Satisfy Eureka 1.2.2 and later when registering

As of Eureka version 1.2.2 and later, when registering an instance encoded as JSON, one must supply a value for the instance.dataCenterInfo.@Class field, which must be set appropriately for the sibling "name" field's value. Take care of setting this value for the "Amazon" and "MyOwn" data center types, but allow callers to specify the value for their own custom data center types for which we cannot anticipate a suitable value.
athlum · Jan 26, 2017 · 2b3ac93 · 2b3ac93
1 parent df904f6
commit 2b3ac93
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Showing 5 changed files with 110 additions and 42 deletions.
diff --git a/marshal.go b/marshal.go
@@ -320,7 +320,7 @@ func (m metadataMap) UnmarshalXML(d *xml.Decoder, start xml.StartElement) error
 	return nil
 }
 
-func metadataValue(i DataCenterInfo) interface{} {
+func metadataValue(i *DataCenterInfo) interface{} {
 	if i.Name == Amazon {
 		return i.Metadata
 	}
@@ -334,7 +334,7 @@ var (
 
 // MarshalXML is a custom XML marshaler for DataCenterInfo, writing either Metadata or AlternateMetadata
 // depending on the type of data center indicated by the Name.
-func (i DataCenterInfo) MarshalXML(e *xml.Encoder, start xml.StartElement) error {
+func (i *DataCenterInfo) MarshalXML(e *xml.Encoder, start xml.StartElement) error {
 	if err := e.EncodeToken(start); err != nil {
 		return err
 	}
@@ -351,6 +351,7 @@ func (i DataCenterInfo) MarshalXML(e *xml.Encoder, start xml.StartElement) error
 
 type preliminaryDataCenterInfo struct {
 	Name     string      `xml:"name" json:"name"`
+	Class    string      `xml:"-" json:"@class"`
 	Metadata metadataMap `xml:"metadata" json:"metadata"`
 }
 
@@ -378,6 +379,7 @@ func populateAmazonMetadata(dst *AmazonMetadataType, src map[string]string) {
 
 func adaptDataCenterInfo(dst *DataCenterInfo, src preliminaryDataCenterInfo) {
 	dst.Name = src.Name
+	dst.Class = src.Class
 	if src.Name == Amazon {
 		populateAmazonMetadata(&dst.Metadata, src.Metadata)
 	} else {
@@ -400,20 +402,31 @@ func (i *DataCenterInfo) UnmarshalXML(d *xml.Decoder, start xml.StartElement) er
 
 // MarshalJSON is a custom JSON marshaler for DataCenterInfo, writing either Metadata or AlternateMetadata
 // depending on the type of data center indicated by the Name.
-func (i DataCenterInfo) MarshalJSON() ([]byte, error) {
+func (i *DataCenterInfo) MarshalJSON() ([]byte, error) {
 	type named struct {
-		Name string `json:"name"`
+		Name  string `json:"name"`
+		Class string `json:"@class"`
 	}
 	if i.Name == Amazon {
 		return json.Marshal(struct {
 			named
 			Metadata AmazonMetadataType `json:"metadata"`
-		}{named{i.Name}, i.Metadata})
+		}{
+			named{i.Name, "com.netflix.appinfo.AmazonInfo"},
+			i.Metadata,
+		})
+	}
+	class := "com.netflix.appinfo.MyDataCenterInfo"
+	if i.Name != MyOwn {
+		class = i.Class
 	}
 	return json.Marshal(struct {
 		named
-		Metadata map[string]string `json:"metadata"`
-	}{named{i.Name}, i.AlternateMetadata})
+		Metadata map[string]string `json:"metadata,omitempty"`
+	}{
+		named{i.Name, class},
+		i.AlternateMetadata,
+	})
 }
 
 // UnmarshalJSON is a custom JSON unmarshaler for DataCenterInfo, populating either Metadata or AlternateMetadata

diff --git a/net.go b/net.go
@@ -661,6 +661,9 @@ func (e *EurekaConnection) ReregisterInstance(ins *Instance) error {
 	} else {
 		out, err = e.marshal(ins)
 	}
+	if err != nil {
+		return err
+	}
 
 	body, rcode, err := postBody(reqURL, out, e.UseJson)
 	if err != nil {

diff --git a/struct.go b/struct.go
@@ -132,6 +132,14 @@ type AmazonMetadataType struct {
 type DataCenterInfo struct {
 	// Name indicates which type of data center hosts this instance.
 	Name string
+	// Class indicates the Java class name representing this structure in the Eureka server,
+	// noted only when encoding communication with JSON.
+	//
+	// When registering an instance, if the name is neither "Amazon" nor "MyOwn", this field's
+	// value is used. Otherwise, a suitable default value will be supplied to the server. This field
+	// is available for specifying custom data center types other than the two built-in ones, for
+	// which no suitable default value could be known.
+	Class string
 	// Metadata provides details specific to an Amazon data center,
 	// populated and honored when the Name field's value is "Amazon".
 	Metadata AmazonMetadataType

diff --git a/tests/marshal_test.go b/tests/marshal_test.go
@@ -225,6 +225,7 @@ func TestDataCenterInfoMarshal(t *testing.T) {
 
