(Live) Build and run Golang Web server on

Android.aviSeongJae Park <sj38.park@gmail.com>

Nice To Meet You

SeongJae Park

sj38.park@gmail.com

golang newbie programmer

Disclaimer

The main part of session is live-coding. This slide has only little information.

Inspired by camlistore and outyet

Maybe useless, *just for fun*

Goal Of This Session

Build and run Golang web server on Android

Live Coding

golang: Programming Language

for simple, reliable, and efficient software.

http://blog.golang.org/5years/gophers5th.jpg

Web server

Processes request via HTTP protocol

Web Server Client

Web server

Processes request via HTTP protocol

Listen a socketReceive HTTP request from the socket

Web Server Client

url: /blahblah,method: GET

Web server

Processes request via HTTP protocol

Listen a socketReceive HTTP request from the socketProcess the request

Web Server Client

url: /blahblah,method: GET

Web server

Processes request via HTTP protocol

Listen a socketReceive HTTP request from the socketProcess the requestSend HTTP response to client using the socket

Web Server Client

url: /blahblah,method: GET

Status: OK,Body: <p>welcome</p>

(Live) Simple Golang Webserver

…...

(Live) Simple Golang Webserver

…... complete

net/http rules

The code: https://github.com/sjp38/linuxOutYet/tree/804aa370f5adbf3d4377ee1b1e862cbc49d81c1c

Golang and Android

● Golang Supports Android officially from v1.4○ The support focus on Application; just let .so or .apk

https://blog.golang.org/gopher/gopher.pnghttp://upload.wikimedia.org/wikipedia/commons/thumb/d/d7/Android_robot.svg/511px-Android_robot.svg.png

Golang and Android

● Golang Supports Android officially from v1.4○ The support focus on Application; just let .so or .apk○ Requires complex build process and client code

https://blog.golang.org/gopher/gopher.pnghttp://upload.wikimedia.org/wikipedia/commons/thumb/d/d7/Android_robot.svg/511px-Android_robot.svg.png

Golang and Android

● Golang Supports Android officially from v1.4○ The support focus on Application; just let .so or .apk○ Requires complex build process and client code○ Couldn’t be more simple, easier?

https://blog.golang.org/gopher/gopher.pnghttp://upload.wikimedia.org/wikipedia/commons/thumb/d/d7/Android_robot.svg/511px-Android_robot.svg.png

Golang on Android: Background

Android is a variant of Linux system with ARMx86 Android exist, though...

http://www.kitguru.net/wp-content/uploads/2012/03/linux-android.png

Golang on Android: Background

Android is a variant of Linux system with ARMx86 Android exist, though...

Go supports ARM & Linux Officiallywith static-linking

http://www.kitguru.net/wp-content/uploads/2012/03/linux-android.png

Golang on Android: Background

Android is a variant of Linux system with ARMx86 Android exist, though...

Go supports ARM & Linux Officiallywith static-linking

So, why not?

http://www.kitguru.net/wp-content/uploads/2012/03/linux-android.png

Golang on Android: Plan

1. Cross compile Go program as ARM / Linux

Golang on Android: Plan

1. Cross compile Go program as ARM / Linux2. Include the binary in assets/ of Android app

Golang on Android: Plan

1. Cross compile Go program as ARM / Linux2. Include the binary in assets/ of Android app3. Copy the binary in private space of the app

Golang on Android: Plan

1. Cross compile Go program as ARM / Linux2. Include the binary in assets/ of Android app3. Copy the binary in private space of the app4. Give execute permission to the binary

/data/data/com.example.goRunner/files # ls -al-rwxrwxrwx u0_a55 u0_a55 4512840 2014-11-28 17:45 gobin

Golang on Android: Plan

1. Cross compile Go program as ARM / Linux2. Include the binary in assets/ of Android app3. Copy the binary in private space of the app4. Give execute permission to the binary5. Execute it

/data/data/com.example.goRunner/files # ls -al-rwxrwxrwx u0_a55 u0_a55 4512840 2014-11-28 17:45 gobin

(Live) Golang on Android

……

(Live) Golang on Android: Problem

…… Not successful

go binary runner code:https://github.com/sjp38/goOnAndroidFA/releases/tag/devfair2014.gdg.kr

(Live) Golang on Android: Problem

…… Not successful

It has no /etc/hosts

CA Certs path is different with pure Linux/system/etc/security/cacerts

(Live) Golang on Android: Problem

…… Not successful

It has no /etc/hosts

CA Certs path is different with pure Linux/system/etc/security/cacerts

Android is a variant of, not pure LinuxGOOS=android has same problem, too :’(

(Live) Golang on Android: Solution

It has no /etc/hostsGet IP manually

Certifications path is differentUse those certifications

(Live) Golang on Android: Again

……

(Live) Golang on Android

…… Complete

It’s hacky, but works

The code: https://github.com/sjp38/linuxOutYet/releases/tag/devfair2014.gdg.kr

Summary

Golang program can run on Android

Summary

Golang program can run on AndroidOfficially as .so or .apk file

Summary

Golang program can run on AndroidOfficially as .so or .apk fileOr, as elf binary with unofficial, little hack

Summary

Golang program can run on AndroidOfficially as .so or .apk fileOr, as elf binary with unofficial, little hack

Some features don’t work on Android, yetStill need some hacks

Final Source Code

go web server: https://github.com/sjp38/linuxOutYet/releases/tag/devfair2014.gdg.kr

go program runner(Android app): https://github.com/sjp38/goOnAndroidFA/releases/tag/devfair2014.gdg.kr

This slide has been used for

GDG Korea DevFair 2014

GDG Korea Golang Seoul Meetup

This work by SeongJae Park is licensed under the Creative Commons Attribution-ShareAlike 3.0 Unported

License. To view a copy of this license, visit http://creativecommons.org/licenses/by-sa/3.0/.