Merge pull request #12 from mayuresh82/race_fix

attempt to fix a race condition

Dockerfile

@@ -1,20 +1,21 @@
-FROM golang:alpine as builder
+FROM golang:1.14-alpine as builder
 RUN apk update && \
     apk upgrade && \
     apk add --no-cache git && \
     apk add make
-RUN mkdir -p /opt/gocast
-RUN mkdir -p /go/src/github.com/mayuresh82
-RUN cd /go/src/github.com/mayuresh82 && \
-    git clone https://github.com/mayuresh82/gocast
+
+RUN mkdir -p /go/src/github.com/mayuresh82/gocast
+
+COPY . /go/src/github.com/mayuresh82/gocast
+
 WORKDIR /go/src/github.com/mayuresh82/gocast
+
 RUN make
-RUN cp gocast /opt/gocast/
 
 FROM alpine:latest
 RUN apk --no-cache add ca-certificates bash iptables netcat-openbsd sudo
 WORKDIR /root/
-COPY --from=builder /opt/gocast/gocast .
+COPY --from=builder /go/src/github.com/mayuresh82/gocast .
 
 EXPOSE 8080/tcp
 

LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2020 mayuresh82
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

config.yaml

@@ -24,4 +24,7 @@ bgp:
 apps:
   - name: app1
     vip: 1.1.1.1/32
+    vip_config:
+      # additional per VIP BGP communities
+      bgp_communities: [ aaaa:bbbb ]
     monitor: port:tcp:5000

config/config.go

@@ -26,9 +26,16 @@ type BgpConfig struct {
 	Origin      string
 }
 
+type VipConfig struct {
+	// per VIP BGP communities to announce. This is in addition to the
+	// global config
+	BgpCommunities []string `yaml:"bgp_communities"`
+}
+
 type AppConfig struct {
 	Name      string
 	Vip       string
+	VipConfig VipConfig `yaml:"vip_config"`
 	Monitors  []string
 	Nats      []string
 }

controller/app.go

@@ -6,6 +6,7 @@ import (
 	"strings"
 
 	"github.com/golang/glog"
+	"github.com/mayuresh82/gocast/config"
 )
 
 type MonitorType int
@@ -51,7 +52,8 @@ func (m Monitors) Contains(elem *Monitor) bool {
 
 type App struct {
 	Name      string
-	Vip      *net.IPNet
+	Vip       *Route
+	VipConfig config.VipConfig
 	Monitors  Monitors
 	Nats      []string
 	Source    string
@@ -66,10 +68,15 @@ func (a *App) Equal(other *App) bool {
 			return false
 		}
 	}
-	return a.Name == other.Name && a.Vip.String() == other.Vip.String()
+	return a.Name == other.Name && a.Vip.Net.String() == other.Vip.Net.String()
 }
 
-func NewApp(appName, vip string, monitors []string, nats []string, source string) (*App, error) {
+func (a *App) String() string {
+	return fmt.Sprintf("Name: %s, Vip: %s, VipConf: %v, Monitors: %v, Nats: %v, Source: %s",
+		a.Name, a.Vip.Net.String(), a.VipConfig, a.Monitors, a.Nats, a.Source)
+}
+
+func NewApp(appName, vip string, vipConfig config.VipConfig, monitors []string, nats []string, source string) (*App, error) {
 	if appName == "" {
 		return nil, fmt.Errorf("Invalid app name")
 	}
@@ -78,7 +85,8 @@ func NewApp(appName, vip string, monitors []string, nats []string, source string
 	if err != nil {
 		return nil, fmt.Errorf("Invalid VIP specified, need ip/mask")
 	}
-	app.Vip = ipnet
+	app.Vip = &Route{Net: ipnet, Communities: vipConfig.BgpCommunities}
+	app.VipConfig = vipConfig
 	for _, m := range monitors {
 		// valid monitor formats:
 		// "port:tcp:123" , "exec:/local/check.sh", "consul"

controller/app_test.go

@@ -3,32 +3,36 @@ package controller
 import (
 	"testing"
 