 		Convey("When the data center name is \"Amazon\"", func() {
 			ins.DataCenterInfo.Name = fargo.Amazon
+			ins.DataCenterInfo.Class = "ignored"
 			ins.DataCenterInfo.Metadata.InstanceID = "123"
 			ins.DataCenterInfo.Metadata.HostName = "expected.local"
 
@@ -233,14 +234,16 @@ func TestDataCenterInfoMarshal(t *testing.T) {
 
 				Convey("The marshalled JSON should have these values", func() {
 					So(err, ShouldBeNil)
-					So(string(b), ShouldEqual, `{"name":"Amazon","metadata":{"ami-launch-index":"","local-hostname":"","availability-zone":"","instance-id":"123","public-ipv4":"","public-hostname":"","ami-manifest-path":"","local-ipv4":"","hostname":"expected.local","ami-id":"","instance-type":""}}`)
+					So(string(b), ShouldEqual, `{"name":"Amazon","@class":"com.netflix.appinfo.AmazonInfo","metadata":{"ami-launch-index":"","local-hostname":"","availability-zone":"","instance-id":"123","public-ipv4":"","public-hostname":"","ami-manifest-path":"","local-ipv4":"","hostname":"expected.local","ami-id":"","instance-type":""}}`)
 
 					Convey("The value unmarshalled from JSON should have the same values as the original", func() {
 						d := fargo.DataCenterInfo{}
 						err := json.Unmarshal(b, &d)
 
 						So(err, ShouldBeNil)
-						So(d, ShouldResemble, ins.DataCenterInfo)
+						expected := ins.DataCenterInfo
+						expected.Class = "com.netflix.appinfo.AmazonInfo"
+						So(d, ShouldResemble, expected)
 					})
 				})
 			})
@@ -257,25 +260,49 @@ func TestDataCenterInfoMarshal(t *testing.T) {
 						err := xml.Unmarshal(b, &d)
 
 						So(err, ShouldBeNil)
-						So(d, ShouldResemble, ins.DataCenterInfo)
+						expected := ins.DataCenterInfo
+						expected.Class = ""
+						So(d, ShouldResemble, expected)
 					})
 				})
 			})
 		})
 
 		Convey("When the data center name is not \"Amazon\"", func() {
 			ins.DataCenterInfo.Name = fargo.MyOwn
+			ins.DataCenterInfo.Class = "ignored"
 			ins.DataCenterInfo.AlternateMetadata = map[string]string{
 				"instanceId": "123",
 				"hostName":   "expected.local",
 			}
 
-			Convey("When the data center info is marshalled as JSON", func() {
+			Convey("When the data center info has no class specified and is marshalled as JSON", func() {
+				b, err := json.Marshal(&ins.DataCenterInfo)
+
+				Convey("The marshalled JSON should have these values", func() {
+					So(err, ShouldBeNil)
+					So(string(b), ShouldEqual, `{"name":"MyOwn","@class":"com.netflix.appinfo.MyDataCenterInfo","metadata":{"hostName":"expected.local","instanceId":"123"}}`)
+
+					Convey("The value unmarshalled from JSON should have the same values as the original", func() {
+						d := fargo.DataCenterInfo{}
+						err := json.Unmarshal(b, &d)
+
+						So(err, ShouldBeNil)
+						expected := ins.DataCenterInfo
+						expected.Class = "com.netflix.appinfo.MyDataCenterInfo"
+						So(d, ShouldResemble, expected)
+					})
+				})
+			})
+
+			Convey("When the data center info has both a custom name and class specified and is marshalled as JSON", func() {
+				ins.DataCenterInfo.Name = "Custom"
+				ins.DataCenterInfo.Class = "custom"
 				b, err := json.Marshal(&ins.DataCenterInfo)
 
 				Convey("The marshalled JSON should have these values", func() {
 					So(err, ShouldBeNil)
-					So(string(b), ShouldEqual, `{"name":"MyOwn","metadata":{"hostName":"expected.local","instanceId":"123"}}`)
+					So(string(b), ShouldEqual, `{"name":"Custom","@class":"custom","metadata":{"hostName":"expected.local","instanceId":"123"}}`)
 
