tiny change towards better error handling

Cargo.toml

@@ -16,3 +16,5 @@ hyper = "0.13"
 prometheus = "0.10"
 futures = "0.3"
 anyhow = "1.0"
+log = "0.4"
+env_logger = { version = "0.8", features = ["termcolor", "humantime"] }

src/collectors/github_rate_limit.rs

@@ -1,6 +1,8 @@
 use prometheus::{core::Collector, IntGauge, Opts};
 
 use crate::Config;
+use anyhow::{Context, Error, Result};
+use log::{debug, error};
 use reqwest::header::{ACCEPT, AUTHORIZATION, USER_AGENT};
 use reqwest::{Client, Method, Request};
 use std::collections::HashMap;
@@ -24,7 +26,7 @@ enum GithubReqBuilder {
 }
 
 impl GithubReqBuilder {
-    fn build_request(&self, client: &Client, token: &str) -> Result<Request, reqwest::Error> {
+    fn build_request(&self, client: &Client, token: &str) -> Result<Request, Error> {
         let rb = match self {
             Self::User => client.request(Method::GET, GH_API_USER_ENDPOINT),
             Self::RateLimit => client.request(Method::GET, GH_API_RATE_LIMIT_ENDPOINT),
@@ -37,49 +39,50 @@ impl GithubReqBuilder {
         .header(AUTHORIZATION, format!("{} {}", "token", token))
         .header(ACCEPT, "application/vnd.github.v3+json")
         .build()
+        .map_err(Error::from)
     }
 }
 
 #[derive(Clone)]
 pub struct GitHubRateLimit {
-    descriptions: Vec<prometheus::core::Desc>,
     users: Vec<User>,
 }
 
 impl GitHubRateLimit {
-    pub async fn new(config: &Config) -> Self {
+    pub async fn new(config: &Config) -> Result<Self, Error> {
         let tokens: Vec<String> = config
             .gh_rate_limit_tokens
             .split(',')
             .map(|v| v.trim().to_string())
             .collect();
 
-        let users = Self::get_users_for_tokens(tokens).await;
-        let descriptions = Vec::new();
+        let users = Self::get_users_for_tokens(tokens)
+            .await
+            .context("Unable to get usernames for rate limit stats")?;
 
-        let rv = Self {
-            users,
-            descriptions,
-        };
+        let rv = Self { users };
 
         let refresh_rate = config.gh_rate_limit_stats_cache_refresh;
         let mut rv2 = rv.clone();
         tokio::spawn(async move {
             loop {
-                rv2.update_stats().await;
+                if let Err(e) = rv2.update_stats().await {
+                    error!("{:#?}", e);
+                }
+
                 tokio::time::delay_for(Duration::from_secs(refresh_rate)).await;
             }
         });
 
-        rv
+        Ok(rv)
     }
 
-    async fn get_users_for_tokens(tokens: Vec<String>) -> Vec<User> {
+    async fn get_users_for_tokens(tokens: Vec<String>) -> Result<Vec<User>, Error> {
         let ns = String::from("monitorbot_github_rate_limit");
         let mut rv: Vec<User> = Vec::new();
         for token in tokens.into_iter() {
             let ns2 = ns.clone();
-            let username = GitHubRateLimit::get_github_api_username(&token).await;
+            let username = GitHubRateLimit::get_github_api_username(&token).await?;
             let user_future = tokio::task::spawn_blocking(move || {
                 let rate_limit = IntGauge::with_opts(
                     Opts::new("limit", "Rate limit.")
@@ -119,50 +122,45 @@ impl GitHubRateLimit {
             rv.push(user);
         }
 
-        rv
+        Ok(rv)
     }
 
-    async fn get_github_api_username(token: &str) -> String {
+    async fn get_github_api_username(token: &str) -> Result<String, Error> {
         #[derive(serde::Deserialize)]
         struct GithubUser {
             pub login: String,
         }
 
         let client = reqwest::Client::new();
-        let req = GithubReqBuilder::User
-            .build_request(&client, &token)
-            .unwrap();
-        let u = client
-            .execute(req)
-            .await
-            .unwrap()
-            .json::<GithubUser>()
-            .await
-            .unwrap();
+        let req = GithubReqBuilder::User.build_request(&client, &token)?;
+        let u = client.execute(req).await?.json::<GithubUser>().await?;
 
-        u.login
+        Ok(u.login)
     }
 
-    async fn update_stats(&mut self) {
+    async fn update_stats(&mut self) -> Result<(), Error> {
+        debug!("Updating rate limit stats");
+
         #[derive(Debug, serde::Deserialize)]
         struct GithubRateLimit {
             pub rate: HashMap<String, usize>,
         }
 
         let client = reqwest::Client::new();
-
-        //FIXME: we will (might?) need a RWLock on users structure
         for u in self.users.iter_mut() {
             let req = GithubReqBuilder::RateLimit
                 .build_request(&client, &u.token)
-                .unwrap();
-            let mut data = client
+                .context("Unable to build request to update stats")?;
+
+            let response = client
                 .execute(req)
                 .await
-                .unwrap()
+                .context("Unable to execute request to update stats")?;
+
+            let mut data = response
                 .json::<GithubRateLimit>()
                 .await
-                .unwrap();
+                .context("Unable to deserialize rate limit stats")?;
 
