tasks/service/matching/physical_task_queue_manager.go

// The MIT License
//
// Copyright (c) 2020 Temporal Technologies Inc.  All rights reserved.
//
// Copyright (c) 2020 Uber Technologies, Inc.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.

package matching

import (
	"bytes"
	"context"
	"errors"
	"fmt"
	"sync/atomic"
	"time"

	enumspb "go.temporal.io/api/enums/v1"
	"go.temporal.io/api/serviceerror"
	taskqueuepb "go.temporal.io/api/taskqueue/v1"
	"go.temporal.io/api/workflowservice/v1"

	enumsspb "go.temporal.io/server/api/enums/v1"
	"go.temporal.io/server/api/matchingservice/v1"
	persistencespb "go.temporal.io/server/api/persistence/v1"
	taskqueuespb "go.temporal.io/server/api/taskqueue/v1"
	"go.temporal.io/server/common"
	"go.temporal.io/server/common/clock"
	"go.temporal.io/server/common/cluster"
	"go.temporal.io/server/common/debug"
	"go.temporal.io/server/common/log"
	"go.temporal.io/server/common/log/tag"
	"go.temporal.io/server/common/metrics"
	"go.temporal.io/server/common/namespace"
)

const (
	// Time budget for empty task to propagate through the function stack and be returned to
	// pollForActivityTask or pollForWorkflowTask handler.
	returnEmptyTaskTimeBudget = time.Second

	// Fake Task ID to wrap a task for syncmatch
	syncMatchTaskId = -137

	ioTimeout = 5 * time.Second * debug.TimeoutMultiplier

	// Threshold for counting a AddTask call as a no recent poller call
	noPollerThreshold = time.Minute * 2
)

type (
	addTaskParams struct {
		taskInfo      *persistencespb.TaskInfo
		source        enumsspb.TaskSource
		forwardedFrom string
	}

	physicalTaskQueueManager interface {
		Start()
		Stop()
		WaitUntilInitialized(context.Context) error
		// PollTask blocks waiting for a task Returns error when context deadline is exceeded
		// maxDispatchPerSecond is the max rate at which tasks are allowed to be dispatched
		// from this task queue to pollers
		PollTask(ctx context.Context, pollMetadata *pollMetadata) (*internalTask, error)
		// MarkAlive updates the liveness timer to keep this physicalTaskQueueManager alive.
		MarkAlive()
		// TrySyncMatch tries to match task to a local or remote poller. If not possible, returns false.
		TrySyncMatch(ctx context.Context, params addTaskParams) (bool, error)
		// SpoolTask spools a task to persistence to be matched asynchronously when a poller is available.
		SpoolTask(params addTaskParams) error
		ProcessSpooledTask(ctx context.Context, task *internalTask) error
		// DispatchSpooledTask dispatches a task to a poller. When there are no pollers to pick
		// up the task, this method will return error. Task will not be persisted to db
		DispatchSpooledTask(ctx context.Context, task *internalTask, userDataChanged <-chan struct{}) error
		// DispatchQueryTask will dispatch query to local or remote poller. If forwarded then result or error is returned,
		// if dispatched to local poller then nil and nil is returned.
		DispatchQueryTask(ctx context.Context, taskId string, request *matchingservice.QueryWorkflowRequest) (*matchingservice.QueryWorkflowResponse, error)
		// DispatchNexusTask dispatches a nexus task to a local or remote poller. If forwarded then result or
		// error is returned, if dispatched to local poller then nil and nil is returned.
		DispatchNexusTask(ctx context.Context, taskId string, request *matchingservice.DispatchNexusTaskRequest) (*matchingservice.DispatchNexusTaskResponse, error)
		UpdatePollerInfo(pollerIdentity, *pollMetadata)
		GetAllPollerInfo() []*taskqueuepb.PollerInfo
		HasPollerAfter(accessTime time.Time) bool
		// LegacyDescribeTaskQueue returns pollers info and legacy TaskQueueStatus for this physical queue
		LegacyDescribeTaskQueue(includeTaskQueueStatus bool) *matchingservice.DescribeTaskQueueResponse
		// Describe returns information about the physical task queue
		Describe() *taskqueuespb.PhysicalTaskQueueInfo
		UnloadFromPartitionManager()
		String() string
		QueueKey() *PhysicalTaskQueueKey
	}

