Add pausing deployments during upgrades

internal/pkg/handler/pause_deployment.go

@@ -0,0 +1,242 @@
+package handler
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"time"
+
+	"github.com/sirupsen/logrus"
+	"github.com/stakater/Reloader/internal/pkg/options"
+	"github.com/stakater/Reloader/pkg/kube"
+	app "k8s.io/api/apps/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	patchtypes "k8s.io/apimachinery/pkg/types"
+)
+
+// Keeps track of currently active timers
+var activeTimers = make(map[string]*time.Timer)
+
+// Returns unique key for the activeTimers map
+func getTimerKey(namespace, deploymentName string) string {
+	return fmt.Sprintf("%s/%s", namespace, deploymentName)
+}
+
+// Checks if a deployment is currently paused
+func IsPaused(deployment *app.Deployment) bool {
+	return deployment.Spec.Paused
+}
+
+// Deployment paused by reloader ?
+func IsPausedByReloader(deployment *app.Deployment) bool {
+	if IsPaused(deployment) {
+		pausedAtAnnotationValue := deployment.Annotations[options.PauseDeploymentTimeAnnotation]
+		return pausedAtAnnotationValue != ""
+	}
+	return false
+}
+
+// Returns the time, the deployment was paused by reloader, nil otherwise
+func GetPauseStartTime(deployment *app.Deployment) (*time.Time, error) {
+	if !IsPausedByReloader(deployment) {
+		return nil, nil
+	}
+
+	pausedAtStr := deployment.Annotations[options.PauseDeploymentTimeAnnotation]
+	parsedTime, err := time.Parse(time.RFC3339, pausedAtStr)
+	if err != nil {
+		return nil, err
+	}
+
+	return &parsedTime, nil
+}
+
+// ParsePauseDuration parses the pause interval value and returns a time.Duration
+func ParsePauseDuration(pauseIntervalValue string) (time.Duration, error) {
+	pauseDuration, err := time.ParseDuration(pauseIntervalValue)
+	if err != nil {
+		logrus.Warnf("Failed to parse pause interval value '%s': %v", pauseIntervalValue, err)
+		return 0, err
+	}
+	return pauseDuration, nil
+}
+
+// Pauses a deployment for a specified duration and creates a timer to resume it
+// after the specified duration
+func PauseDeployment(deployment *app.Deployment, clients kube.Clients, namespace, pauseIntervalValue string) (*app.Deployment, error) {
+	deploymentName := deployment.Name
+	pauseDuration, err := ParsePauseDuration(pauseIntervalValue)
+
+	if err != nil {
+		return nil, err
+	}
+
+	if !IsPaused(deployment) {
+		logrus.Infof("Pausing Deployment '%s' in namespace '%s' for %s", deploymentName, namespace, pauseDuration)
+
+		deploymentFuncs := GetDeploymentRollingUpgradeFuncs()
+
+		pausePatch, err := CreatePausePatch()
+		if err != nil {
+			logrus.Errorf("Failed to create pause patch for deployment '%s': %v", deploymentName, err)
+			return deployment, err
+		}
+
+		err = deploymentFuncs.PatchFunc(clients, namespace, deployment, patchtypes.StrategicMergePatchType, pausePatch)
+
+		if err != nil {
+			logrus.Errorf("Failed to patch deployment '%s' in namespace '%s': %v", deploymentName, namespace, err)
+			return deployment, err
+		}
+
+		updatedDeployment, err := clients.KubernetesClient.AppsV1().Deployments(namespace).Get(context.TODO(), deploymentName, metav1.GetOptions{})
+
+		CreateResumeTimer(deployment, clients, namespace, pauseDuration)
+		return updatedDeployment, err
+	}
+
+	if !IsPausedByReloader(deployment) {
+		logrus.Infof("Deployment '%s' in namespace '%s' already paused", deploymentName, namespace)
+		return deployment, nil
+	}
+
+	// Deployment has already been paused by reloader, check for timer
+	logrus.Debugf("Deployment '%s' in namespace '%s' is already paused by reloader", deploymentName, namespace)
+
+	timerKey := getTimerKey(namespace, deploymentName)
+	_, timerExists := activeTimers[timerKey]
+
+	if !timerExists {
+		logrus.Warnf("Timer does not exist for already paused deployment '%s' in namespace '%s', creating new one",
+			deploymentName, namespace)
+		HandleMissingTimer(deployment, pauseDuration, clients, namespace)
+	}
+	return deployment, nil
+}
+
+// Handles the case where missing timers for deployments that have been paused by reloader.
