use std::net::SocketAddr;
use std::sync::Arc;
use async_trait::async_trait;
use futures::future::Future;
use hyper::header::HeaderValue;
use hyper::server::conn::AddrStream;
use hyper::service::{make_service_fn, service_fn};
use hyper::{Body, Request, Response, Server};
use hyper::{HeaderMap, StatusCode};
use opentelemetry::{
global,
metrics::{Counter, ValueRecorder},
trace::{FutureExt, SpanRef, TraceContextExt, Tracer},
Context, KeyValue,
};
use garage_util::error::Error as GarageError;
use garage_util::metrics::{gen_trace_id, RecordDuration};
pub(crate) trait ApiEndpoint: Send + Sync + 'static {
fn name(&self) -> &'static str;
fn add_span_attributes(&self, span: SpanRef<'_>);
}
pub trait ApiError: std::error::Error + Send + Sync + 'static {
fn http_status_code(&self) -> StatusCode;
fn add_http_headers(&self, header_map: &mut HeaderMap<HeaderValue>);
fn http_body(&self, garage_region: &str, path: &str) -> Body;
}
#[async_trait]
pub(crate) trait ApiHandler: Send + Sync + 'static {
const API_NAME: &'static str;
const API_NAME_DISPLAY: &'static str;
type Endpoint: ApiEndpoint;
type Error: ApiError;
fn parse_endpoint(&self, r: &Request<Body>) -> Result<Self::Endpoint, Self::Error>;
async fn handle(
&self,
req: Request<Body>,
endpoint: Self::Endpoint,
) -> Result<Response<Body>, Self::Error>;
}
pub(crate) struct ApiServer<A: ApiHandler> {
region: String,
api_handler: A,
// Metrics
request_counter: Counter<u64>,
error_counter: Counter<u64>,
request_duration: ValueRecorder<f64>,
}
impl<A: ApiHandler> ApiServer<A> {
pub fn new(region: String, api_handler: A) -> Arc<Self> {
let meter = global::meter("garage/api");
Arc::new(Self {
region,
api_handler,
request_counter: meter
.u64_counter(format!("api.{}.request_counter", A::API_NAME))
.with_description(format!(
"Number of API calls to the various {} API endpoints",
A::API_NAME_DISPLAY
))
.init(),
error_counter: meter
.u64_counter(format!("api.{}.error_counter", A::API_NAME))
.with_description(format!(
"Number of API calls to the various {} API endpoints that resulted in errors",
A::API_NAME_DISPLAY
))
.init(),
request_duration: meter
.f64_value_recorder(format!("api.{}.request_duration", A::API_NAME))
.with_description(format!(
"Duration of API calls to the various {} API endpoints",
A::API_NAME_DISPLAY
))
.init(),
})
}
pub async fn run_server(
self: Arc<Self>,
bind_addr: SocketAddr,
shutdown_signal: impl Future<Output = ()>,
) -> Result<(), GarageError> {
let service = make_service_fn(|conn: &AddrStream| {
let this = self.clone();
let client_addr = conn.remote_addr();
async move {
Ok::<_, GarageError>(service_fn(move |req: Request<Body>| {
let this = this.clone();
this.handler(req, client_addr)
}))
}
});
let server = Server::bind(&bind_addr).serve(service);
let graceful = server.with_graceful_shutdown(shutdown_signal);
info!(
"{} API server listening on http://{}",
A::API_NAME_DISPLAY,
bind_addr
);
graceful.await?;
Ok(())
}
async fn handler(
self: Arc<Self>,
req: Request<Body>,
addr: SocketAddr,
) -> Result<Response<Body>, GarageError> {
let uri = req.uri().clone();
info!("{} {} {}", addr, req.method(), uri);
debug!("{:?}", req);
let tracer = opentelemetry::global::tracer("garage");
let span = tracer
.span_builder(format!("{} API call (unknown)", A::API_NAME_DISPLAY))
.with_trace_id(gen_trace_id())
.with_attributes(vec![
KeyValue::new("method", format!("{}", req.method())),
KeyValue::new("uri", req.uri().to_string()),
])
.start(&tracer);
let res = self
.handler_stage2(req)
.with_context(Context::current_with_span(span))
.await;
match res {
Ok(x) => {
debug!("{} {:?}", x.status(), x.headers());
Ok(x)
}
Err(e) => {
let body: Body = e.http_body(&self.region, uri.path());
let mut http_error_builder = Response::builder().status(e.http_status_code());
if let Some(header_map) = http_error_builder.headers_mut() {
e.add_http_headers(header_map)
}
let http_error = http_error_builder.body(body)?;
if e.http_status_code().is_server_error() {
warn!("Response: error {}, {}", e.http_status_code(), e);
} else {
info!("Response: error {}, {}", e.http_status_code(), e);
}
Ok(http_error)
}
}
}
async fn handler_stage2(&self, req: Request<Body>) -> Result<Response<Body>, A::Error> {
let endpoint = self.api_handler.parse_endpoint(&req)?;
debug!("Endpoint: {}", endpoint.name());
let current_context = Context::current();
let current_span = current_context.span();
current_span.update_name::<String>(format!(
"{} API {}",
A::API_NAME_DISPLAY,
endpoint.name()
));
current_span.set_attribute(KeyValue::new("endpoint", endpoint.name()));
endpoint.add_span_attributes(current_span);
let metrics_tags = &[KeyValue::new("api_endpoint", endpoint.name())];
let res = self
.api_handler
.handle(req, endpoint)
.record_duration(&self.request_duration, &metrics_tags[..])
.await;
self.request_counter.add(1, &metrics_tags[..]);
let status_code = match &res {
Ok(r) => r.status(),
Err(e) => e.http_status_code(),
};
if status_code.is_client_error() || status_code.is_server_error() {
self.error_counter.add(
1,
&[
metrics_tags[0].clone(),
KeyValue::new("status_code", status_code.as_str().to_string()),
],
);
}
res
}
}
