change(scan): Create a scanner storage database, but don't use it yet

Cargo.lock

@@ -5804,6 +5804,7 @@ dependencies = [
  "indexmap 2.1.0",
  "jubjub",
  "rand 0.8.5",
+ "semver 1.0.20",
  "serde",
  "tokio",
  "tower",

zebra-consensus/src/config.rs

@@ -4,7 +4,7 @@ use serde::{Deserialize, Serialize};
 
 /// Configuration for parallel semantic verification:
 /// <https://zebra.zfnd.org/dev/rfcs/0002-parallel-verification.html#definitions>
-#[derive(Clone, Debug, Deserialize, Serialize)]
+#[derive(Clone, Debug, Eq, PartialEq, Deserialize, Serialize)]
 #[serde(
     deny_unknown_fields,
     default,

zebra-network/src/config.rs

@@ -46,7 +46,7 @@ pub use cache_dir::CacheDir;
 const MAX_SINGLE_SEED_PEER_DNS_RETRIES: usize = 0;
 
 /// Configuration for networking code.
-#[derive(Clone, Debug, Serialize)]
+#[derive(Clone, Debug, Eq, PartialEq, Serialize)]
 #[serde(deny_unknown_fields, default)]
 pub struct Config {
     /// The address on which this node should listen for connections.

zebra-rpc/src/config.rs

@@ -7,7 +7,7 @@ use serde::{Deserialize, Serialize};
 pub mod mining;
 
 /// RPC configuration section.
-#[derive(Clone, Debug, Deserialize, Serialize)]
+#[derive(Clone, Debug, Eq, PartialEq, Deserialize, Serialize)]
 #[serde(deny_unknown_fields, default)]
 pub struct Config {
     /// IP address and port for the RPC server.

zebra-scan/Cargo.toml

@@ -22,6 +22,7 @@ categories = ["cryptography::cryptocurrencies"]
 
 color-eyre = "0.6.2"
 indexmap = { version = "2.0.1", features = ["serde"] }
+semver = "1.0.20"
 serde = { version = "1.0.193", features = ["serde_derive"] }
 tokio = "1.34.0"
 tower = "0.4.13"
@@ -31,7 +32,7 @@ zcash_client_backend = "0.10.0-rc.1"
 zcash_primitives = "0.13.0-rc.1"
 
 zebra-chain = { path = "../zebra-chain", version = "1.0.0-beta.31" }
-zebra-state = { path = "../zebra-state", version = "1.0.0-beta.31" }
+zebra-state = { path = "../zebra-state", version = "1.0.0-beta.31", features = ["shielded-scan"] }
 
 [dev-dependencies]
 

zebra-scan/src/config.rs

@@ -3,21 +3,46 @@
 use indexmap::IndexMap;
 use serde::{Deserialize, Serialize};
 
+use zebra_state::Config as DbConfig;
+
 use crate::storage::SaplingScanningKey;
 
 #[derive(Clone, Debug, Eq, PartialEq, Deserialize, Serialize)]
 #[serde(deny_unknown_fields, default)]
 /// Configuration for scanning.
 pub struct Config {
     /// The sapling keys to scan for and the birthday height of each of them.
-    // TODO: any value below sapling activation as the birthday height should default to sapling activation.
+    //
+    // TODO: allow keys without birthdays
     pub sapling_keys_to_scan: IndexMap<SaplingScanningKey, u32>,
+
+    /// The scanner results database config.
+    //
+    // TODO: Remove fields that are only used by the state to create a common database config.
+    #[serde(flatten)]
+    db_config: DbConfig,
 }
 
 impl Default for Config {
     fn default() -> Self {
         Self {
             sapling_keys_to_scan: IndexMap::new(),
+            db_config: DbConfig::default(),
         }
     }
 }
+
+impl Config {
+    /// Returns a config for a temporary database that is deleted when it is dropped.
+    pub fn ephemeral() -> Self {
+        Self {
+            db_config: DbConfig::ephemeral(),
+            ..Self::default()
+        }
+    }
+
+    /// Returns the database-specific config.
+    pub fn db_config(&self) -> &DbConfig {
+        &self.db_config
+    }
+}

zebra-scan/src/init.rs

@@ -0,0 +1,21 @@
+//! Initializing the scanner.
+
+use color_eyre::Report;
+use tokio::task::JoinHandle;
+use tracing::Instrument;
+
+use zebra_chain::parameters::Network;
+
+use crate::{scan, storage::Storage, Config};
+
+/// Initialize the scanner based on its config.
+pub fn init(
+    config: &Config,
+    network: Network,
+    state: scan::State,
+) -> JoinHandle<Result<(), Report>> {
+    let storage = Storage::new(config, network);
+
+    // TODO: add more tasks here?
+    tokio::spawn(scan::start(state, storage).in_current_span())
+}

zebra-scan/src/lib.rs

@@ -5,8 +5,12 @@
 #![doc(html_root_url = "https://docs.rs/zebra_scan")]
 
 pub mod config;
+pub mod init;
 pub mod scan;
 pub mod storage;
 
