Backport of feat: include nodes count in operator usage endpoint and cli command into release/1.16.x (#18012)

* backport of commit 54cdccd019ce32227f679b3fdca499283fdbdf5e

* backport of commit e543f716937fabed12ae2872d242a99416846d86

---------

Co-authored-by: Poonam Jadhav <poonam.jadhav@hashicorp.com>

.changelog/17939.txt

@@ -0,0 +1,4 @@
+```release-note:improvement
+http: GET API `operator/usage` endpoint now returns node count
+cli: `consul operator usage` command now returns node count
+```

agent/consul/state/usage.go

@@ -424,6 +424,11 @@ func (s *Store) ServiceUsage(ws memdb.WatchSet) (uint64, structs.ServiceUsage, e
 		return 0, structs.ServiceUsage{}, fmt.Errorf("failed services lookup: %s", err)
 	}
 
+	nodes, err := firstUsageEntry(ws, tx, tableNodes)
+	if err != nil {
+		return 0, structs.ServiceUsage{}, fmt.Errorf("failed nodes lookup: %s", err)
+	}
+
 	serviceKindInstances := make(map[string]int)
 	for _, kind := range allConnectKind {
 		usage, err := firstUsageEntry(ws, tx, connectUsageTableName(kind))
@@ -443,6 +448,7 @@ func (s *Store) ServiceUsage(ws memdb.WatchSet) (uint64, structs.ServiceUsage, e
 		Services:                 services.Count,
 		ConnectServiceInstances:  serviceKindInstances,
 		BillableServiceInstances: billableServiceInstances.Count,
+		Nodes:                    nodes.Count,
 	}
 	results, err := compileEnterpriseServiceUsage(ws, tx, usage)
 	if err != nil {

agent/operator_endpoint_oss_test.go

@@ -65,6 +65,7 @@ func TestOperator_Usage(t *testing.T) {
 			},
 			// 4 = 6 total service instances - 1 connect proxy - 1 consul service
 			BillableServiceInstances: 4,
+			Nodes:                    2,
 		},
 	}
 	require.Equal(t, expected, raw.(structs.Usage).Usage)

agent/structs/structs.go

@@ -2308,6 +2308,7 @@ type ServiceUsage struct {
 	ServiceInstances         int
 	ConnectServiceInstances  map[string]int
 	BillableServiceInstances int
+	Nodes                    int
 	EnterpriseServiceUsage
 }
 

api/operator_usage.go

@@ -10,6 +10,7 @@ type Usage struct {
 
 // ServiceUsage contains information about the number of services and service instances for a datacenter.
 type ServiceUsage struct {
+	Nodes                   int
 	Services                int
 	ServiceInstances        int
 	ConnectServiceInstances map[string]int

command/operator/usage/instances/usage_instances.go

@@ -99,6 +99,14 @@ func (c *cmd) Run(args []string) int {
 			return 1
 		}
 		c.UI.Output(billableOutput + "\n")
+
+		c.UI.Output("\nNodes")
+		nodesOutput, err := formatNodesCounts(usage.Usage)
+		if err != nil {
+			c.UI.Error(err.Error())
+			return 1
+		}
+		c.UI.Output(nodesOutput + "\n\n")
 	}
 
 	// Output Connect service counts
@@ -115,6 +123,34 @@ func (c *cmd) Run(args []string) int {
 	return 0
 }
 
+func formatNodesCounts(usageStats map[string]api.ServiceUsage) (string, error) {
+	var output bytes.Buffer
+	tw := tabwriter.NewWriter(&output, 0, 2, 6, ' ', 0)
+
+	nodesTotal := 0
+
+	fmt.Fprintf(tw, "Datacenter\t")
+
+	fmt.Fprintf(tw, "Count\t")
+
+	fmt.Fprint(tw, "\t\n")
+
+	for dc, usage := range usageStats {
+		nodesTotal += usage.Nodes
+		fmt.Fprintf(tw, "%s\t%d\n", dc, usage.Nodes)
+	}
+
+	fmt.Fprint(tw, "\t\n")
+	fmt.Fprintf(tw, "Total")
+
+	fmt.Fprintf(tw, "\t%d", nodesTotal)
+
+	if err := tw.Flush(); err != nil {
+		return "", fmt.Errorf("Error flushing tabwriter: %s", err)
+	}
+	return strings.TrimSpace(output.String()), nil
+}
+
 func formatServiceCounts(usageStats map[string]api.ServiceUsage, billable, showDatacenter bool) (string, error) {
 	var output bytes.Buffer
 	tw := tabwriter.NewWriter(&output, 0, 2, 6, ' ', 0)

command/operator/usage/instances/usage_instances_oss_test.go

@@ -117,3 +117,54 @@ Total                                    45`,
 		})
 	}
 }
+
+func TestUsageInstances_formatNodesCounts(t *testing.T) {
+	usageBasic := map[string]api.ServiceUsage{
+		"dc1": {
+			Nodes: 10,
+		},
+	}
+
+	usageMultiDC := map[string]api.ServiceUsage{
+		"dc1": {
+			Nodes: 10,
+		},
+		"dc2": {
+			Nodes: 11,
+		},
+	}
+
+	cases := []struct {
+		name          string
+		usageStats    map[string]api.ServiceUsage
+		expectedNodes string
+	}{
+		{
+			name:       "basic",
+			usageStats: usageBasic,
+			expectedNodes: `
+Datacenter      Count            
+dc1             10
+                
+Total           10`,
+		},
+		{
+			name:       "multi-datacenter",
+			usageStats: usageMultiDC,
+			expectedNodes: `
+Datacenter      Count            
+dc1             10
+dc2             11
+                
+Total           21`,
+		},
+	}
+
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			nodesOutput, err := formatNodesCounts(tc.usageStats)
+			require.NoError(t, err)
+			require.Equal(t, strings.TrimSpace(tc.expectedNodes), nodesOutput)
+		})
+	}
+}

website/content/api-docs/operator/usage.mdx

@@ -64,7 +64,8 @@ $ curl \
         "mesh-gateway": 0,
         "terminating-gateway": 0
       },
-      "BillableServiceInstances": 0
+      "BillableServiceInstances": 0,
+      "Nodes": 1
     }
   },
   "Index": 13,

website/content/commands/operator/usage.mdx

@@ -50,6 +50,12 @@ Billable Services
 Services      Service instances
 2             3
 
+Nodes
+Datacenter      Count            
+dc1             1
+                
+Total           1
+
 Connect Services
 Type                     Service instances
 connect-native           0
@@ -74,6 +80,13 @@ dc2             1             1
 
 Total           3             4
 
+Nodes
+Datacenter      Count            
+dc1             1
+dc2             2
+                
+Total           3
+
 Connect Services
 Datacenter      Type                     Service instances
 dc1             connect-native           0