settings/job/manager.rs
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// Copyright 2021 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
//! Job Management Support
//!
//! # Summary
//!
//! The manager mod defines entities for managing [Job] sources and controlling the execution of
//! pending [workloads](crate::job::work::Load) contained in those [Jobs](Job). [Manager] provides a
//! concrete implementation of a [Job] processor. Outside clients send [Job] sources to the
//! [Manager] over the [MessageHub](crate::message::message_hub::MessageHub). In turn, the [Manager]
//! will process each received source for new [Jobs](Job) and provide the necessary backing, such as
//! caches, to support executing the [Job].
use crate::event::source::Event as SourceEvent;
use crate::event::{self, Event};
use crate::job::source::{self, Error};
use crate::job::{self, Job, Payload, PinStream};
use crate::message::base::MessengerType;
use crate::service::{self, message};
use crate::trace;
use futures::stream::{FuturesUnordered, StreamFuture};
use futures::{FutureExt, StreamExt};
use std::collections::HashMap;
use {fuchsia_async as fasync, fuchsia_trace as ftrace};
type JobStreamItem = (source::Id, Option<Result<Job, Error>>);
/// [Manager] processes incoming streams for new [Job]s. [Job]s are handled and executed by the
/// [Manager] based on the [Job] definitions.
pub(crate) struct Manager {
/// A mapping from [source id](source::Id) to [handler](source::Handler). This mapping is used
/// to retrieve the [handler](source::Handler) for job updates (inserting, retrieving,
/// completing) and source maintenance (cleaning up on exit).
sources: HashMap<source::Id, source::Handler>,
/// A collection of sources given to this manager. Each source is associated with a stream of
/// requests. Each item produced by streaming this collection represents the next request from
/// some particular source. It will produce a tuple of the intended item and the rest of
/// the stream for the corresponding source. The intended item is another tuple that contains a
/// [source id](source::Id) and a [Job]. Once the stream has been closed, `None` will be passed
/// as the [Job] portion of the tuple.
job_futures: FuturesUnordered<StreamFuture<PinStream<JobStreamItem>>>,
/// A [Id generator](source::IdGenerator) responsible for producing unique [Ids](source::Id) for
/// the received sources.
source_id_generator: source::IdGenerator,
/// A Sender used to communicate back to the [Manager] that the execution of a [Job] has
/// completed.
execution_completion_sender: futures::channel::mpsc::UnboundedSender<(source::Id, job::Info)>,
/// A [delegate](message::Delegate) used to generate the necessary messaging components for
/// [Jobs](Job) to use.
message_hub_delegate: message::Delegate,
/// An event publisher used to signal when a source has begun and ended.
event_publisher: event::Publisher,
}
impl Manager {
/// Creates a new [Manager] with the given MessageHub. A reference to the service MessageHub is
/// provided so that it can be passed to [Jobs](Job) for communicating with the rest of the
/// service.
pub(crate) async fn spawn(message_hub_delegate: &message::Delegate) -> message::Signature {
// Create a top-level receptor in the MessageHub to accept new sources from.
let receptor = message_hub_delegate
.create(MessengerType::Unbound)
.await
.expect("messenger should be available")
.1;
// Create a channel for execution tasks to communicate when a Job has been completed.
let (execution_completion_sender, execution_completion_receiver) =
futures::channel::mpsc::unbounded::<(source::Id, job::Info)>();
// Capture the top-level receptor's signature so it can be passed back
// to the caller for sending new sources.
let signature = receptor.get_signature();
let event_publisher =
event::Publisher::create(message_hub_delegate, MessengerType::Unbound).await;
let mut manager = Self {
sources: HashMap::new(),
job_futures: FuturesUnordered::new(),
source_id_generator: source::IdGenerator::new(),
execution_completion_sender,
message_hub_delegate: message_hub_delegate.clone(),
event_publisher,
};
// Spawn a task to run the main event loop, which handles the following events:
// 1) Receiving new sources to process
// 2) Accepting and processing new jobs from sources
// 3) Executing jobs and handling the their results
fasync::Task::local(async move {
let id = ftrace::Id::new();
trace!(id, c"job_manager");
let source_fuse = receptor.fuse();
let execution_fuse = execution_completion_receiver.fuse();
futures::pin_mut!(source_fuse, execution_fuse);
loop {
futures::select! {
source_event = source_fuse.select_next_some() => {
trace!(id, c"process_source_event");
manager.process_source_event(source_event).await;
},
(source_id, job_info) = execution_fuse.select_next_some() => {
trace!(id, c"process_completed_execution");
manager.process_completed_execution(source_id, job_info, id).await;
},
(job_info, stream) = manager.job_futures.select_next_some() => {
trace!(id, c"process_job");
// Since the manager owns job_futures, we should never reach the end of
// the stream.
