feat: Replace garcon with backoff (#392)

Implements SDK-824.

This additionally removes garcon from the public API; the backoff numbers dfx uses are good enough for anyone, and users who want a shorter timeout can use tokio's timeout function.

CHANGELOG.md

@@ -8,6 +8,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+* Remove `garcon` from API. Callers can remove the dependency and any usages of it; all waiting functions no longer take a waiter parameter.
+
 ## [0.22.0] - 2022-10-17
 
 * Drop `disable_range_check` flag from certificate delegation checking.

ic-agent/Cargo.toml

@@ -16,15 +16,16 @@ rust-version = "1.60.0"
 
 [dependencies]
 async-trait = "0.1.53"
+backoff = "0.4.0"
 base32 = "0.4.0"
 base64 = "0.13.0"
 byteorder = "1.3.2"
 candid = "0.8.0"
-garcon = { version = "0.2", features = ["async"] }
+futures-util = "0.3.21"
 hex = "0.4.0"
 http = "0.2.6"
 http-body = "0.4.5"
-hyper-rustls = { version = "0.23.0", features = [ "webpki-roots", "http2" ] }
+hyper-rustls = { version = "0.23.0", features = [ "webpki-roots", "http2" ], optional = true }
 ic-verify-bls-signature = "0.1"
 k256 = { version = "0.11", features = ["pem"] }
 leb128 = "0.2.5"
@@ -38,10 +39,10 @@ serde_cbor = "0.11.2"
 sha2 = "0.10"
 simple_asn1 = "0.6.1"
 thiserror = "1.0.30"
+tokio = { version = "1.21.2", features = ["time"] }
 url = "2.1.0"
 pkcs8 = { version = "0.9", features = ["std"] }
 sec1 = { version = "0.3", features = ["pem"] }
-futures-util = "0.3.21"
 
 [dependencies.hyper]
 version = "0.14"
@@ -66,4 +67,6 @@ tokio = { version = "1.17.0", features = ["full"] }
 
 [features]
 default = ["pem", "reqwest"]
+reqwest = ["dep:reqwest", "dep:hyper-rustls"]
+hyper = ["dep:hyper", "dep:hyper-rustls"]
 ic_ref_tests = ["default"] # Used to separate integration tests for ic-ref which need a server running.

ic-agent/src/agent/agent_error.rs

@@ -19,10 +19,6 @@ pub enum AgentError {
     #[error("The request timed out.")]
     TimeoutWaitingForResponse(),
 
-    /// The waiter was restarted without being started first.
-    #[error("The waiter was restarted without being started first.")]
-    WaiterRestartError(),
-
     /// An error occurred when signing with the identity.
     #[error("Identity had a signing error: {0}")]
     SigningError(String),

ic-agent/src/agent/mod.rs

@@ -12,6 +12,7 @@ pub mod signed;
 pub mod status;
 pub use agent_config::AgentConfig;
 pub use agent_error::AgentError;
+use backoff::{backoff::Backoff, ExponentialBackoffBuilder};
 pub use builder::AgentBuilder;
 pub use nonce::{NonceFactory, NonceGenerator};
 pub use response::{Replied, RequestStatusResponse};
@@ -29,7 +30,6 @@ use crate::{
     identity::Identity,
     to_request_id, RequestId,
 };
-use garcon::Waiter;
 use serde::Serialize;
 use status::Status;
 
@@ -205,19 +205,14 @@ pub enum PollResult {
 ///   agent.fetch_root_key().await?;
 ///   let management_canister_id = Principal::from_text("aaaaa-aa")?;
 ///
-///   let waiter = garcon::Delay::builder()
-///     .throttle(std::time::Duration::from_millis(500))
-///     .timeout(std::time::Duration::from_secs(60 * 5))
-///     .build();
-///
 ///   // Create a call to the management canister to create a new canister ID,
 ///   // and wait for a result.
 ///   // The effective canister id must belong to the canister ranges of the subnet at which the canister is created.
 ///   let effective_canister_id = Principal::from_text("sehci-oaaaa-aaaaa-aaaaa-c").unwrap();
 ///   let response = agent.update(&management_canister_id, "provisional_create_canister_with_cycles")
 ///     .with_effective_canister_id(effective_canister_id)
 ///     .with_arg(&Encode!(&Argument { amount: None })?)
-///     .call_and_wait(waiter)
+///     .call_and_wait()
 ///     .await?;
 ///
 ///   let result = Decode!(response.as_slice(), CreateCanisterResult)?;
@@ -548,13 +543,16 @@ impl Agent {
     }
 
