Caught the indexer stuck for 3.5h at slot 23463870 today while the
chain tip had advanced to 23477134. Ogmios TCP socket was alive but
the server had stopped pushing nextBlock responses; /healthz reported
ogmios_status: "connected" because that flag only tracked tip_slot > 0,
not actual block flow.
OgmiosSource now arms a 90s response watchdog on every nextBlock /
findIntersection send and clears it on any well-formed protocol reply.
On timeout it ws.close()s, re-entering the existing onclose →
scheduleReconnect → findIntersection path that resumes from the saved
cursor. Errors and malformed messages intentionally leave the watchdog
armed so a stuck Ogmios error path also recycles instead of wedging.
OGMIOS_RESPONSE_TIMEOUT_MS env var tunes the window (0 disables).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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