node: Log Panics

Register a panic handler that logs a backtrace via the `backtrace`
crate, instead of setting `RUST_BACKTRACE`.

Co-authored-by: Lorenz Leutgeb <lorenz.leutgeb@radicle.xy>

Cargo.lock

@@ -2908,6 +2908,7 @@ name = "radicle-node"
 version = "0.15.0"
 dependencies = [
  "amplify",
+ "backtrace",
  "bloomy",
  "bytes",
  "chrono",

crates/radicle-node/Cargo.toml

@@ -10,12 +10,13 @@ build = "build.rs"
 rust-version.workspace = true
 
 [features]
-default = ["systemd", "structured-logger"]
+default = ["backtrace", "systemd", "structured-logger"]
 systemd = ["dep:radicle-systemd"]
 test = ["radicle/test", "radicle-crypto/test", "radicle-crypto/cyphernet", "radicle-protocol/test", "qcheck", "snapbox"]
 
 [dependencies]
 amplify = { workspace = true }
+backtrace = { version = "0.3.75", optional = true }
 bloomy = "1.2"
 bytes = { workspace = true }
 chrono = { workspace = true, features = ["clock"] }

crates/radicle-node/src/main.rs

@@ -300,15 +300,40 @@ fn initialize_logging(options: &LogOptions) -> Result<(), Box<dyn std::error::Er
     Ok(())
 }
 
-fn main() {
-    // If `RUST_BACKTRACE` does not have a value, then we set it to capture
-    // backtraces for better debugging, otherwise we keep the environments
-    // value.
-    const RUST_BACKTRACE: &str = "RUST_BACKTRACE";
-    if std::env::var_os(RUST_BACKTRACE).is_none() {
-        std::env::set_var(RUST_BACKTRACE, "1");
+fn panic_hook(info: &std::panic::PanicHookInfo) {
+    #[cfg(feature = "backtrace")]
+    let backtrace = format!("{:?}", backtrace::Backtrace::new());
+
+    #[cfg(not(feature = "backtrace"))]
+    let backtrace = " (no backtrace available)";
+
+    let thread = std::thread::current();
+    let thread = thread.name().unwrap_or("<unnamed>");
+
+    let msg = info
+        .payload()
+        .downcast_ref::<&'static str>()
+        .copied()
+        .or(info.payload().downcast_ref::<String>().map(|s| s.as_str()))
+        .unwrap_or("Box<Any>");
+
+    match info.location() {
+        Some(location) => {
+            log::error!(
+                target: "panic", "thread '{thread}' panicked at '{msg}': {}:{}{backtrace}",
+                location.file(),
+                location.line(),
+            );
+        }
+        None => log::error!(
+            target: "panic", "thread '{thread}' panicked at '{msg}'{backtrace}",
+        ),
     }
 
+    log::logger().flush();
+}
+
+fn main() {
     let options = parse_options().unwrap_or_else(|err| {
         // The lexopt errors read nicely with a comma.
         eprintln!("Failed to parse options, {err:#}");
@@ -320,6 +345,8 @@ fn main() {
         exit(3);
     });
 
+    std::panic::set_hook(Box::new(panic_hook));
+
     if let Err(err) = execute(options) {
         log::error!(target: "node", "{err:#}");
         exit(1);