feat(async)!: add Sleeper trait to allow custom runtime

Author: oleonardolima

Cargo.toml

@@ -30,6 +30,7 @@ serde_json = "1.0"
 tokio = { version = "1.41.0", features = ["full"] }
 electrsd = { version = "0.28.0", features = ["legacy", "esplora_a33e97e1", "bitcoind_25_0"] }
 lazy_static = "1.4.0"
+async-std = { version = "1.13.0"}
 
 [features]
 default = ["blocking", "async", "async-https", "tokio"]

src/async.rs

@@ -12,6 +12,7 @@
 //! Esplora by way of `reqwest` HTTP client.
 
 use std::collections::HashMap;
+use std::marker::PhantomData;
 use std::str::FromStr;
 
 use bitcoin::consensus::{deserialize, serialize, Decodable, Encodable};
@@ -32,16 +33,17 @@ use crate::{
 };
 
 #[derive(Debug, Clone)]
-pub struct AsyncClient {
+pub struct AsyncClient<S = DefaultSleeper> {
     /// The URL of the Esplora Server.
     url: String,
     /// The inner [`reqwest::Client`] to make HTTP requests.
     client: Client,
     /// Number of times to retry a request
     max_retries: usize,
+    sleep_fn: PhantomData<S>,
 }
 
-impl AsyncClient {
+impl<S: Sleeper> AsyncClient<S> {
     /// Build an async client from a builder
     pub fn from_builder(builder: Builder) -> Result<Self, Error> {
         let mut client_builder = Client::builder();
@@ -72,6 +74,7 @@ impl AsyncClient {
             url: builder.base_url,
             client: client_builder.build()?,
             max_retries: builder.max_retries,
+            sleep_fn: PhantomData,
         })
     }
 
@@ -81,6 +84,7 @@ impl AsyncClient {
             url,
             client,
             max_retries: crate::DEFAULT_MAX_RETRIES,
+            sleep_fn: PhantomData,
         }
     }
 
@@ -433,8 +437,7 @@ impl AsyncClient {
         loop {
             match self.client.get(url).send().await? {
                 resp if attempts < self.max_retries && is_status_retryable(resp.status()) => {
-                    tokio::time::sleep(delay).await;
-                    // FIXME: use an sleeper_fn passed as parameter.
+                    S::sleep(delay).await;
                     attempts += 1;
                     delay *= 2;
                 }
@@ -447,3 +450,21 @@ impl AsyncClient {
 fn is_status_retryable(status: reqwest::StatusCode) -> bool {
     RETRYABLE_ERROR_CODES.contains(&status.as_u16())
 }
+
+pub trait Sleeper: 'static {
+    type Sleep: std::future::Future<Output = ()>;
+
+    fn sleep(dur: std::time::Duration) -> Self::Sleep;
+}
+
+#[derive(Default)]
+pub struct DefaultSleeper;
+
+#[cfg(feature = "tokio")]
+impl Sleeper for DefaultSleeper {
+    type Sleep = tokio::time::Sleep;
+
+    fn sleep(dur: std::time::Duration) -> Self::Sleep {
+        tokio::time::sleep(dur)
+    }
+}

src/lib.rs

@@ -178,11 +178,17 @@ impl Builder {
         BlockingClient::from_builder(self)
     }
 
-    // Build an asynchronous client from builder
-    #[cfg(feature = "async")]
+    /// Build an asynchronous client from builder
+    #[cfg(all(feature = "async", feature = "tokio"))]
     pub fn build_async(self) -> Result<AsyncClient, Error> {
         AsyncClient::from_builder(self)
     }
+
+    /// Build an asynchronous client from builder
+    #[cfg(feature = "async")]
+    pub fn build_async_with_sleeper<S: r#async::Sleeper>(self) -> Result<AsyncClient<S>, Error> {
+        AsyncClient::from_builder(self)
+    }
 }
 
 /// Errors that can happen during a request to `Esplora` servers.
@@ -253,6 +259,8 @@ mod test {
     use electrsd::{bitcoind, bitcoind::BitcoinD, ElectrsD};
     use lazy_static::lazy_static;
     use std::env;
+    #[cfg(all(feature = "async", not(feature = "tokio")))]
+    use std::{future::Future, pin::Pin};
     use tokio::sync::Mutex;
     #[cfg(all(feature = "blocking", feature = "async"))]
     use {
@@ -992,4 +1000,31 @@ mod test {
         let tx_async = async_client.get_tx(&txid).await.unwrap();
         assert_eq!(tx, tx_async);
     }
+
+    #[cfg(all(feature = "async", feature = "tokio"))]
+    #[test]
+    fn test_default_tokio_sleeper() {
+        let builder = Builder::new("https://blockstream.info/testnet/api");
+        let client = builder.build_async();
+        assert!(client.is_ok());
+    }
+    #[cfg(all(feature = "async", not(feature = "tokio")))]
+    struct CustomRuntime;
+
+    #[cfg(all(feature = "async", not(feature = "tokio")))]
+    impl r#async::Sleeper for CustomRuntime {
+        type Sleep = Pin<Box<dyn Future<Output = ()>>>;
+
+        fn sleep(dur: std::time::Duration) -> Self::Sleep {
+            Box::pin(async_std::task::sleep(dur))
+        }
+    }
+
+    #[cfg(all(feature = "async", not(feature = "tokio")))]
+    #[test]
+    fn test_custom_runtime() {
+        let builder = Builder::new("https://blockstream.info/testnet/api");
+        let client = builder.build_async_with_sleeper::<CustomRuntime>();
+        assert!(client.is_ok());
+    }
 }