Downloaded 73 times
![4 . 14
GO
nc, err := nats.Connect()
// ...
nc.Subscribe("hello", func(m *nats.Msg){
fmt.Printf("[Received] %s", m.Data)
})
nc.Publish("hello", []byte("world"))](https://image.slidesharecdn.com/docker-nats-meetup-talk-161013184020/85/Simple-and-Scalable-Microservices-Using-NATS-with-Docker-Compose-and-Swarm-17-320.jpg)
![4 . 15
RUBY
require 'nats/client'
NATS.start do |nc|
nc.subscribe("hello") do |msg|
puts "[Received] #{msg}"
end
nc.publish("hello", "world")
end](https://image.slidesharecdn.com/docker-nats-meetup-talk-161013184020/85/Simple-and-Scalable-Microservices-Using-NATS-with-Docker-Compose-and-Swarm-18-320.jpg)
![4 . 16
PYTHON (ASYNCIO)
yield from nc.connect()
@asyncio.coroutine
def handler(msg):
print("[Received] {data}".format(
data=msg.data.decode()))
# Coroutine based subscriber
yield from nc.subscribe("foo", cb=handler)
yield from nc.publish("foo", "bar")](https://image.slidesharecdn.com/docker-nats-meetup-talk-161013184020/85/Simple-and-Scalable-Microservices-Using-NATS-with-Docker-Compose-and-Swarm-19-320.jpg)
![4 . 17
NODE.JS
var nats = require('nats').connect();
// Simple Publisher
nats.publish('foo', 'Hello World!');
// Simple Subscriber
nats.subscribe('foo', function(msg) {
console.log('[Received] ' + msg);
});](https://image.slidesharecdn.com/docker-nats-meetup-talk-161013184020/85/Simple-and-Scalable-Microservices-Using-NATS-with-Docker-Compose-and-Swarm-20-320.jpg)
![4 . 18
C
natsConnection_Publish(nc,"foo",data,5);
natsConnection_Subscribe(&sub,nc,"foo",onMsg, NULL);
void
onMsg(natsConnection *nc, natsSubscription *sub,
natsMsg *msg, void *closure)
{
printf("[Received] %.*sn",
natsMsg_GetData(msg));
// ...
}](https://image.slidesharecdn.com/docker-nats-meetup-talk-161013184020/85/Simple-and-Scalable-Microservices-Using-NATS-with-Docker-Compose-and-Swarm-21-320.jpg)
![4 . 19
C#
using (ISyncSubscription s = c.SubscribeSync("foo"))
{
for (int i = 0; i < 10; i++)
{
Msg m = s.NextMessage();
System.Console.WriteLine("[Received] " + m);
}
}](https://image.slidesharecdn.com/docker-nats-meetup-talk-161013184020/85/Simple-and-Scalable-Microservices-Using-NATS-with-Docker-Compose-and-Swarm-22-320.jpg)
![4 . 20
JAVA
// Simple Publisher
nc.publish("foo", "Hello World".getBytes());
// Simple Async Subscriber
nc.subscribe("foo", m -> {
System.out.println("[Received] %sn",
new String(m.getData()));
});](https://image.slidesharecdn.com/docker-nats-meetup-talk-161013184020/85/Simple-and-Scalable-Microservices-Using-NATS-with-Docker-Compose-and-Swarm-23-320.jpg)
![5 . 6
REQUEST/REPLY
NATS clients libraries have helpers for generating the unique
inboxes which act as ephemeral subscriptions:
nats.NewInbox()
// _INBOX.y1JxglDi76shQQIhPbTDme
Used internally when making a Request:
nc, _ := nats.Connect(nats.DefaultURL)
t := 250*time.Millisecond
// Request sets to AutoUnsubscribe after 1 response
msg, err := nc.Request("help", []byte("please"), t)
if err == nil {
fmt.Println(string(msg.Data))
// => I can help!
