Both electrumx tests did socket.create_connection(("127.0.0.1", 50001)) and
called it proof the service was up. It is not: that is the HOST-published
port, and podman's port forwarder completes the TCP handshake even when
nothing inside the container is listening.
The cost was real. Both tests were green while mempool-api sat in a hard
ECONNREFUSED loop against electrumx:50001 from inside archy-net — the
operator's "mempool doesn't connect to bitcoin". Measured side by side:
127.0.0.1:50001 from the host OPEN, electrumx:50001 from a sibling container
REFUSED.
The cause is not a misconfiguration — mempool-api's CORE_RPC_HOST,
ELECTRUM_HOST and ports are all correct. electrumx has not finished its
initial sync (DB height 959,774 vs chain tip 961,706, ~1,932 blocks, 8d 14h
elapsed) and ElectrumX does not serve sessions until it has caught up.
Now both tests do a server.version round-trip and require a JSON result, so a
forwarder that accepts-and-drops fails. Verified against the live node: the
new probe FAILS today where the old one passed.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