 					Convey("The value unmarshalled from JSON should have the same values as the original", func() {
 						d := fargo.DataCenterInfo{}
@@ -301,7 +328,9 @@ func TestDataCenterInfoMarshal(t *testing.T) {
 						err := xml.Unmarshal(b, &d)
 
 						So(err, ShouldBeNil)
-						So(d, ShouldResemble, ins.DataCenterInfo)
+						expected := ins.DataCenterInfo
+						expected.Class = ""
+						So(d, ShouldResemble, expected)
 					})
 				})
 			})

diff --git a/tests/net_test.go b/tests/net_test.go
@@ -279,25 +279,25 @@ func TestReregistration(t *testing.T) {
 			Convey("Instance registers correctly", func() {
 				err := e.RegisterInstance(&i)
 				So(err, ShouldBeNil)
-			})
-		})
 
-		Convey("Reregister the TESTAPP instance", t, func() {
-			Convey("Instance reregisters correctly", func() {
-				err := e.ReregisterInstance(&i)
-				So(err, ShouldBeNil)
-			})
+				Convey("Reregister the TESTAPP instance", func() {
+					Convey("Instance reregisters correctly", func() {
+						err := e.ReregisterInstance(&i)
+						So(err, ShouldBeNil)
 
-			Convey("Instance can check in", func() {
-				err := e.HeartBeatInstance(&i)
-				So(err, ShouldBeNil)
-			})
+						Convey("Instance can check in", func() {
+							err := e.HeartBeatInstance(&i)
+							So(err, ShouldBeNil)
+						})
 
-			Convey("Instance can be gotten correctly", func() {
-				ii, err := e.GetInstance(i.App, i.HostName)
-				So(err, ShouldBeNil)
-				So(ii.App, ShouldEqual, i.App)
-				So(ii.HostName, ShouldEqual, i.HostName)
+						Convey("Instance can be gotten correctly", func() {
+							ii, err := e.GetInstance(i.App, i.HostName)
+							So(err, ShouldBeNil)
+							So(ii.App, ShouldEqual, i.App)
+							So(ii.HostName, ShouldEqual, i.HostName)
+						})
+					})
+				})
 			})
 		})
 	}
@@ -370,6 +370,17 @@ func TestUpdateStatus(t *testing.T) {
 
 func TestMetadataReading(t *testing.T) {
 	e, _ := fargo.NewConnFromConfigFile("./config_sample/local.gcfg")
+	i := fargo.Instance{
+		HostName:         "i-123456",
+		Port:             9090,
+		PortEnabled:      true,
+		App:              "TESTAPP",
+		IPAddr:           "127.0.0.10",
+		VipAddress:       "127.0.0.10",
+		DataCenterInfo:   fargo.DataCenterInfo{Name: fargo.MyOwn},
+		SecureVipAddress: "127.0.0.10",
+		Status:           fargo.UP,
+	}
 	for _, j := range []bool{false, true} {
 		e.UseJson = j
 		Convey("Read empty instance metadata", t, func() {
@@ -379,19 +390,23 @@ func TestMetadataReading(t *testing.T) {
 			_, err = i.Metadata.GetString("SomeProp")
 			So(err, ShouldBeNil)
 		})
-		Convey("Read valid instance metadata", t, func() {
-			a, err := e.GetApp("TESTAPP")
-			So(err, ShouldBeNil)
-			So(len(a.Instances), ShouldBeGreaterThan, 0)
-			if len(a.Instances) == 0 {
-				return
-			}
-			i := a.Instances[0]
-			err = e.AddMetadataString(i, "SomeProp", "AValue")
-			So(err, ShouldBeNil)
-			v, err := i.Metadata.GetString("SomeProp")
-			So(err, ShouldBeNil)
-			So(v, ShouldEqual, "AValue")
+		Convey("Register an instance to TESTAPP", t, func() {
+			Convey("Instance registers correctly", func() {
+				err := e.RegisterInstance(&i)
+				So(err, ShouldBeNil)
+
+				Convey("Read valid instance metadata", func() {
+					a, err := e.GetApp("TESTAPP")
+					So(err, ShouldBeNil)
+					So(len(a.Instances), ShouldBeGreaterThan, 0)
+					i := a.Instances[0]
+					err = e.AddMetadataString(i, "SomeProp", "AValue")
+					So(err, ShouldBeNil)
+					v, err := i.Metadata.GetString("SomeProp")
+					So(err, ShouldBeNil)
+					So(v, ShouldEqual, "AValue")
+				})
+			})
 		})
 	}
 }