1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
//! Server implementation and builder.

mod conn;
mod incoming;
#[cfg(feature = "tls")]
#[cfg_attr(docsrs, doc(cfg(feature = "tls")))]
mod tls;

pub use conn::Connected;
#[cfg(feature = "tls")]
pub use tls::ServerTlsConfig;

#[cfg(feature = "tls")]
use super::service::TlsAcceptor;

use incoming::TcpIncoming;

#[cfg(feature = "tls")]
pub(crate) use incoming::TlsStream;

#[cfg(feature = "tls")]
use crate::transport::Error;

use super::service::{Or, Routes, ServerIo, ServiceBuilderExt};
use crate::{body::BoxBody, request::ConnectionInfo};
use futures_core::Stream;
use futures_util::{
    future::{self, MapErr},
    TryFutureExt,
};
use http::{HeaderMap, Request, Response};
use hyper::{server::accept, Body};
use std::{
    fmt,
    future::Future,
    net::SocketAddr,
    pin::Pin,
    sync::Arc,
    task::{Context, Poll},
    time::Duration,
};
use tokio::io::{AsyncRead, AsyncWrite};
use tower::{
    limit::concurrency::ConcurrencyLimitLayer, timeout::TimeoutLayer, util::Either, Service,
    ServiceBuilder,
};
use tracing_futures::{Instrument, Instrumented};

type BoxService = tower::util::BoxService<Request<Body>, Response<BoxBody>, crate::Error>;
type TraceInterceptor = Arc<dyn Fn(&HeaderMap) -> tracing::Span + Send + Sync + 'static>;

/// A default batteries included `transport` server.
///
/// This is a wrapper around [`hyper::Server`] and provides an easy builder
/// pattern style builder [`Server`]. This builder exposes easy configuration parameters
/// for providing a fully featured http2 based gRPC server. This should provide
/// a very good out of the box http2 server for use with tonic but is also a
/// reference implementation that should be a good starting point for anyone
/// wanting to create a more complex and/or specific implementation.
#[derive(Default, Clone)]
pub struct Server {
    trace_interceptor: Option<TraceInterceptor>,
    concurrency_limit: Option<usize>,
    timeout: Option<Duration>,
    #[cfg(feature = "tls")]
    tls: Option<TlsAcceptor>,
    init_stream_window_size: Option<u32>,
    init_connection_window_size: Option<u32>,
    max_concurrent_streams: Option<u32>,
    tcp_keepalive: Option<Duration>,
    tcp_nodelay: bool,
}

/// A stack based `Service` router.
#[derive(Debug)]
pub struct Router<A, B> {
    server: Server,
    routes: Routes<A, B, Request<Body>>,
}

/// A trait to provide a static reference to the service's
/// name. This is used for routing service's within the router.
pub trait NamedService {
    /// The `Service-Name` as described [here].
    ///
    /// [here]: https://github.com/grpc/grpc/blob/master/doc/PROTOCOL-HTTP2.md#requests
    const NAME: &'static str;
}

impl<S: NamedService, T> NamedService for Either<S, T> {
    const NAME: &'static str = S::NAME;
}

impl Server {
    /// Create a new server builder that can configure a [`Server`].
    pub fn builder() -> Self {
        Server {
            tcp_nodelay: true,
            ..Default::default()
        }
    }
}

impl Server {
    /// Configure TLS for this server.
    #[cfg(feature = "tls")]
    #[cfg_attr(docsrs, doc(cfg(feature = "tls")))]
    pub fn tls_config(self, tls_config: ServerTlsConfig) -> Result<Self, Error> {
        Ok(Server {
            tls: Some(
                tls_config
                    .tls_acceptor()
                    .map_err(|e| Error::from_source(e))?,
            ),
            ..self
        })
    }

    /// Set the concurrency limit applied to on requests inbound per connection.
    ///
    /// # Example
    ///
    /// ```
    /// # use tonic::transport::Server;
    /// # use tower_service::Service;
    /// # let mut builder = Server::builder();
    /// builder.concurrency_limit_per_connection(32);
    /// ```
    pub fn concurrency_limit_per_connection(self, limit: usize) -> Self {
        Server {
            concurrency_limit: Some(limit),
            ..self
        }
    }

    /// Set a timeout on for all request handlers.
    ///
    /// # Example
    ///
    /// ```
    /// # use tonic::transport::Server;
    /// # use tower_service::Service;
    /// # use std::time::Duration;
    /// # let mut builder = Server::builder();
    /// builder.timeout(Duration::from_secs(30));
    /// ```
    pub fn timeout(&mut self, timeout: Duration) -> &mut Self {
        self.timeout = Some(timeout);
        self
    }

