crds.rs

//! This module implements Cluster Replicated Data Store for
//! asynchronous updates in a distributed network.
//!
//! Data is stored in the CrdsValue type, each type has a specific
//! CrdsValueLabel.  Labels are semantically grouped into a single record
//! that is identified by a Pubkey.
//! * 1 Pubkey maps many CrdsValueLabels
//! * 1 CrdsValueLabel maps to 1 CrdsValue
//! The Label, the record Pubkey, and all the record labels can be derived
//! from a single CrdsValue.
//!
//! The actual data is stored in a single map of
//! `CrdsValueLabel(Pubkey) -> CrdsValue` This allows for partial record
//! updates to be propagated through the network.
//!
//! This means that full `Record` updates are not atomic.
//!
//! Additional labels can be added by appending them to the CrdsValueLabel,
//! CrdsValue enums.
//!
//! Merge strategy is implemented in:
//!     impl PartialOrd for VersionedCrdsValue
//!
//! A value is updated to a new version if the labels match, and the value
//! wallclock is later, or the value hash is greater.

use crate::crds_shards::CrdsShards;
use crate::crds_value::{CrdsValue, CrdsValueLabel};
use bincode::serialize;
use indexmap::map::{Entry, IndexMap};
use solana_sdk::hash::{hash, Hash};
use solana_sdk::pubkey::Pubkey;
use std::cmp;
use std::collections::HashMap;
use std::ops::Index;

const CRDS_SHARDS_BITS: u32 = 8;

#[derive(Clone)]
pub struct Crds {
    /// Stores the map of labels and values
    pub table: IndexMap<CrdsValueLabel, VersionedCrdsValue>,
    pub num_inserts: usize,
    pub shards: CrdsShards,
}

#[derive(PartialEq, Debug)]
pub enum CrdsError {
    InsertFailed,
}

/// This structure stores some local metadata associated with the CrdsValue
/// The implementation of PartialOrd ensures that the "highest" version is always picked to be
/// stored in the Crds
#[derive(PartialEq, Debug, Clone)]
pub struct VersionedCrdsValue {
    pub value: CrdsValue,
    /// local time when inserted
    pub insert_timestamp: u64,
    /// local time when updated
    pub local_timestamp: u64,
    /// value hash
    pub value_hash: Hash,
}

impl PartialOrd for VersionedCrdsValue {
    fn partial_cmp(&self, other: &VersionedCrdsValue) -> Option<cmp::Ordering> {
        if self.value.label() != other.value.label() {
            None
        } else if self.value.wallclock() == other.value.wallclock() {
            Some(self.value_hash.cmp(&other.value_hash))
        } else {
            Some(self.value.wallclock().cmp(&other.value.wallclock()))
        }
    }
}
impl VersionedCrdsValue {
    pub fn new(local_timestamp: u64, value: CrdsValue) -> Self {
        let value_hash = hash(&serialize(&value).unwrap());
        VersionedCrdsValue {
            value,
            insert_timestamp: local_timestamp,
            local_timestamp,
            value_hash,
        }
    }
}

impl Default for Crds {
    fn default() -> Self {
        Crds {
            table: IndexMap::new(),
            num_inserts: 0,
            shards: CrdsShards::new(CRDS_SHARDS_BITS),
        }
    }
}