             let remaining = data.rate.remove("remaining").unwrap_or(0);
             let limit = data.rate.remove("limit").unwrap_or(0);
@@ -172,12 +170,15 @@ impl GitHubRateLimit {
             u.reset.set(reset as i64);
             u.limit.set(limit as i64);
         }
+
+        Ok(())
     }
 }
 
 impl Collector for GitHubRateLimit {
     fn desc(&self) -> std::vec::Vec<&prometheus::core::Desc> {
-        self.descriptions.iter().collect()
+        // descriptions are being defined in the initialization of the metrics options
+        Vec::default()
     }
 
     fn collect(&self) -> std::vec::Vec<prometheus::proto::MetricFamily> {

src/collectors/mod.rs

@@ -1,12 +1,18 @@
 mod github_rate_limit;
+
 pub use crate::collectors::github_rate_limit::GitHubRateLimit;
 
 use crate::MetricProvider;
-use futures::FutureExt;
+use anyhow::{Error, Result};
+use futures::TryFutureExt;
+use log::info;
 
 // register collectors for metrics gathering
-pub async fn register_collectors(p: &MetricProvider) -> Result<(), prometheus::Error> {
+pub async fn register_collectors(p: &MetricProvider) -> Result<(), Error> {
     GitHubRateLimit::new(&p.config)
-        .map(|rl| p.register_collector(rl))
+        .and_then(|rl| async {
+            info!("Registering GitHubRateLimit collector");
+            p.register_collector(rl)
+        })
         .await
 }

src/lib.rs

@@ -2,15 +2,18 @@
 
 pub mod collectors;
 mod config;
+
 pub use config::Config;
 
 use prometheus::core::Collector;
 use prometheus::{Encoder, Registry};
 
+use anyhow::{Error, Result};
 use futures::future;
 use futures::task::{Context, Poll};
 use hyper::service::Service;
 use hyper::{Body, Method, Request, Response, StatusCode};
+use log::{debug, error};
 
 #[derive(Clone, Debug)]
 pub struct MetricProvider {
@@ -24,15 +27,19 @@ impl MetricProvider {
         Self { register, config }
     }
 
-    fn register_collector(
-        &self,
-        collector: impl Collector + 'static,
-    ) -> Result<(), prometheus::Error> {
-        self.register.register(Box::new(collector))
+    fn register_collector(&self, collector: impl Collector + 'static) -> Result<(), Error> {
+        self.register
+            .register(Box::new(collector))
+            .map_err(Error::from)
     }
 
-    fn gather_with_encoder<BUF: std::io::Write>(&self, encoder: impl Encoder, buf: &mut BUF) {
-        encoder.encode(&self.register.gather(), buf).unwrap();
+    fn gather_with_encoder<BUF>(&self, encoder: impl Encoder, buf: &mut BUF) -> Result<(), Error>
+    where
+        BUF: std::io::Write,
+    {
+        encoder
+            .encode(&self.register.gather(), buf)
+            .map_err(Error::from)
     }
 
     pub fn into_service(self) -> MetricProviderFactory {
@@ -50,17 +57,26 @@ impl Service<Request<Body>> for MetricProvider {
     }
 
     fn call(&mut self, req: Request<Body>) -> Self::Future {
+        debug!("New Request to endpoint {}", req.uri().path());
+
         let output = match (req.method(), req.uri().path()) {
             // Metrics handler
             (&Method::GET, "/metrics") => {
                 let encoder = prometheus::TextEncoder::new();
                 let mut buffer = Vec::<u8>::new();
-                self.gather_with_encoder(encoder, &mut buffer);
-
-                Response::builder()
-                    .status(StatusCode::OK)
-                    .body(Body::from(buffer))
-                    .unwrap()
+                match self.gather_with_encoder(encoder, &mut buffer) {
+                    Ok(_) => Response::builder()
+                        .status(StatusCode::OK)
+                        .body(Body::from(buffer))
+                        .unwrap(),
+                    Err(e) => {
+                        error!("{:?}", e);
+                        Response::builder()
+                            .status(StatusCode::INTERNAL_SERVER_ERROR)
+                            .body(Body::empty())
+                            .unwrap()
+                    }
+                }
             }
             // All other paths and methods
             _ => Response::builder()

src/main.rs

@@ -1,27 +1,29 @@
+use anyhow::{bail, Error, Result};
 use hyper::Server;
+use log::info;
 use monitorbot::Config;
 use monitorbot::{collectors::register_collectors, MetricProvider};
 use std::net::SocketAddr;
 
 #[tokio::main]
-async fn main() -> Result<(), Box<dyn std::error::Error>> {
+async fn main() -> Result<(), Error> {
     dotenv::dotenv().ok();
+    env_logger::init();
 
     let config = Config::from_env()?;
     let port = config.port;
     let addr = SocketAddr::from(([0, 0, 0, 0], port));
 
     let provider = MetricProvider::new(config);
     if let Err(e) = register_collectors(&provider).await {
-        eprintln!("Unable to register collectors: {:#?}", e);
-        return Ok(());
+        bail!("(Registering collectors) {}", e)
     }
 
     let server = Server::bind(&addr).serve(provider.into_service());
-    println!("Server listening on port {}", port);
+    info!("Server listening on port: {}", port);
 
     if let Err(e) = server.await {
-        eprintln!("Server error: {}", e);
+        bail!("(Hyper server error) {}", e);
     }
 
     Ok(())