	// physicalTaskQueueManagerImpl manages a single DB-level (aka physical) task queue in memory
	physicalTaskQueueManagerImpl struct {
		status               int32
		partitionMgr         *taskQueuePartitionManagerImpl
		queue                *PhysicalTaskQueueKey
		config               *taskQueueConfig
		backlogMgr           *backlogManagerImpl
		liveness             *liveness
		matcher              *TaskMatcher // for matching a task producer with a poller
		namespaceRegistry    namespace.Registry
		logger               log.Logger
		throttledLogger      log.ThrottledLogger
		matchingClient       matchingservice.MatchingServiceClient
		metricsHandler       metrics.Handler
		clusterMeta          cluster.Metadata
		taggedMetricsHandler metrics.Handler // namespace/taskqueue tagged metric scope
		// pollerHistory stores poller which poll from this taskqueue in last few minutes
		pollerHistory *pollerHistory
		currentPolls  atomic.Int64
		taskValidator taskValidator
	}
)

var _ physicalTaskQueueManager = (*physicalTaskQueueManagerImpl)(nil)

var (
	errRemoteSyncMatchFailed  = serviceerror.NewCanceled("remote sync match failed")
	errMissingNormalQueueName = errors.New("missing normal queue name")
)

func newPhysicalTaskQueueManager(
	partitionMgr *taskQueuePartitionManagerImpl,
	queue *PhysicalTaskQueueKey,
	opts ...taskQueueManagerOpt,
) (*physicalTaskQueueManagerImpl, error) {
	e := partitionMgr.engine
	config := partitionMgr.config
	logger := log.With(partitionMgr.logger, tag.WorkerBuildId(queue.VersionSet()))
	throttledLogger := log.With(partitionMgr.throttledLogger, tag.WorkerBuildId(queue.VersionSet()))
	buildIdTagValue := queue.VersionSet()
	if buildIdTagValue == "" {
		buildIdTagValue = queue.BuildId()
	}
	taggedMetricsHandler := partitionMgr.taggedMetricsHandler.WithTags(
		metrics.OperationTag(metrics.MatchingTaskQueueMgrScope),
		metrics.WorkerBuildIdTag(buildIdTagValue))
	pqMgr := &physicalTaskQueueManagerImpl{
		status:               common.DaemonStatusInitialized,
		partitionMgr:         partitionMgr,
		namespaceRegistry:    e.namespaceRegistry,
		matchingClient:       e.matchingRawClient,
		metricsHandler:       e.metricsHandler,
		clusterMeta:          e.clusterMeta,
		queue:                queue,
		logger:               logger,
		throttledLogger:      throttledLogger,
		config:               config,
		taggedMetricsHandler: taggedMetricsHandler,
	}
	pqMgr.pollerHistory = newPollerHistory()

	pqMgr.liveness = newLiveness(
		clock.NewRealTimeSource(),
		config.MaxTaskQueueIdleTime,
		pqMgr.UnloadFromPartitionManager,
	)

	pqMgr.taskValidator = newTaskValidator(pqMgr.newIOContext, pqMgr.clusterMeta, pqMgr.namespaceRegistry, pqMgr.partitionMgr.engine.historyClient)
	pqMgr.backlogMgr = newBacklogManager(
		pqMgr,
		config,
		e.taskManager,
		logger,
		throttledLogger,
		e.matchingRawClient,
		taggedMetricsHandler,
		partitionMgr.callerInfoContext,
	)

	var fwdr *Forwarder
	var err error
	if !queue.Partition().IsRoot() && queue.Partition().Kind() != enumspb.TASK_QUEUE_KIND_STICKY {
		// Every DB Queue needs its own forwarder so that the throttles do not interfere
		fwdr, err = newForwarder(&config.forwarderConfig, queue, e.matchingRawClient)
		if err != nil {
			return nil, err
		}
	}
	pqMgr.matcher = newTaskMatcher(config, fwdr, pqMgr.taggedMetricsHandler)
	for _, opt := range opts {
		opt(pqMgr)
	}
	return pqMgr, nil
}

func (c *physicalTaskQueueManagerImpl) Start() {
	if !atomic.CompareAndSwapInt32(
		&c.status,
		common.DaemonStatusInitialized,
		common.DaemonStatusStarted,
	) {
		return
	}
	c.liveness.Start()
	c.backlogMgr.Start()
	c.logger.Info("", tag.LifeCycleStarted)
	c.taggedMetricsHandler.Counter(metrics.TaskQueueStartedCounter.Name()).Record(1)
	c.partitionMgr.engine.updatePhysicalTaskQueueGauge(c, 1)
}

