chore: add example how to install additional rpc namespace

Cargo.toml

@@ -47,6 +47,7 @@ members = [
     "testing/ef-tests",
 
     "examples",
+    "examples/additional-rpc-namespace-in-cli",
 ]
 default-members = ["bin/reth"]
 
@@ -84,6 +85,7 @@ revm-primitives = { git = "https://github.com/bluealloy/revm/", branch = "releas
 ## reth
 revm = { version = "3" }
 revm-primitives = "1.1"
+reth = { path = "./bin/reth" }
 reth-primitives = { path = "./crates/primitives" }
 reth-interfaces = { path = "./crates/interfaces" }
 reth-provider = { path = "./crates/storage/provider" }

bin/reth/Cargo.toml

@@ -26,6 +26,8 @@ reth-blockchain-tree = { path = "../../crates/blockchain-tree" }
 reth-rpc-engine-api = { path = "../../crates/rpc/rpc-engine-api" }
 reth-rpc-builder = { path = "../../crates/rpc/rpc-builder" }
 reth-rpc = { path = "../../crates/rpc/rpc" }
+reth-rpc-types = { path = "../../crates/rpc/rpc-types" }
+reth-rpc-api = { path = "../../crates/rpc/rpc-api" }
 reth-rlp.workspace = true
 reth-network = { path = "../../crates/net/network", features = ["serde"] }
 reth-network-api.workspace = true

bin/reth/src/cli/mod.rs

@@ -57,7 +57,7 @@ pub struct Cli<Ext: RethCliExt = ()> {
     verbosity: Verbosity,
 }
 
-impl Cli {
+impl<Ext: RethCliExt> Cli<Ext> {
     /// Execute the configured cli command.
     pub fn run(mut self) -> eyre::Result<()> {
         // add network name to logs dir
@@ -98,7 +98,7 @@ impl Cli {
 /// Convenience function for parsing CLI options, set up logging and run the chosen command.
 #[inline]
 pub fn run() -> eyre::Result<()> {
-    Cli::parse().run()
+    Cli::<()>::parse().run()
 }
 
 /// Commands to be executed

bin/reth/src/lib.rs

@@ -40,5 +40,45 @@ pub mod test_vectors;
 pub mod utils;
 pub mod version;
 
+/// Re-exported from `reth_provider`.
+pub mod providers {
+    pub use reth_provider::*;
+}
+
+/// Re-exported from `reth_tasks`.
+pub mod tasks {
+    pub use reth_tasks::*;
+}
+
+/// Re-exported from `reth_network`.
+pub mod network {
+    pub use reth_network::*;
+    pub use reth_network_api::{noop, reputation, NetworkInfo, PeerKind, Peers, PeersInfo};
+}
+
+/// Re-exported from `reth_transaction_pool`.
+pub mod transaction_pool {
+    pub use reth_transaction_pool::*;
+}
+
+/// Re-export of `reth_rpc_*` crates.
+pub mod rpc {
+
+    /// Re-exported from `reth_rpc_builder`.
+    pub mod builder {
+        pub use reth_rpc_builder::*;
+    }
+
+    /// Re-exported from `reth_rpc_types`.
+    pub mod types {
+        pub use reth_rpc_types::*;
+    }
+
+    /// Re-exported from `reth_rpc_api`.
+    pub mod api {
+        pub use reth_rpc_api::*;
+    }
+}
+
 #[cfg(all(feature = "jemalloc", unix))]
 use jemallocator as _;

bin/reth/src/node/mod.rs

@@ -145,7 +145,7 @@ pub struct Command<Ext: RethCliExt = ()> {
     dev: DevArgs,
 }
 
-impl Command {
+impl<Ext: RethCliExt> Command<Ext> {
     /// Execute `node` command
     pub async fn execute(self, ctx: CliContext) -> eyre::Result<()> {
         info!(target: "reth::cli", "reth {} starting", SHORT_VERSION);

crates/rpc/rpc-builder/src/lib.rs

@@ -731,6 +731,21 @@ impl<Provider, Pool, Network, Tasks, Events>
         }
     }
 
+    /// Returns a reference to the provider
+    pub fn pool(&self) -> &Pool {
+        &self.pool
+    }
+
+    /// Returns a reference to the events type
+    pub fn events(&self) -> &Events {
+        &self.events
+    }
+
+    /// Returns a reference to the tasks type
+    pub fn tasks(&self) -> &Tasks {
+        &self.executor
+    }
+
     /// Returns all installed methods
     pub fn methods(&self) -> Vec<Methods> {
         self.modules.values().cloned().collect()
@@ -1499,8 +1514,8 @@ impl TransportRpcModules<()> {
         &mut self,
         other: impl Into<Methods>,
     ) -> Result<bool, jsonrpsee::core::error::Error> {
-        if let Some(ref mut http) = self.http {
-            return http.merge(other.into()).map(|_| true)
+        if let Some(ref mut ipc) = self.ipc {
+            return ipc.merge(other.into()).map(|_| true)
         }
         Ok(false)
     }

