ji-go-2016

ji-go-2016 is a simple repository holding sources for the Go hands-on session of the JI-2016

An online version of the slides is served here.

For the talk about ADVANCED concurrent programming go here.

Bootstrapping the work environment

Installing the Go toolchain

The Go hands-on session obviously needs for you to install the Go toolchain.

There are 3 ways to do so:

• install Go via your favorite package manager (yum, apt-get, fink, ...)
• install Go via docker
• install Go manually.

While all 3 methods are valid ones, to reduce the complexity of the debugging/configuration/OS matrix, we'll only recommend the last one.

Installing Go manually

This is best explained on the official page: http://golang.org/doc/install

On linux-64b, it would perhaps look like:

$ mkdir /somewhere
$ cd /somewhere
$ curl -O -L https://golang.org/dl/go1.7.1.linux-amd64.tar.gz
$ tar zxf go1.7.1.linux-amd64.tar.gz
$ export GOROOT=/somewhere/go
$ export PATH=$GOROOT/bin:$PATH

$ which go
/somewhere/go/bin/go

$ which godoc
/somewhere/go/bin/godoc

Setting up the work environment

Like python and its $PYTHONPATH environment variable, Go uses $GOPATH to locate packages' source trees. You can choose whatever you like (obviously a directory under which you have read/write access, though.) In the following, we'll assume you chose $HOME/ji-go-work:

$ mkdir -p $HOME/ji-go-work
$ export GOPATH=$HOME/ji-go-work
$ export PATH=$GOPATH/bin:$PATH

Make sure the go tool is correctly setup:

$ go env
GOARCH="amd64"
GOBIN=""
GOCHAR="6"
GOEXE=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOOS="linux"
GOPATH="$HOME/ji-go-work"
GORACE=""
GOROOT="/somewhere/go"
GOTOOLDIR="/somewhere/go/pkg/tool/linux_amd64"
CC="gcc"
GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0"
CXX="g++"
CGO_ENABLED="1"

(on other platforms/architectures, the output might differ slightly. The important env.vars. are GOPATH and GOROOT.)

Testing go get

Now that the go tool is correctly setup, let's try to fetch some code. For this part, you'll need the following tools installed to actually retrieve the code from the repositories:

• git
• hg (a.k.a mercurial)

Without further ado:

$ go get -u -v github.com/sbinet/ji-go-2016/cmd/ji-hello

go get downloaded (cloned, in git speak) the whole github.com/sbinet/ji-go-2016 repository (under $GOPATH/src) and compiled the ji-hello command. As the compilation was successful, it also installed the ji-hello command under $GOPATH/bin.

The ji-hello command is now available from your shell:

$ ji-hello
Hello JI-2016!

$ ji-hello you
Hello you!

Installing one more needed dependency

In order to look at the slides off-line, we'll need the present tool. Let's install it:

$  go get -u -v golang.org/x/tools/cmd/present
golang.org/x/tools (download)
golang.org/x/net (download)
golang.org/x/tools/godoc/static
golang.org/x/net/websocket
golang.org/x/tools/present
golang.org/x/tools/playground/socket
golang.org/x/tools/cmd/present

Setting up your favorite editor

Extensive documentation on how to setup your editor (for code highlighting, code completion, ...) is available here:

https://github.com/golang/go/wiki/IDEsAndTextEditorPlugins

At the very least, you should try to install and setup goimports:

$ go get golang.org/x/tools/cmd/goimports

goimports provides automatic code formating as well as automated insertion/deletion of used/unused packages (in your import package statements.)

Documentation

The Go programming language is quite new (released in 2009) but ships already with quite a fair amount of documentation. Here are a few pointers:

• http://golang.org/doc/code.html
• http://tour.golang.org
• http://golang.org/doc/effective_go.html
• http://dave.cheney.net/resources-for-new-go-programmers
• http://gobyexample.com

For more advanced topics:

• http://talks.golang.org
• http://blog.golang.org
• https://groups.google.com/d/forum/golang-nuts (Go community forum)
• the internets. typical queries are go something or golang something