Run relayer

Relayers will facilitate communication between the two chains by connecting the multi-sig account on the XRPL with the bridge smart contract on Coreum.

The relayer is sitting in between the two chains, between the multi-signing account on the XRPL and the Bridge smart contract on the Coreum blockchain.

They are responsible for listening for events on both chains and trigger actions on the XRPL and Coreum. Relayers are incentivized by receiving fees deducted from transactions.

Minimum hardware setup requirements:

• e2 small machine type with 0.5 vCPU, 2GB of memory and 20BG of disk space (mostly for logs).

Setup env variables and coreumbridge-xrpl-relayer

Pass the doc.

coreumbridge-xrpl-relayer init \
    --coreum-chain-id $COREUM_CHAIN_ID \
    --coreum-grpc-url $COREUM_GRPC_URL  \
    --xrpl-rpc-url $XRPL_RPC_URL \
    --coreum-contract-address $COREUMBRIDGE_XRPL_CONTRACT_ADDRESS

Generate the relayer keys

Generate new keys:

coreumbridge-xrpl-relayer coreum keys add coreum-relayer

coreumbridge-xrpl-relayer xrpl keys add xrpl-relayer

!!! Save output mnemonics to a safe place to be able to recover the relayer later. !!!

The coreum-relayer and xrpl-relayer are key names set by default in the relayer.yaml. If for some reason you want to update them, then updated them in the relayer.yaml as well.

Or import the existing mnemonics:

coreumbridge-xrpl-relayer coreum keys add coreum-relayer --recover

coreumbridge-xrpl-relayer xrpl keys add xrpl-relayer --recover

Extract keys info for the contract deployment

coreumbridge-xrpl-relayer relayer-keys

Output example:

Keys info
    coreumAddress: "testcore1lwzy78a7ulernmvdgvjyagaslsmp7x7g496jj4"
    xrplAddress: "r41Cc8WLZMeUvZfvB4Fc4hRjpHya4T4Nqq"
    xrplPubKey: "022ED182ACEBFE4C55CE0A0EA561468C31336F9B4E71FB487FC84D94A2826F1C10"

The output contains the coreumAddress, xrplAddress and xrplPubKey used for the contract deployment.

Create the Coreum account on chain by sending some tokens to the coreumAddress. The ideal initial amount for the relayer to operate properly is 100 COREUM.

Do the same with the XRPL account by sending 2 XRP tokens to the xrplAddress to activate it. See reserve requirements for more information.

Once the accounts are created share the public keys info with Coreum foundation.

Run

docker run -it --detach-keys="ctrl-c" --name coreumbridge-xrpl-relayer \
    -v $HOME/.coreumbridge-xrpl-relayer:/root/.coreumbridge-xrpl-relayer \
    coreumfoundation/coreumbridge-xrpl-relayer:$COREUMBRIDGE_XRPL_VERSION \
    start

Once you are attached, press any key and enter passwords for two keyrings after this, preses CTRL-c to detach from the container. It is expected that at that time the relayer is initialized and its keys are generated and accounts are funded.

When you run the relayer first time, and the keys are not included to the relayers set yet, you will see errors in the logs such as UnauthorizedSender. It is expected, don't stop the relayer. Once the relayer is included to the relayers set it will start relaying and no such error will be printed.

If the relayer metrics are enabled, you also need to forward the metrics port (default 9090). To enable them update the $HOME/.coreumbridge-xrpl-relayer/relayer.yaml config file and restart the relayer.

Restart running instance

docker stop coreumbridge-xrpl-relayer && docker rm coreumbridge-xrpl-relayer

Once the container is stopped and removed, proceed with the instructions in run section

Exposing relayer metrics

To expose metrics you need to change config located here .coreumbridge-xrpl-relayer/relayer.yaml You need to change the following section:

metrics:
    enabled: true
    server:
        listen_address: 0.0.0.0:10090 #specify the desired port to expose metrics
    periodic_collector:
        repeat_delay: 1m0s

After you've change the config you need to restart the bridge following these instructions

Here's also an example of prometheus configuration to scrape bridge metrics:

      - job_name: coreum-xrpl-mainnet-relayer
        honor_timestamps: true
        honor_labels: true
        scrape_interval: 5s
        scrape_timeout: 5s
        metrics_path: /metrics
        relabel_configs:
          - source_labels: [__address__]
            target_label: instance
            replacement: *your_relayer_instance_name*
        scheme: http
        static_configs:
          - targets:
              - *your_relayer_instance_ip*:10090