core: Reloading with SIGUSR1 if config never changed via admin (#7258)

cmd/commandfuncs.go

@@ -231,8 +231,9 @@ func cmdRun(fl Flags) (int, error) {
 	}
 	// we don't use 'else' here since this value might have been changed in 'if' block; i.e. not mutually exclusive
 	var configFile string
+	var adapterUsed string
 	if !resumeFlag {
-		config, configFile, err = LoadConfig(configFlag, configAdapterFlag)
+		config, configFile, adapterUsed, err = LoadConfig(configFlag, configAdapterFlag)
 		if err != nil {
 			logBuffer.FlushTo(defaultLogger)
 			return caddy.ExitCodeFailedStartup, err
@@ -249,6 +250,19 @@ func cmdRun(fl Flags) (int, error) {
 		}
 	}
 
+	// If we have a source config file (we're running via 'caddy run --config ...'),
+	// record it so SIGUSR1 can reload from the same file. Also provide a callback
+	// that knows how to load/adapt that source when requested by the main process.
+	if configFile != "" {
+		caddy.SetLastConfig(configFile, adapterUsed, func(file, adapter string) error {
+			cfg, _, _, err := LoadConfig(file, adapter)
+			if err != nil {
+				return err
+			}
+			return caddy.Load(cfg, true)
+		})
+	}
+
 	// run the initial config
 	err = caddy.Load(config, true)
 	if err != nil {
@@ -295,7 +309,7 @@ func cmdRun(fl Flags) (int, error) {
 	// if enabled, reload config file automatically on changes
 	// (this better only be used in dev!)
 	if watchFlag {
-		go watchConfigFile(configFile, configAdapterFlag)
+		go watchConfigFile(configFile, adapterUsed)
 	}
 
 	// warn if the environment does not provide enough information about the disk
@@ -350,7 +364,7 @@ func cmdReload(fl Flags) (int, error) {
 	forceFlag := fl.Bool("force")
 
 	// get the config in caddy's native format
-	config, configFile, err := LoadConfig(configFlag, configAdapterFlag)
+	config, configFile, adapterUsed, err := LoadConfig(configFlag, configAdapterFlag)
 	if err != nil {
 		return caddy.ExitCodeFailedStartup, err
 	}
@@ -368,6 +382,10 @@ func cmdReload(fl Flags) (int, error) {
 	if forceFlag {
 		headers.Set("Cache-Control", "must-revalidate")
 	}
+	// Provide the source file/adapter to the running process so it can
+	// preserve its last-config knowledge if this reload came from the same source.
+	headers.Set("Caddy-Config-Source-File", configFile)
+	headers.Set("Caddy-Config-Source-Adapter", adapterUsed)
 
 	resp, err := AdminAPIRequest(adminAddr, http.MethodPost, "/load", headers, bytes.NewReader(config))
 	if err != nil {
@@ -582,7 +600,7 @@ func cmdValidateConfig(fl Flags) (int, error) {
 			fmt.Errorf("input file required when there is no Caddyfile in current directory (use --config flag)")
 	}
 
-	input, _, err := LoadConfig(configFlag, adapterFlag)
+	input, _, _, err := LoadConfig(configFlag, adapterFlag)
 	if err != nil {
 		return caddy.ExitCodeFailedStartup, err
 	}
@@ -797,7 +815,7 @@ func DetermineAdminAPIAddress(address string, config []byte, configFile, configA
 		loadedConfig := config
 		if len(loadedConfig) == 0 {
 			// get the config in caddy's native format
-			loadedConfig, loadedConfigFile, err = LoadConfig(configFile, configAdapter)
+			loadedConfig, loadedConfigFile, _, err = LoadConfig(configFile, configAdapter)
 			if err != nil {
 				return "", err
 			}

cmd/main.go

@@ -100,7 +100,12 @@ func handlePingbackConn(conn net.Conn, expect []byte) error {
 // there is no config available. It prints any warnings to stderr,
 // and returns the resulting JSON config bytes along with
 // the name of the loaded config file (if any).
-func LoadConfig(configFile, adapterName string) ([]byte, string, error) {
+// The return values are:
+//   - config bytes (nil if no config)
+//   - config file used ("" if none)
+//   - adapter used ("" if none)
+//   - error, if any
+func LoadConfig(configFile, adapterName string) ([]byte, string, string, error) {
 	return loadConfigWithLogger(caddy.Log(), configFile, adapterName)
 }
 
@@ -138,7 +143,7 @@ func isCaddyfile(configFile, adapterName string) (bool, error) {
 	return false, nil
 }
 
-func loadConfigWithLogger(logger *zap.Logger, configFile, adapterName string) ([]byte, string, error) {
+func loadConfigWithLogger(logger *zap.Logger, configFile, adapterName string) ([]byte, string, string, error) {
 	// if no logger is provided, use a nop logger
 	// just so we don't have to check for nil
 	if logger == nil {
@@ -147,7 +152,7 @@ func loadConfigWithLogger(logger *zap.Logger, configFile, adapterName string) ([
 