}](https://image.slidesharecdn.com/docker-nats-meetup-talk-161013184020/85/Simple-and-Scalable-Microservices-Using-NATS-with-Docker-Compose-and-Swarm-37-320.jpg)
![5 . 14
DISTRIBUTION QUEUES
Service A workers subscribe to service.Aand create
workersdistribution queue group for balancing the work.
nc, _ := nats.Connect(nats.DefaultURL)
// SUB service.A workers 1rn
nc.QueueSubscribe("service.A", "workers",
func(m *nats.Msg) {
nc.Publish(m.Reply, []byte("hi!"))
})](https://image.slidesharecdn.com/docker-nats-meetup-talk-161013184020/85/Simple-and-Scalable-Microservices-Using-NATS-with-Docker-Compose-and-Swarm-45-320.jpg)
![5 . 35
SUBJECTS AUTHORIZATION
PubSub on certain subjects can be disallowed in the server's
configuration:
authorization {
admin = { publish = ">", subscribe = ">" }
requestor = {
publish = ["req.foo", "req.bar"]
subscribe = "_INBOX.*"
}
users = [
{user: alice, password: foo, permissions: $admin}
{user: bob, password: bar, permissions: $requestor}
]
}](https://image.slidesharecdn.com/docker-nats-meetup-talk-161013184020/85/Simple-and-Scalable-Microservices-Using-NATS-with-Docker-Compose-and-Swarm-66-320.jpg)
![6 . 4
FIRST STEP: COMPILE
github.com/nats-io/gnatsd/Dockerfile
FROM golang:1.6.3
MAINTAINER Derek Collison ＜derek@apcera.com＞
COPY . /go/src/github.com/nats-io/gnatsd
WORKDIR /go/src/github.com/nats-io/gnatsd
RUN CGO_ENABLED=0 go install ...(elided)
EXPOSE 4222 8222
ENTRYPOINT ["gnatsd"]
CMD ["--help"]](https://image.slidesharecdn.com/docker-nats-meetup-talk-161013184020/85/Simple-and-Scalable-Microservices-Using-NATS-with-Docker-Compose-and-Swarm-71-320.jpg)
![6 . 5
SECOND STEP: FROM SCRATCH
github.com/nats-io/nats-docker/Dockerfile
FROM scratch
COPY gnatsd /gnatsd
COPY gnatsd.conf /gnatsd.conf
EXPOSE 4222 6222 8222
ENTRYPOINT ["/gnatsd", "-c", "/gnatsd.conf"]
CMD []](https://image.slidesharecdn.com/docker-nats-meetup-talk-161013184020/85/Simple-and-Scalable-Microservices-Using-NATS-with-Docker-Compose-and-Swarm-72-320.jpg)
![6 . 11
LOCAL NATS CLUSTER VIA DOCKER COMPOSE
Docker Compose tooling comes in handy here for doing
development as it helps us in assembling NATS clusters
locally.
version: "2"
networks:
nats-network: {}
services:
nats-server-A:
networks: ["nats-network"]
image: "nats:0.9.4"
entrypoint: "/gnatsd --routes nats://nats-server-B:6222,nats://nats-server-C:6222 --cluster nats://0.0.0.0:6222"
nats-server-B:
networks: ["nats-network"]
image: "nats:0.9.4"
entrypoint: "/gnatsd --routes nats://nats-server-A:6222,nats://nats-server-C:6222 --cluster nats://0.0.0.0:6222"
nats-server-C:
networks: ["nats-network"]
image: "nats:0.9.4"
entrypoint: "/gnatsd --routes nats://nats-server-A:6222,nats://nats-server-B:6222 --cluster nats://0.0.0.0:6222"](https://image.slidesharecdn.com/docker-nats-meetup-talk-161013184020/85/Simple-and-Scalable-Microservices-Using-NATS-with-Docker-Compose-and-Swarm-78-320.jpg)
Uploaded byApcera
Simple and Scalable Microservices: Using NATS with Docker Compose and Swarm
The document discusses NATS, a high-performance messaging system designed for simplicity and reliability, including its features and integration with Docker. It outlines various client implementations in languages like Go, Ruby, and Python, as well as NATS features such as pub/sub, request/reply, and clustering capabilities. Additionally, it describes how to use NATS with Docker for scalable applications and introduces NATS Streaming for enhanced messaging functionalities.
