feat: proxy REST+SSZ Engine API over h2c (execution-apis #793)#48
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barnabasbusa wants to merge 3 commits into
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feat: proxy REST+SSZ Engine API over h2c (execution-apis #793)#48barnabasbusa wants to merge 3 commits into
barnabasbusa wants to merge 3 commits into
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Maps Engine API REST URL paths to method names (e.g. /engine/v3/payloads → engine_newPayloadV3) for improved log readability when proxying SSZ-encoded traffic. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
The HTTP/1.1-only server dropped consensus clients that speak the
REST+SSZ Engine API (execution-apis #793), which uses HTTP/2 cleartext
prior-knowledge — the connection was reset and clients fell back to
JSON-RPC, so #793 traffic was never observable through the snooper.
- Wrap the downstream server in h2c so it accepts both HTTP/1.1
(JSON-RPC) and HTTP/2 cleartext (REST+SSZ) on the same port.
- Forward each call to the EL using the same HTTP version it arrived
on: HTTP/2 for REST+SSZ, HTTP/1.1 for JSON-RPC.
- Extend SSZ route matching to the #793 fork-scoped endpoints
(/engine/v2/{fork}/payloads|forkchoice|bodies), independently
versioned blobs (/blobs/vN), and the unscoped identity endpoint.
- Show the resolved Engine API method inline on REQUEST/RESPONSE lines
(' -> engine_forkchoiceUpdatedV3') instead of a trailing field, and
echo it on responses so request/response pairs are easy to read.
SSZ bodies were logged as an opaque '<N bytes>' placeholder. SSZ isn't self-describing so we can't pretty-print it like JSON, but emitting the raw body as hex (honouring truncation) keeps the on-wire content visible and decodable offline. The byte count remains on the line via 'length'.
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Summary
Makes the snooper proxy the REST+SSZ Engine API (execution-apis #793) instead of dropping it.
That transport uses HTTP/2 cleartext (h2c) prior-knowledge. The snooper's server was HTTP/1.1-only, so when a consensus client opened an h2c connection (e.g.
GET /engine/v2/capabilities) the connection was reset — the client then silently fell back to JSON-RPC, and none of the #793 traffic was ever observable through the snooper.Changes
h2c downstream server — wrap the handler in
h2c.NewHandlerso the proxy accepts both HTTP/1.1 (JSON-RPC) and HTTP/2 cleartext (REST+SSZ) on the same port.Protocol-matched upstream — forward each call to the EL using the same HTTP version it arrived on (autodetected per request from the inbound connection): HTTP/2 for REST+SSZ, HTTP/1.1 for JSON-RPC. No client is forced onto a transport it didn't choose.
#793 route matching — extend
ssz/route.goto the fork-scoped endpoints (/engine/v2/{fork}/payloads|forkchoice|bodies), independently-versioned blobs (/engine/v2/blobs/vN), and the unscopedidentityendpoint, with tests.Readable logs — show the autodetected protocol and resolved Engine API method inline on REQUEST/RESPONSE lines, e.g.
Supersedes
Includes and replaces the closed #36 (which only added method-name detection for log readability); this PR adds the actual h2c proxying needed to carry the traffic.
Testing
Verified live in a Kurtosis devnet (geth
ssz-engine-apibranch + consensoor):GET /engine/v2/capabilities,/engine/v2/identity, and the fork-scopedPOST /engine/v2/amsterdam/{forkchoice,payloads}/GET .../payloads/{id}SSZ calls all proxy with200and are logged with the correct method. JSON-RPC clients (lighthouse, teku) are unaffected and continue over HTTP/1.1.go test ./...passes.🤖 Generated with Claude Code