Use tiny_http to serve the prometheus metrics.

Cargo.lock

@@ -6,12 +6,41 @@ version = "0.1.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "87b48bbc752e97f1b6d7f237c0fd50056f19417e30b10121d4065d1459270e1d"
 
+[[package]]
+name = "ascii"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bbf56136a5198c7b01a49e3afcbef6cf84597273d298f54432926024107b0109"
+
+[[package]]
+name = "autocfg"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f8aac770f1885fd7e387acedd76065302551364496e46b3dd00860b2f8359b9d"
+
 [[package]]
 name = "cfg-if"
 version = "0.1.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4785bdd1c96b2a846b2bd7cc02e86b6b3dbf14e7e53446c4f54c92a361040822"
 
+[[package]]
+name = "chrono"
+version = "0.4.12"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f0fee792e164f78f5fe0c296cc2eb3688a2ca2b70cdff33040922d298203f0c4"
+dependencies = [
+ "num-integer",
+ "num-traits",
+ "time",
+]
+
+[[package]]
+name = "chunked_transfer"
+version = "1.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1d29eb15132782371f71da8f947dba48b3717bdb6fa771b9b434d645e40a7193"
+
 [[package]]
 name = "ctor"
 version = "0.1.15"
@@ -29,6 +58,7 @@ dependencies = [
  "gflags",
  "nursery",
  "prometheus",
+ "tiny_http",
 ]
 
 [[package]]
@@ -71,6 +101,17 @@ dependencies = [
  "syn",
 ]
 
+[[package]]
+name = "idna"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "02e2673c30ee86b5b96a9cb52ad15718aa1f966f5ab9ad54a8b95d5ca33120a9"
+dependencies = [
+ "matches",
+ "unicode-bidi",
+ "unicode-normalization",
+]
+
 [[package]]
 name = "inventory"
 version = "0.1.7"
@@ -99,12 +140,58 @@ version = "1.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e2abad23fbc42b3700f2f279844dc832adb2b2eb069b2df918f455c4e18cc646"
 
+[[package]]
+name = "libc"
+version = "0.2.71"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9457b06509d27052635f90d6466700c65095fdf75409b3fbdd903e988b886f49"
+
+[[package]]
+name = "log"
+version = "0.4.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "14b6052be84e6b71ab17edffc2eeabf5c2c3ae1fdb464aae35ac50c67a44e1f7"
+dependencies = [
+ "cfg-if",
+]
+
+[[package]]
+name = "matches"
+version = "0.1.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7ffc5c5338469d4d3ea17d269fa8ea3512ad247247c30bd2df69e68309ed0a08"
+
+[[package]]
+name = "num-integer"
+version = "0.1.43"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8d59457e662d541ba17869cf51cf177c0b5f0cbf476c66bdc90bf1edac4f875b"
+dependencies = [
+ "autocfg",
+ "num-traits",
+]
+
+[[package]]
+name = "num-traits"
+version = "0.2.12"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ac267bcc07f48ee5f8935ab0d24f316fb722d7a1292e2913f0cc196b29ffd611"
+dependencies = [
+ "autocfg",
+]
+
 [[package]]
 name = "nursery"
 version = "0.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a4bd2d4e0cd7c6bb256afbc59a5921c3ead56f05d7696c92e05b6978858b6fa5"
 
+[[package]]
+name = "percent-encoding"
+version = "2.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d4fd5641d01c8f18a23da7b6fe29298ff4b55afcccdf78973b24cf3175fee32e"
+
 [[package]]
 name = "proc-macro2"
 version = "1.0.18"
@@ -200,8 +287,88 @@ dependencies = [
  "syn",
 ]
 
