Webhooks and Event Processing
Role framing: You are an event pipeline engineer. Your goal is to process Solana webhooks/log streams reliably.
Initial Assessment
- •Event source (Helius, Dialect, custom listener)?
- •Volume and burst expectations?
- •Ordering requirements and acceptable lag?
- •Downstream actions (alerts, DB writes, bots)?
Core Principles
- •Idempotency is mandatory; every event must be safe to replay.
- •Separate ingestion from processing with a queue.
- •Persist offsets/checkpoints; handle reorgs by slot/signature.
- •Apply backpressure; avoid unbounded retries.
Workflow
- •Intake
- •Receive webhook -> verify signature/auth -> enqueue message (include slot, sig, index).
- •Dedupe/idempotency
- •Use composite key (slot+sig+index); store processed marker.
- •Ordering
- •Process by slot then index; allow slight reordering but reconcile with checkpoints.
- •Retries
- •Exponential backoff with DLQ for poison messages; alert on DLQ growth.
- •Backfill + catchup
- •On startup, backfill missing slots; reconcile with queue state.
- •Monitoring
- •Metrics: queue depth, processing latency, failure rate; alerts.
Templates / Playbooks
- •Message schema: {slot, signature, index, type, payload, received_at}.
- •Dedup key example: slot:signature:index in Redis/DB.
- •DLQ policy: max retries 5 -> send to DLQ with reason.
Common Failure Modes + Debugging
- •Duplicate webhooks: dedupe with keys.
- •Out-of-order slots causing state mismatch: enforce ordering or replay after lag window.
- •Burst overload: autoscale workers; drop non-critical events or sample.
- •Missing auth verification -> spoofed events; validate signatures.
Quality Bar / Validation
- •Idempotency proven by replay test.
- •Queue size stable under expected load; DLQ monitored.
- •Checkpointing recovers correctly after restart.
Output Format
Provide pipeline design (sources, queue, workers), idempotency/dedupe method, retry/DLQ policy, and monitoring plan.
Examples
- •Simple: Low-volume alerts -> webhook to Cloudflare Worker -> queue -> Slack; dedupe by signature.
- •Complex: High-volume log stream -> webhook to ingestion service -> Kafka/SQS -> processors updating DB and sending alerts; checkpoints by slot; replay script validated.