This happens when using ic-agent and deploying to cloudflare worker. I am not sure about the root cause for the error, but I have temporarily fixed it with custom code shared below. Sharing here to highlight the issue and a temporary workaround.
ic-agent = { version = "0.33.0", features = ["wasm-bindgen", "pem"] }
On doing
let request_id = agent
.update(&canister_id, "call_name")
.with_arg(candid::encode_args(()).unwrap())
.call_and_wait()
.await
.unwrap()
Get below error. (using panic::set_hook(Box::new(console_error_panic_hook::hook)); for the trace)
global window unavailable
Stack:
Error
at ht (file:///Users/komalsai/learning/cf-exp/reclaim_canisters/build/worker/shim.mjs:2:6168)
at [object Object]xfd569
at [object Object]x12dbe2
at [object Object]x130e5a
at [object Object]x139097
at [object Object]x136757
at [object Object]x1370db
at [object Object]x13524f
at [object Object]x128e61
at [object Object]x138218
✘ [ERROR] panicked at /Users/komalsai/.cargo/registry/src/index.crates.io-6f17d22bba15001f/ic-agent-0.33.0/src/agent/mod.rs:783:22:
unable to setTimeout: JsValue(RuntimeError: unreachable
RuntimeError: unreachable
at [object Object]x1390dc
at [object Object]x12dc0b
at [object Object]x130e5a
at [object Object]x139097
at [object Object]x136757
at [object Object]x1370db
at [object Object]x13524f
at [object Object]x128e61
at [object Object]x138218
at K (file:///Users/komalsai/learning/cf-exp/reclaim_canisters/build/worker/shim.mjs:2:428))
Stack:
Error
at ht (file:///Users/komalsai/learning/cf-exp/reclaim_canisters/build/worker/shim.mjs:2:6168)
at [object Object]xfd569
at [object Object]x12dbe2
at [object Object]x130e5a
at [object Object]x139097
at [object Object]x136757
at [object Object]x1370db
at [object Object]x132849
at [object Object]x3419e
at [object Object]xbdcc7
A hanging Promise was canceled. This happens when the worker runtime is waiting for a Promise from
JavaScript to resolve, but has detected that the Promise cannot possibly ever resolve because all
code and events related to the Promise's I/O context have already finished.
✘ [ERROR] Uncaught (in response) Error: The script will never generate a response.
After some digging, it is due to this part of code in ic-agent
pub async fn wait(
&self,
request_id: RequestId,
effective_canister_id: Principal,
) -> Result<Vec<u8>, AgentError> {
let mut retry_policy = Self::get_retry_policy();
let mut request_accepted = false;
loop {
match self.poll(&request_id, effective_canister_id).await? {
PollResult::Submitted => {}
PollResult::Accepted => {
if !request_accepted {
// The system will return RequestStatusResponse::Unknown
// (PollResult::Submitted) until the request is accepted
// 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 backoff so the request does not time out.
retry_policy.reset();
request_accepted = true;
}
}
PollResult::Completed(result) => return Ok(result),
};
match retry_policy.next_backoff() {
#[cfg(not(target_family = "wasm"))]
Some(duration) => tokio::time::sleep(duration).await,
#[cfg(all(target_family = "wasm", feature = "wasm-bindgen"))]
Some(duration) => {
wasm_bindgen_futures::JsFuture::from(js_sys::Promise::new(&mut |rs, rj| {
if let Err(e) = web_sys::window()
.expect("global window unavailable")
.set_timeout_with_callback_and_timeout_and_arguments_0(
&rs,
duration.as_millis() as _,
)
{
use wasm_bindgen::UnwrapThrowExt;
rj.call1(&rj, &e).unwrap_throw();
}
}))
.await
.expect("unable to setTimeout");
}
None => return Err(AgentError::TimeoutWaitingForResponse()),
}
}
}
Issue is with set_timeout_with_callback_and_timeout_and_arguments_0 . This approach is for async sleep timeout (shared here - Async sleep in Rust/wasm32? - #6 by zeroexcuses - The Rust Programming Language Forum). Another approach shared in the same post is to use gloo_timers which fixed the issue for me.
My code looks like this now . Essentially had to tweak the wait functionality using gloo-timers.
// Usage instead of call_and_wait()
let request_id = agent
.update(&canister_id, "save_snapshot_json")
.with_arg(candid::encode_args(()).unwrap())
.call()
.await
.unwrap();
let res = custom_agent_wait(&agent, request_id, canister_id)
.await
.unwrap();
-------------------
use gloo_timers::future::TimeoutFuture
fn get_retry_policy() -> ExponentialBackoff<SystemClock> {
ExponentialBackoffBuilder::new()
.with_initial_interval(Duration::from_millis(500))
.with_max_interval(Duration::from_secs(1))
.with_multiplier(1.4)
.with_max_elapsed_time(Some(Duration::from_secs(60 * 5)))
.build()
}
pub async fn custom_agent_wait(
agent: &Agent,
request_id: RequestId,
effective_canister_id: Principal,
) -> Result<Vec<u8>> {
let mut retry_policy = get_retry_policy();
let mut request_accepted = false;
loop {
match agent
.poll(&request_id, effective_canister_id)
.await
.unwrap()
{
PollResult::Submitted => {}
PollResult::Accepted => {
if !request_accepted {
request_accepted = true;
}
}
PollResult::Completed(result) => {
return Ok(result);
}
};
match retry_policy.next_backoff() {
Some(duration) => {
let duration_in_millis = duration.clone().as_millis();
spawn_local(async move {
TimeoutFuture::new(duration_in_millis as u32).await;
web_sys::console::log_1(&"Hello from a timeout!".into());
});
}
None => return Err("Timeout".into()),
}
}
}