Add message queue trigger support (#218)
Adds support for message queue triggers based on the NATS-Streaming message queue. This lets the user map a queue topic to a function, and optionally send the function's response into another queue topic. The message queue trigger manager is designed to be message queue independent, so we should be able add support for more queues by adding implementations for the relatively simple mqtrigger.MessageQueue interface.
This commit is contained in:
Ta-Ching Chen
committed by
Soam Vasani
Soam Vasani
parent
0fd60eab3b
commit
e4fe007838
@@ -0,0 +1,226 @@
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/*
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Copyright 2016 The Fission Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package messageQueue
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import (
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"errors"
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"time"
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log "github.com/sirupsen/logrus"
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"github.com/fission/fission"
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controllerClient "github.com/fission/fission/controller/client"
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)
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const (
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NATS string = "nats-streaming"
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)
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const (
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ADD_TRIGGER requestType = iota
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DELETE_TRIGGER
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GET_ALL_TRIGGERS
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)
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type (
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messageQueueSubscription interface{}
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requestType int
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MessageQueueConfig struct {
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MQType string
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Url string
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}
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MessageQueue interface {
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subscribe(trigger fission.MessageQueueTrigger) (messageQueueSubscription, error)
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unsubscribe(triggerSub messageQueueSubscription) error
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}
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MessageQueueTriggerManager struct {
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reqChan chan request
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mqCfg MessageQueueConfig
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triggers map[string]*triggerSubscription
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controller *controllerClient.Client
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messageQueue MessageQueue
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}
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triggerSubscription struct {
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fission.Metadata
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funcMeta fission.Metadata
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subscription messageQueueSubscription
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}
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request struct {
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requestType
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triggerSub *triggerSubscription
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respChan chan response
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}
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response struct {
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err error
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triggers *map[string]messageQueueSubscription
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}
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)
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func MakeMessageQueueTriggerManager(ctrlClient *controllerClient.Client,
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routerUrl string, mqConfig MessageQueueConfig) *MessageQueueTriggerManager {
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var messageQueue MessageQueue
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var err error
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mqTriggerMgr := MessageQueueTriggerManager{
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reqChan: make(chan request),
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triggers: make(map[string]*triggerSubscription),
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controller: ctrlClient,
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}
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switch mqConfig.MQType {
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case NATS:
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messageQueue, err = makeNatsMessageQueue(routerUrl, mqConfig)
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default:
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err = errors.New("No matched message queue type found")
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}
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if err != nil {
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log.Fatalf("Failed to connect to remote message queue server: %v", err)
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}
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mqTriggerMgr.messageQueue = messageQueue
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go mqTriggerMgr.service()
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go mqTriggerMgr.syncTriggers()
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return &mqTriggerMgr
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}
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func (mqt *MessageQueueTriggerManager) service() {
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for {
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req := <-mqt.reqChan
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switch req.requestType {
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case ADD_TRIGGER:
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var err error
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triggerUid := req.triggerSub.Uid
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if _, ok := mqt.triggers[triggerUid]; ok {
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err = errors.New("Trigger already exists")
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} else {
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mqt.triggers[triggerUid] = req.triggerSub
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}
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req.respChan <- response{err: err}
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case GET_ALL_TRIGGERS:
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copyTriggers := make(map[string]messageQueueSubscription)
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for key, val := range mqt.triggers {
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copyTriggers[key] = val
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}
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req.respChan <- response{triggers: ©Triggers}
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case DELETE_TRIGGER:
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triggerUid := req.triggerSub.Uid
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delete(mqt.triggers, triggerUid)
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}
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}
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}
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func (mqt *MessageQueueTriggerManager) addTrigger(triggerSub *triggerSubscription) error {
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respChan := make(chan response)
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mqt.reqChan <- request{
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requestType: ADD_TRIGGER,
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triggerSub: triggerSub,
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respChan: respChan,
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}
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r := <-respChan
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return r.err
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}
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func (mqt *MessageQueueTriggerManager) getAllTriggers() *map[string]messageQueueSubscription {
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respChan := make(chan response)
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mqt.reqChan <- request{
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requestType: GET_ALL_TRIGGERS,
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respChan: respChan,
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}
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r := <-respChan
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return r.triggers
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}
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func (mqt *MessageQueueTriggerManager) delTrigger(triggerUid string) {
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mqt.reqChan <- request{
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requestType: DELETE_TRIGGER,
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triggerSub: &triggerSubscription{
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Metadata: fission.Metadata{
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Uid: triggerUid,
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},
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},
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}
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}
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func (mqt *MessageQueueTriggerManager) syncTriggers() {
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for {
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// TODO: handle error
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newTriggers, err := mqt.controller.MessageQueueTriggerList(mqt.mqCfg.MQType)
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if err != nil {
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log.Warnf("Failed to sync message queue trigger from controller: %v", err)
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}
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// sync trigger from controller
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newTriggerMap := map[string]fission.MessageQueueTrigger{}
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for _, trigger := range newTriggers {
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newTriggerMap[trigger.Uid] = trigger
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}
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currentTriggerSubMap := mqt.getAllTriggers()
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// register new triggers
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for key, trigger := range newTriggerMap {
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if _, ok := (*currentTriggerSubMap)[key]; ok {
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continue
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}
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sub, err := mqt.messageQueue.subscribe(trigger)
