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use crate::{
context::{create_context_notifier_pair, ServiceHandles},
initializer::{BoxedServiceInitializer, InitializerFn, ServiceInitializationError, ServiceInitializer},
ServiceInitializerContext,
};
use futures::future;
use std::future::Future;
use tari_shutdown::ShutdownSignal;
pub struct StackBuilder {
initializers: Vec<BoxedServiceInitializer>,
shutdown_signal: ShutdownSignal,
}
impl StackBuilder {
pub fn new(shutdown_signal: ShutdownSignal) -> Self {
Self {
initializers: Vec::new(),
shutdown_signal,
}
}
}
impl StackBuilder {
pub fn add_initializer<I>(self, initializer: I) -> Self
where
I: ServiceInitializer + Send + 'static,
I::Future: Send + 'static,
{
self.add_initializer_boxed(initializer.boxed())
}
pub fn add_initializer_fn<TFunc, TFut>(self, initializer: TFunc) -> Self
where
TFunc: FnOnce(ServiceInitializerContext) -> TFut + Send + 'static,
TFut: Future<Output = Result<(), ServiceInitializationError>> + Send + 'static,
{
self.add_initializer_boxed(InitializerFn::new(initializer).boxed())
}
pub fn add_initializer_boxed(mut self, initializer: BoxedServiceInitializer) -> Self {
self.initializers.push(initializer);
self
}
pub async fn build(self) -> Result<ServiceHandles, ServiceInitializationError> {
let StackBuilder {
shutdown_signal,
mut initializers,
} = self;
let (mut notifier, context) = create_context_notifier_pair(shutdown_signal);
let init_futures = initializers
.iter_mut()
.map(|init| ServiceInitializer::initialize(init, context.clone()));
for result in future::join_all(init_futures).await {
result?;
}
let _ = notifier.trigger();
Ok(context.into_inner())
}
}
#[cfg(test)]
mod test {
use super::*;
use crate::{initializer::ServiceInitializer, ServiceInitializerContext};
use futures::{executor::block_on, future, Future};
use std::sync::{
atomic::{AtomicUsize, Ordering},
Arc,
};
use tari_shutdown::Shutdown;
use tower::service_fn;
#[tokio_macros::test]
async fn service_defn_simple() {
let simple_initializer = |_: ServiceInitializerContext| future::ok(());
let shutdown = Shutdown::new();
let handles = StackBuilder::new(shutdown.to_signal())
.add_initializer(simple_initializer)
.build()
.await;
assert!(handles.is_ok());
}
#[derive(Clone)]
struct DummyServiceHandle(usize);
struct DummyInitializer {
state: Arc<AtomicUsize>,
}
impl DummyInitializer {
fn new(state: Arc<AtomicUsize>) -> Self {
Self { state }
}
}
impl ServiceInitializer for DummyInitializer {
type Future = impl Future<Output = Result<(), ServiceInitializationError>>;
fn initialize(&mut self, context: ServiceInitializerContext) -> Self::Future {
context.register_handle(DummyServiceHandle(123));
context.spawn_when_ready(|handles| async move {
let handle = handles.get_handle::<DummyServiceHandle>().unwrap();
assert_eq!(handle.0, 123);
service_fn(|_: ()| future::ok::<_, ()>(handle.0));
});
self.state.fetch_add(1, Ordering::AcqRel);
future::ready(Ok(()))
}
}
#[tokio_macros::test]
async fn service_stack_new() {
let shared_state = Arc::new(AtomicUsize::new(0));
let shutdown = Shutdown::new();
let initializer = DummyInitializer::new(Arc::clone(&shared_state));
let handles = block_on(
StackBuilder::new(shutdown.to_signal())
.add_initializer(initializer)
.build(),
)
.unwrap();
handles.get_handle::<DummyServiceHandle>().unwrap();
assert_eq!(shared_state.load(Ordering::SeqCst), 1);
}
}