Add node/fork endpoint to HTTP API, tidy

beacon_node/http_server/Cargo.toml

@@ -18,12 +18,16 @@ slot_clock = { path = "../../eth2/utils/slot_clock" }
 protos = { path = "../../protos" }
 fork_choice = { path = "../../eth2/fork_choice" }
 grpcio = { version = "0.4", default-features = false, features = ["protobuf-codec"] }
+persistent = "^0.4"
 protobuf = "2.0.2"
 prometheus = "^0.6"
 clap = "2.32.0"
 store = { path = "../store" }
 dirs = "1.0.3"
 futures = "0.1.23"
+serde = "1.0"
+serde_derive = "1.0"
+serde_json = "1.0"
 slog = "^2.2.3"
 slog-term = "^2.4.0"
 slog-async = "^2.3.0"

beacon_node/http_server/src/api.rs

@@ -0,0 +1,69 @@
+use crate::key::BeaconChainKey;
+use beacon_chain::{BeaconChain, BeaconChainTypes};
+use iron::prelude::*;
+use iron::{
+    headers::{CacheControl, CacheDirective, ContentType},
+    status::Status,
+    AfterMiddleware, Handler, IronResult, Request, Response,
+};
+use persistent::Read;
+use router::Router;
+use serde_json::json;
+use std::sync::Arc;
+
+pub fn build_handler<T: BeaconChainTypes + 'static>(
+    beacon_chain: Arc<BeaconChain<T>>,
+) -> impl Handler {
+    let mut router = Router::new();
+
+    router.get("/node/fork", handle_fork::<T>, "fork");
+
+    let mut chain = Chain::new(router);
+
+    // Insert `BeaconChain` so it may be accessed in a request.
+    chain.link(Read::<BeaconChainKey<T>>::both(beacon_chain.clone()));
+    // Set the content-type headers.
+    chain.link_after(SetJsonContentType);
+    // Set the cache headers.
+    chain.link_after(SetCacheDirectives);
+
+    chain
+}
+
+/// Sets the `cache-control` headers on _all_ responses, unless they are already set.
+struct SetCacheDirectives;
+impl AfterMiddleware for SetCacheDirectives {
+    fn after(&self, _req: &mut Request, mut resp: Response) -> IronResult<Response> {
+        // This is run for every requests, AFTER all handlers have been executed
+        if resp.headers.get::<CacheControl>() == None {
+            resp.headers.set(CacheControl(vec![
+                CacheDirective::NoCache,
+                CacheDirective::NoStore,
+            ]));
+        }
+        Ok(resp)
+    }
+}
+
+/// Sets the `content-type` headers on _all_ responses, unless they are already set.
+struct SetJsonContentType;
+impl AfterMiddleware for SetJsonContentType {
+    fn after(&self, _req: &mut Request, mut resp: Response) -> IronResult<Response> {
+        if resp.headers.get::<ContentType>() == None {
+            resp.headers.set(ContentType::json());
+        }
+        Ok(resp)
+    }
+}
+
+fn handle_fork<T: BeaconChainTypes + 'static>(req: &mut Request) -> IronResult<Response> {
+    // TODO: investigate unwrap - I'm _guessing_ we'll never hit it but we should check to be sure.
+    let beacon_chain = req.get::<Read<BeaconChainKey<T>>>().unwrap();
+
+    let response = json!({
+        "fork": beacon_chain.head().beacon_state.fork,
+        "chain_id": beacon_chain.spec.chain_id
+    });
+
+    Ok(Response::with((Status::Ok, response.to_string())))
+}

beacon_node/http_server/src/key.rs

@@ -0,0 +1,12 @@
+use beacon_chain::{BeaconChain, BeaconChainTypes};
+use iron::typemap::Key;
+use std::marker::PhantomData;
+use std::sync::Arc;
+
+pub struct BeaconChainKey<T> {
+    _phantom: PhantomData<T>,
+}
+
+impl<T: BeaconChainTypes + 'static> Key for BeaconChainKey<T> {
+    type Value = Arc<BeaconChain<T>>;
+}

beacon_node/http_server/src/lib.rs

@@ -1,11 +1,11 @@
-mod prometheus_handler;
+mod api;
+mod key;
+mod metrics;
 
 use beacon_chain::{BeaconChain, BeaconChainTypes};
 use futures::Future;
 use iron::prelude::*;
-use iron::{status::Status, Handler, IronResult, Request, Response};
 use network::NetworkMessage;
-use prometheus_handler::PrometheusHandler;
 use router::Router;
 use slog::{info, o, warn};
 use std::sync::Arc;
@@ -26,32 +26,26 @@ impl Default for HttpServerConfig {
     }
 }
 