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if err != nil {
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log.Warnf("Message queue trigger %s created failed: %v", trigger.Name, err)
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continue
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}
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triggerSub := triggerSubscription{
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Metadata: fission.Metadata{
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Name: trigger.Name,
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Uid: trigger.Uid,
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},
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funcMeta: trigger.Function,
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subscription: sub,
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}
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err = mqt.addTrigger(&triggerSub)
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if err != nil {
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log.Warnf("Message queue trigger %s created failed: %v", trigger.Name, err)
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continue
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}
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log.Infof("Message queue trigger %s created", trigger.Name)
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}
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// remove old triggers
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for _, ts := range *currentTriggerSubMap {
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triggerSub := ts.(*triggerSubscription)
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if _, ok := newTriggerMap[triggerSub.Uid]; ok {
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continue
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}
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if err := mqt.messageQueue.unsubscribe(triggerSub.subscription); err != nil {
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log.Warnf("Message queue trigger %s deleted failed: %v", triggerSub.Name, err)
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} else {
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mqt.delTrigger(triggerSub.Uid)
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log.Infof("Message queue trigger %s deleted", triggerSub.Name)
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}
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}
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time.Sleep(3 * time.Second)
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}
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}
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func IsTopicValid(mqType string, topic string) bool {
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switch mqType {
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case NATS:
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return isTopicValidForNats(topic)
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}
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return false
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}
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@@ -0,0 +1,136 @@
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/*
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Copyright 2016 The Fission Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package messageQueue
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import (
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"bytes"
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"errors"
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"fmt"
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"io/ioutil"
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"net/http"
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"strings"
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ns "github.com/nats-io/go-nats-streaming"
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nsUtil "github.com/nats-io/nats-streaming-server/util"
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log "github.com/sirupsen/logrus"
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"github.com/fission/fission"
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)
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const (
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natsClusterID = "fissionMQTrigger"
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natsProtocol = "nats://"
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natsClientID = "fission"
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natsQueueGroup = "fission-messageQueueNatsTrigger"
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)
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type (
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Nats struct {
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nsConn ns.Conn
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routerUrl string
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}
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)
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func makeNatsMessageQueue(routerUrl string, mqCfg MessageQueueConfig) (MessageQueue, error) {
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conn, err := ns.Connect(natsClusterID, natsClientID, ns.NatsURL(mqCfg.Url))
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if err != nil {
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return nil, err
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}
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nats := Nats{
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nsConn: conn,
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routerUrl: routerUrl,
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}
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return nats, nil
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}
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func (nats Nats) subscribe(trigger fission.MessageQueueTrigger) (messageQueueSubscription, error) {
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subj := trigger.Topic
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if !isTopicValidForNats(subj) {
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return nil, errors.New(fmt.Sprintf("Not a valid topic: %s", trigger.Topic))
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}
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opts := []ns.SubscriptionOption{
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// Create a durable subscription to nats, so that triggers could retrieve last unack message.
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// https://github.com/nats-io/go-nats-streaming#durable-subscriptions
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ns.DurableName(trigger.Uid),
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// Nats-streaming server is auto-ack mode by default. Since we want nats-streaming server to
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// resend a message if the trigger does not ack it, we need to enable the manual ack mode, so that
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// trigger could choose to ack message or simply drop it depend on the response of function pod.
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ns.SetManualAckMode(),
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}
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sub, err := nats.nsConn.Subscribe(subj, msgHandler(&nats, trigger), opts...)
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if err != nil {
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return nil, err
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}
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return sub, nil
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}
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func (nats Nats) unsubscribe(subscription messageQueueSubscription) error {
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return subscription.(ns.Subscription).Close()
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}
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func isTopicValidForNats(topic string) bool {
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// nats-streaming does not support wildcard channel.
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return nsUtil.IsSubjectValid(topic)
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}
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func msgHandler(nats *Nats, trigger fission.MessageQueueTrigger) func(*ns.Msg) {
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return func(msg *ns.Msg) {
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url := nats.routerUrl + "/" + strings.TrimPrefix(fission.UrlForFunction(&trigger.Function), "/")
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log.Printf("Making HTTP request to %v", url)
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headers := map[string]string{
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"X-Fission-MQTrigger-Topic": trigger.Topic,
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"X-Fission-MQTrigger-RespTopic": trigger.ResponseTopic,
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}
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// Create request
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req, err := http.NewRequest("POST", url, bytes.NewReader(msg.Data))
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for k, v := range headers {
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req.Header.Add(k, v)
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}
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// Make the request
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resp, err := http.DefaultClient.Do(req)
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if err != nil {
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log.Warningf("Request failed: %v", url)
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return
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}
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defer resp.Body.Close()
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body, err := ioutil.ReadAll(resp.Body)
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if err != nil {
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log.Warningf("Request body error: %v", string(body))
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return
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}
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if resp.StatusCode != 200 {
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log.Printf("Request returned failure: %v", resp.StatusCode)
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return
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}
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// trigger acks message only if a request done successfully
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err = msg.Ack()
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if err != nil {
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log.Warningf("Failed to ack message: %v", err)
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}
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err = nats.nsConn.Publish(trigger.ResponseTopic, body)
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if err != nil {
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log.Warningf("Failed to publish message to topic %s: %v", trigger.ResponseTopic, err)
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}
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}
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}
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