GILMOURDESIGN PATTERNS IN MICRO-SERVICES ARCHITECTURES &

ABOUT

WHO AM I?

▸ twitter: @meson10

▸ mailto: piyush@piyushverma.net

▸ piyushverma.net

SOA (VS SERVERS)

WHAT ARE SERVICES

▸ Logical Entities

▸ Independent

▸ Comprised of more services

▸ Multiple servers for load and tolerance

▸ Scalability

▸ Flexibility

TO ERR IS HUMAN, TO BLAME IT ON SOMEONE IS MANAGEMENT POTENTIAL.

- Someone on Internet

WHY?

WHO DUN IT?

WHY SERVICES?

▸ Software Problem

▸ Scalability

▸ Management Problem

▸ Authority

▸ Responsibility.

DESIGN PATTERNS

REQUEST RESPONSE

REQUEST RESPONSE

CALLER SERVICE

HELLO?

ALOHA!WRONG NUMBER

Message {“Data”nterface{} `json:"data"`

//Actual Payload

Code int `json:"code"` //Response code if this is a response. This uses HTTP error codes

Sender string `json:"sender"` //Origin of the request (unique for each request)}

SENDER_ID

CODE

REQUEST

data := G.NewMessage().SetData("hello?")resp := g.Request(“echo", data, nil)

var msg stringreq.Data(&msg);fmt.Println("Echoclient: received", msg)

opts := G.NewHandlerOpts().SetGroup("exclusive")g.ReplyTo("echo", func(req *G.Request, resp *G.Message) { var msg string req.Data(&msg) resp.SetData(fmt.Sprintf("Pong %v", msg))}, opts)

RESPONSE

REQUEST

ASYNC / SIGNAL-SLOTS

ASYNC: SIGNALS AND SLOTS

Slots

Signal

ITEM.BUY.500

ITEM.BUY.*

ITEM.BUY.*

ITEM.BUY.*

GROUP: PUSH_MSG

FP SCALINGPUSH MESSAGE

SERVERPUSH MESSAGE SERVER

WEB GILMOUR

EMAIL NOTIFIER

SMS NOTIFIER

PUSH MESSAGE SERVER

ITEM PURCHASED

VIP ITEM PURCHASED

ITEM.BUY.420

ASYNC: SLOTS

g := G.Get(redis)g.Slot("example.log", func(req *G.Request) {

var msg stringreq.Data(&msg)log.Println(req.Sender(), "->", msg)

})g.Start()

g.Signal("example.log", G.NewMessage().SetData("log message emitted"))

SIGNAL

RECEIVER / SLOT

SIGNAL-SLOT VS. REQUEST-RESPONSE

ASYNC VS SYNC

WHAT TO USE WHEN?

▸ Request-Response

▸ Confirmed delivery.

▸ Response or Error Guaranteed.

▸ HTTP Like.

▸ Sender responsible for errors.

ASYNC VS SYNC

WHAT TO USE WHEN?

▸ Signal-Slots

▸ UDP-like.

▸ Broadcasting

▸ Wildcard topics

▸ Unreliable delivery.

▸ Receiver responsible for errors.

SERVICE DISCOVERY & LOAD BALANCING

NOTIFICATION SERVER 1

REPLICATED LOAD

BALANCER

X.Y.Y.Z?CALLER SERVICE

REGISTER

I, AM

HEALTHY?

NOTIFICATION SERVER 2

NOTIFICATION SERVER 3

NOTIFICATION SERVER 2

GILMOUR

MANAGER.NOTIFICATION

NOTIFICATION SERVER 1

NOTIFICATION SERVER 3

MANAGER.NOTIFICATION

MANAGER.NOTIFICATION

CALLER SERVICE

MANAGER.NOTIFICATION

{“NOTIFICATION”: “DATA”}

DISCOVERY AND LOAD BALANCING

LOOK MA, NO SERVICE DISCOVERY

▸ Gilmour works on Redis Subscriber Publisher.

