14 +27,23 @@ func TriggerBuilderDetect(appName string) error {
 
 // TriggerBuilderGetProperty writes the builder key to stdout for a given app container
 func TriggerBuilderGetProperty(appName string, key string) error {
-	if key != "selected" && key != "build-dir" {
-		return errors.New("Invalid logs property specified")
+	if _, ok := DefaultProperties[key]; !ok {
+		return errors.New("Invalid builder property specified")
 	}
 
 	fmt.Println(common.PropertyGet("builder", appName, key))
 	return nil
 }
 
+// TriggerBuilderSetProperty writes the builder key to stdout for a given app container
+func TriggerBuilderSetProperty(appName string, key string, value string) error {
+	if _, ok := DefaultProperties[key]; !ok {
+		return errors.New("Invalid builder property specified")
+	}
+
+	return common.PropertyWrite("builder", appName, key, value)
+}
+
 // TriggerBuilderImageIsCNB prints true if an image is cnb based, false otherwise
 func TriggerBuilderImageIsCNB(appName string, image string) error {
 	if common.IsImageCnbBased(image) {
@@ -99,7 +108,30 @@ func TriggerInstall() error {
 		return fmt.Errorf("Unable to install the builder plugin: %s", err.Error())
 	}
 
-	_, err := common.CallPlugnTrigger(common.PlugnTriggerInput{
+	apps, err := common.UnfilteredDokkuApps()
+	if err != nil {
+		return nil
+	}
+
+	for _, appName := range apps {
+		if common.PropertyExists("builder", appName, "detected") {
+			continue
+		}
+
+		results, err := common.CallPlugnTrigger(common.PlugnTriggerInput{
+			Trigger: "config-get",
+			Args:    []string{appName, "DOKKU_APP_TYPE"},
+		})
+		if err != nil {
+			return err
+		}
+
+		if results.StdoutContents() != "" {
+			common.PropertyWrite("builder", appName, "detected", results.StdoutContents())
+		}
+	}
+
+	_, err = common.CallPlugnTrigger(common.PlugnTriggerInput{
 		Trigger: "install-builder-prune",
 	})
 

diff --git a/plugins/common/functions b/plugins/common/functions
@@ -670,7 +670,7 @@ dokku_receive() {
     IMAGE_SOURCE_TYPE="pack"
   fi
 
-  DOKKU_QUIET_OUTPUT=1 config_set --no-restart "$APP" DOKKU_APP_TYPE="$IMAGE_SOURCE_TYPE"
+  plugn trigger builder-set-property "$APP" "detected" "$IMAGE_SOURCE_TYPE"
   if ! dokku_build "$APP" "$IMAGE_SOURCE_TYPE" "$TMP_WORK_DIR"; then
     return 1
   fi

diff --git a/tests/unit/build-env.bats b/tests/unit/build-env.bats
@@ -75,7 +75,7 @@ teardown() {
   echo "status: $status"
   assert_success
 
-  run /bin/bash -c "dokku --quiet config:get $TEST_APP DOKKU_APP_TYPE"
+  run /bin/bash -c "dokku builder:report $TEST_APP --builder-detected"
   echo "output: $output"
   echo "status: $status"
   assert_output "herokuish"