GoLang Tutorials

Jobs and opportunities in the Go world

2012-01-05T04:48:00.000-08:00

Other topics in this series - Table of Contents 5th January 2012: I get quite a few visitors on these pages everyday and given that Go version 1 will become official soon, even though there are just a few job opportunities now, I foresee a spurt in the future. To assist those who are learning to also find available opportunities, I wanted to maintain a list of the early job postings. If you

Interfaces in Go - Part 2: Aiding adaptable, evolutionary design

2012-01-01T13:53:00.000-08:00

Other topics in this series - Table of Contents In discussing interfaces in the first post, I had started off with a familiar example from OOP - a Shaper interface and a couple of concrete shapes that implemented the interface. But as Rob pointed out in this this groups thread, "Go's interfaces aren't a variant on Java or C# interfaces, they're much more. They are a key to large-scale

OAuth2: 3-legged authorization in a Go web application

2011-11-22T14:54:00.000-08:00

Other topics in this series - Table of Contents OAuth is currently the recommended standard for user authorization. I’ll limit this write up to just examples of using the OAuth standard with Google using Go. However there are a lot of good write ups on the web that explains the process well. One of the major uses of OAuth is that a user can authorize your application, using a 3-legged

Using an external api in a Go AppEngine program - urlshortener from Google APIs

2011-11-18T15:41:00.001-08:00

Other topics in this series - Table of Contents This tutorial is almost exactly the same as http://golangtutorials.blogspot.com/2011/11/using-external-api-in-go-web-program.html, except that we will be doing the same program for the AppEngine. There are a few differences on how to make it work, so I shall, even at the cost of repetition for those who are coming directly to this page for

Using an external api in a Go web program - urlshortener from Google APIs

2011-11-18T12:07:00.000-08:00

Other topics in this series - Table of Contents In this tutorial, we will look at how to use an external API within our go program. The one that we shall use is the URL Shortener API. You can try its present functionality at http://goo.gl/. Enter a URL like http://golangtutorials.blogspot.com/ and you will see a shorter URL returned, which is much easier to embed, say, in a service like

Go Templates - Part 3 - Template Sets

2011-11-15T10:45:00.000-08:00

Other topics in this series - Table of Contents See also: Go Templates - Part 1 See also: Go Templates - Part 2 Template sets allow you to group together related templates in one group. For example if a web page had a header, body, and footer, these could be defined within one text file. This could then could be read into your program with one call which will parse all the template

gotest - unit testing and benchmarking Go programs

2011-10-31T16:03:00.000-07:00

Other topics in this series - Table of Contents The Go installation that you have comes with a unit testing package called testing and a tool called gotest that you can use to write unit tests. This unit testing framework, like frameworks in other languages, allow you to write any number of tests that you can run frequently to check the correctness of your code in small units. You can also

Analysing a Google AppEnginge for Go program

2011-10-30T20:11:00.000-07:00

Other topics in this series - Table of Contents In this section, we shall look at an existing demo program that we ran in the Installation and Setup tutorial. This will be a good place to start analysing and understanding Go programs for the Google AppEngine and will allow us to move on to larger programs of our own. Directory Structure The list of files under google_appengine/demos/

Go packages and goinstall - creating and using your own packages in Go

2011-10-30T05:17:00.000-07:00

Other topics in this series - Table of Contents For a small beginner’s introduction to packages you can read my other writeup: Go ‘Hello World’ - A line by line approach. In this tutorial we will look at how you can work with the goinstall tool to create, install, and use your own packages locally. goinstall has larger functionality than this alone and you can read more about it here: Command

Go Templates - Part 2

2011-10-25T18:56:00.000-07:00

Other topics in this series - Table of Contents See also: Go Templates - Part 1 See also: Go Templates - Part 3 - Template Sets There is fairly good documentation about the template package at http://golang.org/pkg/template/. It contains definitions for many of the structures and formats that are parseable by the template package. So here I shall try to only supplement that with a few

Google AppEngine for Go - Installation and Setup

2011-10-24T17:02:00.000-07:00

Other topics in this series - Table of Contents Setting up Google AppEngine for Go is real simple and can have you testing out functionality quickly. There are a few things that might be better to inform you early - they are simpler than setting up certain other development environments, so you might end up searching for complexity and ending up confused for not finding it. A few things to

Control structures - Go defer statement

2011-06-24T08:22:00.000-07:00

Other topics in this series - Table of ContentsThe defer statement allows you to designate specified functions to be executed just before returning from the current function block. Why would this be useful? In programming we often have to allocate/block/lock resources, but then the program abruptly ends in between and is unable to reach the part of the code where we un-allocate/unblock/unlock

