Run a standalone relayer

Run a relayer that queries a standalone attestor for 41002 and builds Besu proofs for 41001.

Before you begin

Complete the tutorial and standalone attestor guides, in order. Keep the standalone attestor for 41002 running. The tutorial’s keystore already holds a funded key, so this guide reuses it rather than importing another.

1. Relayer config

Create a relayer configuration file:

./bin/ibc config new --config ibc-relayer2.yml

Write its configuration, reading the router and multicall addresses from your deployment:

cat > ~/.ibc/ibc-relayer2.yml <<EOF
server:
  listenAddr: 0.0.0.0:3002
db:
  type: sqlite
  url: relayer2.db

chains:
- chainId: "41001"
  evm:
    rpc: http://localhost:8545
    ws: ws://localhost:8546
    ics26Router: "$(./bin/ibc deploy show 41001 | jq -r '.core.router')"
    ibcMulticall: "$(./bin/ibc deploy show 41001 | jq -er '.core.multicall')"
- chainId: "41002"
  evm:
    rpc: http://localhost:8745
    ws: ws://localhost:8746
    ics26Router: "$(./bin/ibc deploy show 41002 | jq -r '.core.router')"
    ibcMulticall: "$(./bin/ibc deploy show 41002 | jq -er '.core.multicall')"

relayer:
  connections:
  - alias: 41001-41002
    clientA:
      chainId: "41001"
      clientId: cli-41001-41002
      signer: relayer
      type: attestation
      autoRelay:
        enabled: true
    clientB:
      chainId: "41002"
      clientId: cli-41001-41002
      signer: relayer
      type: besu
      autoRelay:
        enabled: true

attestors:
- name: attestor-41002
  type: remote
  grpc: 127.0.0.1:3001

signers:
- alias: relayer
  type: local
  file: relayer
EOF

No chain names a deployer, because this relayer deploys nothing.
The client type describes how that end verifies the opposite chain. The client on 41001 trusts the remote attestor for 41002. The client on 41002 verifies Besu proofs from 41001.
The signer on each client end is the key that submits on that end’s own chain, so one connection can use a different key per side.
autoRelay is set on each client end and governs packets leaving that end’s chain. It requires the chain’s ws endpoint.
The listen address and the database are this relayer’s own, so neither collides with the tutorial’s.

2. Validate the config

./bin/ibc config validate relayer --config ibc-relayer2.yml --live

{
  "path": "/home/you/.ibc/ibc-relayer2.yml",
  "relayer": "valid",
  "status": "valid"
}

3. Relay a packet

Start your relayer in a new terminal, and leave it running:

./bin/ibc relayer run --config ibc-relayer2.yml

level=INFO msg="Migrated database" module=bootstrap migrations_applied=4
level=INFO msg="Starting relayer" module=bootstrap
level=INFO msg=Readiness module=bootstrap readiness="{Event:ready ChainsConnected:[41001 41002] HTTP:[::]:3002}"

The relayer is running and waiting for packets. The readiness log confirms startup; use the gRPC health check to monitor ongoing API and database availability. It clears pending packets at startup, then every five minutes; relayer.clearOnStart and relayer.clearInterval change both.

Back in your first terminal, send a transfer and keep the hash:

TX=$(./bin/ibc tx ift send --chain 41001 --ift "$(./bin/ibc deploy show 41001 | jq -r '.tokens[0].address')" --client-id cli-41001-41002 --to deployer --from deployer --amount 1000000000000000000 | jq -r '.txHash') && echo "$TX"

The relayer will pick up the packet automatically and relay it to the destination.

Watch it settle:

./bin/ibc relayer packets --config ibc-relayer2.yml --chain-id 41001 --tx-hash "$TX"

It reads PACKET_STATE_PENDING until the receive and the acknowledgement have both landed, then PACKET_STATE_SUCCEEDED with all three transaction hashes.

Confirm the balance on the destination chain:

./bin/ibc query ift balance --chain 41002 --ift "$(./bin/ibc deploy show 41002 | jq -r '.tokens[0].address')" --address deployer

The balance should be one token higher, meaning the packet was delivered successfully.

About

Tutorial

Run the services

Guides

Reference

Repositories

Before you begin

1. Relayer config

2. Validate the config

3. Relay a packet

​Before you begin

​1. Relayer config

​2. Validate the config

​3. Relay a packet

Before you begin

1. Relayer config

2. Validate the config

3. Relay a packet