Add RabbitMQ pub/sub (#124)

* Add RabbitMQ pub/sub

* Fix lint error (global variable)

* RabbitMQ pub/sub auto ack defaults to false
Fix log message incorrect prefix

* Remove extra line in go.mod

* Revert extra line in go.mod
This commit is contained in:
Francisco Beltrao 2019-11-27 19:37:09 +01:00 committed by Yaron Schneider
parent e644714b17
commit 9e78671fc0
5 changed files with 498 additions and 0 deletions

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@ -7,6 +7,7 @@ Currently supported pub-subs are:
* Redis Streams
* NATS
* Azure Service Bus
* RabbitMQ
## Implementing a new Pub Sub

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@ -0,0 +1,70 @@
package rabbitmq
import (
"fmt"
"strconv"
"github.com/dapr/components-contrib/pubsub"
)
type metadata struct {
consumerID string
host string
durable bool
deleteWhenUnused bool
autoAck bool
requeueInFailure bool
deliveryMode uint8 // Transient (0 or 1) or Persistent (2)
}
// createMetadata creates a new instance from the pubsub metadata
func createMetadata(pubSubMetadata pubsub.Metadata) (*metadata, error) {
result := metadata{deleteWhenUnused: true, autoAck: false}
if val, found := pubSubMetadata.Properties[metadataHostKey]; found && val != "" {
result.host = val
} else {
return &result, fmt.Errorf("%s missing RabbitMQ host", errorMessagePrefix)
}
if val, found := pubSubMetadata.Properties[metadataConsumerIDKey]; found && val != "" {
result.consumerID = val
} else {
return &result, fmt.Errorf("%s missing RabbitMQ consumerID", errorMessagePrefix)
}
if val, found := pubSubMetadata.Properties[metadataDeliveryModeKey]; found && val != "" {
if intVal, err := strconv.Atoi(val); err == nil {
if intVal < 0 || intVal > 2 {
return &result, fmt.Errorf("%s invalid RabbitMQ delivery mode, accepted values are between 0 and 2", errorMessagePrefix)
}
result.deliveryMode = uint8(intVal)
}
}
if val, found := pubSubMetadata.Properties[metadataDurableKey]; found && val != "" {
if boolVal, err := strconv.ParseBool(val); err == nil {
result.durable = boolVal
}
}
if val, found := pubSubMetadata.Properties[metadataDeleteWhenUnusedKey]; found && val != "" {
if boolVal, err := strconv.ParseBool(val); err == nil {
result.deleteWhenUnused = boolVal
}
}
if val, found := pubSubMetadata.Properties[metadataAutoAckKey]; found && val != "" {
if boolVal, err := strconv.ParseBool(val); err == nil {
result.autoAck = boolVal
}
}
if val, found := pubSubMetadata.Properties[metadataRequeueInFailureKey]; found && val != "" {
if boolVal, err := strconv.ParseBool(val); err == nil {
result.requeueInFailure = boolVal
}
}
return &result, nil
}

