Properly log panics with slog (#5075)

* log panics with slog

* update set_hook location

* Merge branch 'unstable' of https://github.com/sigp/lighthouse into slog-panics

Author: jxs

common/task_executor/src/lib.rs

@@ -3,7 +3,7 @@ pub mod test_utils;
 
 use futures::channel::mpsc::Sender;
 use futures::prelude::*;
-use slog::{crit, debug, o, trace};
+use slog::{debug, o, trace};
 use std::sync::Weak;
 use tokio::runtime::{Handle, Runtime};
 
@@ -138,23 +138,11 @@ impl TaskExecutor {
         name: &'static str,
     ) {
         let mut shutdown_sender = self.shutdown_sender();
-        let log = self.log.clone();
-
         if let Some(handle) = self.handle() {
             handle.spawn(async move {
                 let timer = metrics::start_timer_vec(&metrics::TASKS_HISTOGRAM, &[name]);
                 if let Err(join_error) = task_handle.await {
-                    if let Ok(panic) = join_error.try_into_panic() {
-                        let message = panic.downcast_ref::<&str>().unwrap_or(&"<none>");
-
-                        crit!(
-                            log,
-                            "Task panic. This is a bug!";
-                            "task_name" => name,
-                            "message" => message,
-                            "advice" => "Please check above for a backtrace and notify \
-                                         the developers"
-                        );
+                    if let Ok(_panic) = join_error.try_into_panic() {
                         let _ = shutdown_sender
                             .try_send(ShutdownReason::Failure("Panic (fatal error)"));
                     }

lighthouse/src/main.rs

@@ -11,6 +11,7 @@ use futures::TryFutureExt;
 use lighthouse_version::VERSION;
 use malloc_utils::configure_memory_allocator;
 use slog::{crit, info};
+use std::backtrace::Backtrace;
 use std::path::PathBuf;
 use std::process::exit;
 use task_executor::ShutdownReason;
@@ -528,6 +529,21 @@ fn run<E: EthSpec>(
 
     let log = environment.core_context().log().clone();
 
+    // Log panics properly.
+    {
+        let log = log.clone();
+        std::panic::set_hook(Box::new(move |info| {
+            crit!(
+                log,
+                "Task panic. This is a bug!";
+                "location" => info.location().map(ToString::to_string),
+                "message" => info.payload().downcast_ref::<String>(),
+                "backtrace" => %Backtrace::capture(),
+                "advice" => "Please check above for a backtrace and notify the developers",
+            );
+        }));
+    }
+
     let mut tracing_log_path: Option<PathBuf> = clap_utils::parse_optional(matches, "logfile")?;
 
     if tracing_log_path.is_none() {