feat: add expected_network_height metric

CHANGELOG.md

@@ -83,6 +83,9 @@
 - [#4315](https://github.com/ChainSafe/forest/pull/4315) Add support for the
   `Filecoin.StateGetNetworkParams` RPC method.
 
+- [#4326](https://github.com/ChainSafe/forest/pull/4326) Added
+  `expected_network_height` metric to the Prometheus metrics.
+
 ### Changed
 
 - [#4170](https://github.com/ChainSafe/forest/pull/4170) Change the default

src/chain_sync/chain_muxer.rs

@@ -8,7 +8,6 @@ use std::{
     time::SystemTime,
 };
 
-use crate::blocks::{Block, CreateTipsetError, FullTipset, GossipBlock, Tipset, TipsetKey};
 use crate::chain::{ChainStore, Error as ChainStoreError};
 use crate::libp2p::{
     hello::HelloRequest, NetworkEvent, NetworkMessage, PeerId, PeerManager, PubsubMessage,
@@ -17,6 +16,10 @@ use crate::message::SignedMessage;
 use crate::message_pool::{MessagePool, Provider};
 use crate::shim::{clock::SECONDS_IN_DAY, message::Message};
 use crate::state_manager::StateManager;
+use crate::{
+    blocks::{Block, CreateTipsetError, FullTipset, GossipBlock, Tipset, TipsetKey},
+    networks::calculate_expected_epoch,
+};
 use cid::Cid;
 use futures::{
     future::{try_join_all, Future},
@@ -567,7 +570,7 @@ where
         let chain_store = self.state_manager.chain_store().clone();
         let network = self.network.clone();
         let genesis = self.genesis.clone();
-        let genesis_timestamp = self.genesis.block_headers().first().timestamp as i64;
+        let genesis_timestamp = self.genesis.block_headers().first().timestamp;
         let bad_block_cache = self.bad_blocks.clone();
         let mem_pool = self.mpool.clone();
         let tipset_sample_size = self.state_manager.sync_config().tipset_sample_size;
@@ -579,11 +582,11 @@ where
             // Otherwise in some conditions, `forest-cli sync wait` takes very long to exit (only when the node enters FOLLOW mode)
             match (
                 chain_store.heaviest_tipset().epoch(),
-                get_now_epoch(
-                    chrono::Utc::now().timestamp(),
+                calculate_expected_epoch(
+                    chrono::Utc::now().timestamp() as u64,
                     genesis_timestamp,
-                    block_delay as i64,
-                ),
+                    block_delay,
+                ) as i64,
             ) {
                 (local_epoch, now_epoch) if local_epoch >= now_epoch => {
                     return Ok(NetworkHeadEvaluation::InSync)
@@ -623,11 +626,11 @@ where
                     }
                 };
 
-                let now_epoch = get_now_epoch(
-                    chrono::Utc::now().timestamp(),
+                let now_epoch = calculate_expected_epoch(
+                    chrono::Utc::now().timestamp() as u64,
                     genesis_timestamp,
-                    block_delay as i64,
-                );
+                    block_delay,
+                ) as i64;
                 let is_block_valid = |block: &Block| -> bool {
                     let header = &block.header;
                     if !header.is_within_clock_drift() {
@@ -1023,13 +1026,3 @@ where
         }
     }
 }
-
-// The formula matches lotus
-// ```go
-// sinceGenesis := build.Clock.Now().Sub(genesisTime)
-// expectedHeight := int64(sinceGenesis.Seconds()) / int64(build.BlockDelaySecs)
-// ```
-// See <https://github.com/filecoin-project/lotus/blob/b27c861485695d3f5bb92bcb281abc95f4d90fb6/chain/sync.go#L180>
-fn get_now_epoch(now_timestamp: i64, genesis_timestamp: i64, block_delay: i64) -> i64 {
-    now_timestamp.saturating_sub(genesis_timestamp) / block_delay
-}

src/daemon/mod.rs

@@ -25,7 +25,7 @@ use crate::key_management::{
 };
 use crate::libp2p::{Libp2pConfig, Libp2pService, PeerManager};
 use crate::message_pool::{MessagePool, MpoolConfig, MpoolRpcProvider};
-use crate::networks::{ChainConfig, NetworkChain};
+use crate::networks::{self, ChainConfig, NetworkChain};
 use crate::rpc::start_rpc;
 use crate::rpc::RPCState;
 use crate::shim::address::{CurrentNetwork, Network};
@@ -196,6 +196,16 @@ pub(super) async fn start(
         });
     }
 
+    // Read Genesis file
+    // * When snapshot command implemented, this genesis does not need to be
+    //   initialized
+    let genesis_header = read_genesis_header(
+        config.client.genesis_file.as_ref(),
+        chain_config.genesis_bytes(&db).await?.as_deref(),
+        &db,
+    )
+    .await?;
+
     if config.client.enable_metrics_endpoint {
         // Start Prometheus server port
         let prometheus_listener = TcpListener::bind(config.client.metrics_address)
@@ -212,17 +222,14 @@ pub(super) async fn start(
                 .await
                 .context("Failed to initiate prometheus server")
         });
-    }
 
-    // Read Genesis file
-    // * When snapshot command implemented, this genesis does not need to be
-    //   initialized
-    let genesis_header = read_genesis_header(
-        config.client.genesis_file.as_ref(),
-        chain_config.genesis_bytes(&db).await?.as_deref(),
-        &db,
-    )
-    .await?;
+        crate::metrics::default_registry().register_collector(Box::new(
+            networks::metrics::NetworkHeightCollector::new(
+                chain_config.block_delay_secs as u64,
+                genesis_header.timestamp,
+            ),
+        ));
+    }
 