-pub struct IndexHandler {
-    message: String,
-}
-
-impl Handler for IndexHandler {
-    fn handle(&self, _: &mut Request) -> IronResult<Response> {
-        Ok(Response::with((Status::Ok, self.message.clone())))
-    }
-}
-
+/// Build the `iron` HTTP server, defining the core routes.
 pub fn create_iron_http_server<T: BeaconChainTypes + 'static>(
     beacon_chain: Arc<BeaconChain<T>>,
 ) -> Iron<Router> {
-    let index_handler = IndexHandler {
-        message: "Hello world".to_string(),
-    };
-    let prom_handler = PrometheusHandler {
-        beacon_chain: beacon_chain,
-    };
-
     let mut router = Router::new();
-    router.get("/", index_handler, "index");
-    router.get("/metrics", prom_handler, "metrics");
+
+    // A `GET` request to `/metrics` is handled by the `metrics` module.
+    router.get(
+        "/metrics",
+        metrics::build_handler(beacon_chain.clone()),
+        "metrics",
+    );
+
+    // Any request to all other endpoints is handled by the `api` module.
+    router.any("/*", api::build_handler(beacon_chain.clone()), "api");
+
     Iron::new(router)
 }
 
+/// Start the HTTP service on the tokio `TaskExecutor`.
 pub fn start_service<T: BeaconChainTypes + 'static>(
     config: &HttpServerConfig,
     executor: &TaskExecutor,

beacon_node/http_server/src/metrics.rs

@@ -0,0 +1,57 @@
+use crate::key::BeaconChainKey;
+use beacon_chain::{BeaconChain, BeaconChainTypes};
+use iron::prelude::*;
+use iron::{status::Status, Handler, IronResult, Request, Response};
+use persistent::Read;
+use prometheus::{Encoder, IntCounter, Opts, Registry, TextEncoder};
+use slot_clock::SlotClock;
+use std::sync::Arc;
+use types::Slot;
+
+pub fn build_handler<T: BeaconChainTypes + 'static>(
+    beacon_chain: Arc<BeaconChain<T>>,
+) -> impl Handler {
+    let mut chain = Chain::new(handle_metrics::<T>);
+
+    chain.link(Read::<BeaconChainKey<T>>::both(beacon_chain));
+
+    chain
+}
+
+/// Handle a request for Prometheus metrics.
+///
+/// Returns a text string containing all metrics.
+fn handle_metrics<T: BeaconChainTypes + 'static>(req: &mut Request) -> IronResult<Response> {
+    let beacon_chain = req.get::<Read<BeaconChainKey<T>>>().unwrap();
+
+    let r = Registry::new();
+
+    let present_slot = if let Ok(Some(slot)) = beacon_chain.slot_clock.present_slot() {
+        slot
+    } else {
+        Slot::new(0)
+    };
+    register_and_set_slot(
+        &r,
+        "present_slot",
+        "direct_slock_clock_reading",
+        present_slot,
+    );
+
+    // Gather the metrics.
+    let mut buffer = vec![];
+    let encoder = TextEncoder::new();
+    let metric_families = r.gather();
+    encoder.encode(&metric_families, &mut buffer).unwrap();
+
+    let prom_string = String::from_utf8(buffer).unwrap();
+
+    Ok(Response::with((Status::Ok, prom_string)))
+}
+
+fn register_and_set_slot(registry: &Registry, name: &str, help: &str, slot: Slot) {
+    let counter_opts = Opts::new(name, help);
+    let counter = IntCounter::with_opts(counter_opts).unwrap();
+    registry.register(Box::new(counter.clone())).unwrap();
+    counter.inc_by(slot.as_u64() as i64);
+}

beacon_node/http_server/src/prometheus_handler.rs

@@ -1,47 +0,0 @@
-use beacon_chain::{BeaconChain, BeaconChainTypes};
-use iron::{status::Status, Handler, IronResult, Request, Response};
-use prometheus::{Encoder, IntCounter, Opts, Registry, TextEncoder};
-use slot_clock::SlotClock;
-use std::sync::Arc;
-use types::Slot;
-
-pub struct PrometheusHandler<T: BeaconChainTypes> {
-    pub beacon_chain: Arc<BeaconChain<T>>,
-}
-
-impl<T: BeaconChainTypes> PrometheusHandler<T> {}
-
-impl<T: BeaconChainTypes + 'static> Handler for PrometheusHandler<T> {
-    fn handle(&self, _: &mut Request) -> IronResult<Response> {
-        let r = Registry::new();
-
-        let present_slot = if let Ok(Some(slot)) = self.beacon_chain.slot_clock.present_slot() {
-            slot
-        } else {
-            Slot::new(0)
-        };
-        register_and_set_slot(
-            &r,
-            "present_slot",
-            "direct_slock_clock_reading",
-            present_slot,
-        );
-
-        // Gather the metrics.
-        let mut buffer = vec![];
-        let encoder = TextEncoder::new();
-        let metric_families = r.gather();
-        encoder.encode(&metric_families, &mut buffer).unwrap();
-
-        let prom_string = String::from_utf8(buffer).unwrap();
-
-        Ok(Response::with((Status::Ok, prom_string)))
-    }
-}
-
-fn register_and_set_slot(registry: &Registry, name: &str, help: &str, slot: Slot) {
-    let counter_opts = Opts::new(name, help);
-    let counter = IntCounter::with_opts(counter_opts).unwrap();
-    registry.register(Box::new(counter.clone())).unwrap();
-    counter.inc_by(slot.as_u64() as i64);
-}