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@ -0,0 +1,207 @@
package rabbitmq
import (
"fmt"
"testing"
"github.com/dapr/components-contrib/pubsub"
"github.com/stretchr/testify/assert"
)
func getFakeProperties() map[string]string {
props := map[string]string{}
props[metadataHostKey] = "fakehost"
props[metadataConsumerIDKey] = "fakeConsumerID"
return props
}
func TestCreateMetadata(t *testing.T) {
var booleanFlagTests = []struct {
in string
expected bool
}{
{"true", true},
{"TRUE", true},
{"false", false},
{"FALSE", false},
}
t.Run("metadata is correct", func(t *testing.T) {
fakeProperties := getFakeProperties()
fakeMetaData := pubsub.Metadata{
Properties: fakeProperties,
}
// act
m, err := createMetadata(fakeMetaData)
// assert
assert.NoError(t, err)
assert.Equal(t, fakeProperties[metadataHostKey], m.host)
assert.Equal(t, fakeProperties[metadataConsumerIDKey], m.consumerID)
assert.Equal(t, false, m.durable)
assert.Equal(t, false, m.autoAck)
assert.Equal(t, false, m.requeueInFailure)
assert.Equal(t, true, m.deleteWhenUnused)
assert.Equal(t, uint8(0), m.deliveryMode)
})
t.Run("host is not given", func(t *testing.T) {
fakeProperties := getFakeProperties()
fakeMetaData := pubsub.Metadata{
Properties: fakeProperties,
}
fakeMetaData.Properties[metadataHostKey] = ""
// act
m, err := createMetadata(fakeMetaData)
// assert
assert.EqualError(t, err, "rabbitmq pub/sub error: missing RabbitMQ host")
assert.Empty(t, m.host)
assert.Empty(t, m.consumerID)
})
t.Run("consumerID is not given", func(t *testing.T) {
fakeProperties := getFakeProperties()
fakeMetaData := pubsub.Metadata{
Properties: fakeProperties,
}
fakeMetaData.Properties[metadataConsumerIDKey] = ""
// act
m, err := createMetadata(fakeMetaData)
// assert
assert.EqualError(t, err, "rabbitmq pub/sub error: missing RabbitMQ consumerID")
assert.Equal(t, fakeProperties[metadataHostKey], m.host)
assert.Equal(t, fakeProperties[metadataConsumerIDKey], m.consumerID)
assert.Empty(t, m.consumerID)
})
var invalidDeliveryModes = []string{"3", "10", "-1"}
for _, deliveryMode := range invalidDeliveryModes {
t.Run(fmt.Sprintf("deliveryMode value=%s", deliveryMode), func(t *testing.T) {
fakeProperties := getFakeProperties()
fakeMetaData := pubsub.Metadata{
Properties: fakeProperties,
}
fakeMetaData.Properties[metadataDeliveryModeKey] = deliveryMode
// act
m, err := createMetadata(fakeMetaData)
// assert
assert.EqualError(t, err, "rabbitmq pub/sub error: invalid RabbitMQ delivery mode, accepted values are between 0 and 2")
assert.Equal(t, fakeProperties[metadataHostKey], m.host)
assert.Equal(t, fakeProperties[metadataConsumerIDKey], m.consumerID)
assert.Equal(t, uint8(0), m.deliveryMode)
})
}
t.Run("deliveryMode is set", func(t *testing.T) {
fakeProperties := getFakeProperties()
fakeMetaData := pubsub.Metadata{
Properties: fakeProperties,
}
fakeMetaData.Properties[metadataDeliveryModeKey] = "2"
// act
m, err := createMetadata(fakeMetaData)
// assert
assert.NoError(t, err)
assert.Equal(t, fakeProperties[metadataHostKey], m.host)
assert.Equal(t, fakeProperties[metadataConsumerIDKey], m.consumerID)
assert.Equal(t, uint8(2), m.deliveryMode)
})
for _, tt := range booleanFlagTests {
t.Run(fmt.Sprintf("autoAck value=%s", tt.in), func(t *testing.T) {
fakeProperties := getFakeProperties()
fakeMetaData := pubsub.Metadata{
Properties: fakeProperties,
}
fakeMetaData.Properties[metadataAutoAckKey] = tt.in
// act
m, err := createMetadata(fakeMetaData)
// assert
assert.NoError(t, err)
assert.Equal(t, fakeProperties[metadataHostKey], m.host)
assert.Equal(t, fakeProperties[metadataConsumerIDKey], m.consumerID)
assert.Equal(t, tt.expected, m.autoAck)
})
}
for _, tt := range booleanFlagTests {
t.Run(fmt.Sprintf("requeueInFailure value=%s", tt.in), func(t *testing.T) {
fakeProperties := getFakeProperties()
fakeMetaData := pubsub.Metadata{
Properties: fakeProperties,
}
fakeMetaData.Properties[metadataRequeueInFailureKey] = tt.in
// act
m, err := createMetadata(fakeMetaData)
// assert
assert.NoError(t, err)
assert.Equal(t, fakeProperties[metadataHostKey], m.host)
assert.Equal(t, fakeProperties[metadataConsumerIDKey], m.consumerID)
assert.Equal(t, tt.expected, m.requeueInFailure)
})
}
for _, tt := range booleanFlagTests {
t.Run(fmt.Sprintf("deleteWhenUnused value=%s", tt.in), func(t *testing.T) {
fakeProperties := getFakeProperties()
fakeMetaData := pubsub.Metadata{
Properties: fakeProperties,
}
fakeMetaData.Properties[metadataDeleteWhenUnusedKey] = tt.in
// act
m, err := createMetadata(fakeMetaData)
// assert
assert.NoError(t, err)
assert.Equal(t, fakeProperties[metadataHostKey], m.host)
assert.Equal(t, fakeProperties[metadataConsumerIDKey], m.consumerID)
assert.Equal(t, tt.expected, m.deleteWhenUnused)
})
}
for _, tt := range booleanFlagTests {
t.Run(fmt.Sprintf("durable value=%s", tt.in), func(t *testing.T) {
fakeProperties := getFakeProperties()
fakeMetaData := pubsub.Metadata{
Properties: fakeProperties,
}
fakeMetaData.Properties[metadataDurableKey] = tt.in
// act
m, err := createMetadata(fakeMetaData)
// assert
assert.NoError(t, err)
assert.Equal(t, fakeProperties[metadataHostKey], m.host)
assert.Equal(t, fakeProperties[metadataConsumerIDKey], m.consumerID)
assert.Equal(t, tt.expected, m.durable)
})
}
}

