Allow injecting bootstrap info into xDS Filter API for config parsing (grpc#12724)

Extend the xDS Filter API to support injecting bootstrap information
into filters during configuration parsing. This allows filters to access
context information (e.g., allowed gRPC services) from the resource loading
layer during configuration validation and parsing.

- Update `Filter.Provider.parseFilterConfig` and
`parseFilterConfigOverride`
  to accept a `FilterContext` parameter.
- Introduce `BootstrapInfoGrpcServiceContextProvider` to encapsulate
  bootstrap info for context resolution.
- Update `XdsListenerResource` and `XdsRouteConfigureResource` to
  construct and pass `FilterContext` during configuration parsing.
- Update sub-filters (`FaultFilter`, `RbacFilter`,
`GcpAuthenticationFilter`,
  `RouterFilter`) to match the updated `FilterContext` signature.

Known Gaps & Limitations:
1. **MetricHolder**: Propagation of `MetricHolder` is not supported with
   this approach currently and is planned for support in a later phase.
2. **NameResolverRegistry**: Propagation is deferred for consistency.
While it could be passed from `XdsNameResolver` on the client side, there is
no equivalent mechanism on the server side. To ensure consistent
behavior, `DefaultRegistry` is used when validating schemes and creating channels.

Author: sauravzg

xds/src/main/java/io/grpc/xds/FaultFilter.java

@@ -104,7 +104,8 @@ public FaultFilter newInstance(String name) {
     }
 
     @Override
-    public ConfigOrError<FaultConfig> parseFilterConfig(Message rawProtoMessage, int depth) {
+    public ConfigOrError<FaultConfig> parseFilterConfig(
+        Message rawProtoMessage, FilterConfigParseContext context, int depth) {
       HTTPFault httpFaultProto;
       if (!(rawProtoMessage instanceof Any)) {
         return ConfigOrError.fromError("Invalid config type: " + rawProtoMessage.getClass());
@@ -120,8 +121,8 @@ public ConfigOrError<FaultConfig> parseFilterConfig(Message rawProtoMessage, int
 
     @Override
     public ConfigOrError<FaultConfig> parseFilterConfigOverride(
-        Message rawProtoMessage, int depth) {
-      return parseFilterConfig(rawProtoMessage, depth);
+        Message rawProtoMessage, FilterConfigParseContext context, int depth) {
+      return parseFilterConfig(rawProtoMessage, context, depth);
     }
 
     private static ConfigOrError<FaultConfig> parseHttpFault(HTTPFault httpFault) {

xds/src/main/java/io/grpc/xds/Filter.java

@@ -16,10 +16,14 @@
 
 package io.grpc.xds;
 
+
+import com.google.auto.value.AutoValue;
 import com.google.common.base.MoreObjects;
 import com.google.protobuf.Message;
 import io.grpc.ClientInterceptor;
 import io.grpc.ServerInterceptor;
+import io.grpc.xds.client.Bootstrapper.BootstrapInfo;
+import io.grpc.xds.client.Bootstrapper.ServerInfo;
 import java.io.Closeable;
 import java.util.Objects;
 import java.util.concurrent.ScheduledExecutorService;
@@ -93,33 +97,34 @@ default boolean isServerFilter() {
      * Parses the top-level filter config from raw proto message. The message may be either a {@link
      * com.google.protobuf.Any} or a {@link com.google.protobuf.Struct}.
      */
-    ConfigOrError<? extends FilterConfig> parseFilterConfig(Message rawProtoMessage, int depth);
+    ConfigOrError<? extends FilterConfig> parseFilterConfig(
+        Message rawProtoMessage, FilterConfigParseContext context, int depth);
 
     /**
      * Parses the per-filter override filter config from raw proto message. The message may be
      * either a {@link com.google.protobuf.Any} or a {@link com.google.protobuf.Struct}.
      */
     ConfigOrError<? extends FilterConfig> parseFilterConfigOverride(
-        Message rawProtoMessage, int depth);
+        Message rawProtoMessage, FilterConfigParseContext context, int depth);
   }
 
   class Parser {
     private static final int MAX_RECURSION_DEPTH = 8;
 
     static ConfigOrError<? extends FilterConfig> parseFilterConfig(
-        Provider provider, Message rawProtoMessage, int depth) {
+        Provider provider, Message rawProtoMessage, FilterConfigParseContext context, int depth) {
       if (depth >= MAX_RECURSION_DEPTH) {
         return ConfigOrError.fromError("Maximum recursion depth of 8 exceeded");
       }
-      return provider.parseFilterConfig(rawProtoMessage, depth);
+      return provider.parseFilterConfig(rawProtoMessage, context, depth);
     }
 
     static ConfigOrError<? extends FilterConfig> parseFilterConfigOverride(
-        Provider provider, Message rawProtoMessage, int depth) {
+        Provider provider, Message rawProtoMessage, FilterConfigParseContext context, int depth) {
       if (depth >= MAX_RECURSION_DEPTH) {
         return ConfigOrError.fromError("Maximum recursion depth of 8 exceeded");
       }
-      return provider.parseFilterConfigOverride(rawProtoMessage, depth);
+      return provider.parseFilterConfigOverride(rawProtoMessage, context, depth);
     }
   }
 