+	"github.com/mayuresh82/gocast/config"
 	"github.com/stretchr/testify/assert"
 )
 
 func TestAppParsing(t *testing.T) {
 	a := assert.New(t)
-	app1, err := NewApp("app1", "1.1.1.1/32", []string{"port:tcp:123"}, []string{}, "")
+	app1, err := NewApp("app1", "1.1.1.1/32", config.VipConfig{}, []string{"port:tcp:123"}, []string{}, "")
 	a.Nil(err)
-	app2, err := NewApp("app1", "1.1.1.1/32", []string{"port:tcp:123"}, []string{}, "")
+	app2, err := NewApp("app1", "1.1.1.1/32", config.VipConfig{BgpCommunities: []string{"111:222"}}, []string{"port:tcp:123"}, []string{}, "")
 	a.Nil(err)
-	app3, err := NewApp("app3", "2.2.2.2/32", []string{"exec:/bin/testme"}, []string{}, "")
+	app3, err := NewApp("app3", "2.2.2.2/32", config.VipConfig{}, []string{"exec:/bin/testme"}, []string{}, "")
 	a.Nil(err)
 
-	a.Equal("1.1.1.1/32", app1.Vip.String())
+	a.Equal("1.1.1.1/32", app1.Vip.Net.String())
 	a.Equal(Monitor_PORT, app1.Monitors[0].Type)
 	a.Equal("123", app1.Monitors[0].Port)
 	a.Equal("tcp", app1.Monitors[0].Protocol)
+	a.Equal(config.VipConfig{}, app1.VipConfig)
 
 	a.Equal(true, app1.Equal(app2))
 
+	a.Equal("111:222", app2.Vip.Communities[0])
+
 	a.Equal(Monitor_EXEC, app3.Monitors[0].Type)
 	a.Equal("/bin/testme", app3.Monitors[0].Cmd)
 
 	// test errors
-	_, err = NewApp("app4", "4.4.4.4", []string{}, []string{}, "")
+	_, err = NewApp("app4", "4.4.4.4", config.VipConfig{}, []string{}, []string{}, "")
 	a.NotNil(err)
 
-	_, err = NewApp("app4", "4.4.4.4/32", []string{"port:abcd::1023"}, []string{}, "")
+	_, err = NewApp("app4", "4.4.4.4/32", config.VipConfig{}, []string{"port:abcd::1023"}, []string{}, "")
 	a.NotNil(err)
 }

controller/bgp.go

@@ -14,6 +14,11 @@ import (
 	gobgp "github.com/osrg/gobgp/pkg/server"
 )
 
+type Route struct {
+	Net         *net.IPNet
+	Communities []string
+}
+
 type Controller struct {
 	peerAS          int
 	localIP, peerIP net.IP
@@ -90,14 +95,14 @@ func (c *Controller) AddPeer(peer string) error {
 	return c.s.AddPeer(context.Background(), &api.AddPeerRequest{Peer: n})
 }
 
-func (c *Controller) getApiPath(route *net.IPNet) *api.Path {
+func (c *Controller) getApiPath(route *Route) *api.Path {
 	afi := api.Family_AFI_IP
-	if route.IP.To4() == nil {
+	if route.Net.IP.To4() == nil {
 		afi = api.Family_AFI_IP6
 	}
-	prefixlen, _ := route.Mask.Size()
+	prefixlen, _ := route.Net.Mask.Size()
 	nlri, _ := ptypes.MarshalAny(&api.IPAddressPrefix{
-		Prefix:    route.IP.String(),
+		Prefix:    route.Net.IP.String(),
 		PrefixLen: uint32(prefixlen),
 	})
 	a1, _ := ptypes.MarshalAny(&api.OriginAttribute{
@@ -107,7 +112,7 @@ func (c *Controller) getApiPath(route *net.IPNet) *api.Path {
 		NextHop: c.localIP.String(),
 	})
 	var communities []uint32
-	for _, comm := range c.communities {
+	for _, comm := range append(c.communities, route.Communities...) {
 		communities = append(communities, convertCommunity(comm))
 	}
 	a3, _ := ptypes.MarshalAny(&api.CommunitiesAttribute{
@@ -121,7 +126,7 @@ func (c *Controller) getApiPath(route *net.IPNet) *api.Path {
 	}
 }
 
-func (c *Controller) Announce(route *net.IPNet) error {
+func (c *Controller) Announce(route *Route) error {
 	var found bool
 	err := c.s.ListPeer(context.Background(), &api.ListPeerRequest{}, func(p *api.Peer) {
 		if p.Conf.NeighborAddress == c.peerIP.String() {
@@ -140,7 +145,7 @@ func (c *Controller) Announce(route *net.IPNet) error {
 	return err
 }
 
