Gather REPLICA tablet types from Vitess only

go.mod

@@ -13,4 +13,5 @@ require (
 	github.com/patrickmn/go-cache v2.1.0+incompatible
 	github.com/rcrowley/go-metrics v0.0.0-20190826022208-cac0b30c2563
 	golang.org/x/sys v0.0.0-20190602015325-4c4f7f33c9ed // indirect
+	vitess.io/vitess v2.1.1+incompatible
 )

go.sum

@@ -11,6 +11,7 @@ github.com/circonus-labs/circonusllhist v0.1.3/go.mod h1:kMXHVDlOchFAehlya5ePtbp
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/go-sql-driver/mysql v1.5.0 h1:ozyZYNQW3x3HtqT1jira07DN2PArx2v7/mN66gGcHOs=
 github.com/go-sql-driver/mysql v1.5.0/go.mod h1:DCzpHaOWr8IXmIStZouvnhqoel9Qv2LBy8hT2VhHyBg=
+github.com/golang/protobuf v1.2.0 h1:P3YflyNX/ehuJFLhxviNdFxQPkGK5cDcApsge1SqnvM=
 github.com/golang/protobuf v1.2.0/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
 github.com/hashicorp/go-cleanhttp v0.5.0/go.mod h1:JpRdi6/HCYpAwUzNwuwqhbovhLtngrth3wmdIIUrZ80=
 github.com/hashicorp/go-immutable-radix v1.0.0 h1:AKDB1HM5PWEA7i4nhcpwOrO2byshxBjXVn/J/3+z5/0=
@@ -45,6 +46,9 @@ github.com/stretchr/testify v1.3.0 h1:TivCn/peBQ7UY8ooIcPgZFpTNSz0Q2U6UrFlUfqbe0
 github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
 github.com/tv42/httpunix v0.0.0-20150427012821-b75d8614f926/go.mod h1:9ESjWnEqriFuLhtthL60Sar/7RFoluCcXsuvEwTV5KM=
 golang.org/x/net v0.0.0-20181201002055-351d144fa1fc/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
+golang.org/x/sync v0.0.0-20181108010431-42b317875d0f h1:Bl/8QSvNqXvPGPGXa2z5xUTmV7VDcZyvRZ+QQXkXTZQ=
 golang.org/x/sync v0.0.0-20181108010431-42b317875d0f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sys v0.0.0-20190602015325-4c4f7f33c9ed h1:uPxWBzB3+mlnjy9W58qY1j/cjyFjutgw/Vhan2zLy/A=
 golang.org/x/sys v0.0.0-20190602015325-4c4f7f33c9ed/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+vitess.io/vitess v2.1.1+incompatible h1:nuuGHiWYWpudD3gOCLeGzol2EJ25e/u5Wer2wV1O130=
+vitess.io/vitess v2.1.1+incompatible/go.mod h1:h4qvkyNYTOC0xI+vcidSWoka0gQAZc9ZPHbkHo48gP0=

pkg/throttle/throttler.go

@@ -327,13 +327,14 @@ func (throttler *Throttler) refreshMySQLInventory() error {
 				if err != nil {
 					return log.Errorf("Unable to get vitess hosts from %s, %s/%s: %+v", clusterSettings.VitessSettings.API, keyspace, shard, err)
 				}
-				log.Debugf("Read %+v hosts from vitess %s, %s/%s", len(tablets), clusterSettings.VitessSettings.API, keyspace, shard)
+				replicas := vitess.FilterReplicaTablets(tablets)
+				log.Debugf("Read %+v replica hosts from vitess %s, %s/%s", len(replicas), clusterSettings.VitessSettings.API, keyspace, shard)
 				clusterProbes := &mysql.ClusterProbes{
 					ClusterName:      clusterName,
 					IgnoreHostsCount: clusterSettings.IgnoreHostsCount,
 					InstanceProbes:   mysql.NewProbes(),
 				}
-				for _, tablet := range tablets {
+				for _, tablet := range replicas {
 					key := mysql.InstanceKey{Hostname: tablet.MysqlHostname, Port: int(tablet.MysqlPort)}
 					addInstanceKey(&key, clusterName, clusterSettings, clusterProbes.InstanceProbes)
 				}

pkg/vitess/api_client.go

@@ -7,12 +7,15 @@ import (
 	"net/http"
 	"strings"
 	"time"
+
+	"vitess.io/vitess/go/vt/proto/topodata"
 )
 
 // Tablet represents information about a running instance of vttablet.
 type Tablet struct {
-	MysqlHostname string `json:"mysql_hostname,omitempty"`
-	MysqlPort     int32  `json:"mysql_port,omitempty"`
+	MysqlHostname string              `json:"mysql_hostname,omitempty"`
+	MysqlPort     int32               `json:"mysql_port,omitempty"`
+	Type          topodata.TabletType `json:"type,omitempty"`
 }
 
 var httpClient = http.Client{
@@ -30,7 +33,7 @@ func constructAPIURL(api string, keyspace string, shard string) (url string) {
 }
 
 // ParseTablets reads from vitess /api/ks_tablets/<keyspace>/[shard] and returns a
-// tblet (mysql_hostname, mysql_port) listing
+// tablet (mysql_hostname, mysql_port) listing
 func ParseTablets(api string, keyspace string, shard string) (tablets []Tablet, err error) {
 	url := constructAPIURL(api, keyspace, shard)
 	resp, err := httpClient.Get(url)
@@ -47,3 +50,18 @@ func ParseTablets(api string, keyspace string, shard string) (tablets []Tablet,
 	err = json.Unmarshal(body, &tablets)
 	return tablets, err
 }
+
+func isReplicaTablet(tablet Tablet) bool {
+	return tablet.Type == topodata.TabletType_REPLICA
+}
+
+// FilterReplicaTablets parses a list of tablets, returning replica tablets only
+func FilterReplicaTablets(tablets []Tablet) []Tablet {
+	replicas := make([]Tablet, 0)
+	for _, tablet := range tablets {
+		if isReplicaTablet(tablet) {
+			replicas = append(replicas, tablet)
+		}
+	}
+	return replicas
+}

pkg/vitess/api_client_test.go

@@ -0,0 +1,35 @@
+package vitess
+
+import (
+	"testing"
+
+	"vitess.io/vitess/go/vt/proto/topodata"
+)
+
+func TestFilterReplicaTablets(t *testing.T) {
+	replicas := FilterReplicaTablets([]Tablet{
+		{
+			MysqlHostname: t.Name() + "1",
+			Type:          topodata.TabletType_MASTER,
+		},
+		{
+			MysqlHostname: t.Name() + "2", // this node is valid
+			Type:          topodata.TabletType_REPLICA,
+		},
+		{
+			MysqlHostname: t.Name() + "3",
+			Type:          topodata.TabletType_BACKUP,
+		},
+		{
+
+			MysqlHostname: t.Name() + "4",
+			Type:          topodata.TabletType_RESTORE,
+		},
+	})
+	if len(replicas) != 1 {
+		t.Fatalf("Expected 1 replica, got %v", replicas)
+	}
+	if replicas[0].MysqlHostname != t.Name()+"2" {
+		t.Fatalf("Expected hostname %q, got %q", t.Name()+"2", replicas[0].MysqlHostname)
+	}
+}