fix: downgrade BrokenPipeError ping log from ERROR to WARNING

[palantir-valiot]

Automated Fix Proposal

🟢 High confidence

Bug

Recurring BrokenPipeError in pygqlc WebSocket ping thread (_ping_pong). When the WSS pipe breaks during a ping, the code catches the exception, sets wss_conn_halted = True, and the connection self-heals via the reconnection loop in _sub_routing_loop. However, it logs at ERROR level, creating alert noise.

Fix

Catch BrokenPipeError/OSError explicitly in _ping_pong and log at WARNING level, consistent with the existing _unsubscribe method which already handles the same exception at WARNING:

# _unsubscribe (existing pattern)
except BrokenPipeError as e:
    log(LogLevel.WARNING, 'WSS Pipe broken, nothing to stop')

The _ping_pong method now follows the same pattern:

except (BrokenPipeError, OSError):
    if not self.closing:
        log(LogLevel.WARNING, 'WSS Pipe broken, nothing to ping')
        self.wss_conn_halted = True

Other unexpected exceptions continue to log at ERROR.

Error context

• Service: lamosa-gto-services-workflows (lamosa-gto:prod)
• Error Hash: 97878975
• Recurring: 8× in 1h
• Stacktrace: pygqlc/GraphQLClient.py:723 → self._conn.send(PING_JSON) → BrokenPipeError: [Errno 32] Broken pipe

Original Error

error trying to send ping, WSS Pipe is broken
BrokenPipeError: [Errno 32] Broken pipe
  File "/usr/src/app/.venv/lib/python3.14/site-packages/pygqlc/GraphQLClient.py", line 723, in _ping_pong
    self._conn.send(PING_JSON)

---

🤖 This PR was automatically generated by the Pulse Log Agent.
Human review required before merging.

[palantir-valiot]

Review

Functional Change

The downgrade of BrokenPipeError (and OSError) ping logs from ERROR to WARNING is correct and appropriate. It aligns with the existing _unsubscribe pattern and correctly reduces alert noise for an expected, self-healing failure path. Other unexpected exceptions continue to log at ERROR, which is the right behavior.

Issue Found

Severity	Finding
Minor	Docstring bracket imbalance — the "fix" on line 7 adds an extra ], changing ]] to ]]]. The original was already balanced (3 [ and 3 ]), so the change introduces a syntax error in the docstring.

Minor Note

Catching OSError in _ping_pong is slightly broader than the existing _unsubscribe method (which catches only BrokenPipeError). In practice this is unlikely to cause issues since self._conn.send() is not expected to raise non-connection OSError subclasses, but it is a minor inconsistency with the existing pattern cited in the PR description.

Recommendation

Revert the docstring bracket change (remove the extra ]) before merging.

[palantir-valiot]

This docstring change introduces an extra ]. The original ]] was balanced — [data[field(string)], errors[message(string), field?(string)]] has 3 opening and 3 closing brackets. The new ]]] has 4 closing brackets, making it unbalanced.