sqs

README

SQS Broker Plugin for go-micro

Amazon Simple Queue Service broker plugin for go-micro allows you to publish and subscribe messages brokered by SQS. This plugin does not (yet) support automatic creation of queues so those will have to exist in your infrastructure before attempting to send/receive.

AWS Credentials

This plugin uses the official Go SDK for AWS. As such, it will obtain AWS credentials the same way all other aws-go-sdk applications do. The plugin explicitly allows the use of the shared credentials file to make development on workstations easier, but you can also supply the usual AWS_* environment variables in dev/test/prod environments. Also if you're deploying in EC2/ECS, the IAM Role will be picked up automatically and you won't need to supply any credentials.

Publishing and Subscribing

Publishing and subscribing with the plugin should work just like all other brokers. Simply supply the name of the queue in the publish or subscribe arguments:

broker.Publish("queue.fifo", msg)
...
broker.Subscribe("queue.fifo", subscriberFunc)

Options

If you're using a regular (non-fifo) queue you should be able to get by without having to supply any special options. However, if you need to specify a group identifier for a message or a de-duplication identifier, then you'll have to specify a generator function for those. These are both mandatory when using FIFO queues.

Generator Functions

To specify generator functions for the broker, you add them as options as shown:

cmd.Init()

if err := broker.Init(
    sqs.DeduplicationFunction(dedup),
    sqs.GroupIDFunction(groupid),
); err != nil {
    // handle failure
}

These are both functions that accept a pointer to a broker.Message as input and return a string in response:

func dedup(m *broker.Message) string {

}
func groupid(m *broker.Message) string {

}

How you choose to generate group IDs and deduplication IDs is entirely up to you, though the easiest way is to simply store those identifiers in the message header and then return them in the generator function:

return m.Header["dedupid"]

This plugin is under active development and will likely get more configurable options and features in the near future.

Documentation

Index

• func Client(c *sqs.SQS) broker.Option
• func DeduplicationFunction(dedup StringFromMessageFunc) broker.Option
• func GroupIDFunction(groupfunc StringFromMessageFunc) broker.Option
• func MaxReceiveMessages(max int64) broker.SubscribeOption
• func NewBroker(opts ...broker.Option) broker.Broker
• func VisibilityTimeout(seconds int64) broker.SubscribeOption
• func WaitTimeSeconds(seconds int64) broker.SubscribeOption
• type StringFromMessageFunc

Functions

func Client

func Client(c *sqs.SQS) broker.Option

Client receives an instantiated instance of an SQS client which is used instead of initialising a new client

func DeduplicationFunction

func DeduplicationFunction(dedup StringFromMessageFunc) broker.Option

DeduplicationFunction sets the function used to create the deduplication string for a given message

func GroupIDFunction

func GroupIDFunction(groupfunc StringFromMessageFunc) broker.Option

GroupIDFunction sets the function used to create the group ID string for a given message

func MaxReceiveMessages

func MaxReceiveMessages(max int64) broker.SubscribeOption

MaxReceiveMessages indicates how many messages a receive operation should pull during any single call

func NewBroker

func NewBroker(opts ...broker.Option) broker.Broker

NewBroker creates a new broker with options

func VisibilityTimeout

func VisibilityTimeout(seconds int64) broker.SubscribeOption

VisibilityTimeout controls how long a message is hidden from other queue consumers before being put back. If a consumer does not delete the message, it will be put back even if it was "processed"

func WaitTimeSeconds

func WaitTimeSeconds(seconds int64) broker.SubscribeOption

WaitTimeSeconds controls the length of long polling for available messages

Types

type StringFromMessageFunc

type StringFromMessageFunc func(m *broker.Message) string