let (source_id, job) = job_info.expect("job should be present");
manager.process_job(source_id, job, stream, id).await;
}
}
}
})
.detach();
signature
}
// Propagates results of a completed job by cleaning up references, informing the parent source
// of the job completion, and checking if another job can be processed.
async fn process_completed_execution(
&mut self,
source_id: source::Id,
job_info: job::Info,
id: ftrace::Id,
) {
// Fetch the source and inform it that its child Job has completed.
let source_handler = &mut self.sources.get_mut(&source_id).expect("should find source");
source_handler.handle_job_completion(job_info);
self.remove_source_if_necessary(source_id);
// Continue processing available jobs.
self.process_next_job(id).await;
}
// Executes the next job if conditions to run another job are met. If so, the manager consults
// available sources for a candidate job and then executes the first one found.
async fn process_next_job(&mut self, id: ftrace::Id) {
// Iterate through sources and see if any source has a pending job
for (source_id, source_handler) in &mut self.sources {
let source_id = *source_id;
let execution_tx = self.execution_completion_sender.clone();
// Ignore the executed status.
let _ = source_handler
.execute_next(
&mut self.message_hub_delegate,
move |job_info| {
if let Err(error) = execution_tx.unbounded_send((source_id, job_info)) {
panic!("Failed to send message. error: {error:?}");
};
},
id,
)
.await;
}
}
// Processes a new source, generating the associated tracking data and inserting its job stream
// into the monitored job futures.
async fn process_source_event(&mut self, event: service::message::MessageEvent) {
// Manager only expects to receive new job streams from events passed into this method.
let Payload::Source(source) = Payload::try_from(event).expect("should convert to source");
// Extract job stream from payload.
let job_stream = source.lock().await.take().expect("should capture job stream");
// Associate stream with a new id.
let source_id = self.source_id_generator.generate();
// Create a handler to manage jobs produced by this stream.
let _ = self.sources.insert(source_id, source::Handler::new());
// Add the stream to the monitored pool. Associate jobs with the source id along with
// appending an empty value to the end for indicating when the stream has completed.
let stream_fut = job_stream
.map(move |val| (source_id, Some(val)))
.chain(async move { (source_id, None) }.into_stream())
.boxed_local()
.into_future();
self.job_futures.push(stream_fut);
self.event_publisher.send_event(Event::Source(SourceEvent::Start(source_id)));
}
async fn process_job(
&mut self,
source: source::Id,
job: Option<Result<Job, Error>>,
source_stream: PinStream<JobStreamItem>,
id: ftrace::Id,
) {
match job {
Some(Ok(job)) => {
// When the stream produces a job, associate with the appropriate source. Then try
// to see if any job is available to run.
if let Err(e) = self
.sources
.get_mut(&source)
.expect("source should be present")
.add_pending_job(job)
{
tracing::error!("Failed to add job: {:?}", e);
return;
}
}
Some(Err(Error::InvalidInput(error_responder))) => {
// When the stream failed to produce a job due to bad input, report back the error
// through the APIs error responder.
let id = error_responder.id();
if let Err(e) = error_responder.respond(fidl_fuchsia_settings::Error::Failed) {
tracing::warn!(
"Failed to report invalid input error to caller on API {} with id {:?}: \
{:?}",
id,
source,
e
);
}
}
Some(Err(Error::InvalidPolicyInput(error_responder))) => {
// When the stream failed to produce a job due to bad input, report back the error
// through the APIs error responder.
let id = error_responder.id();
if let Err(e) = error_responder.respond(fidl_fuchsia_settings_policy::Error::Failed)
{
tracing::warn!(
"Failed to report invalid policy input error to caller on policy API {} \
with id {:?}: {:?}",
id,
source,
e
);
}
}
Some(Err(Error::Unexpected(err))) if !err.is_closed() => {
// No-op. If the error did not close the stream then just warn and allow the rest
// of the stream to continue processing.
tracing::warn!("Received an unexpected error on source {:?}: {:?}", source, err);
}
Some(Err(err @ (Error::Unexpected(_) | Error::Unsupported))) => {
// All other errors cause the source stream to close. Clean up the source and cancel
// any pending jobs. We still need to wait for any remaining jobs to finish.