     // Initialize ChainStore
     let chain_store = Arc::new(ChainStore::new(

src/health/endpoints.rs

@@ -5,7 +5,7 @@ use std::sync::Arc;
 use ahash::HashMap;
 use axum::extract::{self, Query};
 
-use crate::chain_sync::SyncStage;
+use crate::{chain_sync::SyncStage, networks::calculate_expected_epoch};
 
 use super::{AppError, ForestState};
 
@@ -109,11 +109,12 @@ fn check_sync_state_not_error(state: &Arc<ForestState>, acc: &mut MessageAccumul
 /// in case of forking.
 fn check_epoch_up_to_date(state: &Arc<ForestState>, acc: &mut MessageAccumulator) -> bool {
     const MAX_EPOCH_DIFF: i64 = 5;
-    let now_epoch = chrono::Utc::now()
-        .timestamp()
-        .saturating_add(state.chain_config.block_delay_secs as i64)
-        .saturating_sub(state.genesis_timestamp as i64)
-        / state.chain_config.block_delay_secs as i64;
+
+    let now_epoch = calculate_expected_epoch(
+        chrono::Utc::now().timestamp() as u64,
+        state.genesis_timestamp,
+        state.chain_config.block_delay_secs as u64,
+    ) as i64;
 
     // The current epoch of the node must be not too far behind the network
     if state.sync_state.read().epoch() >= now_epoch - MAX_EPOCH_DIFF {

src/networks/metrics.rs

@@ -0,0 +1,47 @@
+// Copyright 2019-2024 ChainSafe Systems
+// SPDX-License-Identifier: Apache-2.0, MIT
+
+use prometheus_client::{collector::Collector, encoding::EncodeMetric, metrics::gauge::Gauge};
+
+use super::calculate_expected_epoch;
+
+#[derive(Debug)]
+pub struct NetworkHeightCollector {
+    block_delay_secs: u64,
+    genesis_timestamp: u64,
+    network_height: Gauge,
+}
+
+impl NetworkHeightCollector {
+    pub fn new(block_delay_secs: u64, genesis_timestamp: u64) -> Self {
+        Self {
+            block_delay_secs,
+            genesis_timestamp,
+            network_height: Gauge::default(),
+        }
+    }
+}
+
+impl Collector for NetworkHeightCollector {
+    fn encode(
+        &self,
+        mut encoder: prometheus_client::encoding::DescriptorEncoder,
+    ) -> Result<(), std::fmt::Error> {
+        let metric_encoder = encoder.encode_descriptor(
+            "expected_network_height",
+            "The expected network height based on the current time and the genesis block time",
+            None,
+            self.network_height.metric_type(),
+        )?;
+
+        let expected_epoch = calculate_expected_epoch(
+            chrono::Utc::now().timestamp() as u64,
+            self.genesis_timestamp,
+            self.block_delay_secs,
+        );
+        self.network_height.set(expected_epoch as i64);
+        self.network_height.encode(metric_encoder)?;
+
+        Ok(())
+    }
+}

src/networks/mod.rs

@@ -30,6 +30,8 @@ pub mod calibnet;
 pub mod devnet;
 pub mod mainnet;
 
+pub mod metrics;
+
 /// Newest network version for all networks
 pub const NEWEST_NETWORK_VERSION: NetworkVersion = NetworkVersion::V17;
 
@@ -453,6 +455,20 @@ macro_rules! make_height {
     };
 }
 
+// The formula matches lotus
+// ```go
+// sinceGenesis := build.Clock.Now().Sub(genesisTime)
+// expectedHeight := int64(sinceGenesis.Seconds()) / int64(build.BlockDelaySecs)
+// ```
+// See <https://github.com/filecoin-project/lotus/blob/b27c861485695d3f5bb92bcb281abc95f4d90fb6/chain/sync.go#L180>
+pub fn calculate_expected_epoch(
+    now_timestamp: u64,
+    genesis_timestamp: u64,
+    block_delay: u64,
+) -> u64 {
+    now_timestamp.saturating_sub(genesis_timestamp) / block_delay
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -534,4 +550,37 @@ mod tests {
         let epoch = get_upgrade_height_from_env("FOREST_TEST_VAR_3");
         assert_eq!(epoch, None);
     }
+
+    #[test]
+    fn test_calculate_expected_epoch() {
+        // now, genesis, block_delay
+        assert_eq!(0, calculate_expected_epoch(0, 0, 1));
+        assert_eq!(5, calculate_expected_epoch(5, 0, 1));
+
+        let mainnet_genesis = 1598306400;
+        let mainnet_block_delay = 30;
+
+        assert_eq!(
+            0,
+            calculate_expected_epoch(mainnet_genesis, mainnet_genesis, mainnet_block_delay)
+        );
+
+        assert_eq!(
+            0,
+            calculate_expected_epoch(
+                mainnet_genesis + mainnet_block_delay - 1,
+                mainnet_genesis,
+                mainnet_block_delay
+            )
+        );
+
+        assert_eq!(
+            1,
+            calculate_expected_epoch(
+                mainnet_genesis + mainnet_block_delay,
+                mainnet_genesis,
+                mainnet_block_delay
+            )
+        );
+    }
 }