From c1cab5b479491087c9dbc4f70363da639e7f6e54 Mon Sep 17 00:00:00 2001
From: Carlos Rodriguez-Fernandez <carlosrodrifernandez@gmail.com>
Date: Tue, 31 Oct 2023 08:14:49 -0700
Subject: [PATCH] reload config on SIGHUP

Fixes: #118
Signed-off-by: Carlos Rodriguez-Fernandez <carlosrodrifernandez@gmail.com>
---
 README.md |  2 +-
 main.go   | 16 +++++++++++++++-
 2 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/README.md b/README.md
index 37e9a06..1ab61ad 100644
--- a/README.md
+++ b/README.md
@@ -61,7 +61,7 @@ In each host group the `interval`, `network`, and `protocol` are optional.
 
 The interval Duration is in [Go time.ParseDuration()](https://golang.org/pkg/time/#ParseDuration) syntax.
 
-NOTE: The config is only read on startup, SIGHUP is not supported (yet).
+The config is read on startup, and can be reloaded with the SIGHUP signal.
 
 ## Building and running
 
diff --git a/main.go b/main.go
index 9357297..cbbcbcd 100644
--- a/main.go
+++ b/main.go
@@ -20,11 +20,13 @@ import (
 	"net/http"
 	_ "net/http/pprof"
 	"os"
+	"os/signal"
 	"strconv"
 	"strings"
+	"syscall"
 	"time"
 
-	"github.com/prometheus-community/pro-bing"
+	probing "github.com/prometheus-community/pro-bing"
 	"github.com/superq/smokeping_prober/config"
 
 	"github.com/alecthomas/kingpin/v2"
@@ -228,6 +230,18 @@ func main() {
 		http.Handle("/", landingPage)
 	}
 
+	hup := make(chan os.Signal, 1)
+	signal.Notify(hup, syscall.SIGHUP)
+	go func() {
+		for {
+			<-hup
+			level.Info(logger).Log("msg", "Reexecuting and reloading the configuration")
+			if err := syscall.Exec("/proc/self/exe", os.Args, os.Environ()); err != nil {
+				level.Error(logger).Log("msg", "Error reloading config", "err", err)
+			}
+		}
+	}()
+
 	server := &http.Server{}
 	if err := web.ListenAndServe(server, webConfig, logger); err != nil {
 		level.Error(logger).Log("err", err)