Format Logs and add timestamp to logging output option

docs/pages/config-reference.mdx

@@ -56,10 +56,11 @@ teleport:
 
     # Logging configuration. Possible output values to disk via '/var/lib/teleport/teleport.log',
     # 'stdout', 'stderr' and 'syslog'. Possible severity values are INFO, WARN
-    # and ERROR (default).
+    # and ERROR (default). Possible format values include: timestamp, component, message, caller, and level.
     log:
         output: /var/lib/teleport/teleport.log
         severity: ERROR
+        format: [level, timestamp, component, message]
 
     # Configuration for the storage back-end used for the cluster state and the
     # audit log. Several back-end types are supported. See the "High Availability"

lib/config/configuration.go

@@ -401,6 +401,16 @@ func applyLogConfig(loggerConfig Log, logger *log.Logger) error {
 	default:
 		return trace.BadParameter("unsupported logger severity: %q", loggerConfig.Severity)
 	}
+
+	formatter := &textFormatter{
+		InitFormat:   loggerConfig.Format,
+		EnableColors: trace.IsTerminal(os.Stderr),
+	}
+	err := formatter.CheckAndSetDefaults()
+	if err != nil {
+		return trace.Wrap(err)
+	}
+	logger.Formatter = formatter
 	return nil
 }
 

lib/config/configuration_test.go

@@ -1363,3 +1363,37 @@ func TestDatabaseFlags(t *testing.T) {
 		})
 	}
 }
+
+func TestCheckAndSetDefaults(t *testing.T) {
+	tests := []struct {
+		comment      string
+		formatConfig []string
+		hasError     bool
+	}{
+		{
+			comment:      "invalid key (does not exist)",
+			formatConfig: []string{"level", "invalid key"},
+			hasError:     true,
+		},
+		{
+			comment:      "valid keys and formatting",
+			formatConfig: []string{"level", "component", "message"},
+			hasError:     false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.comment, func(t *testing.T) {
+			formatter := &textFormatter{
+				InitFormat: tt.formatConfig,
+			}
+			err := formatter.CheckAndSetDefaults()
+			if tt.hasError {
+				require.Error(t, err)
+			} else {
+				require.NoError(t, err)
+			}
+		})
+	}
+
+}

lib/config/fileconf.go

@@ -459,6 +459,8 @@ type Log struct {
 	Output string `yaml:"output,omitempty"`
 	// Severity defines how verbose the log will be. Possible valus are "error", "info", "warn"
 	Severity string `yaml:"severity,omitempty"`
+	// Format defines the format in which each log line will be outputted. Example format: [timestamp, component, message]
+	Format []string `yaml:"format,omitempty"`
 }
 
 // Global is 'teleport' (global) section of the config file