Support scheduled actions and cancellation (#419)

* Support scheduled actions and cancellation

Support scheduled actions by adding a new queue that actions will be
added to/removed from before they are sent to the dispatcher. The queue
is a priority queue (ordered by start_time). fleet_gateway is
responsible for syncing the queue to storage. Cancellation of an action
will be handled by a new action dispatcher that will remove actions from
the queue (if any) and update the targetID action status.

TODO
- cancel handler
- action expiration
- fleet_gateway tests

* Add queue tests in fleet_gateway_tests, fix check and linting issues

* Force start_time/expiration to be utc

* Remove logic todos, fix logging statement

* Apply suggestions from code review

Co-authored-by: Anderson Queiroz <me@andersonq.me>

Co-authored-by: Anderson Queiroz <me@andersonq.me>

.golangci.yml

@@ -63,7 +63,7 @@ linters:
     - noctx # noctx finds sending http request without context.Context
     - unconvert # Remove unnecessary type conversions
     - wastedassign # wastedassign finds wasted assignment statements.
-    - godox # tool for detection of FIXME, TODO and other comment keywords
+    # - godox # tool for detection of FIXME, TODO and other comment keywords
 
 # all available settings of specific linters
 linters-settings:

CHANGELOG.next.asciidoc

@@ -182,3 +182,4 @@
 - Increase the download artifact timeout to 10mins and add log download statistics. {pull}308[308]
 - Save the agent configuration and the state encrypted on the disk. {issue}535[535] {pull}398[398]
 - Bump node.js version for heartbeat/synthetics to 16.15.0
+- Support scheduled actions and cancellation of pending actions. {issue}393[393] {pull}419[419]

NOTICE.txt

@@ -14073,6 +14073,38 @@ THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 
+--------------------------------------------------------------------------------
+Dependency : github.com/stretchr/objx
+Version: v0.2.0
+Licence type (autodetected): MIT
+--------------------------------------------------------------------------------
+
+Contents of probable licence file $GOMODCACHE/github.com/stretchr/objx@v0.2.0/LICENSE:
+
+The MIT License
+
+Copyright (c) 2014 Stretchr, Inc.
+Copyright (c) 2017-2018 objx contributors
+
+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.
+
+
 --------------------------------------------------------------------------------
 Dependency : github.com/tklauser/go-sysconf
 Version: v0.3.9

go.mod

@@ -109,6 +109,7 @@ require (
 	github.com/sergi/go-diff v1.1.0 // indirect
 	github.com/sirupsen/logrus v1.8.1 // indirect
 	github.com/spf13/pflag v1.0.5 // indirect
+	github.com/stretchr/objx v0.2.0 // indirect
 	github.com/tklauser/go-sysconf v0.3.9 // indirect
 	github.com/tklauser/numcpus v0.3.0 // indirect
 	github.com/yusufpapurcu/wmi v1.2.2 // indirect

go.sum

@@ -1120,6 +1120,7 @@ github.com/stoewer/go-strcase v1.2.0/go.mod h1:IBiWB2sKIp3wVVQ3Y035++gc+knqhUQag
 github.com/stretchr/objx v0.0.0-20180129172003-8a3f7159479f/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/objx v0.1.1/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/objx v0.2.0 h1:Hbg2NidpLE8veEBkEZTL3CvlkUIVzuU9jDplZO54c48=
 github.com/stretchr/objx v0.2.0/go.mod h1:qt09Ya8vawLte6SNmTgCsAVtYtaKzEcn8ATUoHMkEqE=
 github.com/stretchr/testify v0.0.0-20180303142811-b89eecf5ca5d/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
 github.com/stretchr/testify v1.2.1/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=

internal/pkg/agent/application/gateway/fleet/fleet_gateway.go

@@ -6,6 +6,7 @@ package fleet
 
 import (
 	"context"
+	stderr "errors"
 	"fmt"
 	"sync"
 	"time"
@@ -62,6 +63,14 @@ type stateStore interface {
 	AckToken() string
 	SetAckToken(ackToken string)
 	Save() error
+	SetQueue([]fleetapi.Action)
+	Actions() []fleetapi.Action
+}
+
+type actionQueue interface {
+	Add(fleetapi.Action, int64)
+	DequeueActions() []fleetapi.Action
+	Cancel(string) int
 	Actions() []fleetapi.Action
 }
 
@@ -82,6 +91,7 @@ type fleetGateway struct {
 	statusController status.Controller
 	statusReporter   status.Reporter
 	stateStore       stateStore
+	queue            actionQueue
 }
 
 // New creates a new fleet gateway
@@ -95,6 +105,7 @@ func New(
 	acker store.FleetAcker,
 	statusController status.Controller,
 	stateStore stateStore,
+	queue actionQueue,
 ) (gateway.FleetGateway, error) {
 
 	scheduler := scheduler.NewPeriodicJitter(defaultGatewaySettings.Duration, defaultGatewaySettings.Jitter)
@@ -110,6 +121,7 @@ func New(
 		acker,
 		statusController,
 		stateStore,
+		queue,
 	)
 }
 
