#2511: extended reth-rpc example with custom rpc ext (#4508)

Co-authored-by: Matthias Seitz <matthias.seitz@outlook.de>

Cargo.lock

@@ -6327,6 +6327,17 @@ version = "0.3.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "afab94fb28594581f62d981211a9a4d53cc8130bbcbbb89a0440d9b8e81a7746"
 
+[[package]]
+name = "rpc-db"
+version = "0.0.0"
+dependencies = [
+ "eyre",
+ "futures",
+ "jsonrpsee",
+ "reth",
+ "tokio",
+]
+
 [[package]]
 name = "ruint"
 version = "1.10.1"

Cargo.toml

@@ -48,6 +48,7 @@ members = [
     "crates/rpc/rpc-types-compat",
     "examples",
     "examples/additional-rpc-namespace-in-cli",
+    "examples/rpc-db",
 ]
 default-members = ["bin/reth"]
 

bin/reth/src/lib.rs

@@ -46,6 +46,25 @@ pub mod providers {
     pub use reth_provider::*;
 }
 
+/// Re-exported from `reth_primitives`.
+pub mod primitives {
+    pub use reth_primitives::*;
+}
+
+/// Re-exported from `reth_beacon_consensus`.
+pub mod beacon_consensus {
+    pub use reth_beacon_consensus::*;
+}
+/// Re-exported from `reth_blockchain_tree`.
+pub mod blockchain_tree {
+    pub use reth_blockchain_tree::*;
+}
+
+/// Re-exported from `reth_revm`.
+pub mod revm {
+    pub use reth_revm::*;
+}
+
 /// Re-exported from `reth_tasks`.
 pub mod tasks {
     pub use reth_tasks::*;
@@ -79,6 +98,10 @@ pub mod rpc {
     pub mod api {
         pub use reth_rpc_api::*;
     }
+    /// Re-exported from `reth_rpc::eth`.
+    pub mod eth {
+        pub use reth_rpc::eth::*;
+    }
 }
 
 #[cfg(all(feature = "jemalloc", unix))]

bin/reth/src/utils.rs

@@ -26,6 +26,11 @@ use std::{
 };
 use tracing::info;
 
+/// Exposing `open_db_read_only` function
+pub mod db {
+    pub use reth_db::open_db_read_only;
+}
+
 /// Get a single header from network
 pub async fn get_single_header<Client>(
     client: Client,

examples/Cargo.toml

@@ -28,10 +28,6 @@ futures.workspace = true
 async-trait.workspace = true
 tokio.workspace = true
 
-[[example]]
-name = "rpc-db"
-path = "rpc-db.rs"
-
 [[example]]
 name = "db-access"
 path = "db-access.rs"

examples/rpc-db/Cargo.toml

@@ -0,0 +1,13 @@
+[package]
+name = "rpc-db"
+version = "0.0.0"
+publish = false
+edition.workspace = true
+license.workspace = true
+
+[dependencies]
+futures.workspace = true
+jsonrpsee.workspace = true
+reth.workspace = true
+tokio = { workspace = true, features = ["full"] }
+eyre = "0.6.8"

examples/rpc-db/src/main.rs

@@ -1,31 +1,45 @@
-// Talking to the DB
-use reth_db::open_db_read_only;
-use reth_primitives::ChainSpecBuilder;
-use reth_provider::{providers::BlockchainProvider, ProviderFactory};
-
+//! Example illustrating how to run the ETH JSON RPC API as standalone over a DB file.
+//!
+//! Run with
+//!
+//! ```not_rust
+//! cargo run -p rpc-db
+//! ```
+//!
+//! This installs an additional RPC method `myrpcExt_customMethod` that can queried via [cast](https://github.com/foundry-rs/foundry)
+//!
+//! ```sh
+//! cast rpc myrpcExt_customMethod
+//! ```
+use reth::{
+    primitives::ChainSpecBuilder,
+    providers::{providers::BlockchainProvider, ProviderFactory},
+    utils::db::open_db_read_only,
+};
 // Bringing up the RPC
-use reth_rpc_builder::{
+use reth::rpc::builder::{
     RethRpcModule, RpcModuleBuilder, RpcServerConfig, TransportRpcModuleConfig,
 };
 
