Feature Request: Support key-value attributes for services

agent/agent_endpoint.go

@@ -579,6 +579,11 @@ func (s *HTTPServer) AgentRegisterService(resp http.ResponseWriter, req *http.Re
 
 	// Get the node service.
 	ns := args.NodeService()
+	if err := structs.ValidateMetadata(ns.ServiceMeta, false); err != nil {
+		resp.WriteHeader(http.StatusBadRequest)
+		fmt.Fprint(resp, fmt.Errorf("Invalid Service Meta: %v", err))
+		return nil, nil
+	}
 
 	// Verify the check type.
 	chkTypes, err := args.CheckTypes()

agent/config/runtime_test.go

@@ -4075,6 +4075,7 @@ func TestSanitize(t *testing.T) {
             "ID": "",
             "Name": "foo",
             "Port": 0,
+            "ServiceMeta": {},
             "Tags": [],
             "Token": "hidden"
         }

agent/consul/state/catalog.go

@@ -610,6 +610,9 @@ func (s *Store) ensureServiceTxn(tx *memdb.Txn, idx uint64, node string, svc *st
 		return fmt.Errorf("failed service lookup: %s", err)
 	}
 
+	if err = structs.ValidateMetadata(svc.ServiceMeta, false); err != nil {
+		return fmt.Errorf("Invalid Service Meta for node %s and serviceID %s: %v", node, svc.ID, err)
+	}
 	// Create the service node entry and populate the indexes. Note that
 	// conversion doesn't populate any of the node-specific information.
 	// That's always populated when we read from the state store.

agent/consul/state/catalog_test.go

@@ -69,6 +69,19 @@ func TestStateStore_EnsureRegistration(t *testing.T) {
 	}
 	verifyNode()
 
+	// Add in a invalid service definition with too long Key value for ServiceMeta
+	req.Service = &structs.NodeService{
+		ID:          "redis1",
+		Service:     "redis",
+		Address:     "1.1.1.1",
+		Port:        8080,
+		ServiceMeta: map[string]string{strings.Repeat("a", 129): "somevalue"},
+		Tags:        []string{"master"},
+	}
+	if err := s.EnsureRegistration(9, req); err == nil {
+		t.Fatalf("Service should not have been registered since ServiceMeta is invalid")
+	}
+
 	// Add in a service definition.
 	req.Service = &structs.NodeService{
 		ID:      "redis1",

agent/structs/service_definition.go

@@ -6,6 +6,7 @@ type ServiceDefinition struct {
 	Name              string
 	Tags              []string
 	Address           string
+	ServiceMeta       map[string]string
 	Port              int
 	Check             CheckType
 	Checks            CheckTypes
@@ -19,6 +20,7 @@ func (s *ServiceDefinition) NodeService() *NodeService {
 		Service:           s.Name,
 		Tags:              s.Tags,
 		Address:           s.Address,
+		ServiceMeta:       s.ServiceMeta,
 		Port:              s.Port,
 		EnableTagOverride: s.EnableTagOverride,
 	}

agent/structs/structs.go

@@ -368,6 +368,7 @@ type ServiceNode struct {
 	ServiceName              string
 	ServiceTags              []string
 	ServiceAddress           string
+	ServiceMeta              map[string]string
 	ServicePort              int
 	ServiceEnableTagOverride bool
 
@@ -379,6 +380,10 @@ type ServiceNode struct {
 func (s *ServiceNode) PartialClone() *ServiceNode {
 	tags := make([]string, len(s.ServiceTags))
 	copy(tags, s.ServiceTags)
+	nsmeta := make(map[string]string)
+	for k, v := range s.ServiceMeta {
+		nsmeta[k] = v
+	}
 
 	return &ServiceNode{
 		// Skip ID, see above.
@@ -390,6 +395,7 @@ func (s *ServiceNode) PartialClone() *ServiceNode {
 		ServiceTags:              tags,
 		ServiceAddress:           s.ServiceAddress,
 		ServicePort:              s.ServicePort,
+		ServiceMeta:              nsmeta,
 		ServiceEnableTagOverride: s.ServiceEnableTagOverride,
 		RaftIndex: RaftIndex{
 			CreateIndex: s.CreateIndex,
@@ -406,6 +412,7 @@ func (s *ServiceNode) ToNodeService() *NodeService {
 		Tags:              s.ServiceTags,
 		Address:           s.ServiceAddress,
 		Port:              s.ServicePort,
+		ServiceMeta:       s.ServiceMeta,
 		EnableTagOverride: s.ServiceEnableTagOverride,
 		RaftIndex: RaftIndex{
 			CreateIndex: s.CreateIndex,
@@ -422,6 +429,7 @@ type NodeService struct {
 	Service           string
 	Tags              []string
 	Address           string
+	ServiceMeta       map[string]string
 	Port              int
 	EnableTagOverride bool
 
