Auto merge of #2961 - Turbo87:backend-sentry, r=pietroalbini

Report errors and slow requests on the backend to Sentry

This PR implements initial Sentry integration for our backend API via https://github.com/getsentry/sentry-rust.

It will automatically report panics to Sentry, as well as internal server errors (unfortunately without stacktrace for now) and slow requests, similar to our current `println!()` logging.

r? `@pietroalbini`

Author: bors

.env.sample

@@ -56,3 +56,7 @@ export GH_CLIENT_SECRET=
 # export MAILGUN_SMTP_LOGIN=
 # export MAILGUN_SMTP_PASSWORD=
 # export MAILGUN_SMTP_SERVER=
+
+# Credentials for connecting to the Sentry error reporting service.
+# export SENTRY_DSN_API=
+export SENTRY_ENV_API=local

Cargo.lock

@@ -76,6 +76,7 @@ regex = "1.3.9"
 reqwest = { version = "0.10", features = ["blocking", "gzip", "json"] }
 scheduled-thread-pool = "0.2.0"
 semver = { version = "0.10", features = ["diesel", "serde"] }
+sentry = "0.20.1"
 serde = { version = "1.0.0", features = ["derive"] }
 serde_json = "1.0.0"
 sha2 = "0.9"

Cargo.toml

@@ -2,6 +2,7 @@
 
 use cargo_registry::{boot, App, Env};
 use std::{
+    borrow::Cow,
     fs::File,
     sync::{mpsc::channel, Arc, Mutex},
     thread,
@@ -12,6 +13,7 @@ use civet::Server as CivetServer;
 use conduit_hyper::Service;
 use futures_util::future::FutureExt;
 use reqwest::blocking::Client;
+use sentry::{ClientOptions, IntoDsn};
 
 const CORE_THREADS: usize = 4;
 
@@ -24,6 +26,21 @@ enum Server {
 use Server::*;
 
 fn main() -> Result<(), Box<dyn std::error::Error>> {
+    let _sentry = dotenv::var("SENTRY_DSN_API")
+        .ok()
+        .into_dsn()
+        .expect("SENTRY_DSN_API is not a valid Sentry DSN value")
+        .map(|dsn| {
+            let mut opts = ClientOptions::from(dsn);
+            opts.environment = Some(
+                dotenv::var("SENTRY_ENV_API")
+                    .map(Cow::Owned)
+                    .expect("SENTRY_ENV_API must be set when using SENTRY_DSN_API"),
+            );
+
+            sentry::init(opts)
+        });
+
     // Initialize logging
     env_logger::init();