175
pubsub/rabbitmq/rabbitmq.go Normal file
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@ -0,0 +1,175 @@
package rabbitmq
import (
"fmt"
log "github.com/Sirupsen/logrus"
"github.com/dapr/components-contrib/pubsub"
"github.com/streadway/amqp"
)
const (
fanoutExchangeKind = "fanout"
logMessagePrefix = "rabbitmq pub/sub:"
errorMessagePrefix = "rabbitmq pub/sub error:"
metadataHostKey = "host"
metadataConsumerIDKey = "consumerID"
metadataDurableKey = "durable"
metadataDeleteWhenUnusedKey = "deletedWhenUnused"
metadataAutoAckKey = "autoAck"
metadataDeliveryModeKey = "deliveryMode"
metadataRequeueInFailureKey = "requeueInFailure"
)
// RabbitMQ allows sending/receiving messages in pub/sub format
type rabbitMQ struct {
connection *amqp.Connection
channel *amqp.Channel
metadata *metadata
declaredExchanges map[string]bool
}
// NewRabbitMQ creates a new RabbitMQ pub/sub
func NewRabbitMQ() pubsub.PubSub {
return createRabbitMQ()
}
func createRabbitMQ() *rabbitMQ {
return &rabbitMQ{declaredExchanges: make(map[string]bool)}
}
// Init does metadata parsing and connection creation
func (r *rabbitMQ) Init(metadata pubsub.Metadata) error {
meta, err := createMetadata(metadata)
if err != nil {
return err
}
r.metadata = meta
conn, err := amqp.Dial(meta.host)
if err != nil {
return err
}
ch, err := conn.Channel()
if err != nil {
return err
}
r.connection = conn
r.channel = ch
return nil
}
func (r *rabbitMQ) Publish(req *pubsub.PublishRequest) error {
err := r.ensureExchangeDeclared(req.Topic)
if err != nil {
return err
}
log.Debugf("%s publishing message to topic '%s'", logMessagePrefix, req.Topic)
err = r.channel.Publish(req.Topic, "", false, false, amqp.Publishing{
ContentType: "text/plain",
Body: req.Data,
DeliveryMode: r.metadata.deliveryMode,
})
if err != nil {
return err
}
return nil
}
func (r *rabbitMQ) Subscribe(req pubsub.SubscribeRequest, handler func(msg *pubsub.NewMessage) error) error {
err := r.ensureExchangeDeclared(req.Topic)
if err != nil {
return err
}
queueName := fmt.Sprintf("%s-%s", r.metadata.consumerID, req.Topic)
log.Debugf("%s declaring queue '%s'", logMessagePrefix, queueName)
q, err := r.channel.QueueDeclare(queueName, r.metadata.durable, r.metadata.deleteWhenUnused, true, false, nil)
if err != nil {
return err
}
log.Debugf("%s binding queue '%s' to exchange '%s'", logMessagePrefix, q.Name, req.Topic)
err = r.channel.QueueBind(q.Name, "", req.Topic, false, nil)
if err != nil {
return err
}
msgs, err := r.channel.Consume(
q.Name,
queueName, // consumerId
r.metadata.autoAck, // autoAck
!r.metadata.durable, // exclusive
false, // noLocal
false, // noWait
nil,
)
if err != nil {
return err
}
go r.listenMessages(msgs, req.Topic, handler)
return nil
}
func (r *rabbitMQ) listenMessages(msgs <-chan amqp.Delivery, topic string, handler func(msg *pubsub.NewMessage) error) {
for d := range msgs {
r.handleMessage(d, topic, handler)
}
}
func (r *rabbitMQ) handleMessage(d amqp.Delivery, topic string, handler func(msg *pubsub.NewMessage) error) {
pubsubMsg := &pubsub.NewMessage{
Data: d.Body,
Topic: topic,
}
err := handler(pubsubMsg)
if err != nil {
log.Errorf("%s error handling message from topic '%s', %s", logMessagePrefix, topic, err)
}
// if message is not auto acked we need to ack/nack
if !r.metadata.autoAck {
if err != nil {
requeue := r.metadata.requeueInFailure && !d.Redelivered
log.Debugf("%s nacking message '%s' from topic '%s', requeue=%t", logMessagePrefix, d.MessageId, topic, requeue)
if err = r.channel.Nack(d.DeliveryTag, false, requeue); err != nil {
log.Errorf("%s error nacking message '%s' from topic '%s', %s", logMessagePrefix, d.MessageId, topic, err)
}
} else {
log.Debugf("%s acking message '%s' from topic '%s'", logMessagePrefix, d.MessageId, topic)
if err = r.channel.Ack(d.DeliveryTag, false); err != nil {
log.Errorf("%s error acking message '%s' from topic '%s', %s", logMessagePrefix, d.MessageId, topic, err)
}
}
}
}
func (r *rabbitMQ) ensureExchangeDeclared(exchange string) error {
if _, exists := r.declaredExchanges[exchange]; !exists {
log.Debugf("%s declaring exchange '%s' of kind '%s'", logMessagePrefix, exchange, fanoutExchangeKind)
err := r.channel.ExchangeDeclare(exchange, fanoutExchangeKind, true, false, false, false, nil)
if err != nil {
return err
}
r.declaredExchanges[exchange] = true
}
return nil
}

