provisioner/local-exec: Optional "working_dir" argument

This new argument allows overriding of the working directory of the child process, with the default still being the working directory of Terraform itself.

builtin/provisioners/local-exec/resource_provisioner.go

@@ -34,6 +34,11 @@ func Provisioner() terraform.ResourceProvisioner {
 				Elem:     &schema.Schema{Type: schema.TypeString},
 				Optional: true,
 			},
+
+			"working_dir": &schema.Schema{
+				Type:     schema.TypeString,
+				Optional: true,
+			},
 		},
 
 		ApplyFunc: applyFn,
@@ -69,6 +74,8 @@ func applyFn(ctx context.Context) error {
 	}
 	cmdargs = append(cmdargs, command)
 
+	workingdir := data.Get("working_dir").(string)
+
 	// Setup the reader that will read the output from the command.
 	// We use an os.Pipe so that the *os.File can be passed directly to the
 	// process, and not rely on goroutines copying the data which may block.
@@ -82,6 +89,10 @@ func applyFn(ctx context.Context) error {
 	cmd := exec.CommandContext(ctx, cmdargs[0], cmdargs[1:]...)
 	cmd.Stderr = pw
 	cmd.Stdout = pw
+	// Dir specifies the working directory of the command.
+	// If Dir is the empty string (this is default), runs the command
+	// in the calling process's current directory.
+	cmd.Dir = workingdir
 
 	output, _ := circbuf.NewBuffer(maxBufSize)
 

builtin/provisioners/local-exec/resource_provisioner_test.go

@@ -145,3 +145,32 @@ func TestResourceProvider_ApplyCustomInterpreter(t *testing.T) {
 		t.Errorf("wrong output\ngot:  %s\nwant: %s", got, want)
 	}
 }
+
+func TestResourceProvider_ApplyCustomWorkingDirectory(t *testing.T) {
+	testdir := "working_dir_test"
+	os.Mkdir(testdir, 0755)
+	defer os.Remove(testdir)
+
+	c := testConfig(t, map[string]interface{}{
+		"working_dir": testdir,
+		"command":     "echo `pwd`",
+	})
+
+	output := new(terraform.MockUIOutput)
+	p := Provisioner()
+
+	if err := p.Apply(output, nil, c); err != nil {
+		t.Fatalf("err: %v", err)
+	}
+
+	dir, err := os.Getwd()
+	if err != nil {
+		t.Fatalf("err: %v", err)
+	}
+
+	got := strings.TrimSpace(output.OutputMessage)
+	want := dir + "/" + testdir
+	if got != want {
+		t.Errorf("wrong output\ngot:  %s\nwant: %s", got, want)
+	}
+}

website/docs/provisioners/local-exec.html.markdown

@@ -39,6 +39,10 @@ The following arguments are supported:
   It is evaluated in a shell, and can use environment variables or Terraform
   variables.
 
+* `working_dir` - (Optional) If provided, specifies the working directory where
+  `command` will be executed. It can be provided as as a relative path to the
+   current working directory or as an absolute path. The directory must exist.
+
 * `interpreter` - (Optional) If provided, this is a list of interpreter
   arguments used to execute the command. The first argument is the
   interpreter itself. It can be provided as a relative path to the current