Add beacon.watch (#3362)

> This is currently a WIP and all features are subject to alteration or removal at any time.

## Overview

The successor to #2873.

Contains the backbone of `beacon.watch` including syncing code, the initial API, and several core database tables.

See `watch/README.md` for more information, requirements and usage.

watch/src/blockprint/database.rs

@@ -0,0 +1,224 @@
+use crate::database::{
+    self,
+    schema::{beacon_blocks, blockprint},
+    watch_types::{WatchHash, WatchSlot},
+    Error, PgConn, MAX_SIZE_BATCH_INSERT,
+};
+
+use diesel::prelude::*;
+use diesel::sql_types::{Integer, Text};
+use diesel::{Insertable, Queryable};
+use log::debug;
+use serde::{Deserialize, Serialize};
+use std::collections::HashMap;
+use std::time::Instant;
+
+type WatchConsensusClient = String;
+pub fn list_consensus_clients() -> Vec<WatchConsensusClient> {
+    vec![
+        "Lighthouse".to_string(),
+        "Lodestar".to_string(),
+        "Nimbus".to_string(),
+        "Prysm".to_string(),
+        "Teku".to_string(),
+        "Unknown".to_string(),
+    ]
+}
+
+#[derive(Debug, Queryable, Insertable, Serialize, Deserialize)]
+#[diesel(table_name = blockprint)]
+pub struct WatchBlockprint {
+    pub slot: WatchSlot,
+    pub best_guess: WatchConsensusClient,
+}
+
+#[derive(Debug, QueryableByName, diesel::FromSqlRow)]
+pub struct WatchValidatorBlockprint {
+    #[diesel(sql_type = Integer)]
+    pub proposer_index: i32,
+    #[diesel(sql_type = Text)]
+    pub best_guess: WatchConsensusClient,
+    #[diesel(sql_type = Integer)]
+    pub slot: WatchSlot,
+}
+
+/// Insert a batch of values into the `blockprint` table.
+///
+/// On a conflict, it will do nothing, leaving the old value.
+pub fn insert_batch_blockprint(
+    conn: &mut PgConn,
+    prints: Vec<WatchBlockprint>,
+) -> Result<(), Error> {
+    use self::blockprint::dsl::*;
+
+    let mut count = 0;
+    let timer = Instant::now();
+
+    for chunk in prints.chunks(MAX_SIZE_BATCH_INSERT) {
+        count += diesel::insert_into(blockprint)
+            .values(chunk)
+            .on_conflict_do_nothing()
+            .execute(conn)?;
+    }
+
+    let time_taken = timer.elapsed();
+    debug!("Blockprint inserted, count: {count}, time_taken: {time_taken:?}");
+    Ok(())
+}
+
+/// Selects the row from the `blockprint` table where `slot` is minimum.
+pub fn get_lowest_blockprint(conn: &mut PgConn) -> Result<Option<WatchBlockprint>, Error> {
+    use self::blockprint::dsl::*;
+    let timer = Instant::now();
+
+    let result = blockprint
+        .order_by(slot.asc())
+        .limit(1)
+        .first::<WatchBlockprint>(conn)
+        .optional()?;
+
+    let time_taken = timer.elapsed();
+    debug!("Blockprint requested: lowest, time_taken: {time_taken:?}");
+    Ok(result)
+}
+
+/// Selects the row from the `blockprint` table where `slot` is maximum.
+pub fn get_highest_blockprint(conn: &mut PgConn) -> Result<Option<WatchBlockprint>, Error> {
+    use self::blockprint::dsl::*;
+    let timer = Instant::now();
+
+    let result = blockprint
+        .order_by(slot.desc())
+        .limit(1)
+        .first::<WatchBlockprint>(conn)
+        .optional()?;
+
+    let time_taken = timer.elapsed();
+    debug!("Blockprint requested: highest, time_taken: {time_taken:?}");
+    Ok(result)
+}
+
+/// Selects a single row of the `blockprint` table corresponding to a given `root_query`.
+pub fn get_blockprint_by_root(
+    conn: &mut PgConn,
+    root_query: WatchHash,
+) -> Result<Option<WatchBlockprint>, Error> {
+    use self::beacon_blocks::dsl::{beacon_blocks, root};
+    use self::blockprint::dsl::*;
+    let timer = Instant::now();
+
+    let join = beacon_blocks.inner_join(blockprint);
+
+    let result = join
+        .select((slot, best_guess))
