docs: add docs for instantiating EthFilter (#14224)

Co-authored-by: Dan Cline <6798349+Rjected@users.noreply.github.com>

crates/rpc/rpc-eth-api/src/types.rs

@@ -1,19 +1,24 @@
 //! Trait for specifying `eth` network dependent API types.
 
-use std::{
-    error::Error,
-    fmt::{self},
-};
-
+use crate::{AsEthApiError, FromEthApiError, RpcNodeCore};
 use alloy_network::Network;
 use alloy_rpc_types_eth::Block;
 use reth_provider::{ProviderTx, ReceiptProvider, TransactionsProvider};
 use reth_rpc_types_compat::TransactionCompat;
 use reth_transaction_pool::{PoolTransaction, TransactionPool};
-
-use crate::{AsEthApiError, FromEthApiError, RpcNodeCore};
+use std::{
+    error::Error,
+    fmt::{self},
+};
 
 /// Network specific `eth` API types.
+///
+/// This trait defines the network specific rpc types and helpers required for the `eth_` and
+/// adjacent endpoints. `NetworkTypes` is [`Network`] as defined by the alloy crate, see also
+/// [`alloy_network::Ethereum`].
+///
+/// This type is stateful so that it can provide additional context if necessary, e.g. populating
+/// receipts with additional data.
 pub trait EthApiTypes: Send + Sync + Clone {
     /// Extension of [`FromEthApiError`], with network specific errors.
     type Error: Into<jsonrpsee_types::error::ErrorObject<'static>>

crates/rpc/rpc/src/eth/core.rs

@@ -40,6 +40,11 @@ const DEFAULT_BROADCAST_CAPACITY: usize = 2000;
 /// separately in submodules. The rpc handler implementation can then delegate to the main impls.
 /// This way [`EthApi`] is not limited to [`jsonrpsee`] and can be used standalone or in other
 /// network handlers (for example ipc).
+///
+/// ## Trait requirements
+///
+/// While this type requires various unrestricted generic components, trait bounds are enforced when
+/// additional traits are implemented for this type.
 #[derive(Deref)]
 pub struct EthApi<Provider: BlockReader, Pool, Network, EvmConfig> {
     /// All nested fields bundled together.
@@ -62,7 +67,31 @@ impl<Provider, Pool, Network, EvmConfig> EthApi<Provider, Pool, Network, EvmConf
 where
     Provider: BlockReaderIdExt,
 {
-    /// Convenience fn to obtain a new [`EthApiBuilder`] instance with mandatory components
+    /// Convenience fn to obtain a new [`EthApiBuilder`] instance with mandatory components.
+    ///
+    /// Creating an [`EthApi`] requires a few mandatory components:
+    ///  - provider: The type responsible for fetching requested data from disk.
+    ///  - transaction pool: To interact with the pool, submitting new transactions (e.g.
+    ///    `eth_sendRawTransactions`).
+    ///  - network: required to handle requests related to network state (e.g. `eth_syncing`).
+    ///  - evm config: Knows how create a new EVM instance to transact,estimate,call,trace.
+    ///
+    /// # Create an instance with noop ethereum implementations
+    ///
+    /// ```no_run
+    /// use reth_evm_ethereum::EthEvmConfig;
+    /// use reth_network_api::noop::NoopNetwork;
+    /// use reth_provider::noop::NoopProvider;
+    /// use reth_rpc::EthApi;
+    /// use reth_transaction_pool::noop::NoopTransactionPool;
+    /// let eth_api = EthApi::builder(
+    ///     NoopProvider::default(),
+    ///     NoopTransactionPool::default(),
+    ///     NoopNetwork::default(),
+    ///     EthEvmConfig::mainnet(),
+    /// )
+    /// .build();
+    /// ```
     pub fn builder(
         provider: Provider,
         pool: Pool,

crates/rpc/rpc/src/eth/filter.rs

@@ -43,6 +43,8 @@ use tracing::{error, trace};
 const MAX_HEADERS_RANGE: u64 = 1_000; // with ~530bytes per header this is ~500kb
 
 /// `Eth` filter RPC implementation.
+///
+/// This type handles `eth_` rpc requests related to filters (`eth_getLogs`).
 pub struct EthFilter<Eth: EthApiTypes> {
     /// All nested fields bundled together
     inner: Arc<EthFilterInner<Eth>>,
@@ -69,6 +71,25 @@ where
     /// See also [`EthFilterConfig`].
     ///
     /// This also spawns a task that periodically clears stale filters.
+    ///
+    /// # Create a new instance with [`EthApi`](crate::EthApi)
+    ///
+    /// ```no_run
+    /// use reth_evm_ethereum::EthEvmConfig;
+    /// use reth_network_api::noop::NoopNetwork;
+    /// use reth_provider::noop::NoopProvider;
+    /// use reth_rpc::{EthApi, EthFilter};
+    /// use reth_tasks::TokioTaskExecutor;
+    /// use reth_transaction_pool::noop::NoopTransactionPool;
+    /// let eth_api = EthApi::builder(
+    ///     NoopProvider::default(),
+    ///     NoopTransactionPool::default(),
+    ///     NoopNetwork::default(),
+    ///     EthEvmConfig::mainnet(),
+    /// )
+    /// .build();
+    /// let filter = EthFilter::new(eth_api, Default::default(), TokioTaskExecutor::default().boxed());
+    /// ```
     pub fn new(eth_api: Eth, config: EthFilterConfig, task_spawner: Box<dyn TaskSpawner>) -> Self {
         let EthFilterConfig { max_blocks_per_filter, max_logs_per_response, stale_filter_ttl } =
             config;