Category Programming

While working with structures, there’s a possibility to initialize the structure without providing the keys of fields. type SomeSturct struct { FirstField string SecondField bool } // ... myStruct := SomeSturct{"", false} If we want to force other (or even ourselfs) to explicitly providing the keys, we can add _ struct{} in the end of the structure. type SomeSturct struct { FirstField string SecondField bool _ struct{} } // COMPILATION ERROR myStruct := SomeSturct{"", false} The code above will produce too few values in SomeSturct literal error.

While developing a library, we create a directory structure to keep the code organized. However, some exported functions or struct should not be used by users of the library. The achieve that, call the package internal. . ├── bar │ ├── bar.go │ └── internal │ └── foobar.go ├── internal │ └── foo.go └── main.go In the example above, the foo.go can be included only in the main.go. What’s more, only the bar.

In the microservices’ world, one thing what’s worth considering is a graceful shutdown. This is important to not lose data while shutting down a container. The container orchestrator like Kubernetes can restart the container by sending SIGTERM or SIGINT signal. Those signals can be handled to safely close all connections and finish background tasks. Signals are propagated using os.Signal channel. You can add the above code to your main. var gracefulStop = make(chan os.

When it comes to interfaces, a good practice is to create an interface where you’ll use it. Creating interfaces in advanced is not recommended in Go. There are two exceptions: you’re creating a library which will be used in different projects you’ll have more than 1 implementation In the example below, we have a storage implementation. type inMemoryStorage struct { mutex *sync.Mutex storage map[string]*Value } func NewStorage() *inMemoryStorage { return &inMemoryStorage{ storage: map[string