docs(exex): include code for ExEx book from real files (#11545)

book/sources/exex/hello-world/Cargo.toml

@@ -0,0 +1,13 @@
+[package]
+name = "my-exex"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+reth = { git = "https://github.com/paradigmxyz/reth.git" } # Reth
+reth-exex = { git = "https://github.com/paradigmxyz/reth.git" } # Execution Extensions
+reth-node-ethereum = { git = "https://github.com/paradigmxyz/reth.git" } # Ethereum Node implementation
+reth-tracing = { git = "https://github.com/paradigmxyz/reth.git" } # Logging
+
+eyre = "0.6" # Easy error handling
+futures-util = "0.3" # Stream utilities for consuming notifications

book/sources/exex/hello-world/src/bin/1.rs

@@ -0,0 +1,9 @@
+use reth_node_ethereum::EthereumNode;
+
+fn main() -> eyre::Result<()> {
+    reth::cli::Cli::parse_args().run(|builder, _| async move {
+        let handle = builder.node(EthereumNode::default()).launch().await?;
+
+        handle.wait_for_node_exit().await
+    })
+}

book/sources/exex/hello-world/src/bin/2.rs

@@ -0,0 +1,20 @@
+use reth::api::FullNodeComponents;
+use reth_exex::ExExContext;
+use reth_node_ethereum::EthereumNode;
+
+async fn my_exex<Node: FullNodeComponents>(mut _ctx: ExExContext<Node>) -> eyre::Result<()> {
+    #[allow(clippy::empty_loop)]
+    loop {}
+}
+
+fn main() -> eyre::Result<()> {
+    reth::cli::Cli::parse_args().run(|builder, _| async move {
+        let handle = builder
+            .node(EthereumNode::default())
+            .install_exex("my-exex", |ctx| async move { Ok(my_exex(ctx)) })
+            .launch()
+            .await?;
+
+        handle.wait_for_node_exit().await
+    })
+}

book/sources/exex/hello-world/src/bin/3.rs

@@ -0,0 +1,39 @@
+use futures_util::TryStreamExt;
+use reth::api::FullNodeComponents;
+use reth_exex::{ExExContext, ExExEvent, ExExNotification};
+use reth_node_ethereum::EthereumNode;
+use reth_tracing::tracing::info;
+
+async fn my_exex<Node: FullNodeComponents>(mut ctx: ExExContext<Node>) -> eyre::Result<()> {
+    while let Some(notification) = ctx.notifications.try_next().await? {
+        match &notification {
+            ExExNotification::ChainCommitted { new } => {
+                info!(committed_chain = ?new.range(), "Received commit");
+            }
+            ExExNotification::ChainReorged { old, new } => {
+                info!(from_chain = ?old.range(), to_chain = ?new.range(), "Received reorg");
+            }
+            ExExNotification::ChainReverted { old } => {
+                info!(reverted_chain = ?old.range(), "Received revert");
+            }
+        };
+
+        if let Some(committed_chain) = notification.committed_chain() {
+            ctx.events.send(ExExEvent::FinishedHeight(committed_chain.tip().num_hash()))?;
+        }
+    }
+
+    Ok(())
+}
+
+fn main() -> eyre::Result<()> {
+    reth::cli::Cli::parse_args().run(|builder, _| async move {
+        let handle = builder
+            .node(EthereumNode::default())
+            .install_exex("my-exex", |ctx| async move { Ok(my_exex(ctx)) })
+            .launch()
+            .await?;
+
+        handle.wait_for_node_exit().await
+    })
+}