metric_monitoring_exporter_test.go

/*
Copyright 2024 Google LLC

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package spanner

import (
	"context"
	"net"
	"strings"
	"sync"
	"time"

	"cloud.google.com/go/monitoring/apiv3/v2/monitoringpb"
	metricpb "google.golang.org/genproto/googleapis/api/metric"
	"google.golang.org/grpc"
	"google.golang.org/grpc/keepalive"
	"google.golang.org/grpc/metadata"
	"google.golang.org/protobuf/types/known/emptypb"
)

type MetricsTestServer struct {
	lis                         net.Listener
	srv                         *grpc.Server
	Endpoint                    string
	userAgent                   string
	createMetricDescriptorReqs  []*monitoringpb.CreateMetricDescriptorRequest
	createServiceTimeSeriesReqs []*monitoringpb.CreateTimeSeriesRequest
	RetryCount                  int
	mu                          sync.Mutex
}

func (m *MetricsTestServer) Shutdown() {
	// this will close mts.lis
	m.srv.GracefulStop()
}

// Pops out the UserAgent from the most recent CreateTimeSeriesRequests or CreateServiceTimeSeriesRequests.
func (m *MetricsTestServer) UserAgent() string {
	m.mu.Lock()
	defer m.mu.Unlock()
	ua := m.userAgent
	m.userAgent = ""
	return ua
}

// Pops out the CreateServiceTimeSeriesRequests which the test server has received so far.
func (m *MetricsTestServer) CreateServiceTimeSeriesRequests() []*monitoringpb.CreateTimeSeriesRequest {
	m.mu.Lock()
	defer m.mu.Unlock()
	reqs := m.createServiceTimeSeriesReqs
	m.createServiceTimeSeriesReqs = nil
	return reqs
}

func (m *MetricsTestServer) appendCreateMetricDescriptorReq(ctx context.Context, req *monitoringpb.CreateMetricDescriptorRequest) {
	m.mu.Lock()
	defer m.mu.Unlock()
	m.createMetricDescriptorReqs = append(m.createMetricDescriptorReqs, req)
}

func (m *MetricsTestServer) appendCreateServiceTimeSeriesReq(ctx context.Context, req *monitoringpb.CreateTimeSeriesRequest) {
	m.mu.Lock()
	defer m.mu.Unlock()
	m.createServiceTimeSeriesReqs = append(m.createServiceTimeSeriesReqs, req)
	if md, ok := metadata.FromIncomingContext(ctx); ok {
		m.userAgent = strings.Join(md.Get("User-Agent"), ";")
	}
}

func (m *MetricsTestServer) Serve() error {
	return m.srv.Serve(m.lis)
}

type fakeMetricServiceServer struct {
	monitoringpb.UnimplementedMetricServiceServer
	metricsTestServer *MetricsTestServer
}

func (f *fakeMetricServiceServer) CreateServiceTimeSeries(
	ctx context.Context,
	req *monitoringpb.CreateTimeSeriesRequest,
) (*emptypb.Empty, error) {
	f.metricsTestServer.appendCreateServiceTimeSeriesReq(ctx, req)
	return &emptypb.Empty{}, nil
}

func (f *fakeMetricServiceServer) CreateMetricDescriptor(
	ctx context.Context,
	req *monitoringpb.CreateMetricDescriptorRequest,
) (*metricpb.MetricDescriptor, error) {
	f.metricsTestServer.appendCreateMetricDescriptorReq(ctx, req)
	return &metricpb.MetricDescriptor{}, nil
}

func NewMetricTestServer() (*MetricsTestServer, error) {
	srv := grpc.NewServer(grpc.KeepaliveParams(keepalive.ServerParameters{Time: 5 * time.Minute}))
	lis, err := net.Listen("tcp", "localhost:0")
	if err != nil {
		return nil, err
	}
	testServer := &MetricsTestServer{
		Endpoint: lis.Addr().String(),
		lis:      lis,
		srv:      srv,
	}

	monitoringpb.RegisterMetricServiceServer(
		srv,
		&fakeMetricServiceServer{metricsTestServer: testServer},
	)

	return testServer, nil
}