chore: replace homegrown errors with anyhow

CHANGELOG.md

@@ -7,6 +7,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ## [Unreleased]
 ### Changed
 - update dependencies, including stable tokio this time.
+- migrate error handling to anyhow
 
 ## [v0.3.0] - 2021-04-19
 ### Added

Cargo.lock

@@ -9,6 +9,23 @@ dependencies = [
  "winapi",
 ]
 
+[[package]]
+name = "anyhow"
+version = "1.0.40"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "28b2cd92db5cbd74e8e5028f7e27dd7aa3090e89e4f2a197cc7c8dfb69c7063b"
+
+[[package]]
+name = "async-anyhow-logger"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "06a2f0f9e176eb6d5185a049090385608c2294b14ef1647af489414521b0de1c"
+dependencies = [
+ "anyhow",
+ "futures",
+ "log",
+]
+
 [[package]]
 name = "atty"
 version = "0.2.14"
@@ -432,6 +449,8 @@ dependencies = [
 name = "peshming"
 version = "0.3.0"
 dependencies = [
+ "anyhow",
+ "async-anyhow-logger",
  "chrono",
  "clap",
  "fern",

Cargo.toml

@@ -19,3 +19,5 @@ chrono = "0.4.19"
 serde = { version = "1.0.125", features = ["derive"] }
 tokio-ping = { git = "https://github.com/jcgruenhage/tokio-ping", branch = "main" }
 futures-util = "0.3.14"
+anyhow = "1.0.40"
+async-anyhow-logger = "0.1.0"

src/config.rs

@@ -17,6 +17,7 @@
  *   You should have received a copy of the GNU Affero General Public License   *
  *   along with this program.  If not, see <https://www.gnu.org/licenses/>.     *
  ********************************************************************************/
+use anyhow::{Context, Result};
 use clap::{clap_app, crate_authors, crate_description, crate_name, crate_version};
 use log::info;
 use serde::{Deserialize, Serialize};
@@ -69,21 +70,7 @@ pub(crate) fn setup_fern(level: u64) {
     }
 }
 
-pub(crate) fn read_config(path: &str) -> Result<Config, Error> {
-    let config_file_content = std::fs::read_to_string(path)?;
-    Ok(toml::from_str(&config_file_content)?)
-}
-
-pub(crate) struct Error {}
-
-impl std::convert::From<std::io::Error> for Error {
-    fn from(_: std::io::Error) -> Self {
-        Error {}
-    }
-}
-
-impl std::convert::From<toml::de::Error> for Error {
-    fn from(_: toml::de::Error) -> Self {
-        Error {}
-    }
+pub(crate) fn read_config(path: &str) -> Result<Config> {
+    let config_file_content = std::fs::read_to_string(path).context("Couldn't read config file")?;
+    Ok(toml::from_str(&config_file_content).context("Couldn't parse config file")?)
 }

src/main.rs

@@ -17,33 +17,29 @@
  *   You should have received a copy of the GNU Affero General Public License   *
  *   along with this program.  If not, see <https://www.gnu.org/licenses/>.     *
  ********************************************************************************/
-use log::error;
+use anyhow::{Context, Result};
 
 mod config;
 mod metrics;
 mod ping;
+
 use crate::config::{read_config, setup_clap, setup_fern};
 use crate::metrics::start_serving_metrics;
 use crate::ping::start_pinging_hosts;
 
 #[tokio::main]
-async fn main() -> Result<(), ()> {
+async fn main() -> Result<()> {
     let clap = setup_clap();
     setup_fern(clap.occurrences_of("v"));
-    let config = match read_config(clap.value_of("config").unwrap()) {
-        Ok(config) => config,
-        Err(_) => {
-            error!("Couldn't read config file!");
-            return Err(());
-        }
-    };
+    let config =
+        read_config(clap.value_of("config").unwrap()).context("Couldn't read config file!")?;
+
+    let ping_fut = start_pinging_hosts(config.clone());
+    let serve_fut = start_serving_metrics(config.clone());
+
+    futures::pin_mut!(ping_fut);
+    futures::pin_mut!(serve_fut);
 
-    tokio::spawn(start_pinging_hosts(config.clone()));
-    match start_serving_metrics(config.clone()).await {
-        Ok(_) => Ok(()),
-        Err(error) => {
-            error!("Couldn't serve metrics: {}", error);
-            Err(())
-        }
-    }
+    futures::future::select(ping_fut, serve_fut).await;
+    Ok(())
 }

src/metrics.rs

@@ -18,6 +18,7 @@
  *   along with this program.  If not, see <https://www.gnu.org/licenses/>.     *
  ********************************************************************************/
 use crate::config::Config;
+use anyhow::{Context, Result};
 use hyper::{
     header::CONTENT_TYPE,
     server::Server,
@@ -50,7 +51,7 @@ lazy_static! {
     .unwrap();
 }
 