 // Code which we'd ideally like to not need to import if you're only spinning up
 // read-only parts of the API and do not require access to pending state or to
 // EVM sims
-use reth_beacon_consensus::BeaconConsensus;
-use reth_blockchain_tree::{
-    BlockchainTree, BlockchainTreeConfig, ShareableBlockchainTree, TreeExternals,
+use reth::{
+    beacon_consensus::BeaconConsensus,
+    blockchain_tree::{
+        BlockchainTree, BlockchainTreeConfig, ShareableBlockchainTree, TreeExternals,
+    },
+    revm::Factory as ExecutionFactory,
 };
-use reth_revm::Factory as ExecutionFactory;
+
 // Configuring the network parts, ideally also wouldn't ned to think about this.
-use reth_network_api::noop::NoopNetwork;
-use reth_provider::test_utils::TestCanonStateSubscriptions;
-use reth_tasks::TokioTaskExecutor;
-use reth_transaction_pool::noop::NoopTransactionPool;
+use reth::{providers::test_utils::TestCanonStateSubscriptions, tasks::TokioTaskExecutor};
 use std::{path::Path, sync::Arc};
 
-// Example illustrating how to run the ETH JSON RPC API as standalone over a DB file.
-// TODO: Add example showing how to spin up your own custom RPC namespace alongside
-// the other default name spaces.
+use myrpc_ext::{MyRpcExt, MyRpcExtApiServer};
+// Custom rpc extension
+pub mod myrpc_ext;
+
 #[tokio::main]
 async fn main() -> eyre::Result<()> {
     // 1. Setup the DB
@@ -55,16 +69,20 @@ async fn main() -> eyre::Result<()> {
     };
 
     let rpc_builder = RpcModuleBuilder::default()
-        .with_provider(provider)
+        .with_provider(provider.clone())
         // Rest is just noops that do nothing
-        .with_pool(NoopTransactionPool::default())
-        .with_network(NoopNetwork::default())
+        .with_noop_pool()
+        .with_noop_network()
         .with_executor(TokioTaskExecutor::default())
         .with_events(TestCanonStateSubscriptions::default());
 
     // Pick which namespaces to expose.
     let config = TransportRpcModuleConfig::default().with_http([RethRpcModule::Eth]);
-    let server = rpc_builder.build(config);
+    let mut server = rpc_builder.build(config);
+
+    // Add a custom rpc namespace
+    let custom_rpc = MyRpcExt { provider };
+    server.merge_configured(custom_rpc.into_rpc())?;
 
     // Start the server & keep it alive
     let server_args =

examples/rpc-db/src/myrpc_ext.rs

@@ -0,0 +1,33 @@
+// Reth block related imports
+use reth::{primitives::Block, providers::BlockReaderIdExt};
+
+// Rpc related imports
+use jsonrpsee::proc_macros::rpc;
+use reth::rpc::eth::error::EthResult;
+
+/// trait interface for a custom rpc namespace: `MyRpc`
+///
+/// This defines an additional namespace where all methods are configured as trait functions.
+#[rpc(server, namespace = "myrpcExt")]
+pub trait MyRpcExtApi {
+    /// Returns block 0.
+    #[method(name = "customMethod")]
+    fn custom_method(&self) -> EthResult<Option<Block>>;
+}
+
+/// The type that implements `myRpc` rpc namespace trait
+pub struct MyRpcExt<Provider> {
+    pub provider: Provider,
+}
+
+impl<Provider> MyRpcExtApiServer for MyRpcExt<Provider>
+where
+    Provider: BlockReaderIdExt + 'static,
+{
+    /// Showcasing how to implement a custom rpc method
+    /// using the provider.
+    fn custom_method(&self) -> EthResult<Option<Block>> {
+        let block = self.provider.block_by_number(0)?;
+        Ok(block)
+    }
+}