+[[package]]
+name = "time"
+version = "0.1.43"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ca8a50ef2360fbd1eeb0ecd46795a87a19024eb4b53c5dc916ca1fd95fe62438"
+dependencies = [
+ "libc",
+ "winapi",
+]
+
+[[package]]
+name = "tiny_http"
+version = "0.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "15ce4fc3c4cdea1a4399bb1819a539195fb69db4bbe0bde5b7c7f18fed412e02"
+dependencies = [
+ "ascii",
+ "chrono",
+ "chunked_transfer",
+ "log",
+ "url",
+]
+
+[[package]]
+name = "tinyvec"
+version = "0.3.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "53953d2d3a5ad81d9f844a32f14ebb121f50b650cd59d0ee2a07cf13c617efed"
+
+[[package]]
+name = "unicode-bidi"
+version = "0.3.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "49f2bd0c6468a8230e1db229cff8029217cf623c767ea5d60bfbd42729ea54d5"
+dependencies = [
+ "matches",
+]
+
+[[package]]
+name = "unicode-normalization"
+version = "0.1.13"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6fb19cf769fa8c6a80a162df694621ebeb4dafb606470b2b2fce0be40a98a977"
+dependencies = [
+ "tinyvec",
+]
+
 [[package]]
 name = "unicode-xid"
 version = "0.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f7fe0bb3479651439c9112f72b6c505038574c9fbb575ed1bf3b797fa39dd564"
+
+[[package]]
+name = "url"
+version = "2.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "829d4a8476c35c9bf0bbce5a3b23f4106f79728039b726d292bb93bc106787cb"
+dependencies = [
+ "idna",
+ "matches",
+ "percent-encoding",
+]
+
+[[package]]
+name = "winapi"
+version = "0.3.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5c839a674fcd7a98952e593242ea400abe93992746761e38641405d28b00f419"
+dependencies = [
+ "winapi-i686-pc-windows-gnu",
+ "winapi-x86_64-pc-windows-gnu",
+]
+
+[[package]]
+name = "winapi-i686-pc-windows-gnu"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ac3b87c63620426dd9b991e5ce0329eff545bccbbb34f3be09ff6fb6ab51b7b6"
+
+[[package]]
+name = "winapi-x86_64-pc-windows-gnu"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "712e227841d057c1ee1cd2fb22fa7e5a5461ae8e48fa2ca79ec42cfc1931183f"

Cargo.toml

@@ -9,4 +9,5 @@ edition = "2018"
 [dependencies]
 gflags = "^0.3"
 nursery = "^0.0.1"
-prometheus = "^0.9.0"
+prometheus = "^0.9.0"
+tiny_http = "^0.7.0"

src/main.rs

@@ -9,6 +9,7 @@ use nursery::thread;
 use nursery::{Nursery, Waitable};
 use prometheus;
 use prometheus::{CounterVec, Encoder, IntGaugeVec, Opts, Registry, TextEncoder};
+use tiny_http;
 
 gflags::define! {
     /// Print this help text.
@@ -179,17 +180,26 @@ fn main() {
         parent.schedule(Box::new(connect_thread));
     }
     let render_thread = thread::Pending::new(move || {
+        let server = tiny_http::Server::http("localhost:8080").unwrap();
         loop {
-            let mut buffer = vec![];
+            eprintln!("Waiting for request");
-            // Gather the metrics.
+            match server.recv() {
-            let encoder = TextEncoder::new();
+                Ok(req) => {
-            let metric_families = r.gather();
+                    let mut buffer = vec![];
-            encoder.encode(&metric_families, &mut buffer).unwrap();
+                    // Gather the metrics.
+                    let encoder = TextEncoder::new();
+                    let metric_families = r.gather();
+                    encoder.encode(&metric_families, &mut buffer).unwrap();
 
-            // Output to the standard output.
+                    let response = tiny_http::Response::from_data(buffer).with_status_code(200);
-            println!("{}", String::from_utf8(buffer).unwrap());
+                    if let Err(e) = req.respond(response) {
-            // Then we wait for some period of time.
+                        eprintln!("Error responding to request {}", e);
-            std::thread::sleep(std::time::Duration::from_secs(DELAYSECS.flag))
+                    }
+                }
+                Err(e) => {
+                    eprintln!("Invalid http request! {}", e);
+                }
+            }
         }
     });
     parent.schedule(Box::new(render_thread));