[DRAFT] Pedro/tru 356 store necessary data locally for the proof of concept

crates/forrestrie-examples/examples/dump_state_to_json.rs

@@ -0,0 +1,34 @@
+/*
+Copyright 2024-, Semiotic AI, Inc.
+SPDX-License-Identifier: Apache-2.0
+*/
+
+//! Dumps a single head state into json. Useful for not relying on fetching it,
+//! decreases the time necessary for verifying a proof.
+use std::{fs::File, io::Write};
+
+use forrestrie::beacon_state::HeadState;
+use types::MainnetEthSpec;
+
+const LIGHT_CLIENT_DATA_URL: &str =
+    "https://www.lightclientdata.org/eth/v2/debug/beacon/states/head";
+
+#[tokio::main]
+async fn main() {
+    // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+    // Get the head state of the Beacon chain from a Beacon API provider.
+    let state_handle = tokio::spawn(async move {
+        let url = LIGHT_CLIENT_DATA_URL.to_string();
+        println!("Requesting head state ... (this can take a while!)");
+        let response = reqwest::get(url).await.unwrap();
+        let head_state: HeadState<MainnetEthSpec> = response.json().await.unwrap();
+        head_state
+    });
+
+    let mut file = File::create("head_state.json").expect("Failed to create file");
+    let head_state = state_handle.await.unwrap();
+    let json_string =
+        serde_json::to_string(&head_state).expect("Failed to serialize head_state to JSON");
+    file.write_all(json_string.as_bytes())
+        .expect("Failed to write to file");
+}

crates/forrestrie-examples/examples/post_capella_era_from_deserialize.rs

@@ -0,0 +1,98 @@
+// Copyright 2024-, Semiotic AI, Inc.
+// SPDX-License-Identifier: Apache-2.0
+
+//! In this example, we verify a complete era of beacon blocks to be canonical.
+//! We first read from storage a complete era of beacon blocks (8192 beacon blocks), compute the associated historical summary and
+//! compare it against the historical summary from a current consensus stated.
+
+use std::{fs::File, io::Read};
+
+use forrestrie::beacon_state::{
+    compute_block_roots_proof_only, HeadState, CAPELLA_START_ERA, HISTORY_TREE_DEPTH,
+    SLOTS_PER_HISTORICAL_ROOT,
+};
+use primitive_types::H256;
+use trin_validation::constants::EPOCH_SIZE;
+use types::{historical_summary::HistoricalSummary, MainnetEthSpec};
+
+use merkle_proof::verify_merkle_proof;
+use merkle_proof::MerkleTree;
+
+/// This slot is the starting slot of the Beacon block era.
+const BEACON_SLOT_NUMBER: u64 = 10436608;
+
+#[tokio::main]
+async fn main() {
+    println!("this also takes a while because the HeadState is a 700mb file");
+    // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+    // Get the head state of the Beacon chain from deserializing storage.
+    let mut file = File::open("head_state.json").expect("Failed to open file");
+    let mut json_string = String::new();
+    file.read_to_string(&mut json_string)
+        .expect("Failed to read file");
+
+    let head_state: HeadState<MainnetEthSpec> =
+        serde_json::from_str(&json_string).expect("Failed to deserialize head_state from JSON");
+
+    // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+    // get the block roots from deserializing storage.
+    let mut file = File::open("beacon_block_roots.json").expect("Failed to open file");
+    let mut json_string = String::new();
+    file.read_to_string(&mut json_string)
+        .expect("Failed to read file");
+
+    let beacon_block_roots: Vec<H256> =
+        serde_json::from_str(&json_string).expect("Failed to deserialize head_state from JSON");
+
+    let era = BEACON_SLOT_NUMBER as usize / SLOTS_PER_HISTORICAL_ROOT;
+    let era_index = era - CAPELLA_START_ERA;
+
+    // Caculate the block_summary_root from the beacon blocks. Note that the block_summary_root is a field in the HistoricalSummary.
+    let beacon_block_roots_tree_hash_root =
+        MerkleTree::create(&beacon_block_roots, HISTORY_TREE_DEPTH).hash();
+
+    let historical_summary: &HistoricalSummary = head_state
+        .data()
+        .historical_summaries()
+        .unwrap()
+        .get(era_index)
+        .unwrap();
+
+    let block_summary_root = historical_summary.block_summary_root();
+    println!(
+        "{:?}, {:?}",
+        beacon_block_roots_tree_hash_root, block_summary_root
+    );
+
+    // if the roots match, it means that the whole era is included in the historical_summary
+    assert_eq!(beacon_block_roots_tree_hash_root, block_summary_root);
+
+    // It is also possible to make a verifiable merkle proof for it
+
+    let index = BEACON_SLOT_NUMBER as usize % SLOTS_PER_HISTORICAL_ROOT as usize;
+    let proof =
+        compute_block_roots_proof_only::<MainnetEthSpec>(&beacon_block_roots, index).unwrap();
+
+    let block_roots_tree_hash_root = historical_summary.block_summary_root();
+    assert_eq!(proof.len(), HISTORY_TREE_DEPTH);
+
+    // Verify the proof for a single block
+    let historical_root_index: i32 = (BEACON_SLOT_NUMBER as usize % EPOCH_SIZE as usize)
+        .try_into()
+        .unwrap();
+    let block_root = beacon_block_roots[historical_root_index as usize];
+
+    assert!(
+        verify_merkle_proof(
+            // This is the equivalent beacon root of the slot in BEACON_SLOT_NUMBER constant
+            block_root,
+            &proof,             // the proof of the block's inclusion in the block roots
+            HISTORY_TREE_DEPTH, // the depth of the block roots tree
+            index,              // the index of the block in the era
+            block_roots_tree_hash_root  // The root of the block roots
+        ),
+        "Merkle proof verification failed"
+    );
+
+    println!("successfully verified merkle proof")
+}