From f1909dbba797a82de68bb14caca2951adc389817 Mon Sep 17 00:00:00 2001
From: Ben Moss <benm@vmware.com>
Date: Tue, 20 Apr 2021 17:51:36 -0400
Subject: [PATCH] Improve performance of eventfilter lookups (#5288)

* Improve performance of eventfilter lookups

Only do event field lookups as needed, don't pre-emptively cache them
into a map

* Add tests for all supported attribute fields
---
 pkg/eventfilter/attributes/filter.go      | 59 ++++++++++++++---------
 pkg/eventfilter/attributes/filter_test.go | 38 +++++++++++++++
 2 files changed, 73 insertions(+), 24 deletions(-)

diff --git a/pkg/eventfilter/attributes/filter.go b/pkg/eventfilter/attributes/filter.go
index 73fef82b1e..a58c3910ab 100644
--- a/pkg/eventfilter/attributes/filter.go
+++ b/pkg/eventfilter/attributes/filter.go
@@ -35,31 +35,8 @@ func NewAttributesFilter(attrs map[string]string) eventfilter.Filter {
 }
 
 func (attrs attributesFilter) Filter(ctx context.Context, event cloudevents.Event) eventfilter.FilterResult {
-	// Set standard context attributes. The attributes available may not be
-	// exactly the same as the attributes defined in the current version of the
-	// CloudEvents spec.
-	ce := map[string]interface{}{
-		"specversion":     event.SpecVersion(),
-		"type":            event.Type(),
-		"source":          event.Source(),
-		"subject":         event.Subject(),
-		"id":              event.ID(),
-		"time":            event.Time().String(),
-		"dataschema":      event.DataSchema(),
-		"schemaurl":       event.DataSchema(),
-		"datacontenttype": event.DataContentType(),
-		"datamediatype":   event.DataMediaType(),
-		// TODO: use data_base64 when SDK supports it.
-		"datacontentencoding": event.DeprecatedDataContentEncoding(),
-	}
-	ext := event.Extensions()
-	for k, v := range ext {
-		ce[k] = v
-	}
-
 	for k, v := range attrs {
-		var value interface{}
-		value, ok := ce[k]
+		value, ok := lookup(event, k)
 		// If the attribute does not exist in the event (extension context attributes) or if the event attribute
 		// has an empty string value (optional attributes) - which means it was never set in the incoming event,
 		// return false.
@@ -76,4 +53,38 @@ func (attrs attributesFilter) Filter(ctx context.Context, event cloudevents.Even
 	return eventfilter.PassFilter
 }
 
+func lookup(event cloudevents.Event, attr string) (interface{}, bool) {
+	// Set standard context attributes. The attributes available may not be
+	// exactly the same as the attributes defined in the current version of the
+	// CloudEvents spec.
+	switch attr {
+	case "specversion":
+		return event.SpecVersion(), true
+	case "type":
+		return event.Type(), true
+	case "source":
+		return event.Source(), true
+	case "subject":
+		return event.Subject(), true
+	case "id":
+		return event.ID(), true
+	case "time":
+		return event.Time().String(), true
+	case "dataschema":
+		return event.DataSchema(), true
+	case "schemaurl":
+		return event.DataSchema(), true
+	case "datacontenttype":
+		return event.DataContentType(), true
+	case "datamediatype":
+		return event.DataMediaType(), true
+	case "datacontentencoding":
+		// TODO: use data_base64 when SDK supports it.
+		return event.DeprecatedDataContentEncoding(), true
+	default:
+		val, ok := event.Extensions()[attr]
+		return val, ok
+	}
+}
+
 var _ eventfilter.Filter = attributesFilter{}
diff --git a/pkg/eventfilter/attributes/filter_test.go b/pkg/eventfilter/attributes/filter_test.go
index e4e044cbfe..f0ecf9d265 100644
--- a/pkg/eventfilter/attributes/filter_test.go
+++ b/pkg/eventfilter/attributes/filter_test.go
@@ -163,3 +163,41 @@ func attributesWithSubject(t, s, sub string) map[string]string {
 		"subject": sub,
 	}
 }
+
+func TestAllSupportedAttributeFieldsV1(t *testing.T) {
+	e := cloudevents.NewEvent(cloudevents.VersionV1)
+	e.SetType(eventType)
+	e.SetSource(eventSource)
+	e.SetID("1234")
+	e.SetDataSchema("wow")
+	e.SetSubject("cool")
+	e.SetDataContentType("cheers;mate")
+
+	attributes := map[string]string{
+		"specversion":     e.SpecVersion(),
+		"type":            e.Type(),
+		"source":          e.Source(),
+		"subject":         e.Subject(),
+		"id":              e.ID(),
+		"time":            e.Time().String(),
+		"dataschema":      e.DataSchema(),
+		"schemaurl":       e.DataSchema(),
+		"datacontenttype": e.DataContentType(),
+		"datamediatype":   e.DataMediaType(),
+	}
+	if result := NewAttributesFilter(attributes).Filter(context.TODO(), e); result != eventfilter.PassFilter {
+		t.Errorf("Expected pass, got %v", result)
+	}
+}
+
+func TestV03Event(t *testing.T) {
+	e := cloudevents.NewEvent(cloudevents.VersionV03)
+	e.SetDataContentEncoding("perfect")
+
+	attributes := map[string]string{
+		"datacontentencoding": e.DeprecatedDataContentEncoding(),
+	}
+	if result := NewAttributesFilter(attributes).Filter(context.TODO(), e); result != eventfilter.PassFilter {
+		t.Errorf("Expected pass, got %v", result)
+	}
+}