@@ -438,6 +446,7 @@ func (s *NodeService) IsSame(other *NodeService) bool {
 		!reflect.DeepEqual(s.Tags, other.Tags) ||
 		s.Address != other.Address ||
 		s.Port != other.Port ||
+		!reflect.DeepEqual(s.ServiceMeta, other.ServiceMeta) ||
 		s.EnableTagOverride != other.EnableTagOverride {
 		return false
 	}
@@ -457,6 +466,7 @@ func (s *NodeService) ToServiceNode(node string) *ServiceNode {
 		ServiceTags:              s.Tags,
 		ServiceAddress:           s.Address,
 		ServicePort:              s.Port,
+		ServiceMeta:              s.ServiceMeta,
 		ServiceEnableTagOverride: s.EnableTagOverride,
 		RaftIndex: RaftIndex{
 			CreateIndex: s.CreateIndex,

agent/structs/structs_test.go

@@ -133,11 +133,14 @@ func testServiceNode() *ServiceNode {
 		NodeMeta: map[string]string{
 			"tag": "value",
 		},
-		ServiceID:                "service1",
-		ServiceName:              "dogs",
-		ServiceTags:              []string{"prod", "v1"},
-		ServiceAddress:           "127.0.0.2",
-		ServicePort:              8080,
+		ServiceID:      "service1",
+		ServiceName:    "dogs",
+		ServiceTags:    []string{"prod", "v1"},
+		ServiceAddress: "127.0.0.2",
+		ServicePort:    8080,
+		ServiceMeta: map[string]string{
+			"service": "metadata",
+		},
 		ServiceEnableTagOverride: true,
 		RaftIndex: RaftIndex{
 			CreateIndex: 1,
@@ -175,6 +178,17 @@ func TestStructs_ServiceNode_PartialClone(t *testing.T) {
 	if reflect.DeepEqual(sn, clone) {
 		t.Fatalf("clone wasn't independent of the original")
 	}
+
+	revert := make([]string, len(sn.ServiceTags)-1)
+	copy(revert, sn.ServiceTags[0:len(sn.ServiceTags)-1])
+	sn.ServiceTags = revert
+	if !reflect.DeepEqual(sn, clone) {
+		t.Fatalf("bad: %v VS %v", clone, sn)
+	}
+	sn.ServiceMeta["new_meta"] = "new_value"
+	if reflect.DeepEqual(sn, clone) {
+		t.Fatalf("clone wasn't independent of the original for ServiceMeta")
+	}
 }
 
 func TestStructs_ServiceNode_Conversions(t *testing.T) {
@@ -196,10 +210,14 @@ func TestStructs_ServiceNode_Conversions(t *testing.T) {
 
 func TestStructs_NodeService_IsSame(t *testing.T) {
 	ns := &NodeService{
-		ID:                "node1",
-		Service:           "theservice",
-		Tags:              []string{"foo", "bar"},
-		Address:           "127.0.0.1",
+		ID:      "node1",
+		Service: "theservice",
+		Tags:    []string{"foo", "bar"},
+		Address: "127.0.0.1",
+		ServiceMeta: map[string]string{
+			"meta1": "value1",
+			"meta2": "value2",
+		},
 		Port:              1234,
 		EnableTagOverride: true,
 	}
@@ -214,6 +232,11 @@ func TestStructs_NodeService_IsSame(t *testing.T) {
 		Address:           "127.0.0.1",
 		Port:              1234,
 		EnableTagOverride: true,
+		ServiceMeta: map[string]string{
+			// We don't care about order
+			"meta2": "value2",
+			"meta1": "value1",
+		},
 		RaftIndex: RaftIndex{
 			CreateIndex: 1,
 			ModifyIndex: 2,
@@ -245,6 +268,7 @@ func TestStructs_NodeService_IsSame(t *testing.T) {
 	check(func() { other.Tags = []string{"foo"} }, func() { other.Tags = []string{"foo", "bar"} })
 	check(func() { other.Address = "XXX" }, func() { other.Address = "127.0.0.1" })
 	check(func() { other.Port = 9999 }, func() { other.Port = 1234 })
+	check(func() { other.ServiceMeta["meta2"] = "wrongValue" }, func() { other.ServiceMeta["meta2"] = "value2" })
 	check(func() { other.EnableTagOverride = false }, func() { other.EnableTagOverride = true })
 }
 

api/agent.go

@@ -60,12 +60,13 @@ type MembersOpts struct {
 
 // AgentServiceRegistration is used to register a new service
 type AgentServiceRegistration struct {
-	ID                string   `json:",omitempty"`
-	Name              string   `json:",omitempty"`
-	Tags              []string `json:",omitempty"`
-	Port              int      `json:",omitempty"`
-	Address           string   `json:",omitempty"`
-	EnableTagOverride bool     `json:",omitempty"`
+	ID                string            `json:",omitempty"`
+	Name              string            `json:",omitempty"`
+	Tags              []string          `json:",omitempty"`
+	Port              int               `json:",omitempty"`
+	Address           string            `json:",omitempty"`
+	EnableTagOverride bool              `json:",omitempty"`
+	ServiceMeta       map[string]string `json:",omitempty"`
 	Check             *AgentServiceCheck
 	Checks            AgentServiceChecks
 }

api/catalog.go

@@ -22,6 +22,7 @@ type CatalogService struct {
 	ServiceName              string
 	ServiceAddress           string
 	ServiceTags              []string
+	ServiceMeta              map[string]string
 	ServicePort              int
 	ServiceEnableTagOverride bool
 	CreateIndex              uint64

website/source/api/agent/service.html.md

@@ -53,6 +53,9 @@ $ curl \
     "Service": "redis",
     "Tags": [],
     "Address": "",
+    "ServiceMeta": {
+      "redis_version": "4.0"
+    },
     "Port": 8000
   }
 }
@@ -96,14 +99,17 @@ The table below shows this endpoint's support for
   provided, the agent's address is used as the address for the service during
   DNS queries.
 
