From bc088967b756af16ada19190b1da8accd6a04213 Mon Sep 17 00:00:00 2001
From: Tobias Schmidt <tobidt@gmail.com>
Date: Sat, 4 Mar 2017 10:55:15 -0400
Subject: [PATCH] Use warn level for log messages about target communication
 errors

---
 dns.go  |  4 ++--
 http.go |  4 ++--
 icmp.go | 26 +++++++++-----------------
 tcp.go  |  4 ++--
 4 files changed, 15 insertions(+), 23 deletions(-)

diff --git a/dns.go b/dns.go
index ff4b4c4..90c8982 100644
--- a/dns.go
+++ b/dns.go
@@ -124,9 +124,9 @@ func probeDNS(target string, w http.ResponseWriter, module Module) bool {
 	}
 
 	if dialProtocol[len(dialProtocol)-1] == '6' {
-		fmt.Fprintf(w, "probe_ip_protocol 6\n")
+		fmt.Fprintln(w, "probe_ip_protocol 6")
 	} else {
-		fmt.Fprintf(w, "probe_ip_protocol 4\n")
+		fmt.Fprintln(w, "probe_ip_protocol 4")
 	}
 
 	client := new(dns.Client)
diff --git a/http.go b/http.go
index a101831..d57b455 100644
--- a/http.go
+++ b/http.go
@@ -105,9 +105,9 @@ func probeHTTP(target string, w http.ResponseWriter, module Module) (success boo
 	}
 
 	if dialProtocol == "tcp6" {
-		fmt.Fprintf(w, "probe_ip_protocol 6\n")
+		fmt.Fprintln(w, "probe_ip_protocol 6")
 	} else {
-		fmt.Fprintf(w, "probe_ip_protocol 4\n")
+		fmt.Fprintln(w, "probe_ip_protocol 4")
 	}
 
 	client := &http.Client{
diff --git a/icmp.go b/icmp.go
index 3f4db62..60ae926 100644
--- a/icmp.go
+++ b/icmp.go
@@ -81,7 +81,7 @@ func probeICMP(target string, w http.ResponseWriter, module Module) (success boo
 	fmt.Fprintf(w, "probe_dns_lookup_time_seconds %f\n", time.Since(resolveStart).Seconds())
 
 	if err != nil {
-		log.Errorf("Error resolving address %s: %s", target, err)
+		log.Warnf("Error resolving address %s: %s", target, err)
 		return
 	}
 
@@ -89,33 +89,26 @@ func probeICMP(target string, w http.ResponseWriter, module Module) (success boo
 		requestType = ipv6.ICMPTypeEchoRequest
 		replyType = ipv6.ICMPTypeEchoReply
 		socket, err = icmp.ListenPacket("ip6:ipv6-icmp", "::")
-		fmt.Fprintf(w, "probe_ip_protocol 6\n")
+		fmt.Fprintln(w, "probe_ip_protocol 6")
 	} else {
 		requestType = ipv4.ICMPTypeEcho
 		replyType = ipv4.ICMPTypeEchoReply
 		socket, err = icmp.ListenPacket("ip4:icmp", "0.0.0.0")
-		fmt.Fprintf(w, "probe_ip_protocol 4\n")
+		fmt.Fprintln(w, "probe_ip_protocol 4")
 	}
 
 	if err != nil {
-		log.Errorf("Error listening to socket: %s", err)
+		log.Errorf("Error listening to socket for %s: %s", target, err)
 		return
 	}
 	defer socket.Close()
 
-	if err != nil {
-		log.Errorf("Error resolving address %s: %s", target, err)
-		return
-	}
-
-	seq := getICMPSequence()
-	pid := os.Getpid() & 0xffff
-
 	wm := icmp.Message{
 		Type: requestType,
 		Code: 0,
 		Body: &icmp.Echo{
-			ID: pid, Seq: int(seq),
+			ID:   os.Getpid() & 0xffff,
+			Seq:  int(getICMPSequence()),
 			Data: []byte("Prometheus Blackbox Exporter"),
 		},
 	}
@@ -126,7 +119,7 @@ func probeICMP(target string, w http.ResponseWriter, module Module) (success boo
 		return
 	}
 	if _, err := socket.WriteTo(wb, ip); err != nil {
-		log.Errorf("Error writing to socket for %s: %s", target, err)
+		log.Warnf("Error writing to socket for %s: %s", target, err)
 		return
 	}
 
@@ -147,7 +140,7 @@ func probeICMP(target string, w http.ResponseWriter, module Module) (success boo
 		n, peer, err := socket.ReadFrom(rb)
 		if err != nil {
 			if nerr, ok := err.(net.Error); ok && nerr.Timeout() {
-				log.Infof("Timeout reading from socket for %s: %s", target, err)
+				log.Warnf("Timeout reading from socket for %s: %s", target, err)
 				return
 			}
 			log.Errorf("Error reading from socket for %s: %s", target, err)
@@ -162,8 +155,7 @@ func probeICMP(target string, w http.ResponseWriter, module Module) (success boo
 			rb[3] = 0
 		}
 		if bytes.Compare(rb[:n], wb) == 0 {
-			success = true
-			return
+			return true
 		}
 	}
 }
diff --git a/tcp.go b/tcp.go
index ec9f099..ae27254 100644
--- a/tcp.go
+++ b/tcp.go
@@ -60,9 +60,9 @@ func dialTCP(target string, w http.ResponseWriter, module Module) (net.Conn, err
 	}
 
 	if dialProtocol == "tcp6" {
-		fmt.Fprintf(w, "probe_ip_protocol 6\n")
+		fmt.Fprintln(w, "probe_ip_protocol 6")
 	} else {
-		fmt.Fprintf(w, "probe_ip_protocol 4\n")
+		fmt.Fprintln(w, "probe_ip_protocol 4")
 	}
 
 	if !module.TCP.TLS {
-- 
2.25.1