 #[cfg(test)]
 mod tests;
+
+pub use config::Config;
+pub use init::init;

zebra-scan/src/scan.rs

@@ -21,7 +21,8 @@ use zebra_chain::{
 
 use crate::storage::Storage;
 
-type State = Buffer<
+/// The generic state type used by the scanner.
+pub type State = Buffer<
     BoxService<zebra_state::Request, zebra_state::Response, zebra_state::BoxError>,
     zebra_state::Request,
 >;
@@ -35,7 +36,7 @@ const CHECK_INTERVAL: Duration = Duration::from_secs(10);
 /// Start the scan task given state and storage.
 ///
 /// - This function is dummy at the moment. It just makes sure we can read the storage and the state.
-/// - Modificatiuons here might have an impact in the `scan_task_starts` test.
+/// - Modifications here might have an impact in the `scan_task_starts` test.
 /// - Real scanning code functionality will be added in the future here.
 pub async fn start(mut state: State, storage: Storage) -> Result<(), Report> {
     // We want to make sure the state has a tip height available before we start scanning.

zebra-scan/src/storage.rs

@@ -1,31 +1,71 @@
 //! Store viewing keys and results of the scan.
 
+#![allow(dead_code)]
+
 use std::collections::HashMap;
 
-use zebra_chain::{block::Height, transaction::Hash};
+use zebra_chain::{block::Height, parameters::Network, transaction::Hash};
+
+use crate::config::Config;
+
+pub mod db;
 
 /// The type used in Zebra to store Sapling scanning keys.
 /// It can represent a full viewing key or an individual viewing key.
 pub type SaplingScanningKey = String;
 
 /// Store key info and results of the scan.
-#[allow(dead_code)]
+///
+/// `rocksdb` allows concurrent writes through a shared reference,
+/// so clones of the scanner storage represent the same database instance.
+/// When the final clone is dropped, the database is closed.
+#[derive(Clone, Debug)]
 pub struct Storage {
+    // Configuration
+    //
+    // This configuration cannot be modified after the database is initialized,
+    // because some clones would have different values.
+    //
+    // TODO: add config if needed?
+
+    // Owned State
+    //
+    // Everything contained in this state must be shared by all clones, or read-only.
+    //
+    /// The underlying database.
+    ///
+    /// `rocksdb` allows reads and writes via a shared reference,
+    /// so this database object can be freely cloned.
+    /// The last instance that is dropped will close the underlying database.
+    //
+    // This database is created but not actually used for results.
+    // TODO: replace the fields below with a database instance.
+    db: db::ScannerDb,
+
     /// The sapling key and an optional birthday for it.
     sapling_keys: HashMap<SaplingScanningKey, Option<Height>>,
 
     /// The sapling key and the related transaction id.
     sapling_results: HashMap<SaplingScanningKey, Vec<Hash>>,
 }
 
-#[allow(dead_code)]
 impl Storage {
-    /// Create a new storage.
-    pub fn new() -> Self {
-        Self {
-            sapling_keys: HashMap::new(),
-            sapling_results: HashMap::new(),
+    /// Opens and returns the on-disk scanner results storage for `config` and `network`.
+    /// If there is no existing storage, creates a new storage on disk.
+    ///
+    /// TODO:
+    /// New keys in `config` are inserted into the database with their birthday heights. Shielded
+    /// activation is the minimum birthday height.
+    ///
+    /// Birthdays and scanner progress are marked by inserting an empty result for that height.
+    pub fn new(config: &Config, network: Network) -> Self {
+        let mut storage = Self::new_db(config, network);
+
+        for (key, birthday) in config.sapling_keys_to_scan.iter() {
+            storage.add_sapling_key(key.clone(), Some(zebra_chain::block::Height(*birthday)));
         }
+
+        storage
     }
 
     /// Add a sapling key to the storage.
@@ -43,18 +83,18 @@ impl Storage {
     }
 
     /// Get the results of a sapling key.
+    //
+    // TODO: Rust style - remove "get_" from these names
     pub fn get_sapling_results(&self, key: &str) -> Vec<Hash> {
         self.sapling_results.get(key).cloned().unwrap_or_default()
     }
 