// Stop does not unload the queue from its partition. It is intended to be called by the partition manager when
// unloading a queues. For stopping and unloading a queue call unloadFromPartitionManager instead.
func (c *physicalTaskQueueManagerImpl) Stop() {
	if !atomic.CompareAndSwapInt32(
		&c.status,
		common.DaemonStatusStarted,
		common.DaemonStatusStopped,
	) {
		return
	}
	c.backlogMgr.Stop()
	c.matcher.Stop()
	c.liveness.Stop()
	c.logger.Info("", tag.LifeCycleStopped)
	c.taggedMetricsHandler.Counter(metrics.TaskQueueStoppedCounter.Name()).Record(1)
	c.partitionMgr.engine.updatePhysicalTaskQueueGauge(c, -1)
}

func (c *physicalTaskQueueManagerImpl) WaitUntilInitialized(ctx context.Context) error {
	return c.backlogMgr.WaitUntilInitialized(ctx)
}

func (c *physicalTaskQueueManagerImpl) SpoolTask(params addTaskParams) error {
	if params.forwardedFrom == "" {
		// request sent by history service
		c.liveness.markAlive()
	}
	return c.backlogMgr.SpoolTask(params.taskInfo)
}

// PollTask blocks waiting for a task.
// Returns error when context deadline is exceeded
// maxDispatchPerSecond is the max rate at which tasks are allowed
// to be dispatched from this task queue to pollers
func (c *physicalTaskQueueManagerImpl) PollTask(
	ctx context.Context,
	pollMetadata *pollMetadata,
) (*internalTask, error) {
	c.liveness.markAlive()

	c.currentPolls.Add(1)
	defer c.currentPolls.Add(-1)

	namespaceEntry, err := c.namespaceRegistry.GetNamespaceByID(c.queue.NamespaceId())
	if err != nil {
		return nil, err
	}

	// the desired global rate limit for the task queue comes from the
	// poller, which lives inside the client side worker. There is
	// one rateLimiter for this entire task queue and as we get polls,
	// we update the ratelimiter rps if it has changed from the last
	// value. Last poller wins if different pollers provide different values
	c.matcher.UpdateRatelimit(pollMetadata.ratePerSecond)

	if !namespaceEntry.ActiveInCluster(c.clusterMeta.GetCurrentClusterName()) {
		return c.matcher.PollForQuery(ctx, pollMetadata)
	}

	for {
		task, err := c.matcher.Poll(ctx, pollMetadata)
		if err != nil {
			return nil, err
		}

		// It's possible to get an expired task here: taskReader checks for expiration when
		// reading from persistence, and physicalTaskQueueManager checks for expiration in
		// ProcessSpooledTask, but the one task blocked in the matcher could expire while it's
		// there. In that case, go back for another task.
		// If we didn't do this, the task would be rejected when we call RecordXTaskStarted on
		// history, but this is more efficient.
		if task.event != nil && IsTaskExpired(task.event.AllocatedTaskInfo) {
			c.taggedMetricsHandler.Counter(metrics.ExpiredTasksPerTaskQueueCounter.Name()).Record(1)
			task.finish(nil)
			continue
		}

		task.namespace = c.partitionMgr.ns.Name()
		task.backlogCountHint = c.backlogMgr.BacklogCountHint
		return task, nil
	}
}

func (c *physicalTaskQueueManagerImpl) MarkAlive() {
	c.liveness.markAlive()
}

// DispatchSpooledTask dispatches a task to a poller. When there are no pollers to pick
// up the task or if rate limit is exceeded, this method will return error. Task
// *will not* be persisted to db
func (c *physicalTaskQueueManagerImpl) DispatchSpooledTask(
	ctx context.Context,
	task *internalTask,
	userDataChanged <-chan struct{},
) error {
	return c.matcher.MustOffer(ctx, task, userDataChanged)
}

func (c *physicalTaskQueueManagerImpl) ProcessSpooledTask(
	ctx context.Context,
	task *internalTask,
) error {
	if !c.taskValidator.maybeValidate(task.event.AllocatedTaskInfo, c.queue.TaskType()) {
		task.finish(nil)
		c.taggedMetricsHandler.Counter(metrics.ExpiredTasksPerTaskQueueCounter.Name()).Record(1)
		// Don't try to set read level here because it may have been advanced already.
		return nil
	}
	return c.partitionMgr.ProcessSpooledTask(ctx, task, c.queue.BuildId())
}

// DispatchQueryTask will dispatch query to local or remote poller. If forwarded then result or error is returned,
// if dispatched to local poller then nil and nil is returned.
func (c *physicalTaskQueueManagerImpl) DispatchQueryTask(
	ctx context.Context,
	taskId string,
	request *matchingservice.QueryWorkflowRequest,
) (*matchingservice.QueryWorkflowResponse, error) {
	task := newInternalQueryTask(taskId, request)
	return c.matcher.OfferQuery(ctx, task)
}

func (c *physicalTaskQueueManagerImpl) DispatchNexusTask(
	ctx context.Context,
	taskId string,
	request *matchingservice.DispatchNexusTaskRequest,
) (*matchingservice.DispatchNexusTaskResponse, error) {
	task := newInternalNexusTask(taskId, request)
	return c.matcher.OfferNexusTask(ctx, task)
}

func (c *physicalTaskQueueManagerImpl) UpdatePollerInfo(id pollerIdentity, pollMetadata *pollMetadata) {
	c.pollerHistory.updatePollerInfo(id, pollMetadata)
}

