Ability to override the hostname (useful for containers)

infping.go

@@ -49,10 +49,11 @@ func main() {
 	createDatabaseIfNotExist(influxClient)
 
 	hosts := viper.GetStringSlice("hosts")
+	hostname := viper.GetString("hostname")
 	fpingConfig := prepareFpingConfiguration()
 
 	log.Printf("Launching fping with hosts: %s", strings.Join(hosts, ", "))
-	err := runAndRead(hosts, influxClient, fpingConfig)
+	err := runAndRead(hosts, influxClient, fpingConfig, hostname)
 
 	if err != nil {
 		log.Fatal("Failed when obtaining and storing pings", err)
@@ -72,11 +73,7 @@ func parsePrefixTemplate(tplString string) (string, error) {
 	}
 
 	params := prefixTemplateParams{}
-	params.Hostname, err = os.Hostname()
-	params.Hostname = strings.ToLower(params.Hostname)
-	if err != nil {
-		return "", err
-	}
+	params.Hostname = strings.ToLower(viper.GetString("hostname"))
 
 	splitHostname := strings.Split(params.Hostname, ".")
 	reverseAny(splitHostname)
@@ -115,6 +112,7 @@ func setDefaults() {
 	viper.SetDefault("fping.period", "1000")
 	viper.SetDefault("fping.custom", map[string]string{})
 	viper.SetDefault("hosts", []string{"localhost"})
+	viper.SetDefault("hostname", mustHostname())
 }
 
 func readConfiguration() {
@@ -230,3 +228,12 @@ func prepareFpingConfiguration() map[string]string {
 
 	return fpingConfig
 }
+
+// mustHostname returns the local hostname or throws an error
+func mustHostname() string {
+	name, err := os.Hostname()
+	if err != nil {
+		panic("unable to find hostname " + err.Error())
+	}
+	return strings.ToLower(name)
+}

parse.go

@@ -27,14 +27,12 @@ package main
 import (
 	"bufio"
 	"log"
-	"os"
 	"os/exec"
 	"strconv"
 	"strings"
 	"time"
 )
 
-var hostname = mustHostname()
 var lastTime = time.Now()
 
 // Point represents the fping results for a single host
@@ -49,7 +47,7 @@ type Point struct {
 }
 
 // runAndRead executes fping, parses the output into a Point, and then writes it to Influx
-func runAndRead(hosts []string, con Client, fpingConfig map[string]string) error {
+func runAndRead(hosts []string, con Client, fpingConfig map[string]string, hostname string) error {
 	runner, err := createRunner(hosts, fpingConfig)
 	if err != nil {
 		return err
@@ -73,7 +71,7 @@ func runAndRead(hosts []string, con Client, fpingConfig map[string]string) error
 		if len(fields) == 1 {
 			handleInvalidOutput(fields)
 		} else {
-			handleValidOutput(fields, con)
+			handleValidOutput(fields, con, hostname)
 		}
 	}
 
@@ -107,7 +105,7 @@ func handleInvalidOutput(fields []string) {
 	}
 }
 
-func handleValidOutput(fields []string, con Client) {
+func handleValidOutput(fields []string, con Client, hostname string) {
 	host := fields[0]
 	data := fields[4]
 	dataSplit := strings.Split(data, "/")
@@ -156,11 +154,3 @@ func mustFloat(data string) float64 {
 	return flt
 }
 
-// mustHostname returns the local hostname or throws an error
-func mustHostname() string {
-	name, err := os.Hostname()
-	if err != nil {
-		panic("unable to find hostname " + err.Error())
-	}
-	return strings.ToLower(name)
-}