     /// Call request_status on the RequestId in a loop and return the response as a byte vector.
-    pub async fn wait<W: Waiter>(
+    pub async fn wait(
         &self,
         request_id: RequestId,
         effective_canister_id: Principal,
-        mut waiter: W,
     ) -> Result<Vec<u8>, AgentError> {
-        waiter.start();
+        let mut retry_policy = ExponentialBackoffBuilder::new()
+            .with_initial_interval(Duration::from_millis(200))
+            .with_max_interval(Duration::from_secs(1))
+            .with_multiplier(1.4)
+            .build();
         let mut request_accepted = false;
         loop {
             match self.poll(&request_id, effective_canister_id).await? {
@@ -566,21 +564,19 @@ impl Agent {
                         // and we generally cannot know how long that will take.
                         // State transitions between Received and Processing may be
                         // instantaneous. Therefore, once we know the request is accepted,
-                        // we should restart the waiter so the request does not time out.
+                        // we should restart the backoff so the request does not time out.
 
-                        waiter
-                            .restart()
-                            .map_err(|_| AgentError::WaiterRestartError())?;
+                        retry_policy.reset();
                         request_accepted = true;
                     }
                 }
                 PollResult::Completed(result) => return Ok(result),
             };
 
-            waiter
-                .async_wait()
-                .await
-                .map_err(|_| AgentError::TimeoutWaitingForResponse())?;
+            match retry_policy.next_backoff() {
+                Some(duration) => tokio::time::sleep(duration).await,
+                None => return Err(AgentError::TimeoutWaitingForResponse()),
+            }
         }
     }
 
@@ -1127,26 +1123,12 @@ impl Future for UpdateCall<'_> {
         self.request_id.as_mut().poll(cx)
     }
 }
-impl UpdateCall<'_> {
-    fn and_wait<'out, W>(
-        self,
-        waiter: W,
-    ) -> Pin<Box<dyn core::future::Future<Output = Result<Vec<u8>, AgentError>> + Send + 'out>>
-    where
-        Self: 'out,
-        W: Waiter + 'out,
-    {
-        async fn run<W>(_self: UpdateCall<'_>, waiter: W) -> Result<Vec<u8>, AgentError>
-        where
-            W: Waiter,
-        {
-            let request_id = _self.request_id.await?;
-            _self
-                .agent
-                .wait(request_id, _self.effective_canister_id, waiter)
-                .await
-        }
-        Box::pin(run(self, waiter))
+impl<'a> UpdateCall<'a> {
+    async fn and_wait(self) -> Result<Vec<u8>, AgentError> {
+        let request_id = self.request_id.await?;
+        self.agent
+            .wait(request_id, self.effective_canister_id)
+            .await
     }
 }
 /// An Update Request Builder.
@@ -1227,8 +1209,8 @@ impl<'agent> UpdateBuilder<'agent> {
 
     /// Make an update call. This will call request_status on the RequestId in a loop and return
     /// the response as a byte vector.
-    pub async fn call_and_wait<W: Waiter>(&self, waiter: W) -> Result<Vec<u8>, AgentError> {
-        self.call().and_wait(waiter).await
+    pub async fn call_and_wait(&self) -> Result<Vec<u8>, AgentError> {
+        self.call().and_wait().await
     }
 
     /// Make an update call. This will return a RequestId.

ic-agent/src/lib.rs

@@ -68,19 +68,14 @@
 //!   agent.fetch_root_key().await?;
 //!   let management_canister_id = Principal::from_text("aaaaa-aa")?;
 //!
-//!   let waiter = garcon::Delay::builder()
-//!     .throttle(std::time::Duration::from_millis(500))
-//!     .timeout(std::time::Duration::from_secs(60 * 5))
-//!     .build();
-//!
 //!   // Create a call to the management canister to create a new canister ID,
 //!   // and wait for a result.
 //!   // The effective canister id must belong to the canister ranges of the subnet at which the canister is created.
 //!   let effective_canister_id = Principal::from_text("sehci-oaaaa-aaaaa-aaaaa-c").unwrap();
 //!   let response = agent.update(&management_canister_id, "provisional_create_canister_with_cycles")
 //!     .with_effective_canister_id(effective_canister_id)
 //!     .with_arg(&Encode!(&Argument { amount: None})?)
-//!     .call_and_wait(waiter)
+//!     .call_and_wait()
 //!     .await?;
 //!
 //!   let result = Decode!(response.as_slice(), CreateCanisterResult)?;

ic-utils/Cargo.toml

@@ -19,7 +19,6 @@ rust-version = "1.60.0"
 [dependencies]
 async-trait = "0.1.40"
 candid = "0.8.0"
-garcon = { version = "0.2", features = ["async"] }
 ic-agent = { path = "../ic-agent", version = "0.22", default-features = false }
 serde = "1.0.115"
 serde_bytes = "0.11"