+// Could occur after new leader election or reloader restart
+func HandleMissingTimer(deployment *app.Deployment, pauseDuration time.Duration, clients kube.Clients, namespace string) {
+	deploymentName := deployment.Name
+	pauseStartTime, err := GetPauseStartTime(deployment)
+	if err != nil {
+		logrus.Errorf("Error parsing pause start time for deployment '%s' in namespace '%s': %v. Resuming deployment immediately",
+			deploymentName, namespace, err)
+		ResumeDeployment(deployment, namespace, clients)
+		return
+	}
+
+	if pauseStartTime == nil {
+		return
+	}
+
+	elapsedPauseTime := time.Since(*pauseStartTime)
+	remainingPauseTime := pauseDuration - elapsedPauseTime
+
+	if remainingPauseTime <= 0 {
+		logrus.Infof("Pause period for deployment '%s' in namespace '%s' has expired. Resuming immediately",
+			deploymentName, namespace)
+		ResumeDeployment(deployment, namespace, clients)
+		return
+	}
+
+	logrus.Infof("Creating missing timer for already paused deployment '%s' in namespace '%s' with remaining time %s",
+		deploymentName, namespace, remainingPauseTime)
+	CreateResumeTimer(deployment, clients, namespace, remainingPauseTime)
+}
+
+// CreateResumeTimer creates a timer to resume the deployment after the specified duration
+func CreateResumeTimer(deployment *app.Deployment, clients kube.Clients, namespace string, pauseDuration time.Duration) {
+	deploymentName := deployment.Name
+	timerKey := getTimerKey(namespace, deployment.Name)
+
+	// Check if there's an existing timer for this deployment
+	if _, exists := activeTimers[timerKey]; exists {
+		logrus.Debugf("Timer already exists for deployment '%s' in namespace '%s', Skipping creation",
+			deploymentName, namespace)
+		return
+	}
+
+	// Create and store the new timer
+	timer := time.AfterFunc(pauseDuration, func() {
+		ResumeDeployment(deployment, namespace, clients)
+	})
+
+	// Add the new timer to the map
+	activeTimers[timerKey] = timer
+
+	logrus.Debugf("Created pause timer for deployment '%s' in namespace '%s' with duration %s",
+		deploymentName, namespace, pauseDuration)
+}
+
+// ResumeDeployment resumes a deployment that has been paused by reloader
+func ResumeDeployment(deployment *app.Deployment, namespace string, clients kube.Clients) {
+	deploymentName := deployment.Name
+
+	currentDeployment, err := clients.KubernetesClient.AppsV1().Deployments(namespace).Get(context.TODO(), deploymentName, metav1.GetOptions{})
+
+	if err != nil {
+		logrus.Errorf("Failed to get deployment '%s' in namespace '%s': %v", deploymentName, namespace, err)
+		return
+	}
+
+	if !IsPausedByReloader(currentDeployment) {
+		logrus.Infof("Deployment '%s' in namespace '%s' not paused by Reloader. Skipping resume", deploymentName, namespace)
+		return
+	}
+
+	deploymentFuncs := GetDeploymentRollingUpgradeFuncs()
+
+	resumePatch, err := CreateResumePatch()
+	if err != nil {
+		logrus.Errorf("Failed to create resume patch for deployment '%s': %v", deploymentName, err)
+		return
+	}
+
+	// Remove the timer
+	timerKey := getTimerKey(namespace, deploymentName)
+	if timer, exists := activeTimers[timerKey]; exists {
+		timer.Stop()
+		delete(activeTimers, timerKey)
+		logrus.Debugf("Removed pause timer for deployment '%s' in namespace '%s'", deploymentName, namespace)
+	}
+
+	err = deploymentFuncs.PatchFunc(clients, namespace, currentDeployment, patchtypes.StrategicMergePatchType, resumePatch)
+
+	if err != nil {
+		logrus.Errorf("Failed to resume deployment '%s' in namespace '%s': %v", deploymentName, namespace, err)
+		return
+	}
+
+	logrus.Infof("Successfully resumed deployment '%s' in namespace '%s'", deploymentName, namespace)
+}
+
+func CreatePausePatch() ([]byte, error) {
+	patchData := map[string]interface{}{
+		"spec": map[string]interface{}{
+			"paused": true,
+		},
+		"metadata": map[string]interface{}{
+			"annotations": map[string]string{
+				options.PauseDeploymentTimeAnnotation: time.Now().Format(time.RFC3339),
+			},
+		},
+	}
+
+	return json.Marshal(patchData)
+}
+
+func CreateResumePatch() ([]byte, error) {
+	patchData := map[string]interface{}{
+		"spec": map[string]interface{}{
+			"paused": false,
+		},
+		"metadata": map[string]interface{}{
+			"annotations": map[string]interface{}{
+				options.PauseDeploymentTimeAnnotation: nil,
+			},
+		},
+	}
+
+	return json.Marshal(patchData)
+}