Add current_billing_period activity endpoint param (#20694)

* Add current_billing_period activity endpoint param

This commit introduces a new parameter: `current_billing_period`, which
can be used in lieu of `start_time` and `end_time` options.

GET ... /sys/internal/counters/activity?current_billing_period=true now
results in a response which contains the full billing period
information.

* changelog

* Update internal counters docs

changelog/20694.txt

@@ -0,0 +1,4 @@
+```release-note:improvement
+api: GET ... /sys/internal/counters/activity?current_billing_period=true now
+results in a response which contains the full billing period
+```

vault/logical_system_activity.go

@@ -29,6 +29,10 @@ func (b *SystemBackend) activityQueryPath() *framework.Path {
 		},
 
 		Fields: map[string]*framework.FieldSchema{
+			"current_billing_period": {
+				Type:        framework.TypeBool,
+				Description: "Query utilization for configured billing period",
+			},
 			"start_time": {
 				Type:        framework.TypeTime,
 				Description: "Start of query interval",
@@ -236,16 +240,23 @@ func (b *SystemBackend) handleClientExport(ctx context.Context, req *logical.Req
 }
 
 func (b *SystemBackend) handleClientMetricQuery(ctx context.Context, req *logical.Request, d *framework.FieldData) (*logical.Response, error) {
+	var startTime, endTime time.Time
 	b.Core.activityLogLock.RLock()
 	a := b.Core.activityLog
 	b.Core.activityLogLock.RUnlock()
 	if a == nil {
 		return logical.ErrorResponse("no activity log present"), nil
 	}
 
-	startTime, endTime, err := parseStartEndTimes(a, d)
-	if err != nil {
-		return logical.ErrorResponse(err.Error()), nil
+	if d.Get("current_billing_period").(bool) {
+		startTime = b.Core.BillingStart()
+		endTime = time.Now().UTC()
+	} else {
+		var err error
+		startTime, endTime, err = parseStartEndTimes(a, d)
+		if err != nil {
+			return logical.ErrorResponse(err.Error()), nil
+		}
 	}
 
 	var limitNamespaces int

website/content/api-docs/system/internal-counters.mdx

@@ -346,6 +346,10 @@ This endpoint was added in Vault 1.6.
 - `limit_namespaces` `(int, optional)` - Controls the total number of by_namespace data returned. This can
    be used to return the client counts for the specified number of namespaces having highest activity. 
    If no `limit_namespaces` parameter is specified, client counts for all namespaces in specified usage period is returned.
+- `current_billing_period` `(bool, optional)` - Uses the builtin billing start
+  timestamp as `start_time` and the current time as the `end_time`, returning a
+  response with the current billing period information without having to
+  explicitly provide a start and end time.
 
 
 ### Sample Request