garage/src/api/generic_server.rs

365 lines
9.5 KiB
Rust

use std::convert::Infallible;
use std::fs::{self, Permissions};
use std::os::unix::fs::PermissionsExt;
use std::sync::Arc;
use async_trait::async_trait;
use futures::future::Future;
use futures::stream::{futures_unordered::FuturesUnordered, StreamExt};
use http_body_util::BodyExt;
use hyper::header::HeaderValue;
use hyper::server::conn::http1;
use hyper::service::service_fn;
use hyper::{body::Incoming as IncomingBody, Request, Response};
use hyper::{HeaderMap, StatusCode};
use hyper_util::rt::TokioIo;
use tokio::io::{AsyncRead, AsyncWrite};
use tokio::net::{TcpListener, TcpStream, UnixListener, UnixStream};
use tokio::sync::watch;
use opentelemetry::{
global,
metrics::{Counter, ValueRecorder},
trace::{FutureExt, SpanRef, TraceContextExt, Tracer},
Context, KeyValue,
};
use garage_util::error::Error as GarageError;
use garage_util::forwarded_headers;
use garage_util::metrics::{gen_trace_id, RecordDuration};
use garage_util::socket_address::UnixOrTCPSocketAddress;
use crate::helpers::{BoxBody, ErrorBody};
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) -> ErrorBody;
}
#[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<IncomingBody>) -> Result<Self::Endpoint, Self::Error>;
async fn handle(
&self,
req: Request<IncomingBody>,
endpoint: Self::Endpoint,
) -> Result<Response<BoxBody<Self::Error>>, 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: UnixOrTCPSocketAddress,
unix_bind_addr_mode: Option<u32>,
must_exit: watch::Receiver<bool>,
) -> Result<(), GarageError> {
let server_name = format!("{} API", A::API_NAME_DISPLAY);
info!("{} server listening on {}", server_name, bind_addr);
match bind_addr {
UnixOrTCPSocketAddress::TCPSocket(addr) => {
let listener = TcpListener::bind(addr).await?;
let handler = move |request, socketaddr| self.clone().handler(request, socketaddr);
server_loop(server_name, listener, handler, must_exit).await
}
UnixOrTCPSocketAddress::UnixSocket(ref path) => {
if path.exists() {
fs::remove_file(path)?
}
let listener = UnixListener::bind(path)?;
let listener = UnixListenerOn(listener, path.display().to_string());
fs::set_permissions(
path,
Permissions::from_mode(unix_bind_addr_mode.unwrap_or(0o222)),
)?;
let handler = move |request, socketaddr| self.clone().handler(request, socketaddr);
server_loop(server_name, listener, handler, must_exit).await
}
}
}
async fn handler(
self: Arc<Self>,
req: Request<IncomingBody>,
addr: String,
) -> Result<Response<BoxBody<A::Error>>, http::Error> {
let uri = req.uri().clone();
if let Ok(forwarded_for_ip_addr) =
forwarded_headers::handle_forwarded_for_headers(req.headers())
{
info!(
"{} (via {}) {} {}",
forwarded_for_ip_addr,
addr,
req.method(),
uri
);
} else {
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 = 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
.map(|body| BoxBody::new(body.map_err(|_: Infallible| unreachable!()))))
}
}
}
async fn handler_stage2(
&self,
req: Request<IncomingBody>,
) -> Result<Response<BoxBody<A::Error>>, 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
}
}
// ==== helper functions ====
#[async_trait]
pub trait Accept: Send + Sync + 'static {
type Stream: AsyncRead + AsyncWrite + Send + Sync + 'static;
async fn accept(&self) -> std::io::Result<(Self::Stream, String)>;
}
#[async_trait]
impl Accept for TcpListener {
type Stream = TcpStream;
async fn accept(&self) -> std::io::Result<(Self::Stream, String)> {
self.accept()
.await
.map(|(stream, addr)| (stream, addr.to_string()))
}
}
pub struct UnixListenerOn(pub UnixListener, pub String);
#[async_trait]
impl Accept for UnixListenerOn {
type Stream = UnixStream;
async fn accept(&self) -> std::io::Result<(Self::Stream, String)> {
self.0
.accept()
.await
.map(|(stream, _addr)| (stream, self.1.clone()))
}
}
pub async fn server_loop<A, H, F, E>(
server_name: String,
listener: A,
handler: H,
mut must_exit: watch::Receiver<bool>,
) -> Result<(), GarageError>
where
A: Accept,
H: Fn(Request<IncomingBody>, String) -> F + Send + Sync + Clone + 'static,
F: Future<Output = Result<Response<BoxBody<E>>, http::Error>> + Send + 'static,
E: Send + Sync + std::error::Error + 'static,
{
let (conn_in, mut conn_out) = tokio::sync::mpsc::unbounded_channel();
let connection_collector = tokio::spawn({
let server_name = server_name.clone();
async move {
let mut connections = FuturesUnordered::new();
loop {
let collect_next = async {
if connections.is_empty() {
futures::future::pending().await
} else {
connections.next().await
}
};
tokio::select! {
result = collect_next => {
trace!("{} server: HTTP connection finished: {:?}", server_name, result);
}
new_fut = conn_out.recv() => {
match new_fut {
Some(f) => connections.push(f),
None => break,
}
}
}
}
if !connections.is_empty() {
info!(
"{} server: {} connections still open",
server_name,
connections.len()
);
while let Some(conn_res) = connections.next().await {
trace!(
"{} server: HTTP connection finished: {:?}",
server_name,
conn_res
);
info!(
"{} server: {} connections still open",
server_name,
connections.len()
);
}
}
}
});
while !*must_exit.borrow() {
let (stream, client_addr) = tokio::select! {
acc = listener.accept() => acc?,
_ = must_exit.changed() => continue,
};
let io = TokioIo::new(stream);
let handler = handler.clone();
let serve = move |req: Request<IncomingBody>| handler(req, client_addr.clone());
let fut = tokio::task::spawn(async move {
let io = Box::pin(io);
if let Err(e) = http1::Builder::new()
.serve_connection(io, service_fn(serve))
.await
{
debug!("Error handling HTTP connection: {}", e);
}
});
conn_in.send(fut)?;
}
info!("{} server exiting", server_name);
drop(conn_in);
connection_collector.await?;
Ok(())
}