ji-2014-go is a simple repository holding sources for the Go hands-on session of the JI-2014

An online version of the slides is served here.

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.

WARNING: Do note that installing Go via homebrew on MacOSX is known to have some deficiencies. On Macs, it is really recommended you use the manual method.

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/go1.3.3.linux-amd64.tar.gz
$ tar zxf go1.3.3.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

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.)

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-2014-go/cmd/ji-hello

go get downloaded (cloned, in git speak) the whole github.com/sbinet/ji-2014-go 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-2014!

$ ji-hello you
Hello you!

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

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

https://code.google.com/p/go-wiki/wiki/IDEsAndTextEditorPlugins

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

https://godoc.org/code.google.com/p/go.tools/cmd/goimports

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

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