From 366e127f12e40c643ed164d66cf14e0fa4f580e5 Mon Sep 17 00:00:00 2001
From: Luki Boras <boras1988@gmail.com>
Date: Wed, 15 Nov 2023 21:28:45 +0100
Subject: [PATCH] Add leftmost wildcard support to descriptor values

Signed-off-by: Luki Boras <boras1988@gmail.com>
---
 src/config/config_impl.go  | 24 ++++++++++++++----------
 test/config/config_test.go | 16 ++++++++++++++--
 test/config/wildcard.yaml  |  7 ++++++-
 3 files changed, 34 insertions(+), 13 deletions(-)

diff --git a/src/config/config_impl.go b/src/config/config_impl.go
index 2bdbf9d4..4a0b23c4 100644
--- a/src/config/config_impl.go
+++ b/src/config/config_impl.go
@@ -40,9 +40,9 @@ type YamlRoot struct {
 }
 
 type rateLimitDescriptor struct {
-	descriptors  map[string]*rateLimitDescriptor
-	limit        *RateLimit
-	wildcardKeys []string
+	descriptors    map[string]*rateLimitDescriptor
+	limit          *RateLimit
+	wildcardValues []string
 }
 
 type rateLimitDomain struct {
@@ -189,9 +189,9 @@ func (this *rateLimitDescriptor) loadDescriptors(config RateLimitConfigToLoad, p
 		newDescriptor.loadDescriptors(config, newParentKey+".", descriptorConfig.Descriptors, statsManager)
 		this.descriptors[finalKey] = newDescriptor
 
-		// Preload keys ending with "*" symbol.
-		if finalKey[len(finalKey)-1:] == "*" {
-			this.wildcardKeys = append(this.wildcardKeys, finalKey)
+		// Preload keys starting or ending with "*" symbol.
+		if strings.HasPrefix(descriptorConfig.Value, "*") || strings.HasSuffix(descriptorConfig.Value, "*") {
+			this.wildcardValues = append(this.wildcardValues, descriptorConfig.Value)
 		}
 	}
 }
@@ -313,10 +313,14 @@ func (this *rateLimitConfigImpl) GetLimit(
 		logger.Debugf("looking up key: %s", finalKey)
 		nextDescriptor := descriptorsMap[finalKey]
 
-		if nextDescriptor == nil && len(prevDescriptor.wildcardKeys) > 0 {
-			for _, wildcardKey := range prevDescriptor.wildcardKeys {
-				if strings.HasPrefix(finalKey, strings.TrimSuffix(wildcardKey, "*")) {
-					nextDescriptor = descriptorsMap[wildcardKey]
+		if nextDescriptor == nil && len(prevDescriptor.wildcardValues) > 0 {
+			for _, wildcardValue := range prevDescriptor.wildcardValues {
+				if strings.HasSuffix(entry.Value, strings.TrimPrefix(wildcardValue, "*")) {
+					nextDescriptor = descriptorsMap[entry.Key+"_"+wildcardValue]
+					break
+				}
+				if strings.HasPrefix(entry.Value, strings.TrimSuffix(wildcardValue, "*")) {
+					nextDescriptor = descriptorsMap[entry.Key+"_"+wildcardValue]
 					break
 				}
 			}
diff --git a/test/config/config_test.go b/test/config/config_test.go
index 3ed3984b..823fcb34 100644
--- a/test/config/config_test.go
+++ b/test/config/config_test.go
@@ -591,14 +591,24 @@ func TestWildcardConfig(t *testing.T) {
 	wildcard1 := rlConfig.GetLimit(
 		context.TODO(), "test-domain",
 		&pb_struct.RateLimitDescriptor{
-			Entries: []*pb_struct.RateLimitDescriptor_Entry{{Key: "wild", Value: "foo1"}},
+			Entries: []*pb_struct.RateLimitDescriptor_Entry{{Key: "rightWild", Value: "foo1"}},
 		})
 	wildcard2 := rlConfig.GetLimit(
 		context.TODO(), "test-domain",
 		&pb_struct.RateLimitDescriptor{
-			Entries: []*pb_struct.RateLimitDescriptor_Entry{{Key: "wild", Value: "foo2"}},
+			Entries: []*pb_struct.RateLimitDescriptor_Entry{{Key: "rightWild", Value: "foo2"}},
 		})
 	wildcard3 := rlConfig.GetLimit(
+		context.TODO(), "test-domain",
+		&pb_struct.RateLimitDescriptor{
+			Entries: []*pb_struct.RateLimitDescriptor_Entry{{Key: "leftWild", Value: "afoo"}},
+		})
+	wildcard4 := rlConfig.GetLimit(
+		context.TODO(), "test-domain",
+		&pb_struct.RateLimitDescriptor{
+			Entries: []*pb_struct.RateLimitDescriptor_Entry{{Key: "leftWild", Value: "bfoo"}},
+		})
+	wildcard5 := rlConfig.GetLimit(
 		context.TODO(), "test-domain",
 		&pb_struct.RateLimitDescriptor{
 			Entries: []*pb_struct.RateLimitDescriptor_Entry{{Key: "nestedWild", Value: "val1"}, {Key: "wild", Value: "goo2"}},
@@ -606,6 +616,8 @@ func TestWildcardConfig(t *testing.T) {
 	assert.NotNil(wildcard1)
 	assert.Equal(wildcard1, wildcard2)
 	assert.NotNil(wildcard3)
+	assert.Equal(wildcard3, wildcard4)
+	assert.NotNil(wildcard5)
 
 	// Doesn't match non-matching values
 	noMatch := rlConfig.GetLimit(
diff --git a/test/config/wildcard.yaml b/test/config/wildcard.yaml
index e99bac66..37cd7dda 100644
--- a/test/config/wildcard.yaml
+++ b/test/config/wildcard.yaml
@@ -1,11 +1,16 @@
 # Basic configuration for testing.
 domain: test-domain
 descriptors:
-  - key: wild
+  - key: rightWild
     value: foo*
     rate_limit:
       unit: minute
       requests_per_unit: 20
+  - key: leftWild
+    value: "*foo"
+    rate_limit:
+      unit: minute
+      requests_per_unit: 20
   - key: noWild
     value: foo
     rate_limit: