refactor: implement most of ps plugin in golang

plugins/docker-options/functions.go

@@ -0,0 +1,36 @@
+package dockeroptions
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"github.com/dokku/dokku/plugins/common"
+)
+
+func getPhaseFilePath(appName string, phase string) string {
+	return filepath.Join(common.AppRoot(appName), "DOCKER_OPTIONS_"+strings.ToUpper(phase))
+}
+
+func touchPhaseFile(appName string, phase string) error {
+	phaseFilePath := getPhaseFilePath(appName, phase)
+
+	_, err := os.Stat(phaseFilePath)
+	if !os.IsNotExist(err) {
+		return nil
+	}
+
+	file, err := os.Create(phaseFilePath)
+	if err != nil {
+		return fmt.Errorf("Unable to create docker options phase file %s.%s: %s", appName, phase, err.Error())
+	}
+	defer file.Close()
+
+	return nil
+}
+
+func writeDockerOptionsForPhase(appName string, phase string, options []string) error {
+	phaseFilePath := getPhaseFilePath(appName, phase)
+	return common.WriteSliceToFile(phaseFilePath, options)
+}