Introduction to gRPC - Mete Atamel - Codemotion Rome 2017

A high performance, open-source, universal RPC framework

Mete AtamelDeveloper Advocate for Google Cloud

@meteatamel

Confidential & ProprietaryGoogle Cloud Platform 2

Mete AtamelDeveloper Advocate for Google Cloud

@meteatamel

[email protected]

meteatamel.wordpress.com

Please send talk feedback: bit.ly/atamel

@meteatamel

Google Cloud Platform

Agenda

IntroductionRPC, motivation for gRPC

gRPC BasicsWhat is gRPC? Design goals

Some me the code!HelloWorld gRPC sample and demo

gRPC BenefitsHTTP/2, Protocol Buffers, multi-language support, connection options

Some me more code!Streaming gRPC sample and demo

@meteatamel


Introduction

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class GreeterService { String greeating(String text);}

class GreeterClient { var greeter = new GreeterService(); greeter.greeting(“World”);}

Regular Procedure Call @meteatamel


In distributed computing a remote procedure call (RPC) is when a computer program causes a procedure (subroutine) to execute in another address space (commonly on another computer on a shared network), which is coded as if it were a normal (local) procedure call, without the programmer explicitly coding the details for the remote interaction

That is, the programmer writes essentially the same code whether the subroutine is local to the executing program, or remote*

Remote Procedure Call (RPC)

*Wikipedia

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GreeterClient

RPC

GreetService

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How do clients call the service?

How does the server expose the service?

How does the data serialized/deserialized over the wire? XML, JSON, Binary?

What is the nature of the connection? Request/reply, streaming?

What about authentication?

RPC Questions @meteatamel


1. Build your own custom RPC framework

++ Exactly how you like it: I did this with Adobe Flex Data Services!-- You need to answer the questions earlier & code

2. Use gRPC: A high performance, open-source universal RPC framework

++ Many of the questions already answered & implemented by community-- You need to buy into gRPC style, gRPC generated code

Choices @meteatamel


A story of building your own RPC framework @meteatamel


Thoughts on Flash - April 2010 @meteatamel


For simple services, HTTP REST is probably enough

→ HTTP verbs (GET, POST, PUT, DELETE etc.) are rich enough→ REST semantics are well understood

For more complex services where efficiency is important, RPC can help

→ Domain specific: imagine a bank transfer scenario→ More strongly typed experience via stubs→ Efficiency with HTTP/2, Protocol Buffer

Why not REST? @meteatamel


Basics

@meteatamel


Stands for gRPC Remote Procedure Calls

A high performance, open source, general purpose standards-based, feature-richRPC framework

Open sourced version of Stubby RPC used in Google

Actively developed and production-ready, current version is 1.2.0

What is gRPC? @meteatamel


Services not Objects, Messages not ReferencesCoverage & SimplicityFree & OpenInteroperability & ReachGeneral Purpose & PerformantLayeredPayload AgnosticStreamingBlocking & Non-BlockingCancellation & Timeout

Motivation and Design Principlesgrpc.io/blog/principles

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A high level service definition to describe the API using Protocol Buffers

Client and server code generated from the service definition in 10+ languages

Efficiency in serialization with Protocol Buffers and connection with HTTP/2

Connection options: Unary, server-side streaming, client-side streaming, bi-directional streaming

Authentication options: SSL/TLS, token based authentication

How does it work? @meteatamel


At the high level

Java Service

gRPC Service

Python Service

gRPC Stub

gRPC Service

gRPC Service

GoLang Service

C++ Service

gRPC Stub

gRPC Stub

gRPC ServicegRPC

Stub

gRPC Stub

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Show me the code: 4 easy steps

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service GreetingService { rpc greeting (HelloRequest) returns (HelloResponse) {}}

Step 1: Create greeter.proto

message HelloRequest { string name = 1;}

message HelloResponse { string message = 1;}

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Generate client and server code to extend from using proto3 compiler

For Java, there is protobuf-maven-plugin for Maven and protobuf-gradle-plugin for Gradl to help

For .NET, Grpc.Tools.1.0.1 NuGet package has protoc.exe

Step 2: Generate client and server stubs @meteatamel


Create a service implementation extending from generated base class

Create a server with port and using the service implementation

Start the server

Step 3: Create server @meteatamel


Create a channel for the connection

Create a blocking or non-blocking client stub with the channel

Create a request

Send the request using the stub

Handle the responses in sync or async mode

Step 4: Create client @meteatamel


Demo: Greeter Server & Client (Java)

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gRPC Benefits

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HTTP/2: low latency transport of content

Protocol Buffers: efficient serialization

Multi-language Support

Connection Options: Unary, server, client, bi-directional streaming

Main benefits @meteatamel


Let’s talk about HTTP/2

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History of HTTP

1991 1993 1995 1997 1999

HTTP/0.9

2001 2003 2005 2007 2009 2011 2013

HTTP/1.0

2015 2017

HTTP/1.1 ?

