starknet_transaction_prover: add /health endpoint via HealthLayer

[avi-starkware]

Adds a tower middleware that short-circuits GET /health ahead of
jsonrpsee (which would 405 a GET) and returns {"status":"ok"}. Wired
outermost in both the HTTP and HTTPS middleware chains so load balancers
can probe before any per-request work runs.

Co-Authored-By: Claude Opus 4.7 (1M context) noreply@anthropic.com

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PR Summary

Low Risk
Isolated middleware with a static JSON response; no auth, RPC, or proving logic changes.

Overview
Adds a Tower HealthLayer that answers GET /health with 200 and {"status":"ok"} before jsonrpsee (which would reject GET). HealthLayer is wired outermost on both plain HTTP and HTTPS middleware stacks so probes skip CORS, OHTTP, and compression. HEALTH_PATH is re-exported from the server module; unit tests cover the happy path and fall-through for non-GET or other paths.

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[reviewable-StarkWare]

This change is 

[avi-starkware]

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• starknet_transaction_prover: origin-level breadcrumbs for validation errors #14172
• starknet_transaction_prover: /health returns 503 when service is saturated #14171
• starknet_transaction_prover: bump prover_panics_total on panic hook fire #14170
• starknet_transaction_prover: HTTP request count + latency + in-flight metrics #14169
• starknet_transaction_prover: proving-job duration + outcome metrics #14168
• starknet_transaction_prover: Prometheus /metrics endpoint with build_info #14167
• starknet_transaction_prover: global panic hook + graceful SIGTERM shutdown #14166
• starknet_transaction_prover: per-request structured log with request-id #14165
• starknet_transaction_prover: redact URL credentials in logs and add startup banner #14164
• starknet_transaction_prover: add /health endpoint via HealthLayer #14163 👈 (View in Graphite)
• starknet_transaction_prover: add --log-format text|json CLI flag #14162
• main

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[cursor]

Cursor Bugbot has reviewed your changes and found 1 potential issue.

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Inner service called without poll_ready violating tower contract

Medium Severity

poll_ready unconditionally returns Poll::Ready(Ok(())) without propagating to the inner service, yet call directly invokes self.inner.call(request) for non-health requests. This violates the tower Service contract — call may only be invoked after the service's own poll_ready has returned ready. The sibling OhttpService in crates/tower_ohttp/src/layer.rs handles this correctly by cloning the inner service and calling inner.oneshot(request) which internally polls readiness. If a backpressure-sensitive layer (e.g., ConcurrencyLimit or Buffer) is ever added to the middleware chain, this could cause panics or dropped requests.

Additional Locations (1)

• crates/starknet_transaction_prover/src/server/health.rs#L61-L62

 

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[avi-starkware]

@avi-starkware resolved 1 discussion.
Reviewable status: 0 of 4 files reviewed, all discussions resolved.