▸ No querying discovery process.

▸ Call service and not servers.

DISCOVERY AND LOAD BALANCING

LOOK MA, NO LOAD BALANCING

▸ Has Capacity, Will Serve.

▸ Message delivered to one and all.

▸ Fittest node acquires lock first.

ERRORS: DETECTION & HANDLING

GILMOUR ERRORS

ERROR DETECTION

▸ Timeouts

▸ server side - execution timed out.

▸ client side - response too late

▸ confirm_subscribers

GILMOUR ERRORS

WEB GILMOUR

EMAIL NOTIFIER

SMS NOTIFIER

PUSH MESSAGE

Slots

ERROR REPORTER

Signal

GILMOUR ERRORS

CALLER SERVICE

HELLO?

WRONG NUMBER

SENDER_ID

CODE

ERROR REPORTER

type gilmourError struct {topic string //topic to which the request was sentrequestData string //request payloaduserData string //implementation dependent informationsender string //sender from the requesttimestamp string //timestamp of errorbacktrace interface{} //backtrace of the errorcode int //response code (non-200)

}

GILMOUR ERRORS

ERROR HANDLING

▸ Ignore

▸ Publish

▸ Queue

func main() {redis := backends.MakeRedis("127.0.0.1:6379", "pass")g := G.Get(redis)

//g.SetErrorPolicy(protocol.ErrorPolicyQueue)//g.SetErrorPolicy(protocol.ErrorPolicyIgnore)g.SetErrorPolicy(protocol.ErrorPolicyPublish)

}

GILMOUR ERRORS

ERROR SAMPLE

OPS: MONITORING

OPS: MONITORING

SERVERS

▸ Log forwarding & aggregation

▸ Error Reporting

▸ Server and Health Monitoring

OPS: MONITORING

SERVICES

▸ Are the services servicing?

▸ Do services have spare capacity?

▸ Do services respond in time?

▸ Health Bulletin: github.com/gilmour-libs/health-bulletin

OPS: MONITORING

OPS: MONITORING

OPS: MONITORING

Feb 23 12:25:14 qa-next-backend-manager0.datascale.io gilmour_health: D, [2016-02-23T06:55:12.930435 #22111] DEBUG -- : Ensuring topics have at least one subscriber

Feb 23 12:25:14 qa-next-backend-manager0.datascale.io gilmour_health: D, [2016-02-23T06:55:12.931160 #22111] DEBUG -- : Ensuring that gilmour servers respond to health ping

Feb 23 12:26:14 qa-next-backend-manager0.datascale.io backend_manager: D, [2016-02-23T06:56:12.932775 #9605] DEBUG -- : Executing handler for gilmour.health.ip-10-0-0-146-pid-9605-uuid-9d0484dd-08e5-4ec3-a3e4-9a109634712b from 2881867d41f24228b462b9eff0b7e88e

2016-04-03 00:06:56 d0e4ea929645600e2fa97657091613a4 -> Cleared VPC jenkins-backend-manager-pipeline-qa-172016-04-03 00:06:56 d0e4ea929645600e2fa97657091613a4 -> Clearing databag customer_jenkins-backend-manager-pipeline-qa-17_config::vpc_config2016-04-03 00:06:57 d0e4ea929645600e2fa97657091613a4 -> Deleted data_bag[customer_jenkins-backend-manager-pipeline-qa-17_config]2016-04-03 00:06:57 d0e4ea929645600e2fa97657091613a4 -> Clearing DNS entries2016-04-03 00:07:00 d0e4ea929645600e2fa97657091613a4 -> Cleaning Chef environment2016-04-03 00:07:01 d0e4ea929645600e2fa97657091613a4 -> Deleted customer_jenkins-backend-manager-pipeline-qa-17

