1. Micro on NATS
Microservices with messaging

2. Who am I?
Asim Aslam
Working on Micro
Previously at Hailo
Before then Google
@chuhnk
asimaslam.com

3. What is Micro?
A microservice ecosystem
Simplifying building and managing distributed systems
What does that even mean?
Building OSS tools that make it easier to write and run micro service applications
Written in Go
100% Open Source

4. Micro A Microservice Toolkit
Go Micro - Pluggable RPC framework for writing microservices
API - API gateway. Translates HTTP to RPC. Path-to-Service resolution
Web - Dashboard and reverse proxy. Web apps as first class citizens
CLI - Command line interface. Straight forward. No frills.
Sidecar - HTTP interface with all the features of Go Micro
Bot - Hubot style bot for ChatOps. CLI Features. A bot? Really? Yea dude!

5. Go Micro RPC Framework
Registry - Service Discovery
Selector - Client side load balancer
Transport - Synchronous Communication
Broker - Asynchronous Communication
Codec - Message encoding
Client - RPC Client
Server - RPC Server

6. Why NATS?
Built for high performance and scale
Highly available - client and server side clustering
Extremely lightweight - written in Go, no persistence features
At most once delivery - fire and forget
Simple, focused and made for microservices
Written by Derek Collison, with two decades of experience building messaging systems

7. Micro on NATS NATS Plugins
Go-Micro has a pluggable architecture
Each feature written as a Go interface. Just implement the interface.
Integrate NATS using plugins for:
Registry - Service Discovery
Transport - Synchronous Communication
Broker - Asynchronous Communication

8. Transport Synchronous Communication
Handles request-response
Supports bidirectional streaming
Socket style semantics; Send(), Recv(), Close()
type Transport interface {
Dial(addr string, opts ...DialOption) (Client, error)
Listen(addr string, opts ...ListenOption) (Listener, error)
String() string
}

9. Transport
1. Server Listen - Subscribes to unique topic, wait for pseudo connections
2. Client Dial - Subscribes to unique topic, publishes to Server with reply topic set
3. Server Socket - Pseudo Socket created for every new “connection”
4. Client Socket - Same as server. Send() - Publish, Recv() - Subscribed messages

10. Broker Asynchronous Communication
Publish and Subscribe mechanism
Includes notion of Topics and Channels (Queues)
Distribute messages between subscribers
type Broker interface {
….
Connect() error
Disconnect() error
Publish(string, *Message, ...PublishOption) error
Subscribe(string, Handler, ...SubscribeOption) (Subscriber, error)
String() string
}

11. Broker
1. Subscribe - Register interest to Topic. Specify Queue to distribute messages
2. Publish - Asynchronously publish to Topic
3. Encoding - Broker encodes Message to JSON

12. Registry Service Discovery
Service discovery using a message bus? What magic is this?
type Registry interface {
Register(*Service, ...RegisterOption) error
Deregister(*Service) error
GetService(string) ([]*Service, error)
ListServices() ([]*Service, error)
Watch() (Watcher, error)
String() string
}

13. Broadcast Queries!
1. All services subscribe for queries on a broadcast topic
2. Publish query on broadcast topic with reply address
3. Instances of queried service respond
4. Wait for responses until upper time limit
5. Aggregate and return results

14. Scaling Like A Boss
Cluster per AZ or Region
Multi-AZ deployment
Fault tolerant of AZ failure
Pattern for high availability
Multi-region deployment
Use DNS latency based routing

15. Thanks for listening!
Micro on NATS blog post
blog.micro.mu/2016/04/11/micro-on-nats.html
Micro on GitHub Follow on Twitter!
github.com/micro @MicroHQ
Micro on Web Join the Slack community!
micro.mu slack.micro.mu