Merge pull request #2621 from cloudflare/milan/replica-routing-compat…

…-flag

Add `replicaRouting` compat flag

src/workerd/api/actor.c++

@@ -53,11 +53,13 @@ public:
  GlobalActorOutgoingFactory(uint channelId,
  jsg::Ref<DurableObjectId> id,
  kj::Maybe<kj::String> locationHint,
- ActorGetMode mode)
+ ActorGetMode mode,
+ bool enableReplicaRouting)
  : channelId(channelId),
  id(kj::mv(id)),
  locationHint(kj::mv(locationHint)),
- mode(mode) {}
+ mode(mode),
+ enableReplicaRouting(enableReplicaRouting) {}
 
  kj::Own<WorkerInterface> newSingleUseClient(kj::Maybe<kj::String> cfStr) override {
  auto& context = IoContext::current();
@@ -71,7 +73,7 @@ public:
  // Lazily initialize actorChannel
  if (actorChannel == kj::none) {
  actorChannel = context.getGlobalActorChannel(
- channelId, id->getInner(), kj::mv(locationHint), mode, span);
+ channelId, id->getInner(), kj::mv(locationHint), mode, enableReplicaRouting, span);
  }
 
  return KJ_REQUIRE_NONNULL(actorChannel)
@@ -87,6 +89,7 @@ private:
  jsg::Ref<DurableObjectId> id;
  kj::Maybe<kj::String> locationHint;
  ActorGetMode mode;
+ bool enableReplicaRouting;
  kj::Maybe<kj::Own<IoChannelFactory::ActorChannel>> actorChannel;
 };
 
@@ -147,8 +150,10 @@ jsg::Ref<DurableObject> DurableObjectNamespace::getImpl(jsg::Lock& js,
  locationHint = kj::mv(o.locationHint);
  }
 
- auto outgoingFactory = context.addObject<Fetcher::OutgoingFactory>(
- kj::heap<GlobalActorOutgoingFactory>(channel, id.addRef(), kj::mv(locationHint), mode));
+ bool enableReplicaRouting = FeatureFlags::get(js).getReplicaRouting();
+ auto outgoingFactory =
+ context.addObject<Fetcher::OutgoingFactory>(kj::heap<GlobalActorOutgoingFactory>(
+ channel, id.addRef(), kj::mv(locationHint), mode, enableReplicaRouting));
  auto requiresHost = FeatureFlags::get(js).getDurableObjectFetchRequiresSchemeAuthority()
  ? Fetcher::RequiresHostAndProtocol::YES
  : Fetcher::RequiresHostAndProtocol::NO;

src/workerd/io/compatibility-date.capnp

@@ -588,4 +588,10 @@ struct CompatibilityFlags @0x8f8c1b68151b6cef {
  # Enables node:zlib implementation while it is in-development.
  # Once the node:zlib implementation is complete, this will be automatically enabled when
  # nodejs_compat is enabled.
+
+ replicaRouting @60 :Bool
+ $compatEnableFlag("replica_routing")
+ $experimental;
+ # Enables routing to a replica on the client-side.
+ # Doesn't mean requests *will* be routed to a replica, only that they can be.
 }

src/workerd/io/io-channels.h

@@ -151,6 +151,7 @@ class IoChannelFactory {
  const ActorIdFactory::ActorId& id,
  kj::Maybe<kj::String> locationHint,
  ActorGetMode mode,
+ bool enableReplicaRouting,
  SpanParent parentSpan) = 0;
 
  // Get an actor stub from the given namespace for the actor with the given name.

src/workerd/io/io-context.h

@@ -721,9 +721,10 @@ class IoContext final: public kj::Refcounted, private kj::TaskSet::ErrorHandler
  const ActorIdFactory::ActorId& id,
  kj::Maybe<kj::String> locationHint,
  ActorGetMode mode,
+ bool enableReplicaRouting,
  SpanParent parentSpan) {
  return getIoChannelFactory().getGlobalActor(
- channel, id, kj::mv(locationHint), mode, kj::mv(parentSpan));
+ channel, id, kj::mv(locationHint), mode, enableReplicaRouting, kj::mv(parentSpan));
  }
  kj::Own<IoChannelFactory::ActorChannel> getColoLocalActorChannel(
  uint channel, kj::StringPtr id, SpanParent parentSpan) {

src/workerd/server/server.c++

@@ -2205,9 +2205,11 @@ private:
  const ActorIdFactory::ActorId& id,
  kj::Maybe<kj::String> locationHint,
  ActorGetMode mode,
+ bool enableReplicaRouting,
  SpanParent parentSpan) override {
  JSG_REQUIRE(mode == ActorGetMode::GET_OR_CREATE, Error,
  "workerd only supports GET_OR_CREATE mode for getting actor stubs");
+ JSG_REQUIRE(!enableReplicaRouting, Error, "workerd does not support replica routing.");
  auto& channels =
  KJ_REQUIRE_NONNULL(ioChannels.tryGet<LinkedIoChannels>(), "link() has not been called");
 

src/workerd/tests/test-fixture.c++

@@ -99,6 +99,7 @@ struct DummyIoChannelFactory final: public IoChannelFactory {
  const ActorIdFactory::ActorId& id,
  kj::Maybe<kj::String> locationHint,
  ActorGetMode mode,
+ bool enableReplicaRouting,
  SpanParent parentSpan) override {
  KJ_FAIL_REQUIRE("no actor channels");
  }