refactor: migrate docker-options subcommands to go

Ports the user-facing CLI subcommands and lifecycle triggers from bash to go, mirroring the layout used by the ports plugin. The on-disk format (`DOCKER_OPTIONS_BUILD/DEPLOY/RUN` files), the `docker-args-build/deploy/run` triggers, and every exported helper consumed by other plugins are unchanged. Reserves the `--process` and `--global` flags on add, remove, and clear so usage today exits with a not-yet-implemented error and the surface is locked in ahead of the process-scoping work tracked in #2441.

plugins/docker-options/triggers.go

@@ -0,0 +1,65 @@
+package dockeroptions
+
+import (
+	"fmt"
+	"io"
+	"os"
+
+	"github.com/dokku/dokku/plugins/common"
+)
+
+// TriggerPostAppCloneSetup copies docker option files from the source app to the cloned app
+func TriggerPostAppCloneSetup(oldAppName string, newAppName string) error {
+	for _, phase := range availablePhases {
+		if err := copyPhaseFile(oldAppName, newAppName, phase); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// TriggerPostAppRenameSetup copies docker option files from the old app name to the new app name
+func TriggerPostAppRenameSetup(oldAppName string, newAppName string) error {
+	for _, phase := range availablePhases {
+		if err := copyPhaseFile(oldAppName, newAppName, phase); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// TriggerPostDelete deletes the docker option files for an app
+func TriggerPostDelete(appName string) error {
+	for _, phase := range availablePhases {
+		if err := removePhaseFile(appName, phase); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func copyPhaseFile(srcApp string, dstApp string, phase string) error {
+	srcPath := getPhaseFilePath(srcApp, phase)
+	if !common.FileExists(srcPath) {
+		return nil
+	}
+
+	src, err := os.Open(srcPath)
+	if err != nil {
+		return fmt.Errorf("Unable to open docker options phase file %s.%s: %s", srcApp, phase, err.Error())
+	}
+	defer src.Close()
+
+	dstPath := getPhaseFilePath(dstApp, phase)
+	dst, err := os.OpenFile(dstPath, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0600)
+	if err != nil {
+		return fmt.Errorf("Unable to create docker options phase file %s.%s: %s", dstApp, phase, err.Error())
+	}
+	defer dst.Close()
+
+	if _, err := io.Copy(dst, src); err != nil {
+		return fmt.Errorf("Unable to copy docker options phase file %s.%s to %s.%s: %s", srcApp, phase, dstApp, phase, err.Error())
+	}
+
+	return nil
+}