    /// Sets the [`SETTINGS_INITIAL_WINDOW_SIZE`][spec] option for HTTP2
    /// stream-level flow control.
    ///
    /// Default is 65,535
    ///
    /// [spec]: https://http2.github.io/http2-spec/#SETTINGS_INITIAL_WINDOW_SIZE
    pub fn initial_stream_window_size(self, sz: impl Into<Option<u32>>) -> Self {
        Server {
            init_stream_window_size: sz.into(),
            ..self
        }
    }

    /// Sets the max connection-level flow control for HTTP2
    ///
    /// Default is 65,535
    pub fn initial_connection_window_size(self, sz: impl Into<Option<u32>>) -> Self {
        Server {
            init_connection_window_size: sz.into(),
            ..self
        }
    }

    /// Sets the [`SETTINGS_MAX_CONCURRENT_STREAMS`][spec] option for HTTP2
    /// connections.
    ///
    /// Default is no limit (`None`).
    ///
    /// [spec]: https://http2.github.io/http2-spec/#SETTINGS_MAX_CONCURRENT_STREAMS
    pub fn max_concurrent_streams(self, max: impl Into<Option<u32>>) -> Self {
        Server {
            max_concurrent_streams: max.into(),
            ..self
        }
    }

    /// Set whether TCP keepalive messages are enabled on accepted connections.
    ///
    /// If `None` is specified, keepalive is disabled, otherwise the duration
    /// specified will be the time to remain idle before sending TCP keepalive
    /// probes.
    ///
    /// Default is no keepalive (`None`)
    ///
    pub fn tcp_keepalive(self, tcp_keepalive: Option<Duration>) -> Self {
        Server {
            tcp_keepalive,
            ..self
        }
    }

    /// Set the value of `TCP_NODELAY` option for accepted connections. Enabled by default.
    pub fn tcp_nodelay(self, enabled: bool) -> Self {
        Server {
            tcp_nodelay: enabled,
            ..self
        }
    }

    /// Intercept inbound headers and add a [`tracing::Span`] to each response future.
    pub fn trace_fn<F>(self, f: F) -> Self
    where
        F: Fn(&HeaderMap) -> tracing::Span + Send + Sync + 'static,
    {
        Server {
            trace_interceptor: Some(Arc::new(f)),
            ..self
        }
    }

    /// Create a router with the `S` typed service as the first service.
    ///
    /// This will clone the `Server` builder and create a router that will
    /// route around different services.
    pub fn add_service<S>(&mut self, svc: S) -> Router<S, Unimplemented>
    where
        S: Service<Request<Body>, Response = Response<BoxBody>>
            + NamedService
            + Clone
            + Send
            + 'static,
        S::Future: Send + 'static,
        S::Error: Into<crate::Error> + Send,
    {
        Router::new(self.clone(), svc)
    }

    /// Create a router with the optional `S` typed service as the first service.
    ///
    /// This will clone the `Server` builder and create a router that will
    /// route around different services.
    ///
    /// # Note
    /// Even when the argument given is `None` this will capture *all* requests to this service name.
    /// As a result, one cannot use this to toggle between two identically named implementations.
    pub fn add_optional_service<S>(
        &mut self,
        svc: Option<S>,
    ) -> Router<Either<S, Unimplemented>, Unimplemented>
    where
        S: Service<Request<Body>, Response = Response<BoxBody>>
            + NamedService
            + Clone
            + Send
            + 'static,
        S::Future: Send + 'static,
        S::Error: Into<crate::Error> + Send,
    {
        let svc = match svc {
            Some(some) => Either::A(some),
            None => Either::B(Unimplemented::default()),
        };
        Router::new(self.clone(), svc)
    }

    pub(crate) async fn serve_with_shutdown<S, I, F, IO, IE>(
        self,
        svc: S,
        incoming: I,
        signal: Option<F>,
    ) -> Result<(), super::Error>
    where
        S: Service<Request<Body>, Response = Response<BoxBody>> + Clone + Send + 'static,
        S::Future: Send + 'static,
        S::Error: Into<crate::Error> + Send,
        I: Stream<Item = Result<IO, IE>>,
        IO: AsyncRead + AsyncWrite + Connected + Unpin + Send + 'static,
        IE: Into<crate::Error>,
        F: Future<Output = ()>,
    {
        let span = self.trace_interceptor.clone();
        let concurrency_limit = self.concurrency_limit;
        let init_connection_window_size = self.init_connection_window_size;
        let init_stream_window_size = self.init_stream_window_size;
        let max_concurrent_streams = self.max_concurrent_streams;
        let timeout = self.timeout.clone();

        let tcp = incoming::tcp_incoming(incoming, self);
        let incoming = accept::from_stream::<_, _, crate::Error>(tcp);

        let svc = MakeSvc {
            inner: svc,
            concurrency_limit,
            timeout,
            span,
        };

        let server = hyper::Server::builder(incoming)
            .http2_only(true)
            .http2_initial_connection_window_size(init_connection_window_size)
            .http2_initial_stream_window_size(init_stream_window_size)
            .http2_max_concurrent_streams(max_concurrent_streams);

        if let Some(signal) = signal {
            server
                .serve(svc)
                .with_graceful_shutdown(signal)
                .await
                .map_err(super::Error::from_source)?
        } else {
            server.serve(svc).await.map_err(super::Error::from_source)?;
        }