impl Crds {
    /// must be called atomically with `insert_versioned`
    pub fn new_versioned(&self, local_timestamp: u64, value: CrdsValue) -> VersionedCrdsValue {
        VersionedCrdsValue::new(local_timestamp, value)
    }
    pub fn would_insert(
        &self,
        value: CrdsValue,
        local_timestamp: u64,
    ) -> (bool, VersionedCrdsValue) {
        let new_value = self.new_versioned(local_timestamp, value);
        let label = new_value.value.label();
        // New value is outdated and fails to insert, if it already exists in
        // the table with a more recent wallclock.
        let outdated = matches!(self.table.get(&label), Some(current) if new_value <= *current);
        (!outdated, new_value)
    }
    /// insert the new value, returns the old value if insert succeeds
    pub fn insert_versioned(
        &mut self,
        new_value: VersionedCrdsValue,
    ) -> Result<Option<VersionedCrdsValue>, CrdsError> {
        let label = new_value.value.label();
        match self.table.entry(label) {
            Entry::Vacant(entry) => {
                assert!(self.shards.insert(entry.index(), &new_value));
                entry.insert(new_value);
                self.num_inserts += 1;
                Ok(None)
            }
            Entry::Occupied(mut entry) if *entry.get() < new_value => {
                let index = entry.index();
                assert!(self.shards.remove(index, entry.get()));
                assert!(self.shards.insert(index, &new_value));
                self.num_inserts += 1;
                Ok(Some(entry.insert(new_value)))
            }
            _ => {
                trace!(
                    "INSERT FAILED data: {} new.wallclock: {}",
                    new_value.value.label(),
                    new_value.value.wallclock(),
                );
                Err(CrdsError::InsertFailed)
            }
        }
    }
    pub fn insert(
        &mut self,
        value: CrdsValue,
        local_timestamp: u64,
    ) -> Result<Option<VersionedCrdsValue>, CrdsError> {
        let new_value = self.new_versioned(local_timestamp, value);
        self.insert_versioned(new_value)
    }
    pub fn lookup(&self, label: &CrdsValueLabel) -> Option<&CrdsValue> {
        self.table.get(label).map(|x| &x.value)
    }

    pub fn lookup_versioned(&self, label: &CrdsValueLabel) -> Option<&VersionedCrdsValue> {
        self.table.get(label)
    }

    fn update_label_timestamp(&mut self, id: &CrdsValueLabel, now: u64) {
        if let Some(e) = self.table.get_mut(id) {
            e.local_timestamp = cmp::max(e.local_timestamp, now);
        }
    }

    /// Update the timestamp's of all the labels that are associated with Pubkey
    pub fn update_record_timestamp(&mut self, pubkey: &Pubkey, now: u64) {
        for label in &CrdsValue::record_labels(pubkey) {
            self.update_label_timestamp(label, now);
        }
    }

    /// Find all the keys that are older or equal to the timeout.
    /// * timeouts - Pubkey specific timeouts with Pubkey::default() as the default timeout.
    pub fn find_old_labels(
        &self,
        now: u64,
        timeouts: &HashMap<Pubkey, u64>,
    ) -> Vec<CrdsValueLabel> {
        let default_timeout = *timeouts
            .get(&Pubkey::default())
            .expect("must have default timeout");
        self.table
            .iter()
            .filter_map(|(k, v)| {
                let timeout = timeouts.get(&k.pubkey()).unwrap_or(&default_timeout);
                if v.local_timestamp.saturating_add(*timeout) <= now {
                    Some(k)
                } else {
                    None
                }
            })
            .cloned()
            .collect()
    }

    pub fn remove(&mut self, key: &CrdsValueLabel) {
        if let Some((index, _, value)) = self.table.swap_remove_full(key) {
            assert!(self.shards.remove(index, &value));
            // The previously last element in the table is now moved to the
            // 'index' position. Shards need to be updated accordingly.
            if index < self.table.len() {
                let value = self.table.index(index);
                assert!(self.shards.remove(self.table.len(), value));
                assert!(self.shards.insert(index, value));
            }
        }
    }
}

#[cfg(test)]
mod test {
    use super::*;
    use crate::contact_info::ContactInfo;
    use crate::crds_value::CrdsData;
    use rand::{thread_rng, Rng};

