✨ [patch] Now Agents can connect to multiple Servers

Signed-off-by: Rintaro Okamura <rintaro.okamura@gmail.com>

go.mod

@@ -45,7 +45,7 @@ require (
 	github.com/aws/aws-sdk-go v1.27.0
 	github.com/cespare/xxhash/v2 v2.1.1
 	github.com/fsnotify/fsnotify v1.4.9
-	github.com/go-redis/redis/v8 v8.4.11
+	github.com/go-redis/redis/v8 v8.6.0
 	github.com/go-sql-driver/mysql v1.5.0
 	github.com/gocql/gocql v0.0.0-20200131111108-92af2e088537
 	github.com/gocraft/dbr/v2 v2.7.1
@@ -59,29 +59,29 @@ require (
 	github.com/klauspost/compress v0.0.0-00010101000000-000000000000
 	github.com/kpango/fastime v1.0.16
 	github.com/kpango/fuid v0.0.0-20200823100533-287aa95e0641
-	github.com/kpango/gache v1.2.4
-	github.com/kpango/glg v1.5.1
-	github.com/mattn/go-sqlite3 v2.0.3+incompatible // indirect
+	github.com/kpango/gache v1.2.5
+	github.com/kpango/glg v1.5.5
 	github.com/pierrec/lz4/v3 v3.3.2
 	github.com/rancher/remotedialer v0.2.5
 	github.com/scylladb/gocqlx v1.5.0
 	github.com/tensorflow/tensorflow v0.0.0-00010101000000-000000000000
-	github.com/urfave/cli/v2 v2.2.0
+	github.com/urfave/cli/v2 v2.3.0
 	github.com/vdaas/vald v0.0.0-00010101000000-000000000000
-	go.opencensus.io v0.22.6
-	go.opentelemetry.io/otel v0.16.0
-	go.opentelemetry.io/otel/exporters/metric/prometheus v0.16.0
+	go.opencensus.io v0.23.0
+	go.opentelemetry.io/otel v0.17.0
+	go.opentelemetry.io/otel/exporters/metric/prometheus v0.17.0
+	go.opentelemetry.io/otel/metric v0.17.0
 	go.uber.org/automaxprocs v1.4.0
 	go.uber.org/goleak v1.1.10
 	go.uber.org/zap v1.16.0
-	golang.org/x/net v0.0.0-20210119194325-5f4716e94777
-	golang.org/x/sys v0.0.0-20210124154548-22da62e12c0c
-	google.golang.org/api v0.38.0
+	golang.org/x/net v0.0.0-20210224082022-3d97a244fca7
+	golang.org/x/sys v0.0.0-20210225134936-a50acf3fe073
+	google.golang.org/api v0.40.0
 	google.golang.org/grpc v1.35.0
 	gopkg.in/yaml.v2 v2.4.0
-	k8s.io/api v0.20.2
-	k8s.io/apimachinery v0.20.2
-	k8s.io/client-go v0.20.2
+	k8s.io/api v0.20.4
+	k8s.io/apimachinery v0.20.4
+	k8s.io/client-go v0.20.4
 	k8s.io/metrics v0.0.0-00010101000000-000000000000
 	sigs.k8s.io/controller-runtime v0.0.0-00010101000000-000000000000
 )

pkg/alvd/agent/config/config.go

@@ -6,7 +6,7 @@ import (
 )
 
 type Config struct {
-	ServerAddress string
+	ServerAddresses []string
 
 	AgentName string
 

pkg/alvd/agent/config/option.go

@@ -18,11 +18,9 @@ func WithAgentName(name string) OptionFunc {
 	}
 }
 
-func WithServerAddress(addr string) OptionFunc {
+func WithServerAddresses(addrs []string) OptionFunc {
 	return func(c *Config) error {
-		if addr != "" {
-			c.ServerAddress = addr
-		}
+		c.ServerAddresses = addrs
 
 		return nil
 	}

pkg/alvd/agent/daemon/daemon.go

@@ -16,7 +16,7 @@ import (
 )
 
 type daemon struct {
-	serverAddress string
+	serverAddresses []string
 
 	agentName string
 	grpcPort  int
@@ -65,31 +65,31 @@ func New(cfg *config.Config) (Daemon, error) {
 	}
 
 	return &daemon{
-		serverAddress: cfg.ServerAddress,
-		agentName:     cfg.AgentName,
-		grpcPort:      cfg.GRPCPort,
-		agent:         a,
-		ngt:           ngt,
-		handler:       h,
+		serverAddresses: cfg.ServerAddresses,
+		agentName:       cfg.AgentName,
+		grpcPort:        cfg.GRPCPort,
+		agent:           a,
+		ngt:             ngt,
+		handler:         h,
 	}, nil
 }
 
 func (d *daemon) Start(ctx context.Context) <-chan error {
 	ctx, d.cancel = context.WithCancel(ctx)
 
