/*
Copyright 2017 The Kubernetes Authors.

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 framework

import (
	"context"
	"flag"
	"fmt"
	"io"
	"net"
	"os"
	"os/exec"
	"strconv"
	"strings"
	"syscall"
	"testing"
	"time"

	"go.uber.org/goleak"
	"google.golang.org/grpc/grpclog"

	"k8s.io/klog/v2"
	"k8s.io/kubernetes/pkg/util/env"
)

const installEtcd = `
Cannot find etcd, cannot run integration tests
Please see https://git.k8s.io/community/contributors/devel/sig-testing/integration-tests.md#install-etcd-dependency for instructions.

You can use 'hack/install-etcd.sh' to install a copy in third_party/.

`

// getEtcdPath returns a path to an etcd executable.
func getEtcdPath() (string, error) {
	return exec.LookPath("etcd")
}

// getAvailablePort returns a TCP port that is available for binding.
func getAvailablePort() (int, error) {
	l, err := net.Listen("tcp", ":0")
	if err != nil {
		return 0, fmt.Errorf("could not bind to a port: %v", err)
	}
	// It is possible but unlikely that someone else will bind this port before we
	// get a chance to use it.
	defer l.Close()
	return l.Addr().(*net.TCPAddr).Port, nil
}

// startEtcd executes an etcd instance. The returned function will signal the
// etcd process and wait for it to exit.
func startEtcd(output io.Writer) (func(), error) {
	etcdURL := env.GetEnvAsStringOrFallback("KUBE_INTEGRATION_ETCD_URL", "http://127.0.0.1:2379")
	conn, err := net.Dial("tcp", strings.TrimPrefix(etcdURL, "http://"))
	if err == nil {
		klog.Infof("etcd already running at %s", etcdURL)
		conn.Close()
		return func() {}, nil
	}
	klog.V(1).Infof("could not connect to etcd: %v", err)

	currentURL, stop, err := RunCustomEtcd("integration_test_etcd_data", nil, output)
	if err != nil {
		return nil, err
	}

	os.Setenv("KUBE_INTEGRATION_ETCD_URL", currentURL)

	return stop, nil
}

func init() {
	// Quiet etcd logs for integration tests
	// Comment out to get verbose logs if desired.
	// This has to be done before there are any goroutines
	// active which use gRPC. During init is safe, albeit
	// then also affects tests which don't use RunCustomEtcd
	// (the place this was done before).
	grpclog.SetLoggerV2(grpclog.NewLoggerV2(io.Discard, io.Discard, os.Stderr))
}

// RunCustomEtcd starts a custom etcd instance for test purposes.
func RunCustomEtcd(dataDir string, customFlags []string, output io.Writer) (url string, stopFn func(), err error) {
	// TODO: Check for valid etcd version.
	etcdPath, err := getEtcdPath()
	if err != nil {
		fmt.Fprint(os.Stderr, installEtcd)
		return "", nil, fmt.Errorf("could not find etcd in PATH: %v", err)
	}
	etcdPort, err := getAvailablePort()
	if err != nil {
		return "", nil, fmt.Errorf("could not get a port: %v", err)
	}
	customURL := fmt.Sprintf("http://127.0.0.1:%d", etcdPort)

	klog.Infof("starting etcd on %s", customURL)

	etcdDataDir, err := os.MkdirTemp(os.TempDir(), dataDir)
	if err != nil {
		return "", nil, fmt.Errorf("unable to make temp etcd data dir %s: %v", dataDir, err)
	}
	klog.Infof("storing etcd data in: %v", etcdDataDir)

