Add pre-fetch quota check for JetStream Sensor backpressure#13
Merged
abdulazillow merged 9 commits intofeature/zgfrom Jan 15, 2026
Merged
Add pre-fetch quota check for JetStream Sensor backpressure#13abdulazillow merged 9 commits intofeature/zgfrom
abdulazillow merged 9 commits intofeature/zgfrom
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- Add BackpressureWaiter to check ResourceQuota before fetching from JetStream - Integrate into trigger_conn.go pullSubscribe loop - Add sensor_quota_blocked metric - Add env var configuration (BACKPRESSURE_QUOTA_NAME, etc.) - Add implementation documentation This prevents message loss when NATS connection is lost during extended backpressure periods (quota full for hours).
TODO: Remove [BACKPRESSURE-TEST] logs after verification complete
- Add setupBackpressure() helper called from both initial and reconnect paths - Add closeCh check after WaitForCapacity to catch close signals during poll
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Thanks, was able to verify that the fix is working. |
dhanashritidke11
approved these changes
Jan 15, 2026
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dhanashritidke11
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dhanashritidke11
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LGTM, Approved
talebzeghmi
approved these changes
Jan 15, 2026
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Add pre-fetch quota check for JetStream Sensor backpressure
Description
Implements pre-fetch quota check for JetStream Sensor to prevent message loss during resource quota exhaustion. When downstream workflow quota is near capacity, the sensor blocks before fetching messages from JetStream, keeping them safely in durable storage.
Problem: When ResourceQuota is full for extended periods, messages held in sensor memory during retries can be lost if the NATS connection drops (orphaned ACK bug).
Solution: Check ResourceQuota capacity before fetching messages from JetStream. Messages stay in durable storage until there's capacity to process them.
Configuration
env:
value: "workflow-quota"
value: "0.95"
value: "30"### New Metric
argo_events_sensor_quota_blocked- Gauge: 1 when blocked, 0 when processing normallyTesting
Unit Tests: Added
backpressure_test.gocovering:HasCapacity()threshold calculationsWaitForCapacity()blocking and context cancellationIntegration Testing:
sensor_quota_blockedmetric toggles correctlyLong-Running Test:
Additional Fixes
setupBackpressure()helper called from both initial connection and reconnection pathscloseChcheck afterWaitForCapacity()to handle connection drops during blockingBackward Compatibility
✅ Fully backward compatible - Backpressure is disabled by default (requires
BACKPRESSURE_QUOTA_NAMEenv var)