Speed up workdir by always returning an empty filelist (rather than a…

… nil one).

Nil indicates that a full snapshot is required. Empty indicates that nothing should be snapshotted.

pkg/commands/workdir.go

@@ -50,9 +50,10 @@ func (w *WorkdirCommand) ExecuteCommand(config *v1.Config, buildArgs *dockerfile
  logrus.Infof("Changed working directory to %s", config.WorkingDir)
 
  // Only create and snapshot the dir if it didn't exist already
+ w.snapshotFiles = []string{}
  if _, err := os.Stat(config.WorkingDir); os.IsNotExist(err) {
  logrus.Infof("Creating directory %s", config.WorkingDir)
- w.snapshotFiles = []string{config.WorkingDir}
+ w.snapshotFiles = append(w.snapshotFiles, config.WorkingDir)
  return os.MkdirAll(config.WorkingDir, 0755)
  }
  return nil

pkg/commands/workdir_test.go

@@ -30,36 +30,49 @@ import (
 // This is needed to make sure WorkingDir handles paths correctly
 // For example, if WORKDIR specifies a non-absolute path, it should be appended to the current WORKDIR
 var workdirTests = []struct {
- path string
- expectedPath string
+ path string
+ expectedPath string
+ snapshotFiles []string
 }{
  {
- path: "/a",
- expectedPath: "/a",
+ path: "/a",
+ expectedPath: "/a",
+ snapshotFiles: []string{"/a"},
  },
  {
- path: "b",
- expectedPath: "/a/b",
+ path: "b",
+ expectedPath: "/a/b",
+ snapshotFiles: []string{"/a/b"},
  },
  {
- path: "c",
- expectedPath: "/a/b/c",
+ path: "c",
+ expectedPath: "/a/b/c",
+ snapshotFiles: []string{"/a/b/c"},
  },
  {
- path: "/d",
- expectedPath: "/d",
+ path: "/d",
+ expectedPath: "/d",
+ snapshotFiles: []string{"/d"},
  },
  {
- path: "$path",
- expectedPath: "/d/usr",
+ path: "$path",
+ expectedPath: "/d/usr",
+ snapshotFiles: []string{"/d/usr"},
  },
  {
- path: "$home",
- expectedPath: "/root",
+ path: "$home",
+ expectedPath: "/root",
+ snapshotFiles: []string{"/root"},
  },
  {
- path: "$path/$home",
- expectedPath: "/root/usr/root",
+ path: "$path/$home",
+ expectedPath: "/root/usr/root",
+ snapshotFiles: []string{"/root/usr/root"},
+ },
+ {
+ path: "/tmp",
+ expectedPath: "/tmp",
+ snapshotFiles: []string{},
  },
 }
 
@@ -78,10 +91,11 @@ func TestWorkdirCommand(t *testing.T) {
  cmd: &instructions.WorkdirCommand{
  Path: test.path,
  },
- snapshotFiles: []string{},
+ snapshotFiles: nil,
  }
  buildArgs := dockerfile.NewBuildArgs([]string{})
  cmd.ExecuteCommand(cfg, buildArgs)
  testutil.CheckErrorAndDeepEqual(t, false, nil, test.expectedPath, cfg.WorkingDir)
+ testutil.CheckErrorAndDeepEqual(t, false, nil, test.snapshotFiles, cmd.snapshotFiles)
  }
 }