-func (c *Controller) Withdraw(route *net.IPNet) error {
+func (c *Controller) Withdraw(route *Route) error {
 	return c.s.DeletePath(context.Background(), &api.DeletePathRequest{Path: c.getApiPath(route)})
 }
 

controller/bgp_test.go

@@ -93,7 +93,8 @@ func TestBgpNew(t *testing.T) {
 		a.FailNow(err.Error())
 	}
 	_, ipnet, _ := net.ParseCIDR("20.30.40.0/24")
-	if err := ctrl.Announce(ipnet); err != nil {
+	r := &Route{Net: ipnet}
+	if err := ctrl.Announce(r); err != nil {
 		a.FailNow(err.Error())
 	}
 

controller/consul.go

@@ -10,6 +10,7 @@ import (
 	"time"
 
 	"github.com/golang/glog"
+	"github.com/mayuresh82/gocast/config"
 )
 
 const (
@@ -85,6 +86,7 @@ func (c *ConsulMon) queryServices() ([]*App, error) {
 			monitors []string
 			nats     []string
 		)
+		var vipConf config.VipConfig
 		for _, tag := range service.Tags {
 			// try to find the requires tags. Only vip is mandatory
 			parts := strings.Split(tag, "=")
@@ -94,6 +96,8 @@ func (c *ConsulMon) queryServices() ([]*App, error) {
 			switch parts[0] {
 			case "gocast_vip":
 				vip = parts[1]
+			case "gocast_vip_communities":
+				vipConf.BgpCommunities = strings.Split(parts[1], ",")
 			case "gocast_monitor":
 				monitors = append(monitors, parts[1])
 			case "gocast_nat":
@@ -104,7 +108,7 @@ func (c *ConsulMon) queryServices() ([]*App, error) {
 			glog.Errorf("No vip Tag found in matched service :%s", service.Service)
 			continue
 		}
-		app, err := NewApp(service.Service, vip, monitors, nats, "consul")
+		app, err := NewApp(service.Service, vip, vipConf, monitors, nats, "consul")
 		if err != nil {
 			glog.Errorf("Unable to add consul app: %v", err)
 			continue

controller/consul_test.go

@@ -6,6 +6,7 @@ import (
 	"net/http"
 	"testing"
 
+	"github.com/mayuresh82/gocast/config"
 	"github.com/stretchr/testify/assert"
 )
 
@@ -15,7 +16,7 @@ var mockConsulData = map[string]string{
 			"ID": "test-app-1",
 			"Service": "test-service",
 			"Tags": [
-				"enable_gocast", "gocast_vip=1.1.1.1/32", "gocast_monitor=consul"
+				"enable_gocast", "gocast_vip=1.1.1.1/32", "gocast_monitor=consul", "gocast_vip_communities=111:222,333:444"
 			]
 		}
 	}}`,
@@ -103,7 +104,9 @@ func TestQueryServices(t *testing.T) {
 		a.FailNow(err.Error())
 	}
 	a.Equal(1, len(apps))
-	app, _ := NewApp("test-service", "1.1.1.1/32", []string{"consul"}, []string{}, "consul")
+	a.Equal([]string{"111:222", "333:444"}, apps[0].Vip.Communities)
+
+	app, _ := NewApp("test-service", "1.1.1.1/32", config.VipConfig{}, []string{"consul"}, []string{}, "consul")
 	a.True(app.Equal(apps[0]))
 
 	// test no match

controller/monitor.go

@@ -58,7 +58,7 @@ type appMon struct {
 	app       *App
 	done      chan bool
 	announced bool
-	checkOn   bool
+	runLoopOn bool
 }
 
 // MonitorMgr manages the lifecycle of registered apps
@@ -69,7 +69,8 @@ type MonitorMgr struct {
 	ctrl     *Controller
 	consul   *ConsulMon
 