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New TCP connection per HTTP connection

Number of parallel HTTP requests =

Number of TCP connections.

HTTP 1.x: Limited Parallelism @meteatamel


HTTP 1.0: Head of line blocking

Without pipelining

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With pipelining

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HTTP/1.1HOL

Blocking

With pipelining

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HTTP Headers

Uncompressed plain text headers for each and every HTTP request

HTTP 1.x: Protocol Overhead @meteatamel


History of HTTP

1991 1993 1995 1997 1999

HTTP/0.9

2001 2003 2005 2007 2009 2011 2013

HTTP/1.0

2015 2017

HTTP/1.1

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SPDY

HTTP/2.0


Released in 2015. Extend (not replace) the semantics of HTTP/1.1

Improve end-user perceived latency

Address the "head of line blocking"

Not require multiple connections

Minimize protocol overhead

HTTP/2 @meteatamel


HTTP/2

Single TCP connection

No Head-of-line blocking

Binary framing layer

Request –> Stream

Header Compression

Transport(TCP)

Application (HTTP/2)

Network (IP)

Session (TLS) [optional]

Binary Framing

HEADERS Frame

DATA Frame

HTTP/2

POST: /upload HTTP/1.1 Host: www.javaday.org.ua Content-Type: application/json Content-Length: 27

HTTP/1.x

{“msg”: “Welcome to 2016!”}

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Stream is a bidirectional flow of bytes within an established connection, which may carry one or more messages.

Message is a complete sequence of frames that map to a logical request or response message.

Frame is the smallest unit of communication in HTTP/2, each containing a frame header, which at a minimum identifies the stream to which the frame belongs: HEADERS for metadata, DATA for payload, RST_STREAM SETTINGS, PUSH_PROMISE, PING, GOAWAY, WINDOW_UPDATE, etc.

HTTP/2 Binary Framing @meteatamel


Interleave multiple requests and responses in parallel without blocking on any one

Use a single TCP connection to deliver multiple requests and responses in parallel.

Enable flow-control, server push, etc.

HTTP/2 Request/Response Multiplexing

Stream 1HEADERS

Stream 2DATA

Stream 3HEADERS

Stream 3DATA

Stream 1DATA

Stream YHEADERS

Stream XDATA

Requests

Responses

HTTP/2 connection

Client Server

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Client and server maintain and update an indexed list of previously seen header fields

Indexes are sent for already seen headers

Values are encoded with a static Huffman code

HPACK: Header compression for HTTP/2

:method GET

:scheme HTTPS

:host myhost.com

:path /image

custom_header some_value

:method GET

:scheme HTTPS

:host myhost.com

:path /image


HEADERS Frame

:method GET

:scheme HTTPS

:host myhost.com

:path /resource


Request #2Request #1

:method GET

:scheme HTTPS

:host myhost.com

:path /resource


:path /resource

+ indexes for already seen values

HEADERS Frame

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HTTP/2: What it means for you?

HTTP/2HTTP/1.1

http2demo.io/

@meteatamel

http://www.http2demo.io/

http://www.http2demo.io/


Protocol Buffers

Publishing 50KB messages at maximum throughput from a single n1-highcpu-16 GPE VM

instance, using 9 gRPC channels.

More impressive than the almost 3x increase in

throughput, is that it took only 1/4 of the CPU resources.

11x difference per CPU3x increase in throughput

https://cloud.google.com/blog/big-data/2016/03/announcing-grpc-alpha-for-google-cloud-pubsub

gRPC vs JSON/HTTP for Google Cloud Pub/Sub

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Multi-Language Support

Java/AndroidGoC/C++C#Node.jsPHPRubyPythonObjective-C

Service definitions and client libraries

MacOSLinuxWindowsAndroidiOS

Platforms supported

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Demo: Greeter Server & Client (C#)

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Connection Options

The client send a sequence of messages to the server using a provided stream. Once the client has finished writing the messages, it waits for the server to read them and return its response.

Client streaming

Both sides send a sequence of messages using a read-write stream. The two streams operate independently. The order of messages in each stream is preserved.

Bi-di streaming

Unary RPCs where the client sends a single request to the server and gets a single response back, just like a normal function call.

Unary

The client sends a request to the server and gets a stream to read a sequence of messages back. The client reads from the returned stream until there are no more messages.

Server streaming

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Demo: Chat app using gRPC streaming

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Confidential & ProprietaryGoogle Cloud Platform 45

grpc.io Mete Atamel@meteatamel

[email protected]

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Date post:	11-Apr-2017
Category:	Technology
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Introduction to gRPC - Mete Atamel - Codemotion Rome 2017

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