feat: add cli ext event hooks example (#4935)

bin/reth/src/cli/ext.rs

@@ -8,7 +8,7 @@ use clap::Args;
 use reth_basic_payload_builder::{BasicPayloadJobGenerator, BasicPayloadJobGeneratorConfig};
 use reth_payload_builder::{PayloadBuilderHandle, PayloadBuilderService};
 use reth_tasks::TaskSpawner;
-use std::fmt;
+use std::{fmt, marker::PhantomData};
 
 /// A trait that allows for extending parts of the CLI with additional functionality.
 ///
@@ -119,6 +119,14 @@ impl RethNodeCommandConfig for DefaultRethNodeCommandConfig {}
 
 impl RethNodeCommandConfig for () {}
 
+/// A helper type for [RethCliExt] extension that don't require any additional clap Arguments.
+#[derive(Debug, Clone, Copy)]
+pub struct NoArgsCliExt<Conf>(PhantomData<Conf>);
+
+impl<Conf: RethNodeCommandConfig> RethCliExt for NoArgsCliExt<Conf> {
+    type Node = NoArgs<Conf>;
+}
+
 /// A helper struct that allows for wrapping a [RethNodeCommandConfig] value without providing
 /// additional CLI arguments.
 ///
@@ -214,6 +222,12 @@ impl<T: RethNodeCommandConfig> RethNodeCommandConfig for NoArgs<T> {
     }
 }
 
+impl<T> From<T> for NoArgs<T> {
+    fn from(value: T) -> Self {
+        Self::with(value)
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;

bin/reth/src/cli/mod.rs

@@ -113,6 +113,15 @@ impl<Ext: RethCliExt> Cli<Ext> {
         reth_tracing::init(layers);
         Ok(guard.flatten())
     }
+
+    /// Configures the given node extension.
+    pub fn with_node_extension<C>(mut self, conf: C) -> Self
+    where
+        C: Into<Ext::Node>,
+    {
+        self.command.set_node_extension(conf.into());
+        self
+    }
 }
 
 /// Convenience function for parsing CLI options, set up logging and run the chosen command.
@@ -156,6 +165,17 @@ pub enum Commands<Ext: RethCliExt = ()> {
     Recover(recover::Command),
 }
 
+impl<Ext: RethCliExt> Commands<Ext> {
+    /// Sets the node extension if it is the [NodeCommand](node::NodeCommand).
+    ///
+    /// This is a noop if the command is not the [NodeCommand](node::NodeCommand).
+    pub fn set_node_extension(&mut self, ext: Ext::Node) {
+        if let Commands::Node(command) = self {
+            command.ext = ext
+        }
+    }
+}
+
 /// The log configuration.
 #[derive(Debug, Args)]
 #[command(next_help_heading = "Logging")]