-	sync.Mutex
+	monMu sync.Mutex
+	clMu  sync.Mutex
 }
 
 func NewMonitor(config *c.Config) *MonitorMgr {
@@ -100,7 +101,7 @@ func NewMonitor(config *c.Config) *MonitorMgr {
 	mon.config = config
 	// add apps defined in config
 	for _, a := range config.Apps {
-		app, err := NewApp(a.Name, a.Vip, a.Monitors, a.Nats, "config")
+		app, err := NewApp(a.Name, a.Vip, a.VipConfig, a.Monitors, a.Nats, "config")
 		if err != nil {
 			glog.Errorf("Failed to add configured app %s: %v", a.Name, err)
 			continue
@@ -123,7 +124,7 @@ func (m *MonitorMgr) consulMon() {
 			}
 			// remove currently running apps that are not discovered in this pass
 			var toRemove []string
-			m.Lock()
+			m.monMu.Lock()
 			for name, mon := range m.monitors {
 				if mon.app.Source != "consul" {
 					continue
@@ -140,10 +141,10 @@ func (m *MonitorMgr) consulMon() {
 					toRemove = append(toRemove, name)
 				}
 			}
+			m.monMu.Unlock()
 			for _, tr := range toRemove {
 				m.Remove(tr)
 			}
-			m.Unlock()
 		}
 		<-time.After(m.config.Agent.ConsulQueryInterval)
 	}
@@ -152,38 +153,51 @@ func (m *MonitorMgr) consulMon() {
 // Add adds a new app into monitor manager
 func (m *MonitorMgr) Add(app *App) {
 	// check if already running
-	m.Lock()
-	defer m.Unlock()
+	m.monMu.Lock()
+	var existing *appMon
 	for _, appMon := range m.monitors {
-		if appMon.app.Equal(app) && appMon.checkOn {
-			glog.V(2).Infof("App %s already exists", app.Name)
-			return
+		if appMon.app.Equal(app) {
+			glog.Infof("App %s already exists", app.Name)
+			existing = appMon
+			break
 		}
-		if appMon.app.Vip.String() == app.Vip.String() && appMon.app.Name != app.Name {
-			glog.Errorf("Error: Vip %s is already being announced by app: %s", app.Vip.String(), appMon.app.Name)
+		if appMon.app.Vip.Net.String() == app.Vip.Net.String() && appMon.app.Name != app.Name {
+			glog.Errorf("Error: Vip %s is already being announced by app: %s", app.Vip.Net.String(), appMon.app.Name)
+			m.monMu.Unlock()
 			return
 		}
 	}
-	m.Remove(app.Name)
+	m.monMu.Unlock()
+	// if the same app already exists but its run loop is not running,
+	// then just restart the run loop
+	if existing != nil {
+		if !existing.runLoopOn {
+			go m.runLoop(existing)
+		}
+	} else {
+		// else add a new app and start its run loop
 		appMon := &appMon{app: app, done: make(chan bool)}
 		m.monitors[app.Name] = appMon
 		go m.runLoop(appMon)
-	glog.Infof("Registered a new app: %v", app)
+		glog.Infof("Registered a new app: %v", app.String())
+	}
 }
 
 // Remove removes an app from monitor manager, stops BGP
 /// announcement and cleans up state
 func (m *MonitorMgr) Remove(appName string) {
+	m.monMu.Lock()
+	defer m.monMu.Unlock()
 	if a, ok := m.monitors[appName]; ok {
-		if a.checkOn {
-			a.done <- true
+		if a.runLoopOn {
+			close(a.done)
 		}
 		if a.announced {
 			if err := m.ctrl.Withdraw(a.app.Vip); err != nil {
 				glog.Errorf("Failed to withdraw route: %v", err)
 			}
 		}
-		if err := deleteLoopback(a.app.Vip); err != nil {
+		if err := deleteLoopback(a.app.Vip.Net); err != nil {
 			glog.Errorf("Failed to remove app: %s: %v", a.app.Name, err)
 		}
 		for _, nat := range a.app.Nats {
@@ -191,13 +205,14 @@ func (m *MonitorMgr) Remove(appName string) {
 			if len(parts) != 2 {
 				continue
 			}
-			if err := natRule("D", a.app.Vip.IP, m.ctrl.localIP, parts[0], parts[1]); err != nil {
+			if err := natRule("D", a.app.Vip.Net.IP, m.ctrl.localIP, parts[0], parts[1]); err != nil {
 				glog.Errorf("Failed to remove app: %s: %v", a.app.Name, err)
 			}
 		}
 	}
 	delete(m.monitors, appName)
 }
+
 func (m *MonitorMgr) runMonitors(app *App) bool {
 	for _, mon := range app.Monitors {
 		var check bool
@@ -223,12 +238,12 @@ func (m *MonitorMgr) runMonitors(app *App) bool {
 
