Feature-guard the sled light store and hide the dependency on sled (#772

)

* Feature-guard the sled-based lightstore

* Hide sled dependency by introducing SledStore::open

* Enable lightstore-sled feature by default

* Update changelog

CHANGELOG.md

@@ -7,7 +7,11 @@
   way of [cargo make]. `tendermint-rpc` test coverage has been expanded here
   too. ([#758])
 
+* `[light-client]` The `sled`-backed lightstore is now feature-guarded under
+   the `lightstore-sled` feature, which is enabled by default for now. ([#772])
+
 [#758]: https://github.com/informalsystems/tendermint-rs/pull/758
+[#772]: https://github.com/informalsystems/tendermint-rs/pull/772
 [cargo make]: https://github.com/sagiegurari/cargo-make
 
 ### BUG FIXES:

light-client/Cargo.toml

@@ -21,10 +21,18 @@ description = """
 [lib]
 crate-type = ["cdylib", "rlib"]
 
+# docs.rs-specific configuration
+[package.metadata.docs.rs]
+# document all features
+all-features = true
+# defines the configuration attribute `docsrs`
+rustdoc-args = ["--cfg", "docsrs"]
+
 [features]
-default = ["rpc-client"]
+default = ["rpc-client", "lightstore-sled"]
 rpc-client = ["tokio", "tendermint-rpc/http-client"]
 secp256k1 = ["tendermint/secp256k1", "tendermint-rpc/secp256k1"]
+lightstore-sled = ["sled"]
 
 [dependencies]
 tendermint = { version = "0.17.0", path = "../tendermint" }
@@ -38,7 +46,7 @@ futures = "0.3.4"
 serde = "1.0.106"
 serde_cbor = "0.11.1"
 serde_derive = "1.0.106"
-sled = "0.34.3"
+sled = { version = "0.34.3", optional = true }
 static_assertions = "1.1.0"
 thiserror = "1.0.15"
 tokio = { version = "0.2", optional = true }

light-client/examples/light_client.rs

@@ -85,9 +85,7 @@ fn make_instance(
     db_path: impl AsRef<Path>,
     opts: &SyncOpts,
 ) -> Result<Instance, BoxError> {
-    let db = sled::open(db_path)?;
-
-    let light_store = SledStore::new(db);
+    let light_store = SledStore::open(db_path)?;
     let rpc_client = rpc::HttpClient::new(addr).unwrap();
     let options = light_client::Options {
         trust_threshold: TrustThreshold::default(),

light-client/src/store.rs

@@ -1,6 +1,7 @@
 //! Interface and implementations of the light block store.
 //!
 //! See the `memory` and `sled` modules for:
+//!
 //! - a transient, in-memory implementation for testing purposes
 //! - a persistent, on-disk, sled-backed implementation for production
 
@@ -10,6 +11,9 @@ use crate::types::{Height, LightBlock, Status};
 use crate::utils::std_ext;
 
 pub mod memory;
+
+#[cfg(feature = "lightstore-sled")]
+#[cfg_attr(docsrs, doc(cfg(feature = "lightstore-sled")))]
 pub mod sled;
 
 /// Store for light blocks.

light-client/src/store/sled.rs

@@ -2,6 +2,8 @@
 
 pub mod utils;
 
+use std::path::Path;
+
 use crate::{
     store::sled::utils::*,
     types::{Height, LightBlock},
@@ -26,7 +28,12 @@ pub struct SledStore {
 }
 
 impl SledStore {
-    /// Create a new persistent store from a sled database
+    /// Open a sled database and create a new persistent store from it.
+    pub fn open(db: impl AsRef<Path>) -> Result<Self, sled::Error> {
+        Ok(Self::new(sled::open(db)?))
+    }
+
+    /// Create a new persistent store from a sled database that is already open.
     pub fn new(db: SledDb) -> Self {
         Self {
             db,

light-node/Cargo.toml

@@ -27,7 +27,7 @@ name = "tendermint-light-node"
 path = "src/bin/tendermint-light-node/main.rs"
 
 [dependencies]
-anomaly = { version = "0.2", features = [ "serializer" ] }
+anomaly = { version = "0.2", features = ["serializer"] }
 async-trait = "0.1"
 gumdrop = "0.7"
 jsonrpc-core = "14.2"
@@ -36,10 +36,9 @@ jsonrpc-http-server = "14.2"
 jsonrpc-derive = "14.2"
 serde = { version = "1", features = ["serde_derive"] }
 serde_json = "1.0"
-sled = "0.34.3"
 tendermint = { version = "0.17.0", path = "../tendermint" }
-tendermint-light-client = { version = "0.17.0", path = "../light-client" }
-tendermint-rpc = { version = "0.17.0", path = "../rpc", features = [ "http-client" ] }
+tendermint-light-client = { version = "0.17.0", path = "../light-client", features = ["lightstore-sled"] }
+tendermint-rpc = { version = "0.17.0", path = "../rpc", features = ["http-client"] }
 thiserror = "1.0"
 tokio = { version = "0.2", features = ["full"] }
 

light-node/src/commands/initialize.rs

@@ -68,10 +68,8 @@ fn initialize_subjectively(
     config: &LightClientConfig,
     timeout: Option<Duration>,
 ) -> Result<Instance, String> {
-    let db = sled::open(config.db_path.clone())
-        .map_err(|e| format!("could not open database: {}", e))?;
-
-    let light_store = SledStore::new(db);
+    let light_store =
+        SledStore::open(&config.db_path).map_err(|e| format!("could not open database: {}", e))?;
 
     if let Some(trusted_state) = light_store.latest_trusted_or_verified() {
         status_warn!(

light-node/src/commands/start.rs

@@ -96,10 +96,11 @@ impl config::Override<LightNodeConfig> for StartCmd {
 
 impl StartCmd {
     fn assert_init_was_run() -> Result<(), String> {
-        let db_path = app_config().light_clients.first().unwrap().db_path.clone();
-        let db = sled::open(db_path).map_err(|e| format!("could not open database: {}", e))?;
+        let config = app_config();
+        let db_path = &config.light_clients.first().unwrap().db_path;
+        let primary_store =
+            SledStore::open(db_path).map_err(|e| format!("could not open database: {}", e))?;
 
-        let primary_store = SledStore::new(db);
         if primary_store.latest_trusted_or_verified().is_none() {
             return Err("no trusted or verified state in store for primary, please initialize with the `initialize` subcommand first".to_string());
         }
@@ -127,10 +128,8 @@ impl StartCmd {
         let rpc_client = tendermint_rpc::HttpClient::new(light_config.address.clone())
             .map_err(|e| format!("failed to create HTTP client: {}", e))?;
 
-        let db_path = light_config.db_path.clone();
-        let db = sled::open(db_path).map_err(|e| format!("could not open database: {}", e))?;
-
-        let light_store = SledStore::new(db);
+        let light_store = SledStore::open(&light_config.db_path)
+            .map_err(|e| format!("could not open database: {}", e))?;
 
         let builder = LightClientBuilder::prod(
             light_config.peer_id,