Introduction # The internet is already growing, no need to say that. With that is growing demands, increasing load on existing infrastructure. New, better protocols are defined in every direction, let it be OpenAPI or HTTP/3. It is not limited to HTTP. With time there has been seen a significant boom in messaging protocols like RabbitMQ and similar related services like Amazon SQS. With this post I have tried to collect as much information as I can about
evolution of HTTP without getting too into any particular part.
Introduction # Are you lost between Handle, HandleFunc, and HandlerFunc? If the answer is yes then this post is for you. To understand these pretty well we need to be familiar with interafces. Although interface is just a keyword, it’s confusing at first when you are switching from Python like language; which does not have a similar keyword.
Introduction # The way we used to deliver resources to the client in a server-client setup is now drifting away from REST to a more modern delivery mechanism. Two of them are gRPC and GraphQL. While both these solve a different kind of problem, REST is going to stay for a while. It is the simplest to learn at least.
Introduction # From The Zen of Go:
If you think it’s slow, first prove it with a benchmark
Don’t assume if things are slow. Benchmark it and see if they are really slow.
One thing to note here is benchmarking a program is different from profiling a program.
Benchmarking is the way we check how fast our algorithm is for a given unit of the program. In benchmarking, we typically see how many iterations can a piece of code can run in a given time.
The internet is filled with Go learning resources. And I am not going to repeat all the links here. I will list only the resources that I went through.
I am a self-taught programmer from start. And have limited knowledge of computer science. Which of course is changing day by day. I had a background in Python before getting into Go. So my recommendations will also be aligned with my experience level.
Introduction # In last post we learned how we can use functional options to pass parameter to our functions. In this post we’ll see an alternative way to do the same thing.
I’ll take the same code from the last post to keep things simple.
Variadic Functions for Options # 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 type Coffee struct { CoffeeBeans bool Sugar bool SteamedMilk bool } func New(opts ...func(Coffee) Coffee) Coffee { coffee := Coffee{CoffeeBeans: true} for _, opt := range opts { coffee = opt(coffee) } return coffee } // WithSugar adds sugar to the coffee. func WithSugar(coffee Coffee) Coffee { coffee.Sugar = true return coffee } // WithSteamedMilk adds steamed milk to the coffee. func WithSteamedMilk(coffee Coffee) Coffee { coffee.SteamedMilk = true return coffee } // Prepare makes a cup of coffee with given items. // Ignore the implementation for now. func (c Coffee) Prepare() string { v := reflect.ValueOf(c) typeOfC := v.Type() var items []string for i := 0; i < v.NumField(); i++ { if v.Field(i).Interface() == true { items = append(items, typeOfC.Field(i).Name) } } return fmt.Sprintf("Preparing coffee with %q:", items) } func main() { s := New(WithSugar) fmt.Println(s.Prepare()) } Here on line 1-5 we define type Coffee (or class if you would like to say). This is the analogy our code is build upon because I like coffee whenever I can.
Introduction # In Python you can assign default value to the functions, like so:
1 2 def my_func(posarg, named_arg=True, another_named_arg="Okay") # logic goes here... But in Go you can’t do this:
1 2 3 func myFunc(posarg, named_arg bool = true, another_named_arg string = "Okay") { // logic goes here... } This will throw a syntax error. Try that?
In this post, we’ll see how can we overcome this issue the go way, with something called Function Options. Not sure if go is the only language that uses this syntax, if there is another language you are using, please let me know. Also, connect with me on LinkedIn
Introduction # Send a POST request in golang is pretty daunting if you have a post body and you’re coming from a scripting language like JavaScript or Python. Here in Go, schema for JSON needs to be defined beforehand in order to marshal and unmarshal string back and forth to JSON.
Simple POST # This marshaling/unmarshalling could be an oneliner if your request body is not nested, or is one level deep, or there is not even a body. Consider this example:
Introduction # Have you ever ran into a situation where you wanted to version your application, but doing git tag and making a separate commit for updating version number was a two-step process? Isn’t that kinda frustrating? You can even miss to update the version number in your code, which happens to be with me a lot. In this post we’ll see how to convert this two-step process into one.
I will start this post with a quote from webassembly.org:
WebAssembly (abbreviated Wasm) is a binary instruction format for a stack-based virtual machine. Wasm is designed as a portable target for compilation of high-level languages like C/C++/Rust, enabling deployment on the web for client and server applications.— webassembly.org That’s a lot of technical jargon. In very simple terms, Wasm provides a way to run code written in multiple languages on the web at near-native speed. Where multiple languages refers to all these languages.
In a previous post we discovered how can we run commands on each push and check if the test is passing against multiple versions of go. This is a continuation of the same concept. We are going to deploy our code to Elastic Beanstalk, straight from git push.
Elastic Beanstalk is nothing but a wrapper around it’s EC2 infrastructure. It is a developer-centric view of deploying an application on AWS. Developers just have to push the code and Beanstalk can take care of Auto Scaling Group, Elastic Load Balancer, databases etc. No need to manage infrastructure manually.
Why use BoltDB # Bolt plays pretty well with Go’s concurrency model, we can do multiple reads concurrently.
For pro and cons, I will contrast it with similar database SQLite. I have done SQLite when I worked with Xentrix to develop GUI tools for the artists.
You may want to connect with me on LinkedIn.
Pro # It is native go. This means you don’t need any database server running, like SQLite. In oppose to Redis and memcached.
You can’t think of deploying your application to production without testing it.
Neither you can manage a large codebase with confidence without it.
Let us go through some basics of unit testing in golang.
This post is structured in the following manner:
unit testing basics in golang (jump) inbuilt code coverage command understanding subtests and helper function (jump) Travis CI integration (jump) running test against multiple version of go Please connect with me on LinkedIn and let’s get started.