    #[test]
    fn test_insert() {
        let mut crds = Crds::default();
        let val = CrdsValue::new_unsigned(CrdsData::ContactInfo(ContactInfo::default()));
        assert_eq!(crds.insert(val.clone(), 0).ok(), Some(None));
        assert_eq!(crds.table.len(), 1);
        assert!(crds.table.contains_key(&val.label()));
        assert_eq!(crds.table[&val.label()].local_timestamp, 0);
    }
    #[test]
    fn test_update_old() {
        let mut crds = Crds::default();
        let val = CrdsValue::new_unsigned(CrdsData::ContactInfo(ContactInfo::default()));
        assert_eq!(crds.insert(val.clone(), 0), Ok(None));
        assert_eq!(crds.insert(val.clone(), 1), Err(CrdsError::InsertFailed));
        assert_eq!(crds.table[&val.label()].local_timestamp, 0);
    }
    #[test]
    fn test_update_new() {
        let mut crds = Crds::default();
        let original = CrdsValue::new_unsigned(CrdsData::ContactInfo(ContactInfo::new_localhost(
            &Pubkey::default(),
            0,
        )));
        assert_matches!(crds.insert(original.clone(), 0), Ok(_));
        let val = CrdsValue::new_unsigned(CrdsData::ContactInfo(ContactInfo::new_localhost(
            &Pubkey::default(),
            1,
        )));
        assert_eq!(
            crds.insert(val.clone(), 1).unwrap().unwrap().value,
            original
        );
        assert_eq!(crds.table[&val.label()].local_timestamp, 1);
    }
    #[test]
    fn test_update_timestamp() {
        let mut crds = Crds::default();
        let val = CrdsValue::new_unsigned(CrdsData::ContactInfo(ContactInfo::new_localhost(
            &Pubkey::default(),
            0,
        )));
        assert_eq!(crds.insert(val.clone(), 0), Ok(None));

        crds.update_label_timestamp(&val.label(), 1);
        assert_eq!(crds.table[&val.label()].local_timestamp, 1);
        assert_eq!(crds.table[&val.label()].insert_timestamp, 0);

        let val2 = CrdsValue::new_unsigned(CrdsData::ContactInfo(ContactInfo::default()));
        assert_eq!(val2.label().pubkey(), val.label().pubkey());
        assert_matches!(crds.insert(val2.clone(), 0), Ok(Some(_)));

        crds.update_record_timestamp(&val.label().pubkey(), 2);
        assert_eq!(crds.table[&val.label()].local_timestamp, 2);
        assert_eq!(crds.table[&val.label()].insert_timestamp, 0);
        assert_eq!(crds.table[&val2.label()].local_timestamp, 2);
        assert_eq!(crds.table[&val2.label()].insert_timestamp, 0);

        crds.update_record_timestamp(&val.label().pubkey(), 1);
        assert_eq!(crds.table[&val.label()].local_timestamp, 2);
        assert_eq!(crds.table[&val.label()].insert_timestamp, 0);

        let mut ci = ContactInfo::default();
        ci.wallclock += 1;
        let val3 = CrdsValue::new_unsigned(CrdsData::ContactInfo(ci));
        assert_matches!(crds.insert(val3, 3), Ok(Some(_)));
        assert_eq!(crds.table[&val2.label()].local_timestamp, 3);
        assert_eq!(crds.table[&val2.label()].insert_timestamp, 3);
    }
    #[test]
    fn test_find_old_records_default() {
        let mut crds = Crds::default();
        let val = CrdsValue::new_unsigned(CrdsData::ContactInfo(ContactInfo::default()));
        assert_eq!(crds.insert(val.clone(), 1), Ok(None));
        let mut set = HashMap::new();
        set.insert(Pubkey::default(), 0);
        assert!(crds.find_old_labels(0, &set).is_empty());
        set.insert(Pubkey::default(), 1);
        assert_eq!(crds.find_old_labels(2, &set), vec![val.label()]);
        set.insert(Pubkey::default(), 2);
        assert_eq!(crds.find_old_labels(4, &set), vec![val.label()]);
    }
    #[test]
    fn test_find_old_records_with_override() {
        let mut rng = thread_rng();
        let mut crds = Crds::default();
        let mut timeouts = HashMap::new();
        let val = CrdsValue::new_rand(&mut rng);
        timeouts.insert(Pubkey::default(), 3);
        assert_eq!(crds.insert(val.clone(), 0), Ok(None));
        assert!(crds.find_old_labels(2, &timeouts).is_empty());
        timeouts.insert(val.pubkey(), 1);
        assert_eq!(crds.find_old_labels(2, &timeouts), vec![val.label()]);
        timeouts.insert(val.pubkey(), u64::MAX);
        assert!(crds.find_old_labels(2, &timeouts).is_empty());
        timeouts.insert(Pubkey::default(), 1);
        assert!(crds.find_old_labels(2, &timeouts).is_empty());
        timeouts.remove(&val.pubkey());
        assert_eq!(crds.find_old_labels(2, &timeouts), vec![val.label()]);
    }
    #[test]
    fn test_remove_default() {
        let mut crds = Crds::default();
        let val = CrdsValue::new_unsigned(CrdsData::ContactInfo(ContactInfo::default()));
        assert_matches!(crds.insert(val.clone(), 1), Ok(_));
        let mut set = HashMap::new();
        set.insert(Pubkey::default(), 1);
        assert_eq!(crds.find_old_labels(2, &set), vec![val.label()]);
        crds.remove(&val.label());
        assert!(crds.find_old_labels(2, &set).is_empty());
    }
    #[test]
    fn test_find_old_records_staked() {
        let mut crds = Crds::default();
        let val = CrdsValue::new_unsigned(CrdsData::ContactInfo(ContactInfo::default()));
        assert_eq!(crds.insert(val.clone(), 1), Ok(None));
        let mut set = HashMap::new();
        //now < timestamp
        set.insert(Pubkey::default(), 0);
        set.insert(val.pubkey(), 0);
        assert!(crds.find_old_labels(0, &set).is_empty());