@@ -146,6 +151,27 @@ default ServerInterceptor buildServerInterceptor(
   @Override
   default void close() {}
 
+  /** Context carrying dynamic metadata for a filter. */
+  @AutoValue
+  abstract static class FilterConfigParseContext {
+    abstract BootstrapInfo bootstrapInfo();
+
+    abstract ServerInfo serverInfo();
+
+    static Builder builder() {
+      return new AutoValue_Filter_FilterConfigParseContext.Builder();
+    }
+
+    @AutoValue.Builder
+    abstract static class Builder {
+      abstract Builder bootstrapInfo(BootstrapInfo info);
+
+      abstract Builder serverInfo(ServerInfo info);
+
+      abstract FilterConfigParseContext build();
+    }
+  }
+
   /** Filter config with instance name. */
   final class NamedFilterConfig {
     // filter instance name

xds/src/main/java/io/grpc/xds/GcpAuthenticationFilter.java

@@ -87,7 +87,7 @@ public GcpAuthenticationFilter newInstance(String name) {
 
     @Override
     public ConfigOrError<GcpAuthenticationConfig> parseFilterConfig(
-        Message rawProtoMessage, int depth) {
+        Message rawProtoMessage, FilterConfigParseContext context, int depth) {
       GcpAuthnFilterConfig gcpAuthnProto;
       if (!(rawProtoMessage instanceof Any)) {
         return ConfigOrError.fromError("Invalid config type: " + rawProtoMessage.getClass());
@@ -122,8 +122,8 @@ public ConfigOrError<GcpAuthenticationConfig> parseFilterConfig(
 
     @Override
     public ConfigOrError<GcpAuthenticationConfig> parseFilterConfigOverride(
-        Message rawProtoMessage, int depth) {
-      return parseFilterConfig(rawProtoMessage, depth);
+        Message rawProtoMessage, FilterConfigParseContext context, int depth) {
+      return parseFilterConfig(rawProtoMessage, context, depth);
     }
   }
 

xds/src/main/java/io/grpc/xds/RbacFilter.java

@@ -94,7 +94,8 @@ public RbacFilter newInstance(String name) {
     }
 
     @Override
-    public ConfigOrError<RbacConfig> parseFilterConfig(Message rawProtoMessage, int depth) {
+    public ConfigOrError<RbacConfig> parseFilterConfig(
+        Message rawProtoMessage, FilterConfigParseContext context, int depth) {
       RBAC rbacProto;
       if (!(rawProtoMessage instanceof Any)) {
         return ConfigOrError.fromError("Invalid config type: " + rawProtoMessage.getClass());
@@ -109,7 +110,8 @@ public ConfigOrError<RbacConfig> parseFilterConfig(Message rawProtoMessage, int
     }
 
     @Override
-    public ConfigOrError<RbacConfig> parseFilterConfigOverride(Message rawProtoMessage, int depth) {
+    public ConfigOrError<RbacConfig> parseFilterConfigOverride(
+        Message rawProtoMessage, FilterConfigParseContext context, int depth) {
       RBACPerRoute rbacPerRoute;
       if (!(rawProtoMessage instanceof Any)) {
         return ConfigOrError.fromError("Invalid config type: " + rawProtoMessage.getClass());

xds/src/main/java/io/grpc/xds/RouterFilter.java

@@ -62,13 +62,13 @@ public RouterFilter newInstance(String name) {
 
     @Override
     public ConfigOrError<? extends FilterConfig> parseFilterConfig(
-        Message rawProtoMessage, int depth) {
+        Message rawProtoMessage, FilterConfigParseContext context, int depth) {
       return ConfigOrError.fromConfig(ROUTER_CONFIG);
     }
 