examples/additional-rpc-namespace-in-cli/Cargo.toml

@@ -0,0 +1,14 @@
+[package]
+name = "additional-rpc-namespace-in-cli"
+version = "0.0.0"
+publish = false
+edition.workspace = true
+license.workspace = true
+
+[dependencies]
+reth.workspace = true
+reth-transaction-pool.workspace = true
+
+clap = { version = "4", features = ["derive"] }
+jsonrpsee = { workspace = true, features = ["server", "macros"] }
+eyre = "0.6"

examples/additional-rpc-namespace-in-cli/src/main.rs

@@ -0,0 +1,112 @@
+//! Example of how to use additional rpc namespaces in the reth CLI
+//!
+//! Run with
+//!
+//! ```not_rust
+//! cargo run -p additional-rpc-namespace-in-cli -- node --http --ws --enable-ext
+//! ```
+//!
+//! This installs an additional RPC method `txpoolExt_transactionCount` that can queried via [cast](https://github.com/foundry-rs/foundry)
+//!
+//! ```sh
+//! cast rpc txpoolExt_transactionCount
+//! ```
+use clap::Parser;
+use jsonrpsee::{core::RpcResult, proc_macros::rpc};
+use reth::{
+    cli::{
+        ext::{RethCliExt, RethRpcConfig, RethRpcServerArgsExt},
+        Cli,
+    },
+    network::{NetworkInfo, Peers},
+    providers::{
+        BlockReaderIdExt, CanonStateSubscriptions, ChainSpecProvider, ChangeSetReader,
+        EvmEnvProvider, StateProviderFactory,
+    },
+    rpc::builder::{RethModuleRegistry, TransportRpcModules},
+    tasks::TaskSpawner,
+};
+use reth_transaction_pool::TransactionPool;
+
+fn main() {
+    Cli::<MyRethCliExt>::parse().run().unwrap();
+}
+
+/// The type that tells the reth CLI what extensions to use
+struct MyRethCliExt;
+
+impl RethCliExt for MyRethCliExt {
+    /// This tells the reth CLI to install the `txpool` rpc namespace via `RethCliTxpoolExt`
+    type RpcExt = RethCliTxpoolExt;
+}
+
+/// Our custom cli args extension that adds one flag to reth default CLI.
+#[derive(Debug, Clone, Copy, Default, clap::Args)]
+struct RethCliTxpoolExt {
+    /// CLI flag to enable the txpool extension namespace
+    #[clap(long)]
+    pub enable_ext: bool,
+}
+
+impl RethRpcServerArgsExt for RethCliTxpoolExt {
+    // This is the entrypoint for the CLI to extend the RPC server with custom rpc namespaces.
+    fn extend_rpc_modules<Conf, Provider, Pool, Network, Tasks, Events>(
+        &self,
+        _config: &Conf,
+        registry: &mut RethModuleRegistry<Provider, Pool, Network, Tasks, Events>,
+        modules: &mut TransportRpcModules<()>,
+    ) -> eyre::Result<()>
+    where
+        Conf: RethRpcConfig,
+        Provider: BlockReaderIdExt
+            + StateProviderFactory
+            + EvmEnvProvider
+            + ChainSpecProvider
+            + ChangeSetReader
+            + Clone
+            + Unpin
+            + 'static,
+        Pool: TransactionPool + Clone + 'static,
+        Network: NetworkInfo + Peers + Clone + 'static,
+        Tasks: TaskSpawner + Clone + 'static,
+        Events: CanonStateSubscriptions + Clone + 'static,
+    {
+        if !self.enable_ext {
+            return Ok(())
+        }
+
+        // here we get the configured pool type from the CLI.
+        let pool = registry.pool().clone();
+        let ext = TxpoolExt { pool };
+
+        // now we merge our extension namespace into all configured transports
+        modules.merge_configured(ext.into_rpc())?;
+
+        println!("txpool extension enabled");
+        Ok(())
+    }
+}
+
+/// trait interface for a custom rpc namespace: `txpool`
+///
+/// This defines an additional namespace where all methods are configured as trait functions.
+#[rpc(server, namespace = "txpoolExt")]
+pub trait TxpoolExtApi {
+    /// Returns the number of transactions in the pool.
+    #[method(name = "transactionCount")]
+    fn transaction_count(&self) -> RpcResult<usize>;
+}
+
+/// The type that implements the `txpool` rpc namespace trait
+pub struct TxpoolExt<Pool> {
+    pool: Pool,
+}
+
+impl<Pool> TxpoolExtApiServer for TxpoolExt<Pool>
+where
+    Pool: TransactionPool + Clone + 'static,
+{
+    fn transaction_count(&self) -> RpcResult<usize> {
+        Ok(self.pool.pool_size().total)
+    }
+}