Creates example code that processes beacon blocks from slots 2000-2034

Cargo.toml

@@ -56,3 +56,6 @@ quote = "1.0.18"
 clap = { version = "4.5.3", features = ["derive"] }
 convert_case = "0.6.0"
 walkdir = "2.3.3"
+
+[profile.release]
+debug = true

ethereum-consensus/examples/data/beacon_blocks/block_2005.ssz

@@ -0,0 +1 @@
+{"code":404,"message":"NOT_FOUND: beacon block at slot 2005","stacktraces":[]}

ethereum-consensus/examples/data/beacon_blocks/block_2006.ssz

@@ -0,0 +1 @@
+{"code":404,"message":"NOT_FOUND: beacon block at slot 2006","stacktraces":[]}

ethereum-consensus/examples/data/beacon_blocks/block_2033.ssz

@@ -0,0 +1 @@
+{"code":404,"message":"NOT_FOUND: beacon block at slot 2033","stacktraces":[]}

ethereum-consensus/examples/state_transition_mainnet_blocks.rs

@@ -0,0 +1,49 @@
+use ethereum_consensus::{
+    phase0::mainnet as spec,
+    state_transition::mainnet::{Context, Executor},
+    types::{mainnet::SignedBeaconBlock, BeaconState},
+};
+use ssz_rs::prelude::*;
+use std::{error::Error, fs};
+
+fn main() -> std::result::Result<(), Box<dyn Error>> {
+    println!("this example illustrates how the spec applies state transitions to mainnet data.");
+
+    // Read and deserialize prestate
+    let state_path = "./ethereum-consensus/examples/data/beacon_states/state_1999.ssz";
+    let f = fs::read(state_path).unwrap();
+    let prestate = spec::BeaconState::deserialize(&f)?;
+    let prestate = BeaconState::Phase0(prestate);
+
+    // Create executor
+    let context = Context::for_mainnet();
+    let mut executor = Executor::new(prestate, context);
+
+    // Read and process blocks 2000-2034
+    for slot in 2000..=2034 {
+        let block_path =
+            format!("./ethereum-consensus/examples/data/beacon_blocks/block_{}.ssz", slot);
+        let block_bytes = fs::read(&block_path)?;
+
+        // Error handling: skip missed slots
+        if block_bytes.len() < 100 {
+            match std::str::from_utf8(&block_bytes) {
+                Ok(text) if text.contains("NOT_FOUND") => {
+                    println!("Slot {} was skipped (no block produced)", slot);
+                    continue;
+                }
+                _ => {
+                    println!("Unexpected small file for slot {}", slot);
+                    continue;
+                }
+            }
+        }
+
+        // Process block
+        let signed_block = spec::SignedBeaconBlock::deserialize(&block_bytes)?;
+        let block = SignedBeaconBlock::Phase0(signed_block);
+        executor.apply_block(&block)?;
+        println!("Block at slot {} was processed.", slot)
+    }
+    Ok(())
+}