-	var tunEch <-chan error
-	d.tunnel, tunEch = tunnel.Connect(ctx, &tunnel.Config{
-		ServerAddress: d.serverAddress,
-		AgentName:     d.agentName,
-		AgentPort:     d.grpcPort,
-	})
+	d.tunnel = tunnel.New(d.agentName, d.grpcPort)
+	tunEch := d.tunnel.Start(ctx)
+	for _, addr := range d.serverAddresses {
+		d.tunnel.Connect(addr)
+	}
 
 	nech := d.ngt.Start(ctx)
 	gech := d.agent.Start(ctx)
 
 	ech := make(chan error, 1)
 
 	go func() {
+		defer close(ech)
 		var err error
 		for {
 			select {

pkg/alvd/agent/service/tunnel/tunnel.go

@@ -12,40 +12,78 @@ import (
 )
 
 type tunnel struct {
-	*Config
-	cancel context.CancelFunc
-}
+	agentName string
+	agentPort int
 
-type Config struct {
-	ServerAddress string
+	cancel       context.CancelFunc
+	cancelByAddr map[string]context.CancelFunc
 
-	AgentName string
-	AgentPort int
+	connectCh    chan string
+	disconnectCh chan string
 }
 
 type Tunnel interface {
+	Start(ctx context.Context) <-chan error
+	Connect(addr string)
+	Disconnect(addr string)
 	Close()
 }
 
-func Connect(ctx context.Context, cfg *Config) (Tunnel, <-chan error) {
-	ctx, cancel := context.WithCancel(ctx)
+func New(name string, port int) Tunnel {
+	return &tunnel{
+		agentName:    name,
+		agentPort:    port,
+		cancelByAddr: make(map[string]context.CancelFunc, 0),
+	}
+}
+
+func (t *tunnel) Start(ctx context.Context) <-chan error {
+	ctx, t.cancel = context.WithCancel(ctx)
 	ech := make(chan error, 1)
+	t.connectCh = make(chan string, 10)
+	t.disconnectCh = make(chan string, 10)
+
+	go func() {
+		defer close(ech)
+		defer close(t.connectCh)
+		defer close(t.disconnectCh)
+		var err error
+		for {
+			select {
+			case <-ctx.Done():
+				err = ctx.Err()
+				if err != nil && err != context.Canceled {
+					log.Errorf("error: %s", err)
+				}
+				return
+			case addr := <-t.connectCh:
+				t.connect(ctx, addr)
+			case addr := <-t.disconnectCh:
+				t.disconnect(ctx, addr)
+			}
+		}
+	}()
+
+	return ech
+}
+
+func (t *tunnel) connect(ctx context.Context, addr string) {
+	ctx, t.cancelByAddr[addr] = context.WithCancel(ctx)
 
 	headers := http.Header{
-		"X-ALVD-ID":        []string{cfg.AgentName},
-		"X-ALVD-GRPC-PORT": []string{strconv.Itoa(cfg.AgentPort)},
+		"X-ALVD-ID":        []string{t.agentName},
+		"X-ALVD-GRPC-PORT": []string{strconv.Itoa(t.agentPort)},
 	}
 
 	go func() {
-		defer close(ech)
 		for {
 			remotedialer.ClientConnect(
 				ctx,
-				fmt.Sprintf("ws://%s/connect", cfg.ServerAddress),
+				fmt.Sprintf("ws://%s/connect", addr),
 				headers,
 				nil,
 				connectAuthorizer,
-				onConnectFunc(cfg.ServerAddress),
+				onConnectFunc(addr),
 			)
 
 			select {
@@ -59,11 +97,22 @@ func Connect(ctx context.Context, cfg *Config) (Tunnel, <-chan error) {
 			}
 		}
 	}()
+}
 
-	return &tunnel{
-		Config: cfg,
-		cancel: cancel,
-	}, ech
+func (t *tunnel) disconnect(ctx context.Context, addr string) {
+	cancel, ok := t.cancelByAddr[addr]
+	if ok {
+		cancel()
+		delete(t.cancelByAddr, addr)
+	}
+}
+
+func (t *tunnel) Connect(addr string) {
+	t.connectCh <- addr
+}
+
+func (t *tunnel) Disconnect(addr string) {
+	t.disconnectCh <- addr
 }
 
 func (t *tunnel) Close() {

pkg/alvd/cli/agent/cli.go

@@ -13,7 +13,7 @@ import (
 )
 