REQUEST LOGGING

COMPOSITION

COMPOSITION

▸ compose - service1 | service2 | composition3

▸ andand - service1 && service2 && composition3

▸ oror - service1 || composition2 || service3

▸ batch

▸ (service1; service2; service3) > out

▸ service1; composition2; service3 > out

▸ parallel

▸ lambda functions

COMPOSITION

popular := g.NewParallel(g.NewRequestComposition("example.popular3"),g.NewRequestComposition("example.popular4"),

)

batch := g.NewPipe(g.NewRequestComposition("example.fetch"),g.NewRequestComposition("example.words"),g.NewRequestComposition("example.count"),popular,

)

data := G.NewMessage()data.SetData("https://s3.amazonaws.com/ds-data-sample/test.txt")msg := <-batch.Execute(data)

COMPOSITION

popular := g.NewParallel(g.NewRequestComposition("example.popular3"),g.NewRequestComposition(“example.popular4"),g.NewRequestComposition("example.popular5"),

)

batch := g.NewPipe(g.NewRequestComposition("example.fetch"),g.NewRequestComposition("example.words"),g.NewRequestComposition("example.stopfilter"),g.NewRequestComposition("example.count"),popular,&MyComposer{},

)data := G.NewMessage()data.SetData("https://s3.amazonaws.com/ds-data-sample/test.txt")msg := <-batch.Execute(data)

COMPOSITION

batch := e.NewPipe(e.NewRequest("weather.fetch"),e.NewRequest("weather.group"),e.NewParallel(

e.NewPipe(e.NewLambda(monthLambda("jan")),e.NewParallel(

e.NewRequest("weather.min"),e.NewRequest("weather.max"),

),),e.NewPipe(

e.NewLambda(monthLambda("feb")),e.NewParallel(

e.NewRequest("weather.min"),e.NewRequest("weather.max"),

),),

),)

TALK IS CHEAP: SHOW SOME DEMO

EXAMPLES: ECHO SERVERS & CLIENT

SAMPLE TEXT

EXAMPLES: POPULAR WORD COUNT

▸ Given

▸ A S3 URL pointing to a file that has (lot of) random text.

▸ Goal

▸ Eliminate stop words from the file.

▸ Find most popular 3, 4, and 5 letter words.

▸ Find these in parallel.

EXAMPLES: WEATHER AGGREGATION

▸ Output

▸ Popular 3 letter words: [way, for]

▸ Popular 4 letter words: [Text, copy]

▸ Popular 5 letter words: [Blind, blind]

EXAMPLES: COMPOSITION

EXAMPLES: WEATHER AGGREGATION

▸ Given

▸ Weather data as per hour, per day, per month of form:

▸ {"Day": 10, "Month": "jan", "Hour": 13, "Degrees": 56}

EXAMPLES: WEATHER AGGREGATION

▸ Goal

▸ For the months of Jan & Feb

▸ Find the maximum temperature recorded.

▸ Find the minimum temperature recorded.

▸ If possible do 3a and 3b in parallel, and in parallel for both months

EXAMPLES: WEATHER AGGREGATION

▸ Output

▸ Temperature on 19th Feb at 2100 hours was 50ºF

▸ Temperature on 21st Feb at 0500 hours was 94ºF

▸ Temperature on 19th Jan at 1900 hours was 50ºF

▸ Temperature on 17th Jan at 2200 hours was 94ºF

EXAMPLES: COMPOSITION

GILMOUR

RECAP

▸ Library only; no external process.

▸ No Load Balancer

▸ No Service Discovery

▸ Signal, Slots.

▸ Broadcast, Wildcard Topics.

▸ Exclusion groups.

▸ Sync - Request, Reply

▸ Error and Health Monitoring - HealthBulletin.

▸ Failure Detection

▸ Composition - Real micro-services.

▸ No message persistence.

GILMOUR

CREDITS & LINKS

▸ Aditya Godbole

▸ aa@gdbl.me

▸ Datascale.IO

▸ datascale.io

▸ Repository

▸ github.com/gilmour-libs