meshregistrator

cmd/meshregistrator/aws.go

@@ -0,0 +1,69 @@
+package main
+
+import (
+	"context"
+	"time"
+
+	"k8s.io/klog/v2"
+)
+
+// merge pods, local and aws, calculate diff from previous frame
+// and write differences
+func writeAWS(ctx context.Context, podsch, localch, awsch chan []ServiceRegistration) {
+	var pods, local, aws []ServiceRegistration
+	var podsDirty, localDirty, awsDirty bool
+	ticker := time.NewTicker(5 * time.Second)
+	defer ticker.Stop()
+
+	for {
+		klog.Info("selecting")
+		select {
+		case <-ctx.Done():
+			klog.Info("writeAWS stopped")
+			return
+		case pods = <-podsch:
+			klog.Info("pods updated")
+			podsDirty = true
+		case local = <-localch:
+			klog.Info("local updated")
+			localDirty = true
+		case aws = <-awsch:
+			klog.Info("aws updated")
+			awsDirty = true
+		case <-ticker.C:
+			if podsDirty {
+				klog.Infof("new pods=%+v\n", pods)
+			}
+			if localDirty {
+				klog.Infof("new local=%+v\n", local)
+			}
+			if awsDirty {
+				klog.Infof("new aws=%+v\n", aws)
+			}
+			if !podsDirty && !localDirty && !awsDirty {
+				klog.Info("nothing updated")
+				continue
+			}
+
+			podsDirty = false
+			localDirty = false
+			awsDirty = false
+		}
+	}
+}
+
+// find registrations in CloudMap that match current node name
+func fetchAWS(ctx context.Context, aws chan []ServiceRegistration) {
+	ticker := time.NewTicker(5 * time.Second)
+	defer ticker.Stop()
+
+	for {
+		select {
+		case <-ctx.Done():
+			klog.Info("fetchAWS stopped")
+			return
+		case <-ticker.C:
+			continue
+		}
+	}
+}

cmd/meshregistrator/local.go

@@ -0,0 +1,70 @@
+package main
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"time"
+
+	"k8s.io/klog/v2"
+)
+
+// check host for services configured via other means and update registration list
+func fetchLocal(ctx context.Context, out chan []ServiceRegistration, servicesDir string) {
+	var oldRegistrations, newRegistrations []ServiceRegistration
+	ticker := time.NewTicker(5 * time.Second)
+	defer ticker.Stop()
+
+	for {
+		select {
+		case <-ctx.Done():
+			klog.Info("fetchLocal stopped")
+			return
+		case <-ticker.C:
+			newRegistrations = []ServiceRegistration{}
+			err := filepath.Walk(servicesDir, func(path string, info os.FileInfo, err error) error {
+				if err != nil {
+					return fmt.Errorf("error accessing %v: %v", path, err)
+				}
+				if info.IsDir() {
+					return nil
+				}
+
+				fh, err := os.Open(path)
+				if err != nil {
+					// ignore broken symlinks
+					return nil
+				}
+
+				serviceInfo := struct {
+					Namespaces []string `json:"namespaces"`
+				}{}
+				bytes, err := ioutil.ReadAll(fh)
+				if err != nil {
+					return fmt.Errorf("error reading %v: %v", path, err)
+				}
+				err = json.Unmarshal(bytes, &serviceInfo)
+				if err != nil {
+					return fmt.Errorf("error parsing %v: %v", path, err)
+				}
+				if serviceInfo.Namespaces == nil {
+					klog.Infof("service has no namespaces: %v", path)
+					return nil
+				}
+				klog.Infof("local service: %v %+v\n", info.Name(), serviceInfo.Namespaces)
+				return nil
+			})
+			if err != nil {
+				klog.Error(err)
+				continue
+			}
+			if registrationsEqual(oldRegistrations, newRegistrations) {
+				continue
+			}
+			out <- newRegistrations
+		}
+	}
+}