 func (m *MonitorMgr) checkCond(am *appMon) error {
 	app := am.app
-	m.Lock()
-	defer m.Unlock()
+	m.clMu.Lock()
+	defer m.clMu.Unlock()
 	if m.runMonitors(app) {
 		glog.V(2).Infof("All Monitors for app: %s succeeded", app.Name)
 		if !am.announced {
-			if err := addLoopback(app.Name, app.Vip); err != nil {
+			if err := addLoopback(app.Name, app.Vip.Net); err != nil {
 				return err
 			}
 			for _, nat := range app.Nats {
@@ -236,7 +251,7 @@ func (m *MonitorMgr) checkCond(am *appMon) error {
 				if len(parts) != 2 {
 					continue
 				}
-				if err := natRule("A", app.Vip.IP, m.ctrl.localIP, parts[0], parts[1]); err != nil {
+				if err := natRule("A", app.Vip.Net.IP, m.ctrl.localIP, parts[0], parts[1]); err != nil {
 					return err
 				}
 			}
@@ -245,7 +260,8 @@ func (m *MonitorMgr) checkCond(am *appMon) error {
 			}
 			am.announced = true
 			if exit, ok := m.cleanups[app.Name]; ok {
-				exit <- true
+				close(exit)
+				delete(m.cleanups, app.Name)
 			}
 		}
 	} else {
@@ -265,7 +281,8 @@ func (m *MonitorMgr) checkCond(am *appMon) error {
 // runLoop periodically checks if an app passes healthchecks
 // and needs VIP announcement
 func (m *MonitorMgr) runLoop(am *appMon) {
-	am.checkOn = true
+	glog.Infof("Starting run-loop for app %s", am.app.Name)
+	am.runLoopOn = true
 	if err := m.checkCond(am); err != nil {
 		glog.Errorln(err)
 	}
@@ -278,7 +295,8 @@ func (m *MonitorMgr) runLoop(am *appMon) {
 				glog.Errorln(err)
 			}
 		case <-am.done:
-			glog.V(2).Infof("Exit run-loop for app: %s", am.app.Name)
+			glog.Infof("Exit run-loop for app: %s", am.app.Name)
+			am.runLoopOn = false
 			return
 		}
 	}
@@ -291,16 +309,16 @@ func (m *MonitorMgr) CloseAll() {
 		glog.Errorf("Failed to shut-down BGP: %v", err)
 	}
 	for _, am := range m.monitors {
-		if am.checkOn {
-			am.done <- true
+		if am.runLoopOn {
+			close(am.done)
 		}
-		deleteLoopback(am.app.Vip)
+		deleteLoopback(am.app.Vip.Net)
 		for _, nat := range am.app.Nats {
 			parts := strings.Split(nat, ":")
 			if len(parts) != 2 {
 				continue
 			}
-			natRule("D", am.app.Vip.IP, m.ctrl.localIP, parts[0], parts[1])
+			natRule("D", am.app.Vip.Net.IP, m.ctrl.localIP, parts[0], parts[1])
 		}
 	}
 }
@@ -313,9 +331,8 @@ func (m *MonitorMgr) Cleanup(app string, exit chan bool) {
 		select {
 		case <-t.C:
 			glog.Infof("Cleaning up app %s", app)
-			m.Lock()
 			m.Remove(app)
-			m.Unlock()
+			return
 		case <-exit:
 			return
 		}

server/server.go

@@ -4,9 +4,12 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
-	"github.com/golang/glog"
-	"github.com/mayuresh82/gocast/controller"
 	"net/http"
+	"strings"
+
+	"github.com/golang/glog"
+	"github.com/mayuresh82/gocast/config"
+	"github.com/mayuresh82/gocast/controller"
 )
 
 // Server is the main entrypoint into the app and serves app requests
@@ -46,7 +49,11 @@ func (s *Server) Serve(ctx context.Context) {
 
 func (s *Server) registerHandler(w http.ResponseWriter, r *http.Request) {
 	queries := r.URL.Query()
-	app, err := controller.NewApp(queries["name"][0], queries["vip"][0], queries["monitor"], queries["nat"], "http")
+	var vipConf config.VipConfig
+	if vipComm, ok := queries["vip_communities"]; ok {
+		vipConf.BgpCommunities = strings.Split(vipComm[0], ",")
+	}
+	app, err := controller.NewApp(queries["name"][0], queries["vip"][0], vipConf, queries["monitor"], queries["nat"], "http")
 	if err != nil {
 		http.Error(w, fmt.Sprintf("Invalid request: %v", err), http.StatusBadRequest)
 		return
@@ -61,9 +68,7 @@ func (s *Server) unregisterHandler(w http.ResponseWriter, r *http.Request) {
 		http.Error(w, "Invalid request, need app name specified", http.StatusBadRequest)
 		return
 	}
-	s.mon.Lock()
 	s.mon.Remove(appName[0])
-	s.mon.Unlock()
 }
 
 func (s *Server) infoHandler(w http.ResponseWriter, r *http.Request) {