     /// Get all keys and their birthdays.
+    //
+    // TODO: any value below sapling activation as the birthday height, or `None`, should default
+    // to sapling activation. This requires the configured network.
+    // Return Height not Option<Height>.
     pub fn get_sapling_keys(&self) -> HashMap<String, Option<Height>> {
         self.sapling_keys.clone()
     }
 }
-
-impl Default for Storage {
-    fn default() -> Self {
-        Self::new()
-    }
-}

zebra-scan/src/storage/db.rs

@@ -0,0 +1,104 @@
+//! Persistent storage for scanner results.
+
+use std::{collections::HashMap, path::Path};
+
+use semver::Version;
+
+use zebra_chain::parameters::Network;
+
+use crate::Config;
+
+use super::Storage;
+
+// Public types and APIs
+pub use zebra_state::ZebraDb as ScannerDb;
+
+/// The directory name used to distinguish the scanner database from Zebra's other databases or
+/// flat files.
+///
+/// We use "private" in the name to warn users not to share this data.
+pub const SCANNER_DATABASE_KIND: &str = "private-scan";
+
+/// The column families supported by the running `zebra-scan` database code.
+///
+/// Existing column families that aren't listed here are preserved when the database is opened.
+pub const SCANNER_COLUMN_FAMILIES_IN_CODE: &[&str] = &[
+    // Sapling
+    "sapling_tx_ids",
+    // Orchard
+    // TODO
+];
+
+impl Storage {
+    /// Opens and returns an on-disk scanner results database instance for `config` and `network`.
+    /// If there is no existing database, creates a new database on disk.
+    ///
+    /// New keys in `config` are not inserted into the database.
+    pub(crate) fn new_db(config: &Config, network: Network) -> Self {
+        Self::new_with_debug(
+            config, network,
+            // TODO: make format upgrades work with any database, then change this to `false`
+            true,
+        )
+    }
+
+    /// Returns an on-disk database instance with the supplied production and debug settings.
+    /// If there is no existing database, creates a new database on disk.
+    ///
+    /// New keys in `config` are not inserted into the database.
+    ///
+    /// This method is intended for use in tests.
+    pub(crate) fn new_with_debug(
+        config: &Config,
+        network: Network,
+        debug_skip_format_upgrades: bool,
+    ) -> Self {
+        let db = ScannerDb::new(
+            config.db_config(),
+            SCANNER_DATABASE_KIND,
+            &Self::database_format_version_in_code(),
+            network,
+            debug_skip_format_upgrades,
+            SCANNER_COLUMN_FAMILIES_IN_CODE
+                .iter()
+                .map(ToString::to_string),
+        );
+
+        let new_storage = Self {
+            db,
+            sapling_keys: HashMap::new(),
+            sapling_results: HashMap::new(),
+        };
+
+        // TODO: report the last scanned height here?
+        tracing::info!("loaded Zebra scanner cache");
+
+        new_storage
+    }
+
+    /// The database format version in the running scanner code.
+    pub fn database_format_version_in_code() -> Version {
+        // TODO: implement scanner database versioning
+        Version::new(0, 0, 0)
+    }
+
+    /// Returns the configured network for this database.
+    pub fn network(&self) -> Network {
+        self.db.network()
+    }
+
+    /// Returns the `Path` where the files used by this database are located.
+    pub fn path(&self) -> &Path {
+        self.db.path()
+    }
+
+    /// Check for panics in code running in spawned threads.
+    /// If a thread exited with a panic, resume that panic.
+    ///
+    /// This method should be called regularly, so that panics are detected as soon as possible.
+    //
+    // TODO: when we implement format changes, call this method regularly
+    pub fn check_for_panics(&mut self) {
+        self.db.check_for_panics()
+    }
+}

zebra-scan/src/tests.rs

@@ -32,10 +32,14 @@ use zcash_primitives::{
 };
 
 use zebra_chain::{
-    block::Block, chain_tip::ChainTip, serialization::ZcashDeserializeInto, transaction::Hash,
+    block::Block, chain_tip::ChainTip, parameters::Network, serialization::ZcashDeserializeInto,
+    transaction::Hash,
 };
 
-use crate::scan::{block_to_compact, scan_block};
+use crate::{
+    config::Config,
+    scan::{block_to_compact, scan_block},
+};
 
 /// Prove that we can create fake blocks with fake notes and scan them using the
 /// `zcash_client_backend::scanning::scan_block` function:
@@ -177,7 +181,7 @@ fn scanning_fake_blocks_store_key_and_results() -> Result<()> {
         zcash_client_backend::encoding::encode_extended_full_viewing_key("zxviews", &extfvk);
 
     // Create a database
-    let mut s = crate::storage::Storage::new();
+    let mut s = crate::storage::Storage::new(&Config::ephemeral(), Network::Mainnet);
 
     // Insert the generated key to the database
     s.add_sapling_key(key_to_be_stored.clone(), None);