Add external versioner (ref #573)

internal/versioner/external.go

@@ -0,0 +1,89 @@
+// Copyright (C) 2015 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at http://mozilla.org/MPL/2.0/.
+
+package versioner
+
+import (
+	"errors"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+)
+
+func init() {
+	// Register the constructor for this type of versioner with the name "external"
+	Factories["external"] = NewExternal
+}
+
+// The type holds our configuration
+type External struct {
+	command    string
+	folderPath string
+}
+
+// The constructor function takes a map of parameters and creates the type.
+func NewExternal(folderID, folderPath string, params map[string]string) Versioner {
+	command := params["command"]
+
+	s := External{
+		command:    command,
+		folderPath: folderPath,
+	}
+
+	if debug {
+		l.Debugf("instantiated %#v", s)
+	}
+	return s
+}
+
+// Move away the named file to a version archive. If this function returns
+// nil, the named file does not exist any more (has been archived).
+func (v External) Archive(filePath string) error {
+	_, err := os.Lstat(filePath)
+	if os.IsNotExist(err) {
+		if debug {
+			l.Debugln("not archiving nonexistent file", filePath)
+		}
+		return nil
+	} else if err != nil {
+		return err
+	}
+
+	if debug {
+		l.Debugln("archiving", filePath)
+	}
+
+	inFolderPath, err := filepath.Rel(v.folderPath, filePath)
+	if err != nil {
+		return err
+	}
+
+	if v.command == "" {
+		return errors.New("Versioner: command is empty, please enter a valid command")
+	}
+
+	cmd := exec.Command(v.command, v.folderPath, inFolderPath)
+	env := os.Environ()
+	// filter STGUIAUTH and STGUIAPIKEY from environment variables
+	filteredEnv := []string{}
+	for _, x := range env {
+		if !strings.HasPrefix(x, "STGUIAUTH=") && !strings.HasPrefix(x, "STGUIAPIKEY=") {
+			filteredEnv = append(filteredEnv, x)
+		}
+	}
+	cmd.Env = filteredEnv
+	err = cmd.Run()
+	if err != nil {
+		return err
+	}
+
+	// return error if the file was not removed
+	if _, err = os.Lstat(filePath); os.IsNotExist(err) {
+		return nil
+	}
+	return errors.New("Versioner: file was not removed by external script")
+}