Auto merge of #1646 - jtgeibel:conduit-hyper-round3, r=sgrif

Add `hyper` support as a boot-time option

If the `USE_HYPER` environment variable is set then `hyper` is used as
the backend server.  If the variable is not set, the default remains a
`civet` based server.

This has a trivial impact on build times and binary sizes, as `hyper`
is already pulled in (as a `Client`) on production via `reqwest`.

This will also aid in profiling performance differences, as backend
instances can be run in parallel in two terminals:

```
$ PORT=8888 cargo run --release --bin server
$ PORT=8889 USE_HYPER=1 cargo run --release --bin server
```

Author: bors

Cargo.lock

@@ -29,7 +29,6 @@ rustdoc-args = [
 
 [dependencies]
 cargo-registry-s3 = { path = "src/s3", version = "0.2.0" }
-old_semver = { path = "src/old_semver", version = "0.1.0" }
 rand = "0.6"
 git2 = "0.6.4"
 flate2 = "1.0"
@@ -76,6 +75,7 @@ conduit-router = "0.8"
 conduit-static = "0.8"
 conduit-git-http-backend = "0.8"
 civet = "0.9"
+conduit-hyper = "0.1.3"
 
 [dev-dependencies]
 conduit-test = "0.8"

Cargo.toml

@@ -12,12 +12,12 @@ The server does the following things:
 3. Reads values from environment variables to configure a new instance of `cargo_registry::App`
 4. Adds middleware to the app by calling `cargo_registry::middleware`
 5. Syncs the categories defined in *src/categories.toml* with the categories in the database
-6. Starts a [civet][] `Server` that uses the `cargo_registry::App` instance
+6. Starts either a [conduit] or a [hyper] server that uses the `cargo_registry::App` instance
 7. Tells Nginx on Heroku that the application is ready to receive requests, if running on Heroku
-8. Blocks forever (or until the process is killed) waiting to receive messages on a channel that no
-   messages are ever sent to, in order to outive the civet `Server` threads
+8. Blocks forever (or until the process is killed)
 
 [civet]: https://crates.io/crates/civet
+[hyper]: https://crates.io/crates/hyper
 
 ## Routes
 

docs/BACKEND.md

@@ -8,7 +8,15 @@ use std::{
     sync::{mpsc::channel, Arc},
 };
 
-use civet::Server;
+use civet::Server as CivetServer;
+use conduit_hyper::Service as HyperService;
+
+enum Server {
+    Civet(CivetServer),
+    Hyper(HyperService<conduit_middleware::MiddlewareBuilder>),
+}
+
+use Server::*;
 
 fn main() {
     let _ = jemalloc_ctl::set_background_thread(true);
@@ -66,9 +74,16 @@ fn main() {
     } else {
         50
     };
-    let mut cfg = civet::Config::new();
-    cfg.port(port).threads(threads).keep_alive(true);
-    let _a = Server::start(cfg, app);
+
+    let server = if env::var("USE_HYPER").is_ok() {
+        println!("Booting with a hyper based server");
+        Hyper(HyperService::new(app, threads as usize))
+    } else {
+        println!("Booting with a civet based server");
+        let mut cfg = civet::Config::new();
+        cfg.port(port).threads(threads).keep_alive(true);
+        Civet(CivetServer::start(cfg, app).unwrap())
+    };
 
     println!("listening on port {}", port);
 
@@ -78,7 +93,13 @@ fn main() {
         File::create("/tmp/app-initialized").unwrap();
     }
 
-    // TODO: handle a graceful shutdown by just waiting for a SIG{INT,TERM}
-    let (_tx, rx) = channel::<()>();
-    rx.recv().unwrap();
+    if let Hyper(server) = server {
+        let addr = ([127, 0, 0, 1], port).into();
+        server.run(addr);
+    } else {
+        // Civet server is already running, but we need to block the main thread forever
+        // TODO: handle a graceful shutdown by just waiting for a SIG{INT,TERM}
+        let (_tx, rx) = channel::<()>();
+        rx.recv().unwrap();
+    }
 }

src/bin/server.rs

@@ -1,7 +1,7 @@
 use std::{io::Read, net::SocketAddr};
 
 use conduit::Request;
-use old_semver::semver;
+use conduit_hyper::semver;
 
 // Can't derive Debug because of Request.
 #[allow(missing_debug_implementations)]