tracing::warn!(
"Unable to process anymore job requests for {:?} due to fatal error: {:?}",
source,
err
);
self.cancel_source(source);
self.event_publisher
.send_event(Event::Source(SourceEvent::Complete(source, Err(err.into()))));
return;
}
None => {
// The end of the stream has been reached (None), so clean up the source.
self.cancel_source(source);
self.event_publisher
.send_event(Event::Source(SourceEvent::Complete(source, Ok(()))));
return;
}
}
self.job_futures.push(source_stream.into_future());
self.process_next_job(id).await;
}
fn cancel_source(&mut self, source_id: source::Id) {
self.sources.get_mut(&source_id).expect("should find source").cancel();
self.remove_source_if_necessary(source_id);
}
fn remove_source_if_necessary(&mut self, source_id: source::Id) {
let source_info = self.sources.get_mut(&source_id).expect("should find source");
if source_info.is_completed() {
let _ = self.sources.remove(&source_id);
}
}
}
#[cfg(test)]
mod tests {
use super::*;
use crate::event::source::CompleteError;
use crate::message::base::Audience;
use crate::service::{build_event_listener, test, MessageHub};
use crate::tests::scaffold::workload::Workload;
use assert_matches::assert_matches;
use async_trait::async_trait;
use futures::channel::mpsc;
use futures::channel::oneshot::{self, Receiver, Sender};
use futures::lock::Mutex;
use std::rc::Rc;
// Validates that multiple messages can be handled from a single source
#[fuchsia::test(allow_stalls = false)]
async fn test_manager_job_processing_multiple_jobs_one_source() {
// Create delegate for communication between components.
let message_hub_delegate = MessageHub::create_hub();
let results = 0..10;
// Create a top-level receptor to receive job results from.
let mut receptor = message_hub_delegate
.create(MessengerType::Unbound)
.await
.expect("should create receptor")
.1;
let manager_signature = Manager::spawn(&message_hub_delegate).await;
// Create a messenger to send job sources to the manager.
let messenger = message_hub_delegate
.create(MessengerType::Unbound)
.await
.expect("should create messenger")
.0;
let (requests_tx, requests_rx) = mpsc::unbounded();
// Send multiple jobs in one source.
for result in results.clone() {
let signature = receptor.get_signature();
requests_tx
.unbounded_send(Ok(Job::new(job::work::Load::Independent(Workload::new(
test::Payload::Integer(result),
signature,
)))))
.expect("Should be able to queue requests");
}
let _ = messenger.message(
Payload::Source(Rc::new(Mutex::new(Some(requests_rx.boxed_local())))).into(),
Audience::Messenger(manager_signature),
);
for result in results {
// Confirm received value matches the value sent from workload.
assert_matches!(receptor.next_of::<test::Payload>().await.expect("should have payload").0,
test::Payload::Integer(value) if value == result);
}
}
// Validates that a request that failed to convert to a job does not block the remaining jobs
// from running.
#[fuchsia::test(allow_stalls = false)]
async fn test_manager_job_processing_handles_errored_conversions() {
struct TestResponder;
impl source::ErrorResponder for TestResponder {
fn id(&self) -> &'static str {
"Test"
}
fn respond(
self: Box<Self>,
error: fidl_fuchsia_settings::Error,
) -> Result<(), fidl::Error> {
assert_eq!(error, fidl_fuchsia_settings::Error::Failed);
Ok(())
}
}
// Create delegate for communication between components.
let message_hub_delegate = MessageHub::create_hub();
const RESULT: i64 = 1;
// Create a top-level receptor to receive job results from.
let mut receptor = message_hub_delegate
.create(MessengerType::Unbound)
.await
.expect("should create receptor")
.1;
let manager_signature = Manager::spawn(&message_hub_delegate).await;
// Create a messenger to send job sources to the manager.
let messenger = message_hub_delegate
.create(MessengerType::Unbound)
.await
.expect("should create messenger")
.0;
let (requests_tx, requests_rx) = mpsc::unbounded();
// Send an error (conversion failed) before a valid job.
requests_tx
.unbounded_send(Err(Error::InvalidInput(Box::new(TestResponder))))
.expect("Should be able to queue requests");
// Now send a valid job, which should be processed after the error.
let signature = receptor.get_signature();
requests_tx
.unbounded_send(Ok(Job::new(job::work::Load::Independent(Workload::new(
test::Payload::Integer(RESULT),
signature,
)))))
.expect("Should be able to queue requests");
let _ = messenger.message(
Payload::Source(Rc::new(Mutex::new(Some(requests_rx.boxed_local())))).into(),
Audience::Messenger(manager_signature),
);
// Confirm received value matches the value sent from the second job.
assert_matches!(receptor.next_of::<test::Payload>().await.expect("should have payload").0,
test::Payload::Integer(value) if value == RESULT);
}
// Validates that a request that failed to convert to a job does not block the remaining jobs
// from running.