        //pubkey shouldn't expire since its timeout is MAX
        set.insert(val.pubkey(), std::u64::MAX);
        assert!(crds.find_old_labels(2, &set).is_empty());

        //default has max timeout, but pubkey should still expire
        set.insert(Pubkey::default(), std::u64::MAX);
        set.insert(val.pubkey(), 1);
        assert_eq!(crds.find_old_labels(2, &set), vec![val.label()]);

        set.insert(val.pubkey(), 2);
        assert!(crds.find_old_labels(2, &set).is_empty());
        assert_eq!(crds.find_old_labels(3, &set), vec![val.label()]);
    }

    #[test]
    fn test_crds_shards() {
        fn check_crds_shards(crds: &Crds) {
            crds.shards
                .check(&crds.table.values().cloned().collect::<Vec<_>>());
        }

        let mut crds = Crds::default();
        let pubkeys: Vec<_> = std::iter::repeat_with(Pubkey::new_rand).take(256).collect();
        let mut rng = thread_rng();
        let mut num_inserts = 0;
        for _ in 0..4096 {
            let pubkey = pubkeys[rng.gen_range(0, pubkeys.len())];
            let value = VersionedCrdsValue::new(
                rng.gen(), // local_timestamp
                CrdsValue::new_unsigned(CrdsData::ContactInfo(ContactInfo::new_localhost(
                    &pubkey,
                    rng.gen(), // now
                ))),
            );
            if crds.insert_versioned(value).is_ok() {
                check_crds_shards(&crds);
                num_inserts += 1;
            }
        }
        assert_eq!(num_inserts, crds.num_inserts);
        assert!(num_inserts > 700);
        assert!(crds.table.len() > 200);
        assert!(num_inserts > crds.table.len());
        check_crds_shards(&crds);
        // Remove values one by one and assert that shards stay valid.
        while !crds.table.is_empty() {
            let index = rng.gen_range(0, crds.table.len());
            let key = crds.table.get_index(index).unwrap().0.clone();
            crds.remove(&key);
            check_crds_shards(&crds);
        }
    }

    #[test]
    fn test_remove_staked() {
        let mut crds = Crds::default();
        let val = CrdsValue::new_unsigned(CrdsData::ContactInfo(ContactInfo::default()));
        assert_matches!(crds.insert(val.clone(), 1), Ok(_));
        let mut set = HashMap::new();

        //default has max timeout, but pubkey should still expire
        set.insert(Pubkey::default(), std::u64::MAX);
        set.insert(val.pubkey(), 1);
        assert_eq!(crds.find_old_labels(2, &set), vec![val.label()]);
        crds.remove(&val.label());
        assert!(crds.find_old_labels(2, &set).is_empty());
    }