 type Opts struct {
-	ServerAddress          string
+	ServerAddresses        []string
 	AgentName              string
 	LogLevel               string
 	Dimension              int
@@ -37,10 +37,10 @@ var Flags = []cli.Flag{
 		Value: "",
 		Usage: "agent name (if not specified, uuid will be generated)",
 	},
-	&cli.StringFlag{
+	&cli.StringSliceFlag{
 		Name:  "server",
-		Value: "0.0.0.0:8000",
-		Usage: "alvd server address",
+		Value: cli.NewStringSlice("0.0.0.0:8000"),
+		Usage: "alvd server addresses",
 	},
 	&cli.StringFlag{
 		Name:  "log-level",
@@ -117,7 +117,7 @@ var Flags = []cli.Flag{
 func ParseOpts(c *cli.Context) *Opts {
 	return &Opts{
 		AgentName:              c.String("name"),
-		ServerAddress:          c.String("server"),
+		ServerAddresses:        c.StringSlice("server"),
 		LogLevel:               c.String("log-level"),
 		Dimension:              c.Int("dimension"),
 		DistanceType:           c.String("distance-type"),
@@ -177,7 +177,7 @@ func NewCommand() *cli.Command {
 func ToConfig(opts *Opts) (*config.Config, error) {
 	cfg, err := config.New(
 		config.WithAgentName(opts.AgentName),
-		config.WithServerAddress(opts.ServerAddress),
+		config.WithServerAddresses(opts.ServerAddresses),
 		config.WithDimension(opts.Dimension),
 		config.WithDistanceType(opts.DistanceType),
 		config.WithObjectType(opts.ObjectType),

pkg/alvd/cli/server/cli.go

@@ -114,7 +114,7 @@ func ToConfig(opts *Opts) (*config.Config, error) {
 	cfg, err := config.New(
 		config.WithAgentEnabled(opts.AgentEnabled),
 		config.WithAgentOpts(opts.Opts),
-		config.WithAddr(opts.ServerAddress),
+		config.WithAddrs(opts.ServerAddresses),
 		config.WithGRPCHost(opts.ServerGRPCHost),
 		config.WithGRPCPort(opts.ServerGRPCPort),
 		config.WithReplicas(opts.Replicas),

pkg/alvd/observability/metrics/metrics.go

@@ -6,9 +6,9 @@ import (
 	"time"
 
 	"github.com/rinx/alvd/internal/log"
-	"go.opentelemetry.io/otel"
 	"go.opentelemetry.io/otel/label"
 	"go.opentelemetry.io/otel/metric"
+	"go.opentelemetry.io/otel/metric/global"
 )
 
 var (
@@ -40,7 +40,7 @@ type Meter interface {
 func Init(interval time.Duration) {
 	once.Do(func() {
 		instance = &meter{
-			meter:    otel.Meter("rinx.github.io/alvd"),
+			meter:    global.Meter("rinx.github.io/alvd"),
 			interval: interval,
 			mch:      make(chan metric.Measurement, 10),
 		}

pkg/alvd/observability/prometheus/prometheus.go

@@ -3,8 +3,8 @@ package prometheus
 import (
 	"net/http"
 
-	"go.opentelemetry.io/otel"
 	"go.opentelemetry.io/otel/exporters/metric/prometheus"
+	"go.opentelemetry.io/otel/metric/global"
 )
 
 type prom struct {
@@ -23,7 +23,7 @@ func New() (Prometheus, error) {
 		return nil, err
 	}
 
-	otel.SetMeterProvider(exporter.MeterProvider())
+	global.SetMeterProvider(exporter.MeterProvider())
 
 	return &prom{
 		exporter: exporter,

pkg/alvd/server/config/config.go

@@ -11,7 +11,7 @@ type Config struct {
 	AgentEnabled bool
 	AgentOpts    *agent.Opts
 
-	Addr     string
+	Addrs    []string
 	GRPCHost string
 	GRPCPort int
 

pkg/alvd/server/config/option.go

@@ -26,11 +26,9 @@ func WithAgentOpts(opts *agent.Opts) OptionFunc {
 	}
 }
 
-func WithAddr(addr string) OptionFunc {
+func WithAddrs(addrs []string) OptionFunc {
 	return func(c *Config) error {
-		if addr != "" {
-			c.Addr = addr
-		}
+		c.Addrs = addrs
 
 		return nil
 	}

pkg/alvd/server/daemon/daemon.go

@@ -64,7 +64,7 @@ func New(cfg *config.Config) (Daemon, error) {
 	}
 
 	return &daemon{
-		addr:    cfg.Addr,
+		addr:    cfg.Addrs[0],
 		gateway: g,
 		tunnel:  tun,
 		manager: m,