     @Override
     public ConfigOrError<? extends FilterConfig> parseFilterConfigOverride(
-        Message rawProtoMessage, int depth) {
+        Message rawProtoMessage, FilterConfigParseContext context, int depth) {
       return ConfigOrError.fromError("Router Filter should not have override config");
     }
   }

xds/src/main/java/io/grpc/xds/XdsListenerResource.java

@@ -527,7 +527,7 @@ static io.grpc.xds.HttpConnectionManager parseHttpConnectionManager(
             "HttpConnectionManager contains duplicate HttpFilter: " + filterName);
       }
       StructOrError<Filter.FilterConfig> filterConfig =
-          parseHttpFilter(httpFilter, filterRegistry, isForClient);
+          parseHttpFilter(httpFilter, filterRegistry, isForClient, args);
       if ((i == proto.getHttpFiltersCount() - 1)
           && (filterConfig == null || !isTerminalFilter(filterConfig.getStruct()))) {
         throw new ResourceInvalidException("The last HttpFilter must be a terminal filter: "
@@ -581,7 +581,8 @@ private static boolean isTerminalFilter(Filter.FilterConfig filterConfig) {
   @Nullable // Returns null if the filter is optional but not supported.
   static StructOrError<Filter.FilterConfig> parseHttpFilter(
       io.envoyproxy.envoy.extensions.filters.network.http_connection_manager.v3.HttpFilter
-          httpFilter, FilterRegistry filterRegistry, boolean isForClient) {
+          httpFilter, FilterRegistry filterRegistry, boolean isForClient,
+      XdsResourceType.Args args) {
     String filterName = httpFilter.getName();
     boolean isOptional = httpFilter.getIsOptional();
     if (!httpFilter.hasTypedConfig()) {
@@ -616,8 +617,12 @@ static StructOrError<Filter.FilterConfig> parseHttpFilter(
           "HttpFilter [" + filterName + "](" + typeUrl + ") is required but unsupported for " + (
               isForClient ? "client" : "server"));
     }
+    Filter.FilterConfigParseContext filterContext = Filter.FilterConfigParseContext.builder()
+        .bootstrapInfo(args.getBootstrapInfo())
+        .serverInfo(args.getServerInfo())
+        .build();
     ConfigOrError<? extends FilterConfig> filterConfig =
-        Filter.Parser.parseFilterConfig(provider, rawConfig, 0);
+        Filter.Parser.parseFilterConfig(provider, rawConfig, filterContext, 0);
     if (filterConfig.errorDetail != null) {
       return StructOrError.fromError(
           "Invalid filter config for HttpFilter [" + filterName + "]: " + filterConfig.errorDetail);

xds/src/main/java/io/grpc/xds/XdsRouteConfigureResource.java

@@ -37,7 +37,6 @@
 import io.envoyproxy.envoy.config.route.v3.ClusterSpecifierPlugin;
 import io.envoyproxy.envoy.config.route.v3.RetryPolicy.RetryBackOff;
 import io.envoyproxy.envoy.config.route.v3.RouteConfiguration;
-import io.envoyproxy.envoy.type.v3.FractionalPercent;
 import io.grpc.Status;
 import io.grpc.internal.GrpcUtil;
 import io.grpc.xds.ClusterSpecifierPlugin.NamedPluginConfig;
@@ -199,7 +198,7 @@ private static StructOrError<VirtualHost> parseVirtualHost(
       routes.add(route.getStruct());
     }
     StructOrError<Map<String, Filter.FilterConfig>> overrideConfigs =
-        parseOverrideFilterConfigs(proto.getTypedPerFilterConfigMap(), filterRegistry);
+        parseOverrideFilterConfigs(proto.getTypedPerFilterConfigMap(), filterRegistry, args);
     if (overrideConfigs.getErrorDetail() != null) {
       return StructOrError.fromError(
           "VirtualHost [" + proto.getName() + "] contains invalid HttpFilter config: "
@@ -211,7 +210,12 @@ private static StructOrError<VirtualHost> parseVirtualHost(
 
   @VisibleForTesting
   static StructOrError<Map<String, FilterConfig>> parseOverrideFilterConfigs(
-      Map<String, Any> rawFilterConfigMap, FilterRegistry filterRegistry) {
+      Map<String, Any> rawFilterConfigMap, FilterRegistry filterRegistry,
+      XdsResourceType.Args args) {
+    Filter.FilterConfigParseContext context = Filter.FilterConfigParseContext.builder()
+        .bootstrapInfo(args.getBootstrapInfo())
+        .serverInfo(args.getServerInfo())
+        .build();
     Map<String, FilterConfig> overrideConfigs = new HashMap<>();
     for (String name : rawFilterConfigMap.keySet()) {
       Any anyConfig = rawFilterConfigMap.get(name);
@@ -255,7 +259,7 @@ static StructOrError<Map<String, FilterConfig>> parseOverrideFilterConfigs(
             "HttpFilter [" + name + "](" + typeUrl + ") is required but unsupported");
       }
       ConfigOrError<? extends Filter.FilterConfig> filterConfig =
-          Filter.Parser.parseFilterConfigOverride(provider, rawConfig, 0);
+          Filter.Parser.parseFilterConfigOverride(provider, rawConfig, context, 0);
       if (filterConfig.errorDetail != null) {
         return StructOrError.fromError(
             "Invalid filter config for HttpFilter [" + name + "]: " + filterConfig.errorDetail);
@@ -282,7 +286,7 @@ static StructOrError<Route> parseRoute(
     }
 
