From 5e2ce039131fd2075125ea07e0a6b7aadf7a8747 Mon Sep 17 00:00:00 2001
From: Gregory Eremin <g@erem.in>
Date: Wed, 27 Jul 2016 00:05:22 +0200
Subject: [PATCH] Handle errors instead of interfaces

---
 daemon.go |  4 ++--
 shezmu.go | 13 +++++++++++--
 2 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/daemon.go b/daemon.go
index 24e0525..447b778 100644
--- a/daemon.go
+++ b/daemon.go
@@ -55,7 +55,7 @@ type BaseDaemon struct {
 }
 
 // PanicHandler is a function that handles panics. Duh!
-type PanicHandler func(interface{})
+type PanicHandler func(error)
 
 // Process creates a task and then adds it to processing queue.
 func (d *BaseDaemon) Process(a Actor) {
@@ -166,7 +166,7 @@ func (d *BaseDaemon) tryEnqueue(t *task) {
 	d.queue <- t
 }
 
-func (d *BaseDaemon) handlePanic(err interface{}) {
+func (d *BaseDaemon) handlePanic(err error) {
 	if d.panicHandler != nil {
 		d.panicHandler(err)
 	}
diff --git a/shezmu.go b/shezmu.go
index 0acb662..d9c706d 100644
--- a/shezmu.go
+++ b/shezmu.go
@@ -209,10 +209,11 @@ func (s *Shezmu) processSystemTask(t *task) {
 
 func (s *Shezmu) processGeneralTask(t *task) {
 	defer func() {
-		if err := recover(); err != nil {
+		if val := recover(); val != nil {
+			err := interfaceToError(val)
 			s.DaemonStats.Error(t.daemon.String())
 			t.daemon.base().handlePanic(err)
-			s.Logger.Printf("Daemon %s recovered from a panic\nError: %v\n", t.daemon, err)
+			s.Logger.Printf("Daemon %s recovered from a panic\nError: %s\n", t.daemon, err.Error())
 			debug.PrintStack()
 		}
 	}()
@@ -227,3 +228,11 @@ func (s *Shezmu) processGeneralTask(t *task) {
 func (t *task) String() string {
 	return fmt.Sprintf("%s[%s]", t.daemon, t.name)
 }
+
+func interfaceToError(val interface{}) error {
+	if terr, ok := val.(error); ok {
+		return terr
+	}
+
+	return fmt.Errorf("%v", val)
+}