feat(temporal-http): Temporal without ext-grpc, over curl or the JSON gateway

[gplanchat]

A new package, gplanchat/durable-bridge-temporal-http (src/Bridge/TemporalHttp), and the seam in the Temporal bridge that lets it in. The Temporal server speaks two transports; the bridge spoke one, through the grpc PHP extension. It now speaks both, and the extension becomes optional.

The seam: WorkflowServiceClientInterface

Every collaborator of the bridge took the generated stub Temporal\Api\Workflowservice\V1\WorkflowServiceClient, whose methods hand back a \Grpc\UnaryCall to wait on. That class extends \Grpc\BaseStub, so nothing in the bridge could even be loaded without the extension.

They now take WorkflowServiceClientInterface: one method per RPC the bridge uses (38), returning the response directly and throwing \RuntimeException with the gRPC status as its code on anything but OK. That contract is what GrpcUnary::wait was already producing, so the call sites lose a wrapper rather than gain one, and the places that read NOT_FOUND or ALREADY_EXISTS off the status pair read it off the exception code instead. The per-RPC methods live once, in two traits behind AbstractWorkflowServiceClient; a transport implements a single call().

Three implementations, chosen by the DSN scheme:

DSN	Class	Port	Covers
temporal://, temporal+tls:// with ext-grpc loaded	GrpcWorkflowServiceClient	7233	the generated stub over the extension, as before
temporal://, temporal+tls:// without it (or transport=grpc-curl)	CurlGrpcWorkflowServiceClient	7233	the same gRPC protocol through PHP curl over HTTP/2: one POST per unary call, the frame in the body, the status in the trailers. Every RPC, workers included, no extension
temporal+http://, temporal+https://	JsonGatewayWorkflowServiceClient	7243	the server's JSON gateway. The client side only: start, signal, query, update, describe, list, history, cancel, terminate, activity completions. No task queue poll and no workflow or Nexus task response, because the server binds none of them over HTTP; calling one throws UNIMPLEMENTED (12) and names the transport to use

The scheme names the wire and the encryption (+tls, +https); tls=1 stays accepted as the older spelling. transport= (auto by default) overrides what the scheme implies: grpc demands the extension and fails without it, grpc-curl forces curl, http is what temporal+http:// sets.

auto is resolved once, at wiring time, by a pure function (WorkflowServiceClientFactory::resolve): the extension when loaded, curl otherwise, an exception naming both remedies when neither is installed. The fallback to curl is logged once per process at INFO, through the PSR-3 logger the host passes (Symfony's logger service, Laravel's bound logger, an optional Magento constructor argument) or error_log for a bare worker. An explicit transport never falls back. durable:execution:diagnose (Symfony) and the two Laravel worker commands print the effective transport, so the question "which one am I on" is answered where it gets asked. No fallback at call time: both transports talk to the same port, a call that fails on one fails on the other, and switching would double the timeouts while hiding the cause.

What was checked

The route table of the JSON gateway is copied from the google.api.http annotations by hand, so JsonGatewayRoutesTest holds it to the protobuf descriptor checked in with the stubs: every route must appear there, and every interface RPC without a route must have no binding. A stub regeneration that moves a route fails there rather than as a 404 in production.

Against temporal server start-dev --http-port 7243:

• the whole integration suite runs through DURABLE_TEMPORAL_TRANSPORT=grpc-curl, workers included (TemporalServerTestCase and worker.php read the variable). Same result as through ext-grpc;
• JsonGatewayRoundTripTest starts, describes and reads an execution over the gateway without any worker.

A new CI job, no-grpc, installs PHP without the extension, runs the unit suite, then the whole integration suite through grpc-curl against the dev server (temporalio/setup-temporal, --http-port 7243). .github/workflows/ci.yml is on the supervised list; the job was asked for explicitly.

Unit suite: same count as before, no test removed or skipped. Six unit test files that mocked the stub now mock the interface and no longer need ext-grpc at all.

Rules touched, on purpose

• composer.json at three levels (root, Temporal bridge, the new package) and composer.lock: a new package cannot exist without them. The Temporal bridge moves ext-grpc from require to suggest and gains psr/log (already in the lock through Symfony) for the fallback line; the factory asserts the extension at runtime for transport=grpc only. The root lock was refreshed offline for the two path packages only.
• The two RPC traits are 131 and 111 lines; the choice of two traits over one 207-line class was made to stay under the 200-line commit limit.
• documentation/adr/ untouched. DUR006 already allows "gRPC/HTTP per implementation choices". DUR019 says "exclusively via gRPC": grpc-curl still is gRPC, http is not. Whether DUR019 wants a superseding ADR is a human call.

Not in this PR

• bin/splitsh-publish.sh and the satellite repository for the new package: the repository and the PAT scope come first, then the line in SPLITS.
• The bench applications (symfony, sylius, laravel, magento) keep transport=grpc.
• OperatorServiceClient (Nexus endpoints in the integration tests) keeps the raw stub and GrpcUnary::wait; nothing in src/ uses it.