bugfix: fix upstream get unwanted /. (envoyproxy#3990)

* bugfix: fix upstream get unwanted /.

Signed-off-by: qicz <qiczzhu@gmail.com>

* ut for bugfix

Signed-off-by: qicz <qiczzhu@gmail.com>

---------

Signed-off-by: qicz <qiczzhu@gmail.com>
Co-authored-by: Xunzhuo <bitliu@tencent.com>

internal/xds/translator/route.go

@@ -401,7 +401,10 @@ func buildXdsURLRewriteAction(destName string, urlRewrite *ir.URLRewrite, pathMa
 			if useRegexRewriteForPrefixMatchReplace(pathMatch, *urlRewrite.Path.PrefixMatchReplace) {
 				routeAction.RegexRewrite = prefix2RegexRewrite(*pathMatch.Prefix)
 			} else {
-				routeAction.PrefixRewrite = *urlRewrite.Path.PrefixMatchReplace
+				// remove trailing / to fix #3989
+				// when the pathMath.Prefix has suffix / but EG has removed it,
+				// and the urlRewrite.Path.PrefixMatchReplace suffix with / the upstream will get unwanted /
+				routeAction.PrefixRewrite = strings.TrimSuffix(*urlRewrite.Path.PrefixMatchReplace, "/")
 			}
 		}
 	}

internal/xds/translator/testdata/in/xds-ir/http-route-rewrite-sufixx-with-slash-url-prefix.yaml

@@ -0,0 +1,27 @@
+name: "http-route"
+http:
+- name: "first-listener"
+  address: "0.0.0.0"
+  port: 10080
+  hostnames:
+  - "*"
+  path:
+    mergeSlashes: true
+    escapedSlashesAction: UnescapeAndRedirect
+  routes:
+  - name: "rewrite-route"
+    pathMatch:
+      prefix: "/origin/"
+    hostname: gateway.envoyproxy.io
+    headerMatches:
+    - name: ":authority"
+      exact: gateway.envoyproxy.io
+    destination:
+      name: "rewrite-route-dest"
+      settings:
+      - endpoints:
+        - host: "1.2.3.4"
+          port: 50000
+    urlRewrite:
+      path:
+        prefixMatchReplace: /rewrite/

internal/xds/translator/testdata/out/xds-ir/http-route-rewrite-sufixx-with-slash-url-prefix.clusters.yaml

@@ -0,0 +1,17 @@
+- circuitBreakers:
+    thresholds:
+    - maxRetries: 1024
+  commonLbConfig:
+    localityWeightedLbConfig: {}
+  connectTimeout: 10s
+  dnsLookupFamily: V4_ONLY
+  edsClusterConfig:
+    edsConfig:
+      ads: {}
+      resourceApiVersion: V3
+    serviceName: rewrite-route-dest
+  lbPolicy: LEAST_REQUEST
+  name: rewrite-route-dest
+  outlierDetection: {}
+  perConnectionBufferLimitBytes: 32768
+  type: EDS

internal/xds/translator/testdata/out/xds-ir/http-route-rewrite-sufixx-with-slash-url-prefix.endpoints.yaml

@@ -0,0 +1,12 @@
+- clusterName: rewrite-route-dest
+  endpoints:
+  - lbEndpoints:
+    - endpoint:
+        address:
+          socketAddress:
+            address: 1.2.3.4
+            portValue: 50000
+      loadBalancingWeight: 1
+    loadBalancingWeight: 1
+    locality:
+      region: rewrite-route-dest/backend/0

internal/xds/translator/testdata/out/xds-ir/http-route-rewrite-sufixx-with-slash-url-prefix.listeners.yaml

@@ -0,0 +1,35 @@
+- address:
+    socketAddress:
+      address: 0.0.0.0
+      portValue: 10080
+  defaultFilterChain:
+    filters:
+    - name: envoy.filters.network.http_connection_manager
+      typedConfig:
+        '@type': type.googleapis.com/envoy.extensions.filters.network.http_connection_manager.v3.HttpConnectionManager
+        commonHttpProtocolOptions:
+          headersWithUnderscoresAction: REJECT_REQUEST
+        http2ProtocolOptions:
+          initialConnectionWindowSize: 1048576
+          initialStreamWindowSize: 65536
+          maxConcurrentStreams: 100
+        httpFilters:
+        - name: envoy.filters.http.router
+          typedConfig:
+            '@type': type.googleapis.com/envoy.extensions.filters.http.router.v3.Router
+            suppressEnvoyHeaders: true
+        mergeSlashes: true
+        normalizePath: true
+        pathWithEscapedSlashesAction: UNESCAPE_AND_REDIRECT
+        rds:
+          configSource:
+            ads: {}
+            resourceApiVersion: V3
+          routeConfigName: first-listener
+        serverHeaderTransformation: PASS_THROUGH
+        statPrefix: http
+        useRemoteAddress: true
+    name: first-listener
+  drainType: MODIFY_ONLY
+  name: first-listener
+  perConnectionBufferLimitBytes: 32768

internal/xds/translator/testdata/out/xds-ir/http-route-rewrite-sufixx-with-slash-url-prefix.routes.yaml

@@ -0,0 +1,19 @@
+- ignorePortInHostMatching: true
+  name: first-listener
+  virtualHosts:
+  - domains:
+    - gateway.envoyproxy.io
+    name: first-listener/gateway_envoyproxy_io
+    routes:
+    - match:
+        headers:
+        - name: :authority
+          stringMatch:
+            exact: gateway.envoyproxy.io
+        pathSeparatedPrefix: /origin
+      name: rewrite-route
+      route:
+        cluster: rewrite-route-dest
+        prefixRewrite: /rewrite
+        upgradeConfigs:
+        - upgradeType: websocket