main.go

/*
Copyright 2018 The Kubernetes Authors.
Copyright 2022 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

    https://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 main

import (
	"context"
	"flag"
	"fmt"
	"math"
	"os"
	"os/signal"
	"path/filepath"
	"strconv"
	"syscall"
	"time"

	"cloud.google.com/go/profiler"
	driver "github.com/googlecloudplatform/gcs-fuse-csi-driver/pkg/csi_driver"
	sidecarmounter "github.com/googlecloudplatform/gcs-fuse-csi-driver/pkg/sidecar_mounter"
	"github.com/googlecloudplatform/gcs-fuse-csi-driver/pkg/webhook"
	"k8s.io/klog/v2"
)

var (
	gcsfusePath                           = flag.String("gcsfuse-path", "/gcsfuse", "gcsfuse path")
	volumeBasePath                        = flag.String("volume-base-path", webhook.SidecarContainerTmpVolumeMountPath+"/.volumes", "volume base path")
	_                                     = flag.Int("grace-period", 0, "grace period for gcsfuse termination. This flag has been deprecated, has no effect and will be removed in the future.")
	kubeconfigPath                        = flag.String("kubeconfig-path", "", "The kubeconfig path.")
	informerResyncDurationSec             = flag.Int("informer-resync-duration-sec", 1800, "informer resync duration in seconds")
	storageServiceAndBucketAccessCap      = flag.Duration("storage-service-check-retry-cap", 60*time.Minute, "storage service creation and bucket access check exponential retry cap")
	storageServiceAndBucketAccessSteps    = flag.Int("storage-service-check-retry-steps", math.MaxInt, "storage service creation and bucket access check exponential retry cap") // Effectively infinite retry steps
	storageServiceAndBucketAccessFactor   = flag.Float64("storage-service-check-retry-factor", 2.0, "storage service creation and bucket access check exponential retry factor")
	storageServiceAndBucketAccessJitter   = flag.Float64("storage-service-check-retry-jitter", 0.1, "storage service creation and bucket access check exponential retry jitter")
	storageServiceAndBucketAccessDuration = flag.Duration("storage-service-check-retry-duration", 5*time.Second, "storage service creation and bucket access check exponential retry initial duration")

	// This is set at compile time.
	version = "unknown"
)

func main() {
	klog.InitFlags(nil)
	flag.Parse()

	klog.Info("*** CUSTOM BUILD: Sidecar Mounter - Manual Test Version ***")
	klog.Infof("Running Google Cloud Storage FUSE CSI driver sidecar mounter version %v", version)

	socketPathPattern := *volumeBasePath + "/*/socket"
	socketPaths, err := filepath.Glob(socketPathPattern)
	if err != nil {
		klog.Fatalf("failed to look up socket paths: %v", err)
	}
	mounter := sidecarmounter.New(*gcsfusePath)
	ctx, cancel := context.WithCancel(context.Background())
	flagsFromDriver := map[string]string{}
	defaultingFlagFilePath := *volumeBasePath + "/" + driver.FlagFileForDefaultingPath
	klog.Infof("Checking if defaulting-flag file %q exists", defaultingFlagFilePath)
	if _, err := os.Stat(defaultingFlagFilePath); err == nil {
		machineTypeBytes, err := os.ReadFile(defaultingFlagFilePath)
		if err != nil {
			klog.Fatalf("failed to read defaulting-flag file: %v", err)
		}
		fileContent := string(machineTypeBytes)
		flagsFromDriver = driver.ParseFlagMapFromFlagFile(fileContent)
	}
	for _, sp := range socketPaths {
		klog.V(4).Infof("in sidecar mounter, found socket path %s", sp)
		// sleep 1.5 seconds before launch the next gcsfuse to avoid
		// 1. different gcsfuse logs mixed together.
		// 2. memory usage peak.
		time.Sleep(1500 * time.Millisecond)
		mc := sidecarmounter.NewMountConfig(sp, flagsFromDriver)
		if mc.EnableCloudProfilerForSidecar {
			cfg := profiler.Config{
				Service: "gke-gcsfuse-sidecar",
			}
			if err := profiler.Start(cfg); err != nil {
				klog.Errorf("Errored while starting cloud profiler, got %v", err)
			} else {
				klog.Infof("Running cloud profiler on %s", cfg.Service)
			}
		}
		if mc != nil {
			if mc.EnableSidecarBucketAccessCheck {
				tm, ssm, err := mounter.SetupTokenAndStorageManager(nil /*k8sClientset*/, mc)
				if err != nil {
					klog.Fatalf("Failed to fetch identity pool and identity provider details required for bucket access check, got error %v", err)
				}
				mounter.TokenManager = tm
				mounter.StorageServiceManager = ssm
				mc.SidecarRetryConfig.Cap = *storageServiceAndBucketAccessCap
				mc.SidecarRetryConfig.Steps = *storageServiceAndBucketAccessSteps
				mc.SidecarRetryConfig.Factor = *storageServiceAndBucketAccessFactor
				mc.SidecarRetryConfig.Duration = *storageServiceAndBucketAccessDuration
				mc.SidecarRetryConfig.Jitter = *storageServiceAndBucketAccessJitter
			}
			if err := mounter.Mount(ctx, mc); err != nil {
				mc.ErrWriter.WriteMsg(fmt.Sprintf("failed to mount bucket %q for volume %q: %v\n", mc.BucketName, mc.VolumeName, err))
			}
		}
	}

	c := make(chan os.Signal, 1)
	signal.Notify(c, syscall.SIGTERM)
	klog.Info("waiting for SIGTERM signal...")

	// Function that monitors the exit file used in regular sidecar containers.
	monitorExitFile := func() {
		ticker := time.NewTicker(5 * time.Second)
		for {
			<-ticker.C
			// If exit file is detected, send a syscall.SIGTERM signal to the signal channel.
			if _, err := os.Stat(*volumeBasePath + "/exit"); err == nil {
				klog.Info("all the other containers terminated in the Pod, exiting the sidecar container.")

				// After the Kubernetes native sidecar container feature is adopted,
				// we should propagate the SIGTERM signal outside of this goroutine.
				cancel()

				if err := os.Remove(*volumeBasePath + "/exit"); err != nil {
					klog.Error("failed to remove the exit file from emptyDir.")
				}

				c <- syscall.SIGTERM

				return
			}
		}
	}

	envVar := os.Getenv("NATIVE_SIDECAR")
	isNativeSidecar, err := strconv.ParseBool(envVar)
	if envVar != "" && err != nil {
		klog.Warningf(`env variable "%s" could not be converted to boolean`, envVar)
	}
	// When the pod contains a regular container, we monitor for the exit file.
	if !isNativeSidecar {
		go monitorExitFile()
	}

	<-c // blocking the process
	klog.Info("received SIGTERM signal, waiting for all the gcsfuse processes exit...")

	if isNativeSidecar {
		klog.V(4).Info("the sidecar mounter is calling ctx.cancel")
		cancel()
	}

	mounter.WaitGroup.Wait()

	klog.Info("exiting sidecar mounter...")
}