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Simple and Scalable Microservices: Using NATS with Docker Compose and Swarm
- 1. Simple and Scalable Microservices NATSand the Docker tooling + Waldemar Quevedo / @wallyqs Docker SF Meetup, Oct 2016
- 2. 1 . 1 2. 1 ABOUT Waldemar Quevedo / So ware Developer at in SF Development of the Apcera Platform Past: PaaS DevOps at Rakuten in Tokyo NATS client maintainer (Ruby, Python) @wallyqs Apcera
- 3. 3 . 1 ABOUTTHIS TALK What is NATS Features from NATS NATS + Docker
- 4. 4 . 1 Whatis NATS?
- 5.
- 6. 4 . 3 NATS HighPerformance Messaging System Created by First written in in 2010 Originally built for Cloud Foundry Rewritten in in 2012 Better performance Open Source, MIT License Used by Apcera, Ericsson, HTC, GE, Baidu Derek Collison Ruby Go https://github.com/nats-io
- 7. 4 . 4 NATS Designconstrained to keep it as operationally simple and reliable as possible while still being both performant and scalable.
- 8. 4 . 5 Actsas an always available dial-tone
- 9. 4 . 6 It'sFast
- 10. single byte message Around10M messages/second
- 11. 4 . 7 4. 8 and Simple
- 12. 4 . 9 DESIGN Concisefeature set (pure PubSub!) No built-in persistence of messages No exactly-once-delivery promises either Those concerns are simplified away from NATS → NATS Streaming
- 13. 4 . 10 DESIGN TCP/IPbased Plain text protocol fire and forget at most once
- 14. 4 . 11 Verysimple protocol telnet demo.nats.io 4222 sub hello 1 +OK pub hello 5 world +OK MSG hello 1 5 world ping PONG nats.io/documentation/nats-protocol
- 15.
- 16.
- 17. 4 . 14 GO nc,err := nats.Connect() // ... nc.Subscribe("hello", func(m *nats.Msg){ fmt.Printf("[Received] %s", m.Data) }) nc.Publish("hello", []byte("world"))
- 18. 4 . 15 RUBY require'nats/client' NATS.start do |nc| nc.subscribe("hello") do |msg| puts "[Received] #{msg}" end nc.publish("hello", "world") end
- 19. 4 . 16 PYTHON(ASYNCIO) yield from nc.connect() @asyncio.coroutine def handler(msg): print("[Received] {data}".format( data=msg.data.decode())) # Coroutine based subscriber yield from nc.subscribe("foo", cb=handler) yield from nc.publish("foo", "bar")
- 20. 4 . 17 NODE.JS varnats = require('nats').connect(); // Simple Publisher nats.publish('foo', 'Hello World!'); // Simple Subscriber nats.subscribe('foo', function(msg) { console.log('[Received] ' + msg); });
- 21. 4 . 18 C natsConnection_Publish(nc,"foo",data,5); natsConnection_Subscribe(&sub,nc,"foo",onMsg,NULL); void onMsg(natsConnection *nc, natsSubscription *sub, natsMsg *msg, void *closure) { printf("[Received] %.*sn", natsMsg_GetData(msg)); // ... }
- 22. 4 . 19 C# using(ISyncSubscription s = c.SubscribeSync("foo")) { for (int i = 0; i < 10; i++) { Msg m = s.NextMessage(); System.Console.WriteLine("[Received] " + m); } }
- 23. 4 . 20 JAVA //Simple Publisher nc.publish("foo", "Hello World".getBytes()); // Simple Async Subscriber nc.subscribe("foo", m -> { System.out.println("[Received] %sn", new String(m.getData())); });
- 24. Many more available! CC# Java Python NGINX Go Node.js Elixir Ruby PHP Erlang Rust Haskell Scala Perl ( italics → community contributed)
- 25. 4 . 21 4. 22 Great community!
- 26.
- 27.