Control structures - Go switch case statement

2011-06-23T08:03:00.000-07:00

Other topics in this series - Table of ContentsThe switch statement may be considered a more powerful version of the if statement where multiple if-else blocks are replaced with a single switch and multiple case blocks. There are differences though between the two and we shall see them in some examples. switch any expression of type T { case any expression of same type T: { code to be

Control structures - Go for loop, break, continue, range

2011-06-22T07:16:00.000-07:00

Other topics in this series - Table of ContentsThe for statement is the only available looping statement in Go. The generic statement definition is: for "initialization statements"; "bool expression that has to evaluate to true"; "statements run prior to every loop except the first" { //code to be executed if the boolean expression evaluates to true } Any of the parts of the for

Control structures - Go if else statement

2011-06-21T11:51:00.000-07:00

Other topics in this series - Table of ContentsPrograms need to be able to take up different courses of action based on different situations - if you want to go to the beach turn left, or if you want to go the movies, turn right. The if else statement is a simple control structure. The general statement in Go is similar to: if some_boolean_expression { // execute this block if

Multiple return values from Go functions

2011-06-15T05:29:00.000-07:00

Other topics in this series - Table of ContentsGo allows you to have a function that returns multiple values. A function definition that returns three values would be defined similar to: func SumProdDiff(i, j int) (int, int, int) Since there is more than one return value, it is necessary to enclose it within parentheses. To return values from a function such as the above, you would have a

Go Templates (Updated Oct 2011)

2011-06-14T08:03:00.000-07:00

Other topics in this series - Table of Contents See also: Go Templates - Part 2 See also: Go Templates - Part 3 - Template Sets When a web service responds with data or html pages, there is usually a lot of content that is standard. Within that there needs to be modifications done based on the user and what has been requested. Templates are a way to merge generic text with more specific text.

Web Programming with Go - first web Hello world

2011-06-11T16:00:00.000-07:00

Other topics in this series - Table of ContentsIf you’ve already gone through some of the earlier tutorials in this series, you should be quite comfortable getting onto programming the web with Go. Let’s jump right to it and then we shall analyze the code. There is a chance that there might be people arriving here for the first time, so we shall also take some time to go over the basic concepts

Channels in Go - range and select

2011-06-11T05:45:00.000-07:00

Other topics in this series - Table of ContentsChannels and rangeThis is the second part of tutorial on channels in Go. If you haven’t yet gone through the first part, Channels in Go, please go through it now. Receivers of data have a problem of knowing when to stop waiting for data. Is there more to come or is it all done? Should we wait or should we move on? One option is to constantly

Channels in Go

2011-06-09T16:09:00.000-07:00

Other topics in this series - Table of ContentsGoroutines allow you to run a piece of code in parallel to others. But to employ it usefully, there are a few additional requirements - we should be able to pass data into the running process and we should be able to get data out of the running process when it is done creating it. Channels provide the way to do that, and they work alongside

Goroutines

2011-06-09T06:43:00.000-07:00

Other topics in this series - Table of ContentsGoroutines allow you to execute tasks in parallel - there are many connotations to the word ‘parallel’ in computing, so, take that with a pinch of salt. Parallel for example could mean the same program running on multiple hardware chips, on multiple machines, on multiple threads within the same machine, or multiplexed on the same thread. The Go

Summary of Object Oriented Programming Goodness in Go, without the pain

2011-06-08T08:35:00.000-07:00

Other topics in this series - Table of Contents If you haven’t gone over some of the related topics on this, please do so now. Here I’ll mostly be summarizing what we already went over so that it is available as a quick reference, especially for all those people who have been used to doing object oriented programming. Structs in Go Anonymous fields in structs Methods on structs Inheritance

Polymorphism in Go

2011-06-08T08:28:00.000-07:00

Other topics in this series - Table of Contents Sometimes I’ve found it easier to explain polymorphism with an illustration. An illustration attempts to simplify and has its drawbacks, but it could help clarify the idea. Assume a martian came to earth and he knows about humans but he doesn’t know about the difference between a man and a woman. He now approaches random humans on the street and

Multiple inheritance in Go

2011-06-08T03:17:00.000-07:00

Other topics in this series - Table of Contents Inheritance is the ability for a type to automatically obtain the behaviors of a parent class. Multiple inheritance is the ability for a type to obtain the behaviors of more than one parent class. As a real world example, if Phone was a type, then MobilePhone could be a type that inherits the behavior of the Phone type. This works in many cases,

Inheritance and subclassing in Go - or its near likeness

2011-06-07T18:03:00.000-07:00

Other topics in this series - Table of Contents Those of you used to other object oriented languages probably already know what inheritance and subclassing is. In simple terms, it is the ability of one type to inherit the behavior of another type. An Employee has all the behaviors of a Human, and then some more. A Ferrari has all the behaviors of a Car, and some more. An Aston Martin has all