@@ -125,6 +137,7 @@ func newFleetGatewayWithScheduler(
 	acker store.FleetAcker,
 	statusController status.Controller,
 	stateStore stateStore,
+	queue actionQueue,
 ) (gateway.FleetGateway, error) {
 
 	// Backoff implementation doesn't support the use of a context [cancellation]
@@ -151,13 +164,14 @@ func newFleetGatewayWithScheduler(
 		statusReporter:   statusController.RegisterComponent("gateway"),
 		statusController: statusController,
 		stateStore:       stateStore,
+		queue:            queue,
 	}, nil
 }
 
 func (f *fleetGateway) worker() {
 	for {
 		select {
-		case <-f.scheduler.WaitTick():
+		case ts := <-f.scheduler.WaitTick():
 			f.log.Debug("FleetGateway calling Checkin API")
 
 			// Execute the checkin call and for any errors returned by the fleet-server API
@@ -168,12 +182,27 @@ func (f *fleetGateway) worker() {
 				continue
 			}
 
-			actions := make([]fleetapi.Action, len(resp.Actions))
-			for idx, a := range resp.Actions {
-				actions[idx] = a
+			actions := f.queueScheduledActions(resp.Actions)
+			actions, err = f.dispatchCancelActions(actions)
+			if err != nil {
+				f.log.Error(err.Error())
 			}
 
+			queued, expired := f.gatherQueuedActions(ts.UTC())
+			f.log.Debugf("Gathered %d actions from queue, %d actions expired", len(queued), len(expired))
+			f.log.Debugf("Expired actions: %v", expired)
+
+			actions = append(actions, queued...)
+
 			var errMsg string
+			// Persist state
+			f.stateStore.SetQueue(f.queue.Actions())
+			if err := f.stateStore.Save(); err != nil {
+				errMsg = fmt.Sprintf("failed to persist action_queue, error: %s", err)
+				f.log.Error(errMsg)
+				f.statusReporter.Update(state.Failed, errMsg, nil)
+			}
+
 			if err := f.dispatcher.Dispatch(context.Background(), f.acker, actions...); err != nil {
 				errMsg = fmt.Sprintf("failed to dispatch actions, error: %s", err)
 				f.log.Error(errMsg)
@@ -194,6 +223,60 @@ func (f *fleetGateway) worker() {
 	}
 }
 
+// queueScheduledActions will add any action in actions with a valid start time to the queue and return the rest.
+// start time to current time comparisons are purposefully not made in case of cancel actions.
+func (f *fleetGateway) queueScheduledActions(input fleetapi.Actions) []fleetapi.Action {
+	actions := make([]fleetapi.Action, 0, len(input))
+	for _, action := range input {
+		start, err := action.StartTime()
+		if err == nil {
+			f.log.Debugf("Adding action id: %s to queue.", action.ID())
+			f.queue.Add(action, start.Unix())
+			continue
+		}
+		if !stderr.Is(err, fleetapi.ErrNoStartTime) {
+			f.log.Warnf("Issue gathering start time from action id %s: %v", action.ID(), err)
+		}
+		actions = append(actions, action)
+	}
+	return actions
+}
+
+// dispatchCancelActions will separate and dispatch any cancel actions from the actions list and return the rest of the list.
+// cancel actions are dispatched seperatly as they may remove items from the queue.
+func (f *fleetGateway) dispatchCancelActions(actions []fleetapi.Action) ([]fleetapi.Action, error) {
+	// separate cancel actions from the actions list
+	cancelActions := make([]fleetapi.Action, 0, len(actions))
+	for i := len(actions) - 1; i >= 0; i-- {
+		action := actions[i]
+		if action.Type() == fleetapi.ActionTypeCancel {
+			cancelActions = append(cancelActions, action)
+			actions = append(actions[:i], actions[i+1:]...)
+		}
+	}
+	// Dispatch cancel actions
+	if len(cancelActions) > 0 {
+		if err := f.dispatcher.Dispatch(context.Background(), f.acker, cancelActions...); err != nil {
+			return actions, fmt.Errorf("failed to dispatch cancel actions: %w", err)
+		}
+	}
+	return actions, nil
+}
+
+// gatherQueuedActions will dequeue actions from the action queue and separate those that have already expired.
+func (f *fleetGateway) gatherQueuedActions(ts time.Time) (queued, expired []fleetapi.Action) {
+	actions := f.queue.DequeueActions()
+	for _, action := range actions {
+		exp, _ := action.Expiration()
+		if ts.After(exp) {
+			expired = append(expired, action)
+			continue
+		}
+		queued = append(queued, action)
+	}
+	return queued, expired
+}
+
 func (f *fleetGateway) doExecute() (*fleetapi.CheckinResponse, error) {
 	f.backoff.Reset()