attempt to discover zookeeper hostname

main.go

@@ -5,10 +5,12 @@ package main
 
 import (
 	"embed"
+	"fmt"
 	"os"
 	"time"
 
 	"go.wit.com/dev/alexflint/arg"
+	"go.wit.com/lib/hostname"
 	"go.wit.com/lib/protobuf/zoopb"
 	"go.wit.com/log"
 )
@@ -20,31 +22,32 @@ var BUILDTIME string
 var resources embed.FS
 
 func main() {
-	var pp *arg.Parser
+	me = new(zoodStruct)
-	pp = arg.MustParse(&argv)
+	me.pp = arg.MustParse(&argv)
 
-	if pp == nil {
+	if me.pp == nil {
-		pp.WriteHelp(os.Stdout)
+		me.pp.WriteHelp(os.Stdout)
 		os.Exit(0)
 	}
 
 	if argv.Daemon {
 		// turn off timestamps for STDOUT (systemd adds them)
 		log.DaemonMode(true)
+		me.machine, me.fullpath = zoopb.InitDaemon()
+	} else {
+		me.machine, me.fullpath = zoopb.InitMachine()
+
 	}
 
-	me = new(stuff)
+	if err := testZoo(); err != nil {
-	me.urlbase = "http://zookeeper.chap.wit.com:8080"
+		log.Info("FAILED TO CONNECT TO ZOOKEEPER: ", err)
-	if argv.URL != "" {
+		log.Info("sleeping for 3 minutes")
-		log.Info("USING ARGV URL:", argv.URL)
+		time.Sleep(3 * time.Minute)
-		me.urlbase = argv.URL
+		os.Exit(0)
 	}
-
 	me.pollDelay = 3 * time.Second
 	me.failcountmax = 20 // die every minute if zookeeper can't be found
 
-	me.machine = zoopb.InitMachine()
-
 	if argv.Test != nil {
 		testURL(me.urlbase, me.machine)
 		os.Exit(0)
@@ -53,6 +56,52 @@ func main() {
 	zood() // talks to zookeeper
 }
 
+func testZoo() error {
+	var err error
+	if argv.URL != "" {
+		log.Info("USING ARGV URL:", argv.URL)
+		if err = testURL(argv.URL, me.machine); err == nil {
+			me.urlbase = argv.URL
+			return nil
+		}
+	}
+
+	zooname := findZookeeper()
+
+	url := fmt.Sprintf("http://%s:8080/", zooname)
+	if err = testURL(url, me.machine); err == nil {
+		me.urlbase = url
+		return nil
+	}
+	url = fmt.Sprintf("https://%s/", zooname)
+	if err = testURL(url, me.machine); err == nil {
+		me.urlbase = url
+		return nil
+	}
+	url = "http://zookeeper.wit.com:8080/"
+	if err = testURL(url, me.machine); err == nil {
+		me.urlbase = url
+		return nil
+	}
+	url = "https://zookeeper.wit.com/"
+	if err = testURL(url, me.machine); err == nil {
+		me.urlbase = url
+		return nil
+	}
+	return err
+}
+
+func findZookeeper() string {
+	hname, dname, err := hostname.GetDomainname()
+	if err != nil {
+		log.Info("error with os.Hostname()", hname, dname, err)
+	}
+	if dname == "" {
+		return "zookeeper.wit.com"
+	}
+	return hostname.Join("zookeeper", dname)
+}
+
 func testURL(urlbase string, pb *zoopb.Machine) error {
 	newpb, wsPB, err := pb.HttpPost(urlbase, "test")
 	if err != nil {

structs.go

@@ -6,13 +6,14 @@ package main
 import (
 	"time"
 
+	"go.wit.com/dev/alexflint/arg"
 	"go.wit.com/lib/protobuf/zoopb"
 )
 
-var me *stuff
+var me *zoodStruct
 
 // this app's variables
-type stuff struct {
+type zoodStruct struct {
 	urlbase      string         // the dns name for the zookeeper
 	hostname     string         // my hostname
 	pollDelay    time.Duration  // how often to report our status
@@ -20,4 +21,6 @@ type stuff struct {
 	machine      *zoopb.Machine // populated from protobuf based zoopb
 	failcount    int            // how many times we've failed to contact the zookeeper
 	failcountmax int            // after this, exit and let systemd restart the daemon
+	fullpath     string         // where to save the machine PB file
+	pp           *arg.Parser    // from go-args
 }