# web3-proxy

Web3-proxy is a fast caching and load balancing proxy for web3 (Ethereum or similar) JsonRPC servers.

**Under construction!** This code is under active development. The basics seem to work, but theres lots of tests and features to write still.

Signed transactions (eth_sendRawTransaction) are sent in parallel to the configured private RPCs (eden, ethermine, flashbots, etc.).

All other requests are sent to an RPC server on the latest block (alchemy, moralis, rivet, your own node, or one of many other providers). If multiple servers are in sync, they are prioritized by `active_requests/soft_limit`. Note that this means that the fastest server is most likely to serve requests and slow servers are unlikely to ever get any requests.

Each server has different limits to configure. The `soft_limit` is the number of parallel active requests where a server starts to slow down. The `hard_limit` is where a server starts giving rate limits or other errors.

```
$ cargo install sea-orm-cli
$ cargo run --release -- --help
```
```
   Compiling web3-proxy v0.1.0 (/home/bryan/src/web3-proxy/web3-proxy)
    Finished release [optimized + debuginfo] target(s) in 17.69s
     Running `target/release/web3-proxy --help`
Usage: web3-proxy [--port <port>] [--workers <workers>] [--config <config>]

Web3-proxy is a fast caching and load balancing proxy for web3 (Ethereum or similar) JsonRPC servers.

Options:
  --port            what port the proxy should listen on
  --workers         number of worker threads
  --config          path to a toml of rpc servers
  --help            display usage information
```

Start the server with the defaults (listen on `http://localhost:8544` and use `./config/example.toml` which proxies to a bunch of public nodes:

```
cargo run --release -- --config ./config/example.toml
```

## Common commands

Check that the proxy is working:

```
curl -X POST -H "Content-Type: application/json" --data '{"jsonrpc":"2.0","method":"web3_clientVersion","id":1}' 127.0.0.1:8544
```

Check that the websocket is working:

```
$ websocat ws://127.0.0.1:8544

{"id": 1, "method": "eth_subscribe", "params": ["newHeads"]}

{"id": 2, "method": "eth_subscribe", "params": ["newPendingTransactions"]}

{"id": 3, "method": "eth_subscribe", "params": ["newPendingFullTransactions"]}

{"id": 4, "method": "eth_subscribe", "params": ["newPendingRawTransactions"]}
```

You can copy `config/example.toml` to `config/production-$CHAINNAME.toml` and then run `docker-compose up --build -d` start proxies for many chains.

## Flame Graphs

Flame graphs make finding slow code painless:

    $ cat /proc/sys/kernel/kptr_restrict
    1
    $ echo 0 | sudo tee /proc/sys/kernel/kptr_restrict
    0
    $ CARGO_PROFILE_RELEASE_DEBUG=true cargo flamegraph


## GDB

Run the proxy under gdb for advanced debugging:

    cargo build --release && RUST_LOG=web3_proxy=debug rust-gdb --args target/debug/web3-proxy --listen-port 7503 --rpc-config-path ./config/production-eth.toml

TODO: also enable debug symbols in the release build by modifying the root Cargo.toml

## Load Testing

Test the proxy:

    wrk -s ./data/wrk/getBlockNumber.lua -t12 -c400 -d30s --latency http://127.0.0.1:8544
    wrk -s ./data/wrk/getLatestBlockByNumber.lua -t12 -c400 -d30s --latency http://127.0.0.1:8544

Test geth (assuming it is on 8545):

    wrk -s ./data/wrk/getBlockNumber.lua -t12 -c400 -d30s --latency http://127.0.0.1:8545
    wrk -s ./data/wrk/getLatestBlockByNumber.lua -t12 -c400 -d30s --latency http://127.0.0.1:8545

Test erigon (assuming it is on 8945):

    wrk -s ./data/wrk/getBlockNumber.lua -t12 -c400 -d30s --latency http://127.0.0.1:8945
    wrk -s ./data/wrk/getLatestBlockByNumber.lua -t12 -c400 -d30s --latency http://127.0.0.1:8945

Note: Testing with `getLatestBlockByNumber.lua` is not great because the latest block changes and so one run is likely to be very different than another.

Run ethspam for a more realistic load test:

    docker run --rm --name spam shazow/ethspam --rpc http://$LOCAL_IP:8544 | versus --concurrency=100 --stop-after=10000 http://$LOCAL_IP:8544; docker stop spam