Port data race problem fix (#284)

* Port data race problem fix

CHANGELOG.md

@@ -28,7 +28,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Added Azure Log Analytics Operator [PR 287](https://github.com/observIQ/stanza/pull/287)
 
 ## [0.13.19] - 2021-04-15
-
+ 
 ### Added
 - Added float64 to Severity parser's supported types [PR 267](https://github.com/observIQ/stanza/issues/267)
 

operator/builtin/parser/syslog/syslog.go

@@ -90,10 +90,7 @@ type SyslogParser struct {
 
 // Process will parse an entry field as syslog.
 func (s *SyslogParser) Process(ctx context.Context, entry *entry.Entry) error {
-	if err := s.ParserOperator.ProcessWith(ctx, entry, s.parse); err != nil {
-		return err
-	}
-	return promoteSeverity(entry)
+	return s.ParserOperator.ProcessWithCallback(ctx, entry, s.parse, promoteSeverity)
 }
 
 // parse will parse a value as syslog.

operator/helper/parser.go

@@ -73,6 +73,10 @@ type ParserOperator struct {
 
 // ProcessWith will run ParseWith on the entry, then forward the entry on to the next operators.
 func (p *ParserOperator) ProcessWith(ctx context.Context, entry *entry.Entry, parse ParseFunction) error {
+	return p.ProcessWithCallback(ctx, entry, parse, nil)
+}
+
+func (p *ParserOperator) ProcessWithCallback(ctx context.Context, entry *entry.Entry, parse ParseFunction, cb func(*entry.Entry) error) error {
 	// Short circuit if the "if" condition does not match
 	skip, err := p.Skip(ctx, entry)
 	if err != nil {
@@ -86,6 +90,13 @@ func (p *ParserOperator) ProcessWith(ctx context.Context, entry *entry.Entry, pa
 	if err := p.ParseWith(ctx, entry, parse); err != nil {
 		return err
 	}
+	if cb != nil {
+		err = cb(entry)
+		if err != nil {
+			return err
+		}
+	}
+
 	p.Write(ctx, entry)
 	return nil
 }