DEVNET.md

Ultralight Devnet Testing

There are a collection of scripts in the cli package's scripts directory to aid in setting up an ephemeral testnet and seeding it with data and initial connections.

Starting the devnet

1. Build all packages -- npm i
2. Run the devnet script from [repo root]/packages/cli -- npx ts-node --esm scripts/devnet.ts --numNodes=[Number of nodes to start]
3. Observe logs to confirm nodes are running
4. Press Ctrl+c to shutdown the devnet at any time

Notes: The nodes started by the script have a JSON-RPC server enabled. The port for the first is 8546 and ascends from there.

Seeding the devnet with content and connections

1. Start the devnet as above
2. Run the seeder script --

npx ts-node scripts/seeder.ts --rpcPort=8546 --numBlocks=[number of blocks to seed into network] --sourceFile="[path/to/json/file/with/block/data.json]" --numNodes=[number of nodes in devnet (same as above)]

This will load the first numBlocks blocks from your sourceFile to the the node with the rpcPort specified.

3. If all goes well, you should see the nodes start to connect with one another

Note: The block data file should contain a json object of the below structure where the RLP is the rlp encoded hex string form of the block:

{
    "0xblock1Hash...": {
        "rlp":"0xabcdef...",
    },
    "0xblock2Hash...": {
        "rlp":"0xabcdef...",
    },
}

The first million blocks from Ethereum mainnet can be acquired here

Monitoring the devnet

The devnet script starts each node up with a Prometheus metrics server running at the RPC port number + 10000. The seeder script outputs a file called targets.json with a list of targets to the current directory that can be provided to Prometheus for metric scraping. Add the below to your prometheus.yml config file. Note that localhost:5051 points to the proxy and reports how many packets have been sent and how many dropped, assuming you provided a value on packet loss.

scrape_configs:
  - job_name: "ultralight_devnet"

    file_sd_configs:
      - files:
        - '/path/to/targets.json'
    
    static_configs:
      - targets: ["localhost:5051"]