    #[test]
    #[allow(clippy::neg_cmp_op_on_partial_ord)]
    fn test_equal() {
        let val = CrdsValue::new_unsigned(CrdsData::ContactInfo(ContactInfo::default()));
        let v1 = VersionedCrdsValue::new(1, val.clone());
        let v2 = VersionedCrdsValue::new(1, val);
        assert_eq!(v1, v2);
        assert!(!(v1 != v2));
        assert_eq!(v1.partial_cmp(&v2), Some(cmp::Ordering::Equal));
        assert_eq!(v2.partial_cmp(&v1), Some(cmp::Ordering::Equal));
    }
    #[test]
    #[allow(clippy::neg_cmp_op_on_partial_ord)]
    fn test_hash_order() {
        let v1 = VersionedCrdsValue::new(
            1,
            CrdsValue::new_unsigned(CrdsData::ContactInfo(ContactInfo::new_localhost(
                &Pubkey::default(),
                0,
            ))),
        );
        let v2 = VersionedCrdsValue::new(1, {
            let mut contact_info = ContactInfo::new_localhost(&Pubkey::default(), 0);
            contact_info.rpc = socketaddr!("0.0.0.0:0");
            CrdsValue::new_unsigned(CrdsData::ContactInfo(contact_info))
        });

        assert_eq!(v1.value.label(), v2.value.label());
        assert_eq!(v1.value.wallclock(), v2.value.wallclock());
        assert_ne!(v1.value_hash, v2.value_hash);
        assert!(v1 != v2);
        assert!(!(v1 == v2));
        if v1 > v2 {
            assert!(v1 > v2);
            assert!(v2 < v1);
            assert_eq!(v1.partial_cmp(&v2), Some(cmp::Ordering::Greater));
            assert_eq!(v2.partial_cmp(&v1), Some(cmp::Ordering::Less));
        } else if v2 > v1 {
            assert!(v1 < v2);
            assert!(v2 > v1);
            assert_eq!(v1.partial_cmp(&v2), Some(cmp::Ordering::Less));
            assert_eq!(v2.partial_cmp(&v1), Some(cmp::Ordering::Greater));
        } else {
            panic!("bad PartialOrd implementation?");
        }
    }
    #[test]
    #[allow(clippy::neg_cmp_op_on_partial_ord)]
    fn test_wallclock_order() {
        let v1 = VersionedCrdsValue::new(
            1,
            CrdsValue::new_unsigned(CrdsData::ContactInfo(ContactInfo::new_localhost(
                &Pubkey::default(),
                1,
            ))),
        );
        let v2 = VersionedCrdsValue::new(
            1,
            CrdsValue::new_unsigned(CrdsData::ContactInfo(ContactInfo::new_localhost(
                &Pubkey::default(),
                0,
            ))),
        );
        assert_eq!(v1.value.label(), v2.value.label());
        assert!(v1 > v2);
        assert!(!(v1 < v2));
        assert!(v1 != v2);
        assert!(!(v1 == v2));
        assert_eq!(v1.partial_cmp(&v2), Some(cmp::Ordering::Greater));
        assert_eq!(v2.partial_cmp(&v1), Some(cmp::Ordering::Less));
    }
    #[test]
    #[allow(clippy::neg_cmp_op_on_partial_ord)]
    fn test_label_order() {
        let v1 = VersionedCrdsValue::new(
            1,
            CrdsValue::new_unsigned(CrdsData::ContactInfo(ContactInfo::new_localhost(
                &Pubkey::new_rand(),
                0,
            ))),
        );
        let v2 = VersionedCrdsValue::new(
            1,
            CrdsValue::new_unsigned(CrdsData::ContactInfo(ContactInfo::new_localhost(
                &Pubkey::new_rand(),
                0,
            ))),
        );
        assert_ne!(v1, v2);
        assert!(!(v1 == v2));
        assert!(!(v1 < v2));
        assert!(!(v1 > v2));
        assert!(!(v2 < v1));
        assert!(!(v2 > v1));
        assert_eq!(v1.partial_cmp(&v2), None);
        assert_eq!(v2.partial_cmp(&v1), None);
    }
}