-async fn serve_req(req: Request<Body>) -> std::result::Result<Response<Body>, hyper::Error> {
+async fn serve_req(req: Request<Body>) -> Result<Response<Body>> {
     match req.uri().path() {
         "/metrics" => serve_metrics().await,
         "/health" => serve_health_check().await,
@@ -58,7 +59,7 @@ async fn serve_req(req: Request<Body>) -> std::result::Result<Response<Body>, hy
     }
 }
 
-async fn serve_metrics() -> std::result::Result<Response<Body>, hyper::Error> {
+async fn serve_metrics() -> Result<Response<Body>> {
     let encoder = TextEncoder::new();
 
     HTTP_COUNTER.inc();
@@ -73,31 +74,31 @@ async fn serve_metrics() -> std::result::Result<Response<Body>, hyper::Error> {
         .status(200)
         .header(CONTENT_TYPE, encoder.format_type())
         .body(Body::from(buffer))
-        .unwrap();
+        .context("Couldn't build metrics response")?;
 
     timer.observe_duration();
 
     Ok(response)
 }
 
-async fn serve_health_check() -> std::result::Result<Response<Body>, hyper::Error> {
+async fn serve_health_check() -> Result<Response<Body>> {
     Ok(Response::builder()
         .status(200)
         .body(Body::from(vec![]))
-        .unwrap())
+        .context("Couldn't build health check response")?)
 }
 
-async fn serve_not_found() -> std::result::Result<Response<Body>, hyper::Error> {
+async fn serve_not_found() -> Result<Response<Body>> {
     Ok(Response::builder()
         .status(404)
         .body(Body::from(vec![]))
-        .unwrap())
+        .context("Couldn't build not found response")?)
 }
 
-pub(crate) async fn start_serving_metrics(config: Config) -> std::result::Result<(), hyper::Error> {
+pub(crate) async fn start_serving_metrics(config: Config) -> Result<()> {
     let serve_future = Server::bind(&config.listener).serve(make_service_fn(|_| async {
         Ok::<_, hyper::Error>(service_fn(serve_req))
     }));
     info!("Listening on {}", &config.listener);
-    serve_future.await
+    Ok(serve_future.await?)
 }

src/ping.rs

@@ -18,8 +18,10 @@
  *   along with this program.  If not, see <https://www.gnu.org/licenses/>.     *
  ********************************************************************************/
 use crate::config::Config;
+use anyhow::{Context, Result};
+use async_anyhow_logger::catch;
 use lazy_static::lazy_static;
-use log::{error, info, trace};
+use log::{info, trace};
 use prometheus::*;
 use std::net::IpAddr;
 use std::time::Duration;
@@ -39,41 +41,33 @@ lazy_static! {
     .unwrap();
 }
 
-pub(crate) async fn start_pinging_hosts(
-    config: Config,
-) -> std::result::Result<(), tokio_ping::Error> {
-    let pinger = match Pinger::new().await {
-        Ok(pinger) => pinger,
-        Err(error) => {
-            error!("Couldn't create pinger: {}", error);
-            std::process::exit(1);
-        }
-    };
+pub(crate) async fn start_pinging_hosts(config: Config) -> Result<()> {
+    let pinger = Pinger::new().await.context("Couldn't create pinger")?;
+    let mut handles = vec![];
     for (host, interval) in config.hosts.clone() {
         info!("Spawn ping task for {}", host);
-        tokio::spawn(ping_host(pinger.clone(), host, interval));
+        handles.push(tokio::spawn(catch(ping_host(pinger.clone(), host, interval))));
     }
+    let (result, _, _) = futures::future::select_all(handles).await;
+    result?;
     Ok(())
 }
 
-async fn ping_host(pinger: Pinger, host: IpAddr, interval: u64) {
+async fn ping_host(pinger: Pinger, host: IpAddr, interval: u64) -> Result<()> {
     let mut pingchain = pinger.chain(host).timeout(Duration::from_secs(3));
     let mut interval = tokio::time::interval(Duration::from_millis(interval));
     let host_string = host.to_string();
     loop {
         interval.tick().await;
-        tokio::spawn(handle_ping_result(pingchain.send(), host_string.clone()));
+        tokio::spawn(catch(handle_ping_result(
+            pingchain.send(),
+            host_string.clone(),
+        )));
     }
 }
 
-async fn handle_ping_result(result: PingFuture, host: String) {
-    let pong = match result.await {
-        Ok(pong) => pong,
-        Err(error) => {
-            error!("Couldn't ping {}: {}", &host, error);
-            return;
-        }
-    };
+async fn handle_ping_result(result: PingFuture, host: String) -> Result<()> {
+    let pong = result.await.context(format!("Couldn't ping {}", &host))?;
     match pong {
         Some(time) => {
             let ms = time.as_millis();
@@ -87,4 +81,6 @@ async fn handle_ping_result(result: PingFuture, host: String) {
             PING_HISTOGRAM.with_label_values(&[&host]).observe(3000.0);
         }
     };
+
+    Ok(())
 }