Merge pull request #2899 from hashicorp/d-mention-env-in-init

Mention env templates in nomad init

command/init.go

@@ -337,6 +337,16 @@ job "example" {
       #   change_signal = "SIGHUP"
       # }
 
+      # The "template" stanza can also be used to create environment variables
+      # for tasks that prefer those to config files. The task will be restarted
+      # when data pulled from Consul or Vault changes.
+      #
+      # template {
+      #   data        = "KEY={{ key \"service/my-key\" }}"
+      #   destination = "local/file.env"
+      #   env         = true
+      # }
+
       # The "vault" stanza instructs the Nomad client to acquire a token from
       # a HashiCorp Vault server. The Nomad servers must be configured and
       # authorized to communicate with Vault. By default, Nomad will inject

nomad/structs/structs.go

@@ -3341,6 +3341,9 @@ func (t *Template) Validate() error {
 		if t.ChangeSignal == "" {
 			multierror.Append(&mErr, fmt.Errorf("Must specify signal value when change mode is signal"))
 		}
+		if t.Envvars {
+			multierror.Append(&mErr, fmt.Errorf("cannot use signals with env var templates"))
+		}
 	default:
 		multierror.Append(&mErr, TemplateChangeModeInvalidError)
 	}

nomad/structs/structs_test.go

@@ -1167,6 +1167,22 @@ func TestTask_Validate_Template(t *testing.T) {
 	if !strings.Contains(err.Error(), "same destination as") {
 		t.Fatalf("err: %s", err)
 	}
+
+	// Env templates can't use signals
+	task.Templates = []*Template{
+		{
+			Envvars:    true,
+			ChangeMode: "signal",
+		},
+	}
+
+	err = task.Validate(ephemeralDisk)
+	if err == nil {
+		t.Fatalf("expected error from Template.Validate")
+	}
+	if expected := "cannot use signals"; !strings.Contains(err.Error(), expected) {
+		t.Errorf("expected to find %q but found %v", expected, err)
+	}
 }
 
 func TestTemplate_Validate(t *testing.T) {