consul/state: fetch node/check sets by service ID

consul/state/state_store.go

@@ -250,7 +250,7 @@ func (s *StateStore) ensureServiceTxn(idx uint64, node string, svc *structs.Node
 
 	// Populate the indexes
 	if existing != nil {
-		entry.CreateIndex = existing.(*structs.NodeService).CreateIndex
+		entry.CreateIndex = existing.(*structs.ServiceNode).CreateIndex
 		entry.ModifyIndex = idx
 	} else {
 		entry.CreateIndex = idx
@@ -537,3 +537,77 @@ func (s *StateStore) deleteCheckTxn(idx uint64, node, id string, tx *memdb.Txn)
 	// TODO: watch triggers
 	return nil
 }
+
+// CheckServiceNodes is used to query all nodes and checks for a given service
+// ID. The results are compounded into a CheckServiceNodes, and the index
+// returned is the maximum index observed over any node, check, or service
+// in the result set.
+func (s *StateStore) CheckServiceNodes(serviceID string) (uint64, structs.CheckServiceNodes, error) {
+	tx := s.db.Txn(false)
+	defer tx.Abort()
+
+	// Query the state store for the service.
+	services, err := tx.Get("services", "service", serviceID)
+	if err != nil {
+		return 0, nil, fmt.Errorf("failed service lookup: %s", err)
+	}
+	return s.parseCheckServiceNodes(tx, services, err)
+}
+
+// parseCheckServiceNodes is used to parse through a given set of services,
+// and query for an associated node and a set of checks. This is the inner
+// method used to return a rich set of results from a more simple query.
+func (s *StateStore) parseCheckServiceNodes(
+	tx *memdb.Txn, iter memdb.ResultIterator,
+	err error) (uint64, structs.CheckServiceNodes, error) {
+	if err != nil {
+		return 0, nil, err
+	}
+
+	var results structs.CheckServiceNodes
+	var lindex uint64
+	for service := iter.Next(); service != nil; service = iter.Next() {
+		// Compute the index
+		svc := service.(*structs.ServiceNode)
+		if svc.ModifyIndex > lindex {
+			lindex = svc.ModifyIndex
+		}
+
+		// Retrieve the node
+		n, err := tx.First("nodes", "id", svc.Node)
+		if err != nil {
+			return 0, nil, fmt.Errorf("failed node lookup: %s", err)
+		}
+		if n == nil {
+			return 0, nil, ErrMissingNode
+		}
+		node := n.(*structs.Node)
+		if node.ModifyIndex > lindex {
+			lindex = node.ModifyIndex
+		}
+
+		// Get the checks
+		idx, checks, err := s.parseChecks(tx.Get("checks", "node_service", svc.Node, svc.ServiceID))
+		if err != nil {
+			return 0, nil, err
+		}
+		if idx > lindex {
+			lindex = idx
+		}
+
+		// Append to the results
+		results = append(results, structs.CheckServiceNode{
+			Node: node,
+			Service: &structs.NodeService{
+				ID:      svc.ServiceID,
+				Service: svc.ServiceName,
+				Address: svc.ServiceAddress,
+				Port:    svc.ServicePort,
+				Tags:    svc.ServiceTags,
+			},
+			Checks: checks,
+		})
+	}
+
+	return lindex, results, nil
+}

consul/state/state_store_test.go

@@ -516,3 +516,83 @@ func TestStateStore_ChecksInState(t *testing.T) {
 		t.Fatalf("expected 3 checks, got: %d", n)
 	}
 }
+
+func TestStateStore_CheckServiceNodes(t *testing.T) {
+	s := testStateStore(t)
+
+	// Querying with no matches gives an empty response
+	idx, results, err := s.CheckServiceNodes("service1")
+	if idx != 0 || results != nil || err != nil {
+		t.Fatalf("expected (0, nil, nil), got: (%d, %#v, %#v)", idx, results, err)
+	}
+
+	// Register some nodes
+	testRegisterNode(t, s, 0, "node1")
+	testRegisterNode(t, s, 1, "node2")
+
+	// Register node-level checks. These should not be returned
+	// in the final result.
+	testRegisterCheck(t, s, 2, "node1", "", "check1", structs.HealthPassing)
+	testRegisterCheck(t, s, 3, "node2", "", "check2", structs.HealthPassing)
+
+	// Register a service against the nodes
+	testRegisterService(t, s, 4, "node1", "service1")
+	testRegisterService(t, s, 5, "node2", "service2")
+
+	// Register checks against the services
+	testRegisterCheck(t, s, 6, "node1", "service1", "check3", structs.HealthPassing)
+	testRegisterCheck(t, s, 7, "node2", "service2", "check4", structs.HealthPassing)
+
+	// Query the state store for nodes and checks which
+	// have been registered with a specific service.
+	idx, results, err = s.CheckServiceNodes("service1")
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	// Check the index returned matches the result set. The index
+	// should be the highest observed from the result, in this case
+	// this comes from the check registration.
+	if idx != 6 {
+		t.Fatalf("bad index: %d", idx)
+	}
+
+	// Make sure we get the expected result
+	if n := len(results); n != 1 {
+		t.Fatalf("expected 1 result, got: %d", n)
+	}
+	csn := results[0]
+	if csn.Node == nil || csn.Service == nil || len(csn.Checks) != 1 {
+		t.Fatalf("bad output: %#v", csn)
+	}
+
+	// Node updates alter the returned index
+	testRegisterNode(t, s, 8, "node1")
+	idx, results, err = s.CheckServiceNodes("service1")
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+	if idx != 8 {
+		t.Fatalf("bad index: %d", idx)
+	}
+
+	// Service updates alter the returned index
+	testRegisterService(t, s, 9, "node1", "service1")
+	idx, results, err = s.CheckServiceNodes("service1")
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+	if idx != 9 {
+		t.Fatalf("bad index: %d", idx)
+	}
+
+	// Check updates alter the returned index
+	testRegisterCheck(t, s, 10, "node1", "service1", "check1", structs.HealthCritical)
+	idx, results, err = s.CheckServiceNodes("service1")
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+	if idx != 10 {
+		t.Fatalf("bad index: %d", idx)
+	}
+}

consul/structs/structs.go

@@ -289,8 +289,8 @@ type HealthChecks []*HealthCheck
 // CheckServiceNode is used to provide the node, it's service
 // definition, as well as a HealthCheck that is associated
 type CheckServiceNode struct {
-	Node    Node
-	Service NodeService
+	Node    *Node
+	Service *NodeService
 	Checks  HealthChecks
 }
 type CheckServiceNodes []CheckServiceNode