fix: carry request.cf through debug port capnp layer#6116
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Merging this PR will degrade performance by 95.18%
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danlapid
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Add cfBlobJson as a parameter to WorkerdBootstrap::startEvent() in the capnp schema, so request.cf travels as a first-class RPC value through the debug port. Sender (workerd-debug-port-client.c++): - startRequest() passes metadata.cfBlobJson via req.setCfBlobJson() on startEvent Receiver (server.c++): - startEvent() extracts cfBlobJson from RPC params, passes to EventDispatcherImpl - getHttpService() includes cfBlobJson in SubrequestMetadata when creating WorkerInterface - EventDispatcherImpl defers WorkerInterface creation (stores SubrequestChannel)
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Summary
request.cfbeing lost when requests go through the debug port (used by Miniflare's native dev registry for cross-worker service bindings)startRequest(metadata)byFetcher::getClientWithTracing()butWorkerdBootstrapSubrequestChannelignored it entirelyChanges
Sender side (
workerd-debug-port-client.c++):CfInjectingWorkerInterface: thinWorkerInterfacewrapper that injectsMF-CF-Blobheader into outgoing HTTP requests whenmetadata.cfBlobJsonis presentWorkerdBootstrapSubrequestChannel::startRequest()now wraps theRpcWorkerInterfacewithCfInjectingWorkerInterfacewhen cf blob is providedReceiver side (
server.c++):CfAwareHttpService: wraps the target service's HTTP interface, extractsMF-CF-Blobheader from incoming requests, and passes cf toSubrequestMetadataEventDispatcherImpldefersWorkerInterfacecreation until the HTTP request arrives (storesSubrequestChannelinstead ofWorkerInterface), enabling cf blob extractionstartEvent()passeskj::addRef(*service)instead ofservice->startRequest({})Context
Part of cloudflare/workers-sdk#12600 — refactoring the Miniflare dev registry to use native debug port RPC instead of a Node.js HTTP proxy.