Backport release/v6.7: Bound frozen RPC router batch allocations

[seidroid]

Backport of #4038 to release/v6.7.

[cursor]

PR Summary

Low Risk
Operational guardrails on the RPC router edge; behavior change only for batches above the limit or very slow writes, with sensible defaults.

Overview
Adds resource limits to frozen-rpc-router: JSON-RPC batches are capped at 1,000 calls by default (--batch-request-limit), and HTTP response writes use a 30s default (--write-timeout on the server).

Batch handling no longer unmarshals the whole array up front. decodeBatchCalls streams the batch with a JSON decoder, stops once the limit is reached, and returns a single JSON-RPC -32600 "batch too large" error for oversize batches—reducing unbounded allocations on huge batch bodies. Config and router construction wire the new settings through; README and tests cover defaults, validation, and rejection behavior.

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Build	Format	Lint	Breaking	Updated (UTC)
✅ passed	✅ passed	✅ passed	✅ passed	Aug 28, 2026, 9:31 AM

[codecov]

Codecov Report

❌ Patch coverage is 59.09091% with 18 lines in your changes missing coverage. Please review.
✅ Project coverage is 60.30%. Comparing base (1e8d054) to head (320d923).

Files with missing lines	Patch %	Lines
cmd/frozen-rpc-router/router.go	55.55%	8 Missing and 8 partials ⚠️
cmd/frozen-rpc-router/main.go	0.00%	2 Missing ⚠️

Additional details and impacted files

@@               Coverage Diff                @@
##           release/v6.7    #4049      +/-   ##
================================================
- Coverage         61.30%   60.30%   -1.00%     
================================================
  Files              2163     2064      -99     
  Lines            188768   177206   -11562     
================================================
- Hits             115726   106868    -8858     
+ Misses            62315    60547    -1768     
+ Partials          10727     9791     -936     

Flag	Coverage Δ
sei-chain-pr	62.12% <59.09%> (?)
sei-db	69.80% <ø> (ø)
sei-db-state-db	?

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
cmd/frozen-rpc-router/config.go	83.33% <100.00%> (+2.38%)	⬆️
cmd/frozen-rpc-router/main.go	0.00% <0.00%> (ø)
cmd/frozen-rpc-router/router.go	65.40% <55.55%> (+1.18%)	⬆️

... and 99 files with indirect coverage changes

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[cursor]

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

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^{Reviewed by Cursor Bugbot for commit 320d923. Configure here.}

[cursor]

Write timeout breaks proxied WebSockets

Medium Severity

The new WriteTimeout is set on the single HTTP server that also reverse-proxies non-POST traffic, including WebSocket upgrades, through liveProxy. Go leaves that write deadline on hijacked connections, and httputil.ReverseProxy does not clear it, so upgraded sockets die when the timer fires. The 30s default cuts off long-lived subscriptions, and --write-timeout cannot be 0 to restore unbounded writes.

Additional Locations (2)

• cmd/frozen-rpc-router/router.go#L173-L177
• cmd/frozen-rpc-router/config.go#L79-L82

 

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