- 28. 4 . 24 Communitycontributed dashboards github.com/cmfatih/natsboard
- 29. 4 . 25 DockerHub activity from NATS users
- 30. 4 . 26 DockerHub activity from NATS users
- 31. 4 . 27 DockerStore (Beta)
- 32. 4 . 28 5. 1 NATS Features
- 33. 5 . 2 FEATURES PurePubSub based Request/Reply Subject routing with wildcards Authorization Distribution queue groups for balancing Cluster mode for HA Auto discovery of topology /varzstyle monitoring Secure TLS connections with certificates
- 34. 5 . 3 REQUEST/REPLY Itis pure PubSub based using and by signaling in the subject: NATS unique identifiers limited interest SUB _INBOX.y1JxglDi76shQQIhPbTDme 2 UNSUB 2 1 PUB help _INBOX.y1JxglDi76shQQIhPbTDme 6 please tells the server to unsubscribe from subscription with sid=2 a er getting 1 message before sending a request on the helpsubject.
- 35. 5 . 4 REQUEST/REPLY Ifanother subscriber is connected and interested in the helpsubject, it will then receive a message with that inbox. SUB help 90 # Message received from server MSG help 90 _INBOX.y1JxglDi76shQQIhPbTDme 6 please # Use the inbox to reply back PUB _INBOX.y1JxglDi76shQQIhPbTDme 11 I can help!
- 36. 5 . 5 REQUEST/REPLY Finally,original requestor will be receiving the message: SUB _INBOX.y1JxglDi76shQQIhPbTDme 2 UNSUB 2 1 PUB help _INBOX.y1JxglDi76shQQIhPbTDme 6 please MSG _INBOX.y1JxglDi76shQQIhPbTDme 2 11 I can help!
- 37. 5 . 6 REQUEST/REPLY NATSclients libraries have helpers for generating the unique inboxes which act as ephemeral subscriptions: nats.NewInbox() // _INBOX.y1JxglDi76shQQIhPbTDme Used internally when making a Request: nc, _ := nats.Connect(nats.DefaultURL) t := 250*time.Millisecond // Request sets to AutoUnsubscribe after 1 response msg, err := nc.Request("help", []byte("please"), t) if err == nil { fmt.Println(string(msg.Data)) // => I can help! }
- 38. REQUEST/REPLY → LOWESTLATENCY Result of publishing a request to all nodes with limited interest means we are getting the fastest reply back:
- 39. 5 . 7 REQUEST/REPLY→ LOWEST LATENCY Result of publishing a request to all nodes with limited interest means we are getting the fastest reply back:
- 40. 5 . 85. 9 SUBJECTS ROUTING Wildcards: * SUB foo.*.bar 90 PUB foo.hello.bar 2 hi MSG foo.hello.bar 90 2 hi e.g. subscribe to all requests being made on the demo site: telnet demo.nats.io 4222 INFO {"auth_required":false,"version":"0.9.4",...} SUB _INBOX.* 99 MSG _INBOX.y1JxglDi76shQQIhPbTDme 99 11 I can help!
- 41. 5 . 10 SUBJECTSROUTING Full wildcard: > SUB hello.> 90 PUB hello.world.again 2 hi MSG hello.world.again 90 2 hi e.g. subscribe to all subjects and see whole traffic going through the server: telnet demo.nats.io 4222 INFO {"auth_required":false,"version":"0.9.4",...} sub > 1 +OK
- 42. 5 . 11 DISTRIBUTIONQUEUES Balance work among nodes randomly
- 43. 5 . 12 DISTRIBUTIONQUEUES Balance work among nodes randomly
- 44. 5 . 13 DISTRIBUTIONQUEUES Balance work among nodes randomly
- 45. 5 . 14 DISTRIBUTIONQUEUES Service A workers subscribe to service.Aand create workersdistribution queue group for balancing the work. nc, _ := nats.Connect(nats.DefaultURL) // SUB service.A workers 1rn nc.QueueSubscribe("service.A", "workers", func(m *nats.Msg) { nc.Publish(m.Reply, []byte("hi!")) })
- 46. 5 . 15 DISTRIBUTIONQUEUES Note: NATS does not assume the audience!
- 47. 5 . 16 DISTRIBUTIONQUEUES All interested subscribers receive the message!