#[fuchsia::test(allow_stalls = false)]
async fn test_manager_job_processing_handles_errored_fidl() {
// Create delegate for communication between components.
let message_hub_delegate = MessageHub::create_hub();
// Create a top-level receptor to receive job results from.
let mut receptor = message_hub_delegate
.create(MessengerType::Unbound)
.await
.expect("should create receptor")
.1;
let mut event_listener = build_event_listener(&message_hub_delegate).await;
let manager_signature = Manager::spawn(&message_hub_delegate).await;
// Create a messenger to send job sources to the manager.
let messenger = message_hub_delegate
.create(MessengerType::Unbound)
.await
.expect("should create messenger")
.0;
let (requests_tx, requests_rx) = mpsc::unbounded();
// Send a fidl error before a valid job.
requests_tx
.unbounded_send(Err(Error::Unexpected(fidl::Error::ClientChannelClosed {
status: zx::Status::PEER_CLOSED,
protocol_name: "",
})))
.expect("Should be able to queue requests");
// Now send a valid job, which should not be processed after the error.
let signature = receptor.get_signature();
requests_tx
.unbounded_send(Ok(Job::new(job::work::Load::Independent(Workload::new(
test::Payload::Integer(1),
signature,
)))))
.expect("Should be able to queue requests");
let _ = messenger.message(
Payload::Source(Rc::new(Mutex::new(Some(requests_rx.boxed_local())))).into(),
Audience::Messenger(manager_signature),
);
// Ensure the source started and completed before moving on.
assert_matches!(
event_listener.next_of::<event::Payload>().await,
Ok((event::Payload::Event(Event::Source(SourceEvent::Start(_))), _))
);
assert_matches!(
event_listener.next_of::<event::Payload>().await,
Ok((
event::Payload::Event(Event::Source(SourceEvent::Complete(
_,
Err(CompleteError::Unexpected)
))),
_
))
);
// Now we can delete the receptor signature so we don't hang the test on the next assertion.
message_hub_delegate.delete(signature);
// Confirm we never get the result from the request.
assert!(receptor.next_of::<test::Payload>().await.is_err());
}
// Validates that an InvalidPolicyInput error causes the stream to close and not run further
// jobs.
#[fuchsia::test(allow_stalls = false)]
async fn test_invalid_policy_input_returns_error() {
struct TestPolicyResponder;
impl source::PolicyErrorResponder for TestPolicyResponder {
fn id(&self) -> &'static str {
"Test"
}
fn respond(
self: Box<Self>,
error: fidl_fuchsia_settings_policy::Error,
) -> Result<(), fidl::Error> {
assert_eq!(error, fidl_fuchsia_settings_policy::Error::Failed);
Ok(())
}
}
// Create delegate for communication between components.
let message_hub_delegate = MessageHub::create_hub();
const RESULT: i64 = 1;
// Create a top-level receptor to receive job results from.
let mut receptor = message_hub_delegate
.create(MessengerType::Unbound)
.await
.expect("should create receptor")
.1;
let manager_signature = Manager::spawn(&message_hub_delegate).await;
// Create a messenger to send job sources to the manager.
let messenger = message_hub_delegate
.create(MessengerType::Unbound)
.await
.expect("should create messenger")
.0;
let (requests_tx, requests_rx) = mpsc::unbounded();
// Send a fidl error before a valid job.
requests_tx
.unbounded_send(Err(Error::InvalidPolicyInput(Box::new(TestPolicyResponder))))
.expect("Should be able to queue requests");
// Now send a valid job, which should not be processed after the error.
let signature = receptor.get_signature();
requests_tx
.unbounded_send(Ok(Job::new(job::work::Load::Independent(Workload::new(
test::Payload::Integer(RESULT),
signature,
)))))
.expect("Should be able to queue requests");
let _ = messenger.message(
Payload::Source(Rc::new(Mutex::new(Some(requests_rx.boxed_local())))).into(),
Audience::Messenger(manager_signature),
);
// Confirm received value matches the value sent from the second job.
assert_matches!(receptor.next_of::<test::Payload>().await.expect("should have payload").0,
test::Payload::Integer(value) if value == RESULT);
}
struct WaitingWorkload {
rx: Receiver<()>,
execute_tx: Sender<()>,
}
impl WaitingWorkload {
fn new(rx: Receiver<()>, tx: Sender<()>) -> Self {
Self { rx, execute_tx: tx }
}
}
// This implementation can be used to imitate a hanging get by delaying or never sending a
// message across its channel.