        Ok(())
    }
}

impl<S> Router<S, Unimplemented> {
    pub(crate) fn new(server: Server, svc: S) -> Self
    where
        S: Service<Request<Body>, Response = Response<BoxBody>>
            + NamedService
            + Clone
            + Send
            + 'static,
        S::Future: Send + 'static,
        S::Error: Into<crate::Error> + Send,
    {
        let svc_name = <S as NamedService>::NAME;
        let svc_route = format!("/{}", svc_name);
        let pred = move |req: &Request<Body>| {
            let path = req.uri().path();

            path.starts_with(&svc_route)
        };
        Self {
            server,
            routes: Routes::new(pred, svc, Unimplemented::default()),
        }
    }
}

impl<A, B> Router<A, B>
where
    A: Service<Request<Body>, Response = Response<BoxBody>> + Clone + Send + 'static,
    A::Future: Send + 'static,
    A::Error: Into<crate::Error> + Send,
    B: Service<Request<Body>, Response = Response<BoxBody>> + Clone + Send + 'static,
    B::Future: Send + 'static,
    B::Error: Into<crate::Error> + Send,
{
    /// Add a new service to this router.
    pub fn add_service<S>(self, svc: S) -> Router<S, Or<A, B, Request<Body>>>
    where
        S: Service<Request<Body>, Response = Response<BoxBody>>
            + NamedService
            + Clone
            + Send
            + 'static,
        S::Future: Send + 'static,
        S::Error: Into<crate::Error> + Send,
    {
        let Self { routes, server } = self;

        let svc_name = <S as NamedService>::NAME;
        let svc_route = format!("/{}", svc_name);
        let pred = move |req: &Request<Body>| {
            let path = req.uri().path();

            path.starts_with(&svc_route)
        };
        let routes = routes.push(pred, svc);

        Router { server, routes }
    }

    /// Add a new optional service to this router.
    ///
    /// # Note
    /// Even when the argument given is `None` this will capture *all* requests to this service name.
    /// As a result, one cannot use this to toggle between two identically named implementations.
    pub fn add_optional_service<S>(
        self,
        svc: Option<S>,
    ) -> Router<Either<S, Unimplemented>, Or<A, B, Request<Body>>>
    where
        S: Service<Request<Body>, Response = Response<BoxBody>>
            + NamedService
            + Clone
            + Send
            + 'static,
        S::Future: Send + 'static,
        S::Error: Into<crate::Error> + Send,
    {
        let Self { routes, server } = self;

        let svc_name = <S as NamedService>::NAME;
        let svc_route = format!("/{}", svc_name);
        let pred = move |req: &Request<Body>| {
            let path = req.uri().path();

            path.starts_with(&svc_route)
        };
        let svc = match svc {
            Some(some) => Either::A(some),
            None => Either::B(Unimplemented::default()),
        };
        let routes = routes.push(pred, svc);

        Router { server, routes }
    }

    /// Consume this [`Server`] creating a future that will execute the server
    /// on [`tokio`]'s default executor.
    ///
    /// [`Server`]: struct.Server.html
    pub async fn serve(self, addr: SocketAddr) -> Result<(), super::Error> {
        let incoming = TcpIncoming::new(addr, self.server.tcp_nodelay, self.server.tcp_keepalive)
            .map_err(super::Error::from_source)?;
        self.server
            .serve_with_shutdown::<_, _, future::Ready<()>, _, _>(self.routes, incoming, None)
            .await
    }

    /// Consume this [`Server`] creating a future that will execute the server
    /// on [`tokio`]'s default executor. And shutdown when the provided signal
    /// is received.
    ///
    /// [`Server`]: struct.Server.html
    pub async fn serve_with_shutdown<F: Future<Output = ()>>(
        self,
        addr: SocketAddr,
        signal: F,
    ) -> Result<(), super::Error> {
        let incoming = TcpIncoming::new(addr, self.server.tcp_nodelay, self.server.tcp_keepalive)
            .map_err(super::Error::from_source)?;
        self.server
            .serve_with_shutdown(self.routes, incoming, Some(signal))
            .await
    }