- 48. 5 . 17 CLUSTERING AvoidSPOF on NATS by assembling a full mesh cluster
- 49. 5 . 18 CLUSTERING Clientsreconnect logic is triggered
- 50. 5 . 19 CLUSTERING Connectingto a NATS cluster of 2 nodes explicitly srvs := "nats://10.240.0.1:4222,nats://10.240.0.2:4223" nc, _ := nats.Connect(srvs) NOTE: NATS servers have a forwarding limit of one hop. Each server will only forward a message that it has received from a client to all connected servers that expressed interest in the message's published subject. A message received from a route will only be distributed to local clients.
- 51. 5 . 20 CLUSTERING Reconnectand disconnect handlers can be useful to trace connection failures. nc, err := nats.Connect(uri, nats.DisconnectHandler(func(nc *nats.Conn) { fmt.Printf("Got disconnected!n") }), nats.ReconnectHandler(func(nc *nats.Conn) { fmt.Printf("Got reconnected to %v!n", nc.ConnectedUrl()) }), nats.ClosedHandler(func(nc *nats.Conn) { fmt.Printf("Connection closed. Reason: %qn", nc.LastError()) }), )
- 52. 5 . 21 CLUSTERAUTO DISCOVERY Since release, topology can be discovered dynamically by clients! v0.9.2
- 53. We can startwith a single node…
- 54. 5 . 22 Thenhave new nodes join the cluster…
- 55. 5 . 23 Asnew nodes join, server announces INFOto clients.
- 56. 5 . 24 Clientsauto reconfigure to be aware of new nodes.
- 57. 5 . 25 Clientsauto reconfigure to be aware of new nodes.
- 58. 5 . 26 Nowfully connected!
- 59. 5 . 27 Onfailure, clients reconnect to an available node.
- 60. 5 . 28 5. 29 MONITORING style monitoring endpoint available for inspecting the internal state of the server. /varz Other available endpoints: - Info of clients connected to this server/connz - Subscriptions metrics/subsz - Cluster routes/routez
- 61. 5 . 30 MONITORING:EXAMPLES Gathering connections metrics from demo: curl demo.nats.io:8222/varz | grep connections Result: "max_connections": 65536, "connections": 25, "total_connections": 12429,
- 62. 5 . 31 MONITORING:EXAMPLES Gathering metrics regarding languages used when connecting to demo curl demo.nats.io:8222/connz?subsz=1 | grep lang | sort | uniq -c Result: 10 "lang": "go", 7 "lang": "node", 8 "lang": "python2",
- 63. 5 . 32 MONITORING pollsfrom these endpoints providing a terminal UInats-top
- 64. 5 . 33 TLS Supportedfor client and route connections, and for monitoring. https_port: 6443 tls { cert_file: "./configs/certs/server-cert.pem" key_file: "./configs/certs/server-key.pem" ca_file: "./configs/certs/ca.pem" # Require client certificates verify: true }
- 65. 5 . 34 CLUSTERTLS Securing route connections with TLS cluster { listen: 0.0.0.0:6222 tls { # Route cert cert_file: "./configs/certs/srva-cert.pem" # Private key key_file: "./configs/certs/srva-key.pem" # Optional certificate authority verifying routes # Required when we have self-signed CA, etc. ca_file: "./configs/certs/ca.pem" } }
- 66. 5 . 35 SUBJECTSAUTHORIZATION PubSub on certain subjects can be disallowed in the server's configuration: authorization { admin = { publish = ">", subscribe = ">" } requestor = { publish = ["req.foo", "req.bar"] subscribe = "_INBOX.*" } users = [ {user: alice, password: foo, permissions: $admin} {user: bob, password: bar, permissions: $requestor} ] }
- 67. 5 . 36 SUBJECTSAUTHORIZATION Clients are not allowed to publish on _SYS(reserved): PUB _SYS.foo 2 hi -ERR 'Permissions Violation for Publish to "_SYS.foo"'
- 68. 6 . 1 NATSand the Docker tooling
- 69. 6 . 2 THENATS DOCKER IMAGE Small binary → Lightweight Docker image No deployment dependencies
