Refactor plugins.Action to separate configuration step

Refactored the Action interface in the plugins package to separate the configuration step from the process method. The new Config method accepts a configuration map and returns an error. The modified server.go uses this Config method to apply configurations before calling Process. File action plugin specifically has been updated to support this new interface where configurations are now updated via Config method before invoking Process.

plugins/action.go

@@ -14,5 +14,6 @@ import (
 // The Process method takes a log message, a slice of match groups, and a
 // configuration map, and returns an error if any occurs during processing.
 type Action interface {
-	Process(logmessage parsesyslog.LogMsg, matchgroup []string, confmap map[string]any) error
+	Config(confmap map[string]any) error
+	Process(logmessage parsesyslog.LogMsg, matchgroup []string) error
 }

plugins/actions/file/file.go

@@ -15,11 +15,26 @@ import (
 )
 
 // File represents a file action that can be performed on a log message.
-type File struct{}
+type File struct {
+	Enabled        bool
+	FilePath       string
+	OutputTemplate string
+	Overwrite      bool
+}
 
-// Process satisfies the plugins.Action interface for the File type
-// It takes in the log message (lm), match groups (mg), and configuration map (cm).
-func (f *File) Process(lm parsesyslog.LogMsg, mg []string, cm map[string]any) error {
+// Config satisfies the plugins.Action interface for the File type
+// It updates the configuration of the File action based on the provided
+// configuration map.
+//
+// It expects the configuration map to have a key "file" which contains a submap
+// with the following keys:
+//   - "output_filepath" (string): Specifies the file path where the output will be written.
+//   - "output_template" (string): Specifies the template to use for formatting the output.
+//   - "overwrite" (bool, optional): If true, the file will be overwritten instead of appended to.
+//
+// If any of the required configuration parameters are missing or invalid, an error
+// is returned.
+func (f *File) Config(cm map[string]any) error {
 	if cm["file"] == nil {
 		return nil
 	}
@@ -27,22 +42,40 @@ func (f *File) Process(lm parsesyslog.LogMsg, mg []string, cm map[string]any) er
 	if !ok {
 		return fmt.Errorf("missing configuration for file action")
 	}
+	f.Enabled = true
+
+	fp, ok := c["output_filepath"].(string)
+	if !ok || fp == "" {
+		return fmt.Errorf("no output_filename configured for file action")
+	}
+	f.FilePath = fp
+
 	ot, ok := c["output_template"].(string)
 	if !ok || ot == "" {
 		return fmt.Errorf("not output_template configured for file action")
 	}
+	f.OutputTemplate = ot
 
-	fn, ok := c["output_filepath"].(string)
-	if !ok || fn == "" {
-		return fmt.Errorf("no output_filename configured for file action")
+	if ow, ok := c["overwrite"].(bool); ok && ow {
+		f.Overwrite = true
+	}
+
+	return nil
+}
+
+// Process satisfies the plugins.Action interface for the File type
+// It takes in the log message (lm), match groups (mg), and configuration map (cm).
+func (f *File) Process(lm parsesyslog.LogMsg, mg []string) error {
+	if !f.Enabled {
+		return nil
 	}
 
 	of := os.O_APPEND | os.O_CREATE | os.O_WRONLY
-	if ow, ok := c["overwrite"].(bool); ok && ow {
-		of = os.O_WRONLY | os.O_CREATE
+	if f.Overwrite {
+		of = os.O_TRUNC | os.O_CREATE | os.O_WRONLY
 	}
 
-	fh, err := os.OpenFile(fn, of, 0o600)
+	fh, err := os.OpenFile(f.FilePath, of, 0o600)
 	if err != nil {
 		return fmt.Errorf("failed to open file for writing in file action: %w", err)
 	}
@@ -50,16 +83,18 @@ func (f *File) Process(lm parsesyslog.LogMsg, mg []string, cm map[string]any) er
 		_ = fh.Close()
 	}()
 
-	t, err := template.Compile(lm, mg, ot)
+	t, err := template.Compile(lm, mg, f.OutputTemplate)
 	if err != nil {
 		return err
 	}
 	_, err = fh.WriteString(t)
 	if err != nil {
-		return fmt.Errorf("failed to write log message to file %q: %w", fn, err)
+		return fmt.Errorf("failed to write log message to file %q: %w",
+			f.FilePath, err)
 	}
-	if err := fh.Sync(); err != nil {
-		return fmt.Errorf("failed to sync memory to file %q: %w", fn, err)
+	if err = fh.Sync(); err != nil {
+		return fmt.Errorf("failed to sync memory to file %q: %w",
+			f.FilePath, err)
 	}
 
 	return nil

server.go

@@ -189,7 +189,11 @@ func (s *Server) processMessage(lm parsesyslog.LogMsg) error {
 			mg := r.Regexp.FindStringSubmatch(lm.Message.String())
 			for n, a := range actions.Actions {
 				s.log.Debug("trying to execute action", slog.String("action_name", n))
-				if err := a.Process(lm, mg, r.Actions); err != nil {
+				if err := a.Config(r.Actions); err != nil {
+					s.log.Error("failed to config action", LogErrKey, err,
+						slog.String("action", n), slog.String("rule_id", r.ID))
+				}
+				if err := a.Process(lm, mg); err != nil {
 					s.log.Error("failed to process action", LogErrKey, err,
 						slog.String("action", n), slog.String("rule_id", r.ID))
 				}