#[async_trait(?Send)]
impl job::work::Sequential for WaitingWorkload {
async fn execute(
self: Box<Self>,
_: message::Messenger,
_: job::data::StoreHandle,
_id: ftrace::Id,
) -> Result<(), job::work::Error> {
self.execute_tx.send(()).expect("Should be able to signal start of execution");
let _ = self.rx.await;
Ok(())
}
}
// Validates that a hanging get on one source does not block jobs from being processed on
// another source.
#[fuchsia::test(allow_stalls = false)]
async fn test_manager_job_processing_multiple_sources() {
// Create delegate for communication between components.
let message_hub_delegate = MessageHub::create_hub();
let manager_signature = Manager::spawn(&message_hub_delegate).await;
// Create a messenger to send job sources to the manager.
let messenger = message_hub_delegate
.create(MessengerType::Unbound)
.await
.expect("should create messenger")
.0;
// Send each job as a separate source.
// The first one should hang (hence the _tx) and never complete, to mimic a hanging get.
let (_tx, rx) = oneshot::channel();
let (execute_tx, execute_rx) = oneshot::channel();
let (requests_tx, requests_rx) = mpsc::unbounded();
requests_tx
.unbounded_send(Ok(Job::new(job::work::Load::Sequential(
Box::new(WaitingWorkload::new(rx, execute_tx)),
job::Signature::new::<usize>(),
))))
.expect("Should be able to send queue");
let _ = messenger.message(
Payload::Source(Rc::new(Mutex::new(Some(requests_rx.boxed_local())))).into(),
Audience::Messenger(manager_signature),
);
// Ensure the requests is in the hanging portion of execute.
execute_rx.await.expect("Should have started hung execution");
// Then send the second request as a new source.
let result = 1;
let mut receptor = message_hub_delegate
.create(MessengerType::Unbound)
.await
.expect("should create receptor")
.1;
let signature = receptor.get_signature();
let (requests_tx, requests_rx) = mpsc::unbounded();
requests_tx
.unbounded_send(Ok(Job::new(job::work::Load::Sequential(
Workload::new(test::Payload::Integer(result), signature),
job::Signature::new::<usize>(),
))))
.expect("Should be able to send queue");
let _ = messenger.message(
Payload::Source(Rc::new(Mutex::new(Some(requests_rx.boxed_local())))).into(),
Audience::Messenger(manager_signature),
);
// Confirm received value matches the value sent from workload.
assert_matches!(receptor.next_of::<test::Payload>().await.expect("should have payload").0,
test::Payload::Integer(value) if value == result);
}
// Validates that sequential jobs like hanging gets are canceled when the source stream ends,
// which corresponds to a client closing their connection.
#[fuchsia::test(allow_stalls = false)]
async fn test_manager_cancels_jobs_on_stream_end() {
// Create delegate for communication between components.
let message_hub_delegate = MessageHub::create_hub();
let manager_signature = Manager::spawn(&message_hub_delegate).await;
// Create a messenger to send job sources to the manager.
let messenger = message_hub_delegate
.create(MessengerType::Unbound)
.await
.expect("should create messenger")
.0;
// Send a job source with one job that hangs forever, to mimic a hanging get.
let (_tx, rx) = oneshot::channel();
let (execute_tx, execute_rx) = oneshot::channel();
let (cancelation_tx, cancelation_rx) = oneshot::channel();
let (requests_tx, requests_rx) = mpsc::unbounded();
requests_tx
.unbounded_send(Ok(Job::new_with_cancellation(
job::work::Load::Sequential(
Box::new(WaitingWorkload::new(rx, execute_tx)),
job::Signature::new::<usize>(),
),
cancelation_tx,
)))
.expect("Should be able to send queue");
let _ = messenger.message(
Payload::Source(Rc::new(Mutex::new(Some(requests_rx.boxed_local())))).into(),
Audience::Messenger(manager_signature),
);
// Ensure the request is in the hanging portion of execute.
execute_rx.await.expect("Should have started hung execution");
// Send the end of the source stream, to mimic a client closing its connection.
requests_tx.close_channel();
// Expect that the job received the cancelation signal.
cancelation_rx.await.expect("Hanging is cancelled");
}
}