Operators with silent errors will log errors as debug and won't return an error

.chloggen/operator-silent-error.yaml

@@ -0,0 +1,27 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: bug_fix
+
+# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
+component: pkg/stanza
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: An operator configured with silent errors shouldn't log errors while processing log entries.
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [35008]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext:
+
+# If your change doesn't affect end users or the exported elements of any package,
+# you should instead start your pull request title with [chore] or use the "Skip Changelog" label.
+# Optional: The change log or logs in which this entry should be included.
+# e.g. '[user]' or '[user, api]'
+# Include 'user' if the change is relevant to end users.
+# Include 'api' if there is a change to a library API.
+# Default: '[user]'
+change_logs: []

pkg/stanza/operator/helper/transformer.go

@@ -102,9 +102,14 @@ func (t *TransformerOperator) HandleEntryError(ctx context.Context, entry *entry
 	if t.OnError == SendOnError || t.OnError == SendOnErrorQuiet {
 		writeErr := t.Write(ctx, entry)
 		if writeErr != nil {
-			return fmt.Errorf("failed to send entry after error: %w", writeErr)
+			err = fmt.Errorf("failed to send entry after error: %w", writeErr)
 		}
 	}
+
+	if t.OnError == SendOnErrorQuiet || t.OnError == DropOnErrorQuiet {
+		return nil
+	}
+
 	return err
 }
 

pkg/stanza/operator/helper/transformer_test.go

@@ -143,7 +143,7 @@ func TestTransformerDropOnErrorQuiet(t *testing.T) {
 	}
 
 	err := transformer.ProcessWith(ctx, testEntry, transform)
-	require.Error(t, err)
+	require.NoError(t, err)
 	output.AssertNotCalled(t, "Process", mock.Anything, mock.Anything)
 
 	// Test output logs
@@ -233,7 +233,7 @@ func TestTransformerSendOnErrorQuiet(t *testing.T) {
 	}
 
 	err := transformer.ProcessWith(ctx, testEntry, transform)
-	require.Error(t, err)
+	require.NoError(t, err)
 	output.AssertCalled(t, "Process", mock.Anything, mock.Anything)
 
 	// Test output logs