Introduction to Finagle

@

puneet@twitter.com

Core Services - Platform Engineering

In the beginning ...

A brave new world ...

TypesafeExpressivePerformant

(thank you JVM)...

Futures

Synchronous Futures

def piDigit ( n : Int ) : Int def piDigit ( n : Int ) : Future[Int]

println ( piDigit ( 100 ) ) piDigit ( 100 ) onSuccess println

Synchronous Futures

Synchronous Futuresdef piDigit ( n : Int ) : Int def piDigit ( n : Int ) : Future[Int]

println ( piDigit ( 100 ) ) piDigit ( 100 ) onSuccess println

println ( piDigit ( 100 ) * 10 ) ) piDigit ( 100 ) map { _ * 10 } onSuccess println

println ( piDigit ( piDigit ( 100 ) ) ) piDigit ( 100 ) flatMap piDigit onSuccess println

println ( ( 0 to 100 ) map piDigit ) Future.collect {

( 0 to 100 ) map piDigit

} onSuccess println

Address resolution

TCP handshake

Serialization => Deserialization

the networking glue ...

: Request => Future [ Response ]

trait UserService {def getByUserId( userId : Long ) : Future [ User ]def getByScreenName( screenName: String ) : Future [ User ]

}

trait TweetService {def findByUserId( userId : Long ) : Future [ Seq[ Tweet ] ]

}

trait UserTweetService {val userService : UserServiceval tweetService : TweetService

def findUserAndTweets(userId : Long

) : Future [ ( User, Seq[Tweet] ) ] = Future.join (

userService.findByUserId( userId ), tweetService.findByUserId( userId )

)

}}

1

2 3 2 3

4

trait ScreenNameTweetService {val userService : UserServiceval tweetService : TweetService

def findByScreenName(screenName: String

) : Future [ Seq[Tweet] ] = {

userService.findByScreenName( screenName ) flatMap {user => tweetService.findByUserId( user.id )

}

}}

1

2 3 4 5

6

other benefits ...

val someService = Http.client(“inet!google.com:80”)

val anotherService =Http.client(

“zk!myzkhost.mycompany.com:2181!/my/zk/path”)

Address Resolution

Source Load Balancing

vs

Thanks!

twitter.github.io/finagle@finagle@pzdk