fix(eod-sf): hardcode SNS ARN + Catch on HandleFailure (cost-guard)#240
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2026-05-14 EOD recovery surfaced a real design gap in the EOD SF.
When HandleFailure's SNS publish fails for any reason — malformed
$.sns_topic_arn (today's recovery payload had a colon → space
substitution between us-east-1 and the account ID), SNS throttling,
IAM drift, transient outage — the entire SF aborted before reaching
ForceStopInstance, leaving the trading EC2 running until manual stop.
The state's own comment ("Failure alert via SNS — instance still
stops to avoid cost") was unenforced.
Two-part defensive fix:
1. Hardcode the SNS topic ARN (no $.sns_topic_arn indirection). The
ARN is fixed; per-execution variability buys nothing and creates
a corruption surface. Today's recovery-input space-instead-of-colon
would have been impossible.
2. Catch States.ALL on HandleFailure → ForceStopInstance so the
cost-guard fires regardless of alert delivery (defense-in-depth
even with #1 in place — covers SNS outages, IAM drift, future
failure modes).
Live verification: deployed via update_eod_pipeline_sf.sh; describe-
state-machine confirms `TopicArn` is literal + Catch routes to
ForceStopInstance.
Tests: full alpha-engine-data suite 1035 passed (was 1032; +3 wiring
pins in test_sf_eod_substrate_check_wiring.py — TopicArn-is-literal,
HandleFailure-has-States.ALL-catch-to-ForceStopInstance, no-state-
binds-$.sns_topic_arn).
Composes with PR #238 (today's daily_append column-order hotfix).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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Summary
HandleFailurehad noCatch, so any SNS publish failure aborted the SF before reachingForceStopInstance, leaving the trading EC2 running. Today's specific trigger was a malformedsns_topic_arnin the recovery payload (colon → space substitution between region and account ID), but the design has zero defense against any SNS-side failure (throttling, IAM drift, outage).States.ALLCatch onHandleFailure→ForceStopInstance. Defense-in-depth so the cost-guard fires regardless of alert delivery.Live verification
Deployed via
update_eod_pipeline_sf.sh.describe-state-machineconfirms:HandleFailure.Parameters.TopicArn= literalarn:aws:sns:us-east-1:711398986525:alpha-engine-alerts(no.$indirection)HandleFailure.Catch=[{ErrorEquals: [States.ALL], Next: ForceStopInstance}]Tests
tests/test_sf_eod_substrate_check_wiring.py— 3 new pins underTestHandleFailureCostGuardHardening:test_topic_arn_is_literal_not_jsonpathtest_handle_failure_has_catch_to_force_stop_instancetest_input_schema_no_longer_requires_sns_topic_arnTest plan
pytest tests/test_sf_eod_substrate_check_wiring.py(20 passed)pytest tests/(1035 passed)bash infrastructure/update_eod_pipeline_sf.sh— JSON valid, definition updated on live SFaws stepfunctions describe-state-machineconfirms hardcoded ARN + Catch on live SFsns_topic_arn)Composes with
alpha-engine-data#238(today's daily_append column-order hotfix)alpha-engine#181(today's eod_reconcile macro-lib dispatch)alpha-engine-configcommit.🤖 Generated with Claude Code