- 70. 6 . 3 2-STEPBUILD PROCESS
- 71. 6 . 4 FIRSTSTEP: COMPILE github.com/nats-io/gnatsd/Dockerfile FROM golang:1.6.3 MAINTAINER Derek Collison ＜derek@apcera.com＞ COPY . /go/src/github.com/nats-io/gnatsd WORKDIR /go/src/github.com/nats-io/gnatsd RUN CGO_ENABLED=0 go install ...(elided) EXPOSE 4222 8222 ENTRYPOINT ["gnatsd"] CMD ["--help"]
- 72. 6 . 5 SECONDSTEP: FROM SCRATCH github.com/nats-io/nats-docker/Dockerfile FROM scratch COPY gnatsd /gnatsd COPY gnatsd.conf /gnatsd.conf EXPOSE 4222 6222 8222 ENTRYPOINT ["/gnatsd", "-c", "/gnatsd.conf"] CMD []
- 73. 6 . 6 THENATS DOCKER IMAGE By default it is exposing these ports: # Clients, Cluster and Monitoring ports EXPOSE 4222 6222 8222 - Clients will be connecting against this port4222 - Port used for the cluster routes6222 - HTTP Monitoring endpoint8222
- 74. 6 . 7 USINGNATS + DOCKER
- 75. All examples canbe found at github.com/wallyqs/nats-docker-examples
- 76. 6 . 8 EXAMPLE:SINGLE NODE API Server which receives HTTP requests and communicates internally through NATS to a pool of workers.
- 77. 6 . 96. 10 EXAMPLE: CLUSTERED SETUP API Server which receives HTTP requests and communicates internally through NATS to a pool of workers.
- 78. 6 . 11 LOCALNATS CLUSTER VIA DOCKER COMPOSE Docker Compose tooling comes in handy here for doing development as it helps us in assembling NATS clusters locally. version: "2" networks: nats-network: {} services: nats-server-A: networks: ["nats-network"] image: "nats:0.9.4" entrypoint: "/gnatsd --routes nats://nats-server-B:6222,nats://nats-server-C:6222 --cluster nats://0.0.0.0:6222" nats-server-B: networks: ["nats-network"] image: "nats:0.9.4" entrypoint: "/gnatsd --routes nats://nats-server-A:6222,nats://nats-server-C:6222 --cluster nats://0.0.0.0:6222" nats-server-C: networks: ["nats-network"] image: "nats:0.9.4" entrypoint: "/gnatsd --routes nats://nats-server-A:6222,nats://nats-server-B:6222 --cluster nats://0.0.0.0:6222"
- 79. NATS + DockerCompose Demo
- 80. 6 . 12 6. 13 DOCKER SWARM BASED NATS CLUSTER Auto discovery becomes helpful in this context, we can assemble one with the following commands. docker network create --driver overlay nats-cluster-example docker service create --network nats-cluster-example --name nats-A nats:0.9.4 -cluster nats://0.0.0.0:6222 docker service create --network nats-cluster-example --name nats-B nats:0.9.4 -routes nats://nats-A:6222 -cluster nats://0.0.0.0:6222 docker service create --network nats-cluster-example --name nats-C nats:0.9.4 -routes nats://nats-A:6222,nats://nats-B:6222 -cluster nats://0.0.0.0:6222
- 81. 6 . 14 DOCKERSWARM BASED NATS CLUSTER Even easier: just use same configuration in all nodes. for node in A B C; do docker service create --network nats-cluster-example --name nats-$node nats:0.9.4 -routes nats://nats-A:6222 -cluster nats://0.0.0.0:6222 done Initial server becomes the seed server, ignoring route to self.
- 82. NATS + DockerSwarm mode Demo
- 83. 6 . 15 7. 1 Summary
- 84. NATS is asimple, fast and reliable solution for the internal communication of a distributed system. Docker flexible tooling is a good complement for building NATS based applications.
- 85. 7 . 2 7. 3 BONUS: NATS STREAMING NATS Streaming recently became an official image too! It is a layer on top of NATS totalling in ~10MB. Further info: github.com/nats-io/nats-streaming-server
- 86. 8 . 1 THANKS! /github.com/nats-io@nats_io Play with the demo site! telnet demo.nats.io 4222