Merge pull request #16 from ibuildthecloud/reload

Reload immediately, not on an interval

content/etc/monit/conf.d/rancher-metadata

@@ -1,3 +1,3 @@
- check process rancher-metadata matching "rancher-metadata"
+ check process rancher-metadata matching "/var/lib/cattle/bin/rancher-metadata"
    start program = "/etc/init.d/rancher-metadata start"
    stop  program = "/etc/init.d/rancher-metadata stop"

main.go

@@ -4,6 +4,7 @@ import (
 	"encoding/json"
 	"flag"
 	"fmt"
+	"io"
 	"io/ioutil"
 	"net"
 	"net/http"
@@ -14,7 +15,6 @@ import (
 	"strconv"
 	"strings"
 	"syscall"
-	"time"
 
 	log "github.com/Sirupsen/logrus"
 	"github.com/golang/gddo/httputil"
@@ -49,11 +49,9 @@ var (
 	router  = mux.NewRouter()
 	answers Versions
 
-	VERSION        string
-	wantRevision   = 1
-	loadedRevision = 0
-	loading        = false
-	ticker         = time.NewTicker(1 * time.Second)
+	VERSION    string
+	loading    = false
+	reloadChan = make(chan chan error)
 )
 
 func main() {
@@ -116,7 +114,6 @@ func parseFlags() {
 func loadAnswers() (err error) {
 	log.Debug("Loading answers")
 	loading = true
-	revision := wantRevision
 	neu, err := ParseAnswers(*answersFile)
 	if err == nil {
 		for _, data := range neu {
@@ -132,9 +129,8 @@ func loadAnswers() (err error) {
 		}
 
 		answers = neu
-		loadedRevision = revision
 		loading = false
-		log.Infof("Loaded answers revision %d for %d versions", revision, len(answers))
+		log.Infof("Loaded answers")
 	} else {
 		log.Errorf("Failed to load answers: %v", err)
 	}
@@ -162,22 +158,18 @@ func watchSignals() {
 	go func() {
 		for _ = range c {
 			log.Info("Received HUP signal")
-			wantRevision += 1
+			reloadChan <- nil
 		}
 	}()
 
 	go func() {
-		for {
-			select {
-			case <-ticker.C:
-				//log.Info("Ping")
-				if !loading && loadedRevision < wantRevision {
-					loadAnswers()
-				}
+		for resp := range reloadChan {
+			err := loadAnswers()
+			if resp != nil {
+				resp <- err
 			}
 		}
 	}()
-
 }
 
 func watchHttp() {
@@ -190,19 +182,16 @@ func watchHttp() {
 }
 
 func httpReload(w http.ResponseWriter, req *http.Request) {
-	wantRevision += 1
-	waitFor := wantRevision
-	log.Debugf("Received HTTP reload request, wait for %d, ", waitFor)
-
-	for {
-		select {
-		case <-time.After(100 * time.Millisecond):
-			//log.Debugf("Now at %d, waiting for %d", loadedRevision, waitFor)
-			if loadedRevision >= waitFor {
-				fmt.Fprintf(w, "OK %d\r\n", loadedRevision)
-				return
-			}
-		}
+	log.Debugf("Received HTTP reload request")
+	respChan := make(chan error)
+	reloadChan <- respChan
+	err := <-respChan
+
+	if err == nil {
+		io.WriteString(w, "OK")
+	} else {
+		w.WriteHeader(500)
+		io.WriteString(w, err.Error())
 	}
 }
 

parse.go

@@ -48,15 +48,16 @@ func convertKeysToStrings(item interface{}) interface{} {
 }
 
 func ParseAnswers(path string) (out Versions, err error) {
+	var tmp Versions
 	data, err := ioutil.ReadFile(path)
 	if err != nil {
 		if os.IsNotExist(err) {
 			log.Warn("Failed to find: ", path)
+			return tmp, nil
 		}
 		return nil, err
 	}
 
-	var tmp Versions
 	err = yaml.Unmarshal(data, &tmp)
 
 	tmp = convertVersionKeysToStrings(tmp)