+- `ServiceMeta` `(map<string|string>: nil)` - Specifies arbitrary KV metadata
+  linked to the service instance.
+
 - `Port` `(int: 0)` - Specifies the port of the service.
 
 - `Check` `(Check: nil)` - Specifies a check. Please see the
   [check documentation](/api/agent/check.html) for more information about the
   accepted fields. If you don't provide a name or id for the check then they
   will be generated. To provide a custom id and/or name set the `CheckID`
   and/or `Name` field.
-  
+
 - `Checks` `(array<Check>: nil`) - Specifies a list of checks. Please see the
   [check documentation](/api/agent/check.html) for more information about the
   accepted fields. If you don't provide a name or id for the check then they
@@ -147,6 +153,9 @@ The table below shows this endpoint's support for
   ],
   "Address": "127.0.0.1",
   "Port": 8000,
+  "ServiceMeta": {
+    "redis_version": "4.0"
+  },
   "EnableTagOverride": false,
   "Check": {
     "DeregisterCriticalServiceAfter": "90m",

website/source/api/catalog.html.md

@@ -54,7 +54,7 @@ The table below shows this endpoint's support for
 - `Service` `(Service: nil)` - Specifies to register a service. If `ID` is not
   provided, it will be defaulted to the value of the `Service.Service` property.
   Only one service with a given `ID` may be present per node. The service
-  `Tags`, `Address`, and `Port` fields are all optional.
+  `Tags`, `Address`, `ServiceMeta` and `Port` fields are all optional.
 
 - `Check` `(Check: nil)` - Specifies to register a check. The register API
   manipulates the health check entry in the Catalog, but it does not setup the
@@ -105,6 +105,9 @@ and vice versa. A catalog entry can have either, neither, or both.
       "v1"
     ],
     "Address": "127.0.0.1",
+    "ServiceMeta": {
+        "redis_version": "4.0"
+    },
     "Port": 8000
   },
   "Check": {
@@ -432,6 +435,9 @@ $ curl \
     "ServiceID": "32a2a47f7992:nodea:5000",
     "ServiceName": "foobar",
     "ServicePort": 5000,
+    "ServiceMeta": {
+        "foobar_meta_value": "baz"
+    },
     "ServiceTags": [
       "tacos"
     ]
@@ -467,6 +473,8 @@ $ curl \
 
 - `ServiceName` is the name of the service
 
+- `ServiceMeta` is a list of user-defined metadata key/value pairs for the service
+
 - `ServicePort` is the port number of the service
 
 - `ServiceTags` is a list of tags for the service
@@ -529,6 +537,7 @@ $ curl \
       "ID": "consul",
       "Service": "consul",
       "Tags": null,
+      "ServiceMeta": {},
       "Port": 8300
     },
     "redis": {
@@ -537,6 +546,9 @@ $ curl \
       "Tags": [
         "v1"
       ],
+      "ServiceMeta": {
+        "redis_version": "4.0"
+      },
       "Port": 8000
     }
   }

website/source/api/health.html.md

@@ -216,6 +216,9 @@ $ curl \
       "Service": "redis",
       "Tags": ["primary"],
       "Address": "10.1.10.12",
+      "ServiceMeta": {
+        "redis_version": "4.0"
+      },
       "Port": 8000
     },
     "Checks": [

website/source/api/query.html.md

@@ -241,6 +241,7 @@ The table below shows this endpoint's support for
     "Near": "node1",
     "OnlyPassing": false,
     "Tags": ["primary", "!experimental"],
+    "ServiceMeta": {"redis_version": "4.0"},
     "NodeMeta": {"instance_type": "m3.large"}
   },
   "DNS": {
@@ -313,6 +314,7 @@ $ curl \
       },
       "OnlyPassing": false,
       "Tags": ["primary", "!experimental"],
+      "ServiceMeta": {"redis_version": "4.0"},
       "NodeMeta": {"instance_type": "m3.large"}
     },
     "DNS": {
@@ -510,6 +512,7 @@ $ curl \
         "ID": "redis",
         "Service": "redis",
         "Tags": null,
+        "ServiceMeta": {"redis_version": "4.0"},
         "Port": 8000
       },
       "Checks": [
@@ -616,6 +619,7 @@ $ curl \
       },
       "OnlyPassing": true,
       "Tags": ["primary"],
+      "ServiceMeta": { "mysql_version": "5.7.20" },
       "NodeMeta": {"instance_type": "m3.large"}
     }
   }