	ctx, cancel := context.WithCancel(context.Background())
	args := []string{
		"--data-dir",
		etcdDataDir,
		"--listen-client-urls",
		customURL,
		"--advertise-client-urls",
		customURL,
		"--listen-peer-urls",
		"http://127.0.0.1:0",
		"-log-level",
		"warn", // set to info or debug for more logs
		"--quota-backend-bytes",
		strconv.FormatInt(8*1024*1024*1024, 10),
	}
	args = append(args, customFlags...)
	cmd := exec.CommandContext(ctx, etcdPath, args...)
	if output == nil {
		cmd.Stdout = os.Stdout
		cmd.Stderr = os.Stderr
	} else {
		cmd.Stdout = output
		cmd.Stderr = output
	}
	stop := func() {
		// try to exit etcd gracefully
		defer cancel()
		cmd.Process.Signal(syscall.SIGTERM)
		go func() {
			select {
			case <-ctx.Done():
				klog.Infof("etcd exited gracefully, context cancelled")
			case <-time.After(5 * time.Second):
				klog.Infof("etcd didn't exit in 5 seconds, killing it")
				cancel()
			}
		}()
		err := cmd.Wait()
		klog.Infof("etcd exit status: %v", err)
		err = os.RemoveAll(etcdDataDir)
		if err != nil {
			klog.Warningf("error during etcd cleanup: %v", err)
		}
	}

	if err := cmd.Start(); err != nil {
		return "", nil, fmt.Errorf("failed to run etcd: %v", err)
	}

	var i int32 = 1
	const pollCount = int32(300)

	for i <= pollCount {
		conn, err := net.DialTimeout("tcp", strings.TrimPrefix(customURL, "http://"), 1*time.Second)
		if err == nil {
			conn.Close()
			break
		}

		if i == pollCount {
			stop()
			return "", nil, fmt.Errorf("could not start etcd")
		}

		time.Sleep(100 * time.Millisecond)
		i = i + 1
	}

	return customURL, stop, nil
}

// EtcdMain starts an etcd instance before running tests.
func EtcdMain(tests func() int) {
	// Bail out early when -help was given as parameter.
	flag.Parse()

	// Must be called *before* creating new goroutines.
	goleakOpts := IgnoreBackgroundGoroutines()

	goleakOpts = append(goleakOpts,
		// lumberjack leaks a goroutine:
		// https://github.com/natefinch/lumberjack/issues/56 This affects tests
		// using --audit-log-path (like
		// ./test/integration/apiserver/admissionwebhook/reinvocation_test.go).
		// In normal production that should be harmless. We don't know here
		// whether the test is using that, so we have to suppress reporting
		// this leak for all tests.
		//
		// Both names occurred in practice.
		goleak.IgnoreTopFunction("k8s.io/kubernetes/vendor/gopkg.in/natefinch/lumberjack%2ev2.(*Logger).millRun"),
		goleak.IgnoreTopFunction("gopkg.in/natefinch/lumberjack%2ev2.(*Logger).millRun"),
	)

	stop, err := startEtcd(nil)
	if err != nil {
		klog.Fatalf("cannot run integration tests: unable to start etcd: %v", err)
	}
	result := tests()
	stop() // Don't defer this. See os.Exit documentation.
	klog.StopFlushDaemon()

	if err := goleakFindRetry(goleakOpts...); err != nil {
		klog.ErrorS(err, "EtcdMain goroutine check")
		result = 1
	}

	os.Exit(result)
}

// GetEtcdURL returns the URL of the etcd instance started by EtcdMain or StartEtcd.
func GetEtcdURL() string {
	return env.GetEnvAsStringOrFallback("KUBE_INTEGRATION_ETCD_URL", "http://127.0.0.1:2379")
}

// StartEtcd starts an etcd instance inside a test. It will abort the test if
// startup fails and clean up after the test automatically. Stdout and stderr
// of the etcd binary go to the provided writer.
//
// In contrast to EtcdMain, StartEtcd will not do automatic leak checking.
// Tests can decide if and where they want to do that.
//
// Starting etcd multiple times per test run instead of once with EtcdMain
// provides better separation between different tests.
func StartEtcd(tb testing.TB, etcdOutput io.Writer) {
	stop, err := startEtcd(etcdOutput)
	if err != nil {
		tb.Fatalf("unable to start etcd: %v", err)
	}
	tb.Cleanup(stop)
}