    /// Consume this [`Server`] creating a future that will execute the server on
    /// the provided incoming stream of `AsyncRead + AsyncWrite`.
    ///
    /// [`Server`]: struct.Server.html
    pub async fn serve_with_incoming<I, IO, IE>(self, incoming: I) -> Result<(), super::Error>
    where
        I: Stream<Item = Result<IO, IE>>,
        IO: AsyncRead + AsyncWrite + Connected + Unpin + Send + 'static,
        IE: Into<crate::Error>,
    {
        self.server
            .serve_with_shutdown::<_, _, future::Ready<()>, _, _>(self.routes, incoming, None)
            .await
    }

    /// Consume this [`Server`] creating a future that will execute the server on
    /// the provided incoming stream of `AsyncRead + AsyncWrite`. Similar to
    /// `serve_with_shutdown` this method will also take a signal future to
    /// gracefully shutdown the server.
    ///
    /// [`Server`]: struct.Server.html
    pub async fn serve_with_incoming_shutdown<I, IO, IE, F>(
        self,
        incoming: I,
        signal: F,
    ) -> Result<(), super::Error>
    where
        I: Stream<Item = Result<IO, IE>>,
        IO: AsyncRead + AsyncWrite + Connected + Unpin + Send + 'static,
        IE: Into<crate::Error>,
        F: Future<Output = ()>,
    {
        self.server
            .serve_with_shutdown(self.routes, incoming, Some(signal))
            .await
    }
}

impl fmt::Debug for Server {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        f.debug_struct("Builder").finish()
    }
}

struct Svc<S> {
    inner: S,
    span: Option<TraceInterceptor>,
    conn_info: ConnectionInfo,
}

impl<S> Service<Request<Body>> for Svc<S>
where
    S: Service<Request<Body>, Response = Response<BoxBody>>,
    S::Error: Into<crate::Error>,
{
    type Response = Response<BoxBody>;
    type Error = crate::Error;
    type Future = MapErr<Instrumented<S::Future>, fn(S::Error) -> crate::Error>;

    fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
        self.inner.poll_ready(cx).map_err(Into::into)
    }

    fn call(&mut self, mut req: Request<Body>) -> Self::Future {
        let span = if let Some(trace_interceptor) = &self.span {
            trace_interceptor(req.headers())
        } else {
            tracing::Span::none()
        };

        req.extensions_mut().insert(self.conn_info.clone());

        self.inner.call(req).instrument(span).map_err(|e| e.into())
    }
}

impl<S> fmt::Debug for Svc<S> {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        f.debug_struct("Svc").finish()
    }
}

struct MakeSvc<S> {
    concurrency_limit: Option<usize>,
    timeout: Option<Duration>,
    inner: S,
    span: Option<TraceInterceptor>,
}

impl<S> Service<&ServerIo> for MakeSvc<S>
where
    S: Service<Request<Body>, Response = Response<BoxBody>> + Clone + Send + 'static,
    S::Future: Send + 'static,
    S::Error: Into<crate::Error> + Send,
{
    type Response = BoxService;
    type Error = crate::Error;
    type Future =
        Pin<Box<dyn Future<Output = Result<Self::Response, Self::Error>> + Send + 'static>>;

    fn poll_ready(&mut self, _cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
        Ok(()).into()
    }

    fn call(&mut self, io: &ServerIo) -> Self::Future {
        let conn_info = crate::request::ConnectionInfo {
            remote_addr: io.remote_addr(),
            peer_certs: io.peer_certs().map(Arc::new),
        };

        let svc = self.inner.clone();
        let concurrency_limit = self.concurrency_limit;
        let timeout = self.timeout.clone();
        let span = self.span.clone();

        Box::pin(async move {
            let svc = ServiceBuilder::new()
                .optional_layer(concurrency_limit.map(ConcurrencyLimitLayer::new))
                .optional_layer(timeout.map(TimeoutLayer::new))
                .service(svc);

            let svc = BoxService::new(Svc {
                inner: svc,
                span,
                conn_info,
            });

            Ok(svc)
        })
    }
}

#[derive(Default, Clone, Debug)]
#[doc(hidden)]
pub struct Unimplemented {
    _p: (),
}

impl Service<Request<Body>> for Unimplemented {
    type Response = Response<BoxBody>;
    type Error = crate::Error;
    type Future = future::Ready<Result<Self::Response, Self::Error>>;

    fn poll_ready(&mut self, _cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
        Ok(()).into()
    }

    fn call(&mut self, _req: Request<Body>) -> Self::Future {
        future::ok(
            http::Response::builder()
                .status(200)
                .header("grpc-status", "12")
                .body(BoxBody::empty())
                .unwrap(),
        )
    }
}