// GetAllPollerInfo returns all pollers that polled from this taskqueue in last few minutes
func (c *physicalTaskQueueManagerImpl) GetAllPollerInfo() []*taskqueuepb.PollerInfo {
	if c.pollerHistory == nil {
		return nil
	}
	return c.pollerHistory.getPollerInfo(time.Time{})
}

func (c *physicalTaskQueueManagerImpl) HasPollerAfter(accessTime time.Time) bool {
	if c.currentPolls.Load() > 0 {
		return true
	}
	if c.pollerHistory == nil {
		return false
	}
	recentPollers := c.pollerHistory.getPollerInfo(accessTime)
	return len(recentPollers) > 0
}

// LegacyDescribeTaskQueue returns information about the target taskqueue, right now this API returns the
// pollers which polled this taskqueue in last few minutes and status of taskqueue's ackManager
// (readLevel, ackLevel, backlogCountHint and taskIDBlock).
func (c *physicalTaskQueueManagerImpl) LegacyDescribeTaskQueue(includeTaskQueueStatus bool) *matchingservice.DescribeTaskQueueResponse {
	response := &matchingservice.DescribeTaskQueueResponse{
		DescResponse: &workflowservice.DescribeTaskQueueResponse{
			Pollers: c.GetAllPollerInfo(),
		},
	}
	if includeTaskQueueStatus {
		response.DescResponse.TaskQueueStatus = c.backlogMgr.BacklogStatus()
		response.DescResponse.TaskQueueStatus.RatePerSecond = c.matcher.Rate()
	}
	return response
}

func (c *physicalTaskQueueManagerImpl) Describe() *taskqueuespb.PhysicalTaskQueueInfo {
	return &taskqueuespb.PhysicalTaskQueueInfo{
		Pollers: c.GetAllPollerInfo(),
	}
}

func (c *physicalTaskQueueManagerImpl) String() string {
	buf := new(bytes.Buffer)
	if c.queue.TaskType() == enumspb.TASK_QUEUE_TYPE_ACTIVITY {
		buf.WriteString("Activity")
	} else {
		buf.WriteString("Workflow")
	}
	_, _ = fmt.Fprintf(buf, "Backlog=%s\n", c.backlogMgr.String())

	return buf.String()
}

func (c *physicalTaskQueueManagerImpl) TrySyncMatch(ctx context.Context, params addTaskParams) (bool, error) {
	if params.forwardedFrom == "" {
		// request sent by history service
		c.liveness.markAlive()
		if c.config.TestDisableSyncMatch() {
			return false, nil
		}
	}
	childCtx, cancel := newChildContext(ctx, c.config.SyncMatchWaitDuration(), time.Second)
	defer cancel()

	// Use fake TaskId for sync match as it hasn't been allocated yet
	fakeTaskIdWrapper := &persistencespb.AllocatedTaskInfo{
		Data:   params.taskInfo,
		TaskId: syncMatchTaskId,
	}

	task := newInternalTask(fakeTaskIdWrapper, nil, params.source, params.forwardedFrom, true)
	return c.matcher.Offer(childCtx, task)
}

// newChildContext creates a child context with desired timeout.
// if tailroom is non-zero, then child context timeout will be
// the minOf(parentCtx.Deadline()-tailroom, timeout). Use this
// method to create child context when childContext cannot use
// all of parent's deadline but instead there is a need to leave
// some time for parent to do some post-work
func newChildContext(
	parent context.Context,
	timeout time.Duration,
	tailroom time.Duration,
) (context.Context, context.CancelFunc) {
	if parent.Err() != nil {
		return parent, func() {}
	}
	deadline, ok := parent.Deadline()
	if !ok {
		return context.WithTimeout(parent, timeout)
	}
	remaining := time.Until(deadline) - tailroom
	if remaining < timeout {
		timeout = max(0, remaining)
	}
	return context.WithTimeout(parent, timeout)
}

func (c *physicalTaskQueueManagerImpl) QueueKey() *PhysicalTaskQueueKey {
	return c.queue
}

func (c *physicalTaskQueueManagerImpl) newIOContext() (context.Context, context.CancelFunc) {
	ctx, cancel := context.WithTimeout(context.Background(), ioTimeout)
	return c.partitionMgr.callerInfoContext(ctx), cancel
}

func (c *physicalTaskQueueManagerImpl) UnloadFromPartitionManager() {
	c.partitionMgr.unloadPhysicalQueue(c)
}