+        .filter(root.eq(root_query))
+        .first::<WatchBlockprint>(conn)
+        .optional()?;
+
+    let time_taken = timer.elapsed();
+    debug!("Blockprint requested: {root_query}, time_taken: {time_taken:?}");
+    Ok(result)
+}
+
+/// Selects a single row of the `blockprint` table corresponding to a given `slot_query`.
+pub fn get_blockprint_by_slot(
+    conn: &mut PgConn,
+    slot_query: WatchSlot,
+) -> Result<Option<WatchBlockprint>, Error> {
+    use self::blockprint::dsl::*;
+    let timer = Instant::now();
+
+    let result = blockprint
+        .filter(slot.eq(slot_query))
+        .first::<WatchBlockprint>(conn)
+        .optional()?;
+
+    let time_taken = timer.elapsed();
+    debug!("Blockprint requested: {slot_query}, time_taken: {time_taken:?}");
+    Ok(result)
+}
+
+/// Selects `slot` from all rows of the `beacon_blocks` table which do not have a corresponding
+/// row in `blockprint`.
+#[allow(dead_code)]
+pub fn get_unknown_blockprint(conn: &mut PgConn) -> Result<Vec<Option<WatchSlot>>, Error> {
+    use self::beacon_blocks::dsl::{beacon_blocks, root, slot};
+    use self::blockprint::dsl::blockprint;
+
+    let join = beacon_blocks.left_join(blockprint);
+
+    let result = join
+        .select(slot)
+        .filter(root.is_null())
+        .order_by(slot.desc())
+        .nullable()
+        .load::<Option<WatchSlot>>(conn)?;
+
+    Ok(result)
+}
+
+/// Constructs a HashMap of `index` -> `best_guess` for each validator's latest proposal at or before
+/// `target_slot`.
+/// Inserts `"Unknown" if no prior proposals exist.
+pub fn construct_validator_blockprints_at_slot(
+    conn: &mut PgConn,
+    target_slot: WatchSlot,
+    slots_per_epoch: u64,
+) -> Result<HashMap<i32, WatchConsensusClient>, Error> {
+    use self::blockprint::dsl::{blockprint, slot};
+
+    let total_validators =
+        database::count_validators_activated_before_slot(conn, target_slot, slots_per_epoch)?
+            as usize;
+
+    let mut blockprint_map = HashMap::with_capacity(total_validators);
+
+    let latest_proposals =
+        database::get_all_validators_latest_proposer_info_at_slot(conn, target_slot)?;
+
+    let latest_proposal_slots: Vec<WatchSlot> = latest_proposals.clone().into_keys().collect();
+
+    let result = blockprint
+        .filter(slot.eq_any(latest_proposal_slots))
+        .load::<WatchBlockprint>(conn)?;
+
+    // Insert the validators which have available blockprints.
+    for print in result {
+        if let Some(proposer) = latest_proposals.get(&print.slot) {
+            blockprint_map.insert(*proposer, print.best_guess);
+        }
+    }
+
+    // Insert the rest of the unknown validators.
+    for validator_index in 0..total_validators {
+        blockprint_map
+            .entry(validator_index as i32)
+            .or_insert_with(|| "Unknown".to_string());
+    }
+
+    Ok(blockprint_map)
+}
+
+/// Counts the number of occurances of each `client` present in the `validators` table at or before some
+/// `target_slot`.
+pub fn get_validators_clients_at_slot(
+    conn: &mut PgConn,
+    target_slot: WatchSlot,
+    slots_per_epoch: u64,
+) -> Result<HashMap<WatchConsensusClient, usize>, Error> {
+    let mut client_map: HashMap<WatchConsensusClient, usize> = HashMap::new();
+
+    // This includes all validators which were activated at or before `target_slot`.
+    let validator_blockprints =
+        construct_validator_blockprints_at_slot(conn, target_slot, slots_per_epoch)?;
+
+    for client in list_consensus_clients() {
+        let count = validator_blockprints
+            .iter()
+            .filter(|(_, v)| (*v).clone() == client)
+            .count();
+        client_map.insert(client, count);
+    }
+
+    Ok(client_map)
+}