Watcher implementation & Stellar on Tilt

[svlachakis]

Stellar Watcher (Draft)

Core Functionality

The Stellar watcher monitors the Wormhole Core Bridge contract on Stellar for cross-chain message publications

Event Polling

• Continuously polls the Soroban RPC getEvents endpoint at configurable intervals (default 700ms)
• Detects new message_published events from the Wormhole contract

Event Parsing

• Decodes base64-encoded XDR event data from Soroban contract events
• Extracts message fields: nonce, sequence, emitter_address, payload, consistency_level
• Converts Stellar-specific formats to Wormhole's standard MessagePublication format

Message Publishing

Publishes parsed messages to the guardian's message processing pipeline with:

• Timestamp: current time
• Emitter chain: Stellar
• Fields: all extracted message fields

Ledger Tracking

• Maintains state of the last processed ledger
• Avoids duplicate processing
• Handles restarts gracefully

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Reobservation Support

Reobservation Request Handling

• Listens for reobservation requests from the guardian network
• Queries events by specific transaction hash
• Re-parses and republishes messages with IsReobservation = true flag
• Enables message recovery and debugging workflows

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Future Work

Tests

• Integration tests for reobservation requests
• End-to-end tests with local Stellar network

Metrics (Maybe?)

• Message observation counters (observed / confirmed / orphaned)
• Reobservation request metrics (success / failure / latency)
• Connection error tracking
• Current ledger height gauges
• RPC call latency histograms

Guardian Set Management (Maybe?)

• Read guardian sets from Soroban contract storage
• Requires implementing simulateTransaction or getLedgerEntries RPC calls or another approach
• Periodic polling to detect guardian set updates
• Publish guardian set changes to the guardian network

Tilt Infra

• Someone needs to look on Tilt infra an make it even better, that's just a POC.

Example Result / Signed VAA

2025-11-07T15:10:43.230Z	INFO	guardian-0.root.61_watch	stellar message published	{"component": "stellar_watcher", "rpc": "[http://stellar.default.svc.cluster.local:8000/soroban/rpc",](http://stellar.default.svc.cluster.local:8000/soroban/rpc%22,) "contract": "CBWQUIB4R65Z2DGC263FQ7BBI7TGIGOLFTYMLE6QPWBD5QDOUVJY3AKR", "chain": "stellar", "ledger": 2438, "tx": "2e5c06ece7fc8191d2028ed6dd06d53506956f1ca7fabfb0e952ec258b33c456", "seq": 1, "consistency": 1}
2025-11-07T15:10:43.251Z	INFO	guardian-0.root	signed VAA with quorum	{"message_id": "61/fda6fcf519faef33c6cce224fe5eb856da4212588c6202eaa32a6db8facdceac/1", "digest": "1e08121ec71dc2e3ce18945b7ffdd71a0fe9773216308230d5e337c61df2222e"}