cmd/meshregistrator/main.go

@@ -0,0 +1,95 @@
+// meshregistrator has multiple goroutines:
+// - fetchPods will take a snapshot of pods running in local kubelet and
+//   turn them into a map of registrations
+// - fetchLocal will gather locally running backends according to
+//   configuration in ...
+// - fetchAWS will download existing registrations in AWS cloudmap
+//   to find potential zombies for cleanup
+// - writeAWS will merge those and execute relevant cloudmap
+//   register/deregister calls
+package main
+
+import (
+	"context"
+	"os"
+	"sync"
+
+	origflag "flag"
+
+	flag "github.com/spf13/pflag"
+
+	"k8s.io/klog/v2"
+)
+
+type MeshregistratorOptions struct {
+	SystemPaastaDir  string
+	YelpSoaDir       string
+	LocalServicesDir string
+	TrackLocal       bool
+	TrackKubelet     bool
+}
+
+// Setup ...
+func (o *MeshregistratorOptions) Setup() {
+	flag.StringVarP(&o.SystemPaastaDir, "systempaastadir", "", "/etc/paasta", "")
+	flag.StringVarP(&o.YelpSoaDir, "yelpsoadir", "", "/nail/etc/services", "")
+	flag.StringVarP(&o.LocalServicesDir, "localservicesdir", "", "/etc/nerve/puppet_services.d", "")
+	flag.BoolVarP(&o.TrackLocal, "tracklocal", "", true, "")
+	flag.BoolVarP(&o.TrackKubelet, "trackkubelet", "", true, "")
+}
+
+func parseFlags(opts *MeshregistratorOptions) error {
+	opts.Setup()
+	flag.Parse()
+	return nil
+}
+
+// A subprocess keeps track of ysoa-configs and some local configuration coming from puppet and other sources to understand Yelp’s service topology
+func main() {
+	klogFlags := origflag.NewFlagSet("klog", origflag.ExitOnError)
+	klog.InitFlags(klogFlags)
+	debug, _ := os.LookupEnv("MESHREGISTRATOR_DEBUG")
+	v := klogFlags.Lookup("v")
+	if v != nil {
+		if debug != "" {
+			v.Value.Set("10")
+		} else {
+			v.Value.Set("0")
+		}
+	}
+
+	var options MeshregistratorOptions
+	parseFlags(&options)
+
+	klog.Infof("starting meshregistrator: %+v", options)
+
+	// sysStore := configstore.NewStore(options.SystemPaastaDir, nil)
+
+	var wg sync.WaitGroup
+	pods := make(chan []ServiceRegistration, 1)
+	local := make(chan []ServiceRegistration, 1)
+	aws := make(chan []ServiceRegistration, 1)
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	if options.TrackKubelet {
+		wg.Add(1)
+		go func() { defer wg.Done(); fetchPods(ctx, pods); cancel() }()
+	}
+
+	if options.TrackLocal {
+		wg.Add(1)
+		go func() { defer wg.Done(); fetchLocal(ctx, local, options.LocalServicesDir); cancel() }()
+	}
+
+	wg.Add(1)
+	go func() { defer wg.Done(); fetchAWS(ctx, aws); cancel() }()
+
+	wg.Add(1)
+	go func() { defer wg.Done(); writeAWS(ctx, pods, local, aws); cancel() }()
+
+	go signalLoop(ctx, cancel)
+	wg.Wait()
+
+	klog.Info("meshregistrator out")
+}

cmd/meshregistrator/pods.go

@@ -0,0 +1,125 @@
+package main
+
+import (
+	"context"
+	"encoding/json"
+	"io/ioutil"
+	"net/http"
+	"time"
+
+	corev1 "k8s.io/api/core/v1"
+	klog "k8s.io/klog/v2"
+)
+
+const HacheckPodName = "hacheck"
+
+// fetch running pods from kubelet and update pods registration list
+func fetchPods(ctx context.Context, out chan []ServiceRegistration) {
+	var oldRegistrations, newRegistrations []ServiceRegistration
+	ticker := time.NewTicker(5 * time.Second)
+	defer ticker.Stop()
+
+	for {
+		select {
+		case <-ctx.Done():
+			klog.Info("fetchPods stopped")
+			return
+		case <-ticker.C:
+			startTime := time.Now().UnixNano()
+			resp, err := http.Get("http://127.0.0.1:10255/pods")
+			if err != nil {
+				klog.Errorf("fetching pods failed: %v", err)
+				continue
+			}
+
+			if resp.StatusCode != http.StatusOK {
+				klog.Errorf("fetching pods bad response: %v", resp.StatusCode)
+				continue
+			}
+
+			bodyBytes, err := ioutil.ReadAll(resp.Body)
+			if err != nil {
+				klog.Errorf("reading body failed: %v", err)
+				continue
+			}
+			loadedTime := time.Now().UnixNano()
+			klog.Infof(
+				"read %v bytes in %vs",
+				len(bodyBytes),
+				float64(loadedTime-startTime)/float64(time.Second),
+			)
+
+			var podList corev1.PodList
+			err = json.Unmarshal(bodyBytes, &podList)
+			if err != nil {
+				klog.Errorf("unmarshaling body failed: %v", err)
+				continue
+			}
+			parsedTime := time.Now().UnixNano()
+
+			klog.Infof(
+				"loaded %v pods in %vs",
+				len(podList.Items),
+				float64(parsedTime-loadedTime)/float64(time.Second),
+			)
+
+			newRegistrations = []ServiceRegistration{}
+			for _, pod := range podList.Items {
+				if pod.Status.Phase != corev1.PodRunning {
+					continue
+				}
+				podRegsJson, ok := pod.Annotations["smartstack_registrations"]
+				if !ok {
+					continue
+				}
+
+				var podRegs []string
+				err := json.Unmarshal([]byte(podRegsJson), &podRegs)
+				if err != nil {
+					klog.Errorf(
+						"pod %v/%v smartstack_registrations failed to load: %v, raw json: %+v",
+						pod.Namespace,
+						pod.Name,
+						err,
+						podRegsJson,
+					)
+					continue
+				}
+
+				var port int32
+				for _, cont := range pod.Spec.Containers {
+					// TODO: use instance name?
+					if cont.Name != HacheckPodName {
+						port = cont.Ports[0].ContainerPort
+						break
+					}
+				}
+				service := pod.Labels["paasta.yelp.com/service"]
+				instance := pod.Labels["paasta.yelp.com/instance"]
+				podIP := pod.Status.PodIP
+
+				for _, reg := range podRegs {
+					newRegistrations = append(newRegistrations, ServiceRegistration{
+						Service:      service,
+						Instance:     instance,
+						PodNode:      pod.Spec.NodeName,
+						PodNs:        pod.Namespace,
+						PodName:      pod.Name,
+						PodIP:        podIP,
+						Port:         port,
+						Registration: reg,
+					})
+				}
+			}
+
+			if registrationsEqual(oldRegistrations, newRegistrations) {
+				klog.V(10).Info("pods registrations did not change")
+				continue
+			}
+
+			klog.Infof("pods registrations updated: %+v", newRegistrations)
+			oldRegistrations = newRegistrations
+			out <- newRegistrations
+		}
+	}
+}