support text format

.gitignore

@@ -1,2 +1,3 @@
 target
 Cargo.lock
+bin

Cargo.toml

@@ -11,4 +11,7 @@ dev = ["clippy"]
 protobuf = "1.0"
 quick-error = "0.2"
 clippy = {version = "*", optional = true}
-fnv = "1.0.3"
+fnv = "1.0.3"
+
+[dependencies.hyper]
+git = "https://github.com/hyperium/hyper.git"

Makefile

@@ -1,4 +1,4 @@
-all: format build test
+all: format build test examples
 
 build:
 	cargo build --features default
@@ -14,4 +14,11 @@ format:
 	cargo fmt -- --write-mode overwrite
 
 clean:
-	cargo clean
+	cargo clean
+
+examples:
+	cargo build --example example_embed
+	cargo build --example example_hyper
+	cp target/debug/examples/* bin/
+
+.PHONY: all examples

examples/example_embed.rs

@@ -0,0 +1,63 @@
+// Copyright 2016 PingCAP, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+extern crate prom;
+extern crate hyper;
+
+use std::thread;
+use std::time::Duration;
+
+use prom::encoder::{TextEncoder, Encoder};
+use prom::{Counter, Opts, Registry};
+
+fn main() {
+    let opts = Opts::new("test", "test help").const_label("a", "1").const_label("b", "2");
+    let counter = Counter::with_opts(opts).unwrap();
+
+    let r = Registry::new();
+    r.register(Box::new(counter.clone())).unwrap();
+
+    counter.inc();
+    assert_eq!(counter.get() as u64, 1);
+    counter.inc_by(42.0).unwrap();
+    assert_eq!(counter.get() as u64, 43);
+
+    let c2 = counter.clone();
+    thread::spawn(move || {
+        for _ in 0..10 {
+            thread::sleep(Duration::from_millis(500));
+            c2.inc();
+        }
+    });
+
+    thread::spawn(move || {
+        for _ in 0..5 {
+            thread::sleep(Duration::from_secs(1));
+            counter.inc();
+        }
+    });
+
+    // Choose your writer and encoder.
+    let mut buffer = Vec::<u8>::new();
+    let encoder = TextEncoder::new();
+    for _ in 0..5 {
+        let metric_familys = r.gather();
+        encoder.encode(&metric_familys, &mut buffer).unwrap();
+
+        // Output to the standard output.
+        println!("{}", String::from_utf8(buffer.clone()).unwrap());
+
+        buffer.clear();
+        thread::sleep(Duration::from_secs(1));
+    }
+}

examples/example_hyper.rs

@@ -0,0 +1,134 @@
+// Copyright 2016 PingCAP, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+extern crate prom;
+extern crate hyper;
+
+use std::thread;
+use std::time::Duration;
+
+use hyper::{StatusCode, Decoder, Next, Encoder as HyperEncoder};
+use hyper::header::{ContentLength, ContentType};
+use hyper::net::HttpStream;
+use hyper::server::{Server, Handler, Request, Response};
+use hyper::mime::Mime;
+
+use prom::errors::{Error, Result};
+use prom::encoder::{Encoder, TextEncoder};
+use prom::{Counter, Opts, Registry};
+
+fn main() {
+    let opts = Opts::new("test", "test help").const_label("a", "1").const_label("b", "2");
+    let counter = Counter::with_opts(opts).unwrap();
+
+    let r = Registry::new();
+    r.register(Box::new(counter.clone())).unwrap();
+
+    counter.inc();
+    assert_eq!(counter.get() as u64, 1);
+    counter.inc_by(42.0).unwrap();
+    assert_eq!(counter.get() as u64, 43);
+
+    let c2 = counter.clone();
+    thread::spawn(move || {
+        loop {
+            thread::sleep(Duration::from_millis(300));
+            c2.inc();
+        }
+    });
+
+    thread::spawn(move || {
+        loop {
+            thread::sleep(Duration::from_millis(1500));
+            counter.inc();
+        }
+    });
+
+    let encoder = TextEncoder::new();
+    // Http server
+    run("127.0.0.1:9898", &r, &encoder).unwrap();
+}
+
+// run runs a http server with a Registry and a Encoder, it blocks current thread.
+pub fn run<'a>(addr: &str, reg: &Registry, encoder: &'a Encoder) -> Result<()> {
+    let reg = reg.clone();
+
+    let addr = try!(addr.parse().or_else(|e| Err(Error::Msg(format!("{:?}", e)))));
+    let server = try!(Server::http(&addr).or_else(|e| Err(Error::Msg(format!("{:?}", e)))));
+    if let Ok((listener, server)) = server.handle(|_| HttpHandler::new(reg.clone(), encoder)) {
+        println!("listening {}", listener);
+
+        server.run();
+    }
+
+    Err(Error::Msg("http server error".to_owned()))
+}
+
+pub struct HttpHandler<'a> {
+    registry: Registry,
+    encoder: &'a (Encoder + 'a),
+    buffer: Vec<u8>,
+    write_pos: usize,
+}
+
+impl<'a> HttpHandler<'a> {
+    pub fn new(registry: Registry, encoder: &'a Encoder) -> HttpHandler<'a> {
+        HttpHandler {
+            registry: registry,
+            encoder: encoder,
+            buffer: Vec::new(),
+            write_pos: 0,
+        }
+    }
+}
+
+impl<'a> Handler<HttpStream> for HttpHandler<'a> {
+    fn on_request(&mut self, _: Request<HttpStream>) -> Next {
+        // TODO: route requests
+        Next::write()
+    }
+
+    fn on_request_readable(&mut self, _: &mut Decoder<HttpStream>) -> Next {
+        Next::write()
+    }
+
+    fn on_response(&mut self, res: &mut Response) -> Next {
+        let metric_familys = self.registry.gather();
+        if let Ok(written) = self.encoder.encode(&metric_familys, &mut self.buffer) {
+            res.headers_mut().set(ContentLength(written as u64));
+        } else {
+            return Next::remove();
+        }
+
+        self.write_pos = 0;
+        res.set_status(StatusCode::Ok);
+        res.headers_mut().set(ContentType((&self.encoder.format_type()).parse::<Mime>().unwrap()));
+        Next::write()
+    }
+
+    fn on_response_writable(&mut self, encoder: &mut HyperEncoder<HttpStream>) -> Next {
+        match encoder.try_write(&self.buffer[self.write_pos..]) {
+            Ok(Some(n)) => {
+                if (self.write_pos + n) == self.buffer.len() {
+                    Next::end()
+                } else {
+                    // a partial write
+                    self.write_pos += n;
+                    Next::write()
+                }
+            }
+            Ok(None) => Next::write(),
+            Err(_) => Next::remove(),
+        }
+    }
+}