 	// specifying an adapter without a config file is ambiguous
 	if adapterName != "" && configFile == "" {
-		return nil, "", fmt.Errorf("cannot adapt config without config file (use --config)")
+		return nil, "", "", fmt.Errorf("cannot adapt config without config file (use --config)")
 	}
 
 	// load initial config and adapter
@@ -158,13 +163,13 @@ func loadConfigWithLogger(logger *zap.Logger, configFile, adapterName string) ([
 		if configFile == "-" {
 			config, err = io.ReadAll(os.Stdin)
 			if err != nil {
-				return nil, "", fmt.Errorf("reading config from stdin: %v", err)
+				return nil, "", "", fmt.Errorf("reading config from stdin: %v", err)
 			}
 			logger.Info("using config from stdin")
 		} else {
 			config, err = os.ReadFile(configFile)
 			if err != nil {
-				return nil, "", fmt.Errorf("reading config from file: %v", err)
+				return nil, "", "", fmt.Errorf("reading config from file: %v", err)
 			}
 			logger.Info("using config from file", zap.String("file", configFile))
 		}
@@ -179,7 +184,7 @@ func loadConfigWithLogger(logger *zap.Logger, configFile, adapterName string) ([
 				cfgAdapter = nil
 			} else if err != nil {
 				// default Caddyfile exists, but error reading it
-				return nil, "", fmt.Errorf("reading default Caddyfile: %v", err)
+				return nil, "", "", fmt.Errorf("reading default Caddyfile: %v", err)
 			} else {
 				// success reading default Caddyfile
 				configFile = "Caddyfile"
@@ -191,14 +196,14 @@ func loadConfigWithLogger(logger *zap.Logger, configFile, adapterName string) ([
 	if yes, err := isCaddyfile(configFile, adapterName); yes {
 		adapterName = "caddyfile"
 	} else if err != nil {
-		return nil, "", err
+		return nil, "", "", err
 	}
 
 	// load config adapter
 	if adapterName != "" {
 		cfgAdapter = caddyconfig.GetAdapter(adapterName)
 		if cfgAdapter == nil {
-			return nil, "", fmt.Errorf("unrecognized config adapter: %s", adapterName)
+			return nil, "", "", fmt.Errorf("unrecognized config adapter: %s", adapterName)
 		}
 	}
 
@@ -208,7 +213,7 @@ func loadConfigWithLogger(logger *zap.Logger, configFile, adapterName string) ([
 			"filename": configFile,
 		})
 		if err != nil {
-			return nil, "", fmt.Errorf("adapting config using %s: %v", adapterName, err)
+			return nil, "", "", fmt.Errorf("adapting config using %s: %v", adapterName, err)
 		}
 		logger.Info("adapted config to JSON", zap.String("adapter", adapterName))
 		for _, warn := range warnings {
@@ -226,11 +231,11 @@ func loadConfigWithLogger(logger *zap.Logger, configFile, adapterName string) ([
 		// validate that the config is at least valid JSON
 		err = json.Unmarshal(config, new(any))
 		if err != nil {
-			return nil, "", fmt.Errorf("config is not valid JSON: %v; did you mean to use a config adapter (the --adapter flag)?", err)
+			return nil, "", "", fmt.Errorf("config is not valid JSON: %v; did you mean to use a config adapter (the --adapter flag)?", err)
 		}
 	}
 
-	return config, configFile, nil
+	return config, configFile, adapterName, nil
 }
 
 // watchConfigFile watches the config file at filename for changes
@@ -256,7 +261,7 @@ func watchConfigFile(filename, adapterName string) {
 	}
 
 	// get current config
-	lastCfg, _, err := loadConfigWithLogger(nil, filename, adapterName)
+	lastCfg, _, _, err := loadConfigWithLogger(nil, filename, adapterName)
 	if err != nil {
 		logger().Error("unable to load latest config", zap.Error(err))
 		return
@@ -268,7 +273,7 @@ func watchConfigFile(filename, adapterName string) {
 	//nolint:staticcheck
 	for range time.Tick(1 * time.Second) {
 		// get current config
-		newCfg, _, err := loadConfigWithLogger(nil, filename, adapterName)
+		newCfg, _, _, err := loadConfigWithLogger(nil, filename, adapterName)
 		if err != nil {
 			logger().Error("unable to load latest config", zap.Error(err))
 			return

cmd/storagefuncs.go

@@ -36,7 +36,7 @@ type storVal struct {
 // determineStorage returns the top-level storage module from the given config.
 // It may return nil even if no error.
 func determineStorage(configFile string, configAdapter string) (*storVal, error) {
-	cfg, _, err := LoadConfig(configFile, configAdapter)
+	cfg, _, _, err := LoadConfig(configFile, configAdapter)
 	if err != nil {
 		return nil, err
 	}