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@ -0,0 +1,45 @@
package rabbitmq
import (
"testing"
"github.com/dapr/components-contrib/pubsub"
"github.com/streadway/amqp"
"github.com/stretchr/testify/assert"
)
func createAmqpMessage(body string) amqp.Delivery {
return amqp.Delivery{Body: []byte(body)}
}
func TestProcessSubscriberMessage(t *testing.T) {
testMetadata := &metadata{autoAck: true}
testRabbitMQSubscriber := createRabbitMQ()
testRabbitMQSubscriber.metadata = testMetadata
const topic = "testTopic"
ch := make(chan amqp.Delivery)
defer close(ch)
messageCount := 0
fakeHandler := func(msg *pubsub.NewMessage) error {
messageCount++
assert.Equal(t, topic, msg.Topic)
assert.NotNil(t, msg.Data)
return nil
}
go testRabbitMQSubscriber.listenMessages(ch, topic, fakeHandler)
assert.Equal(t, messageCount, 0)
ch <- createAmqpMessage("{ \"msg\": \"1\"}")
ch <- createAmqpMessage("{ \"msg\": \"2\"}")
assert.GreaterOrEqual(t, messageCount, 1)
assert.LessOrEqual(t, messageCount, 2)
ch <- createAmqpMessage("{ \"msg\": \"3\"}")
assert.GreaterOrEqual(t, messageCount, 2)
assert.LessOrEqual(t, messageCount, 3)
}