Port changes from #383, #413 to stable branch (#425)

google_guest_agent/cfg/cfg.go

@@ -41,6 +41,9 @@ const (
 	unixConfigPath = `/etc/default/instance_configs.cfg`
 
 	defaultConfig = `
+[Core]
+cloud_logging_enabled = true
+
 [Accounts]
 deprovision_remove = false
 gpasswd_add_cmd = gpasswd -a {user} {group}
@@ -108,8 +111,18 @@ command_request_timeout = 10s
 `
 )
 
+// Core contains the core configuration entries of guest agent, all
+// configurations not tied/specific to a subsystem are defined in here.
+type Core struct {
+	// CloudLoggingEnabled config toggle controls Guest Agent cloud logger.
+	// Disabling it will stop Guest Agent for configuring and logging to Cloud Logging.
+	CloudLoggingEnabled bool `ini:"cloud_logging_enabled,omitempty"`
+}
+
 // Sections encapsulates all the configuration sections.
 type Sections struct {
+	// Core defines the core guest-agent's configuration entries/keys.
+	Core *Core `ini:"Core,omitempty"`
 	// AccountManager defines the address management configurations. It takes precedence over instance's
 	// and project's metadata configuration. The default configuration doesn't define values to it, if the
 	// user has defined it then we shouldn't even consider metadata values. Users must check if this

google_guest_agent/main.go

@@ -150,6 +150,11 @@ func runUpdate(ctx context.Context) {
 
 func runAgent(ctx context.Context) {
 	opts := logger.LogOpts{LoggerName: programName}
+
+	if !cfg.Get().Core.CloudLoggingEnabled {
+		opts.DisableCloudLogging = true
+	}
+
 	if runtime.GOOS == "windows" {
 		opts.FormatFunction = logFormatWindows
 		opts.Writers = []io.Writer{&utils.SerialPort{Port: "COM1"}}

metadata/metadata.go

@@ -454,10 +454,15 @@ func (c *Client) do(ctx context.Context, cfg requestConfig) (*http.Response, err
 		return resp, fmt.Errorf("error connecting to metadata server: %+v", err)
 	}
 
-	statusCodeMsg := "error connecting to metadata server, status code: %d"
-	switch resp.StatusCode {
-	case 404, 412:
-		return resp, fmt.Errorf(statusCodeMsg, resp.StatusCode)
+	if resp == nil {
+		return nil, fmt.Errorf("got nil response from metadata server")
+	}
+
+	if resp.StatusCode != http.StatusOK {
+		defer resp.Body.Close()
+		// Ignore read error as we are returning original error and wrapping MDS error code.
+		r, _ := io.ReadAll(resp.Body)
+		return resp, fmt.Errorf("invalid response from metadata server, status code: %d, reason: %s", resp.StatusCode, string(r))
 	}
 
 	if cfg.hang {