     StructOrError<Map<String, FilterConfig>> overrideConfigsOrError =
-        parseOverrideFilterConfigs(proto.getTypedPerFilterConfigMap(), filterRegistry);
+        parseOverrideFilterConfigs(proto.getTypedPerFilterConfigMap(), filterRegistry, args);
     if (overrideConfigsOrError.getErrorDetail() != null) {
       return StructOrError.fromError(
           "Route [" + proto.getName() + "] contains invalid HttpFilter config: "
@@ -338,12 +342,12 @@ static StructOrError<RouteMatch> parseRouteMatch(
 
     FractionMatcher fractionMatch = null;
     if (proto.hasRuntimeFraction()) {
-      StructOrError<FractionMatcher> parsedFraction =
-          parseFractionMatcher(proto.getRuntimeFraction().getDefaultValue());
-      if (parsedFraction.getErrorDetail() != null) {
-        return StructOrError.fromError(parsedFraction.getErrorDetail());
+      try {
+        fractionMatch =
+            MatcherParser.parseFractionMatcher(proto.getRuntimeFraction().getDefaultValue());
+      } catch (IllegalArgumentException e) {
+        return StructOrError.fromError(e.getMessage());
       }
-      fractionMatch = parsedFraction.getStruct();
     }
 
     List<HeaderMatcher> headerMatchers = new ArrayList<>();
@@ -384,26 +388,7 @@ static StructOrError<PathMatcher> parsePathMatcher(
     }
   }
 
-  private static StructOrError<FractionMatcher> parseFractionMatcher(FractionalPercent proto) {
-    int numerator = proto.getNumerator();
-    int denominator = 0;
-    switch (proto.getDenominator()) {
-      case HUNDRED:
-        denominator = 100;
-        break;
-      case TEN_THOUSAND:
-        denominator = 10_000;
-        break;
-      case MILLION:
-        denominator = 1_000_000;
-        break;
-      case UNRECOGNIZED:
-      default:
-        return StructOrError.fromError(
-            "Unrecognized fractional percent denominator: " + proto.getDenominator());
-    }
-    return StructOrError.fromStruct(FractionMatcher.create(numerator, denominator));
-  }
+
 
   @VisibleForTesting
   static StructOrError<HeaderMatcher> parseHeaderMatcher(
@@ -497,7 +482,7 @@ static StructOrError<RouteAction> parseRouteAction(
         for (io.envoyproxy.envoy.config.route.v3.WeightedCluster.ClusterWeight clusterWeight
             : clusterWeights) {
           StructOrError<ClusterWeight> clusterWeightOrError =
-              parseClusterWeight(clusterWeight, filterRegistry);
+              parseClusterWeight(clusterWeight, filterRegistry, args);
           if (clusterWeightOrError.getErrorDetail() != null) {
             return StructOrError.fromError("RouteAction contains invalid ClusterWeight: "
                 + clusterWeightOrError.getErrorDetail());
@@ -606,9 +591,9 @@ private static StructOrError<VirtualHost.Route.RouteAction.RetryPolicy> parseRet
   @VisibleForTesting
   static StructOrError<VirtualHost.Route.RouteAction.ClusterWeight> parseClusterWeight(
       io.envoyproxy.envoy.config.route.v3.WeightedCluster.ClusterWeight proto,
-      FilterRegistry filterRegistry) {
+      FilterRegistry filterRegistry, XdsResourceType.Args args) {
     StructOrError<Map<String, Filter.FilterConfig>> overrideConfigs =
-        parseOverrideFilterConfigs(proto.getTypedPerFilterConfigMap(), filterRegistry);
+        parseOverrideFilterConfigs(proto.getTypedPerFilterConfigMap(), filterRegistry, args);
     if (overrideConfigs.getErrorDetail() != null) {
       return StructOrError.fromError(
           "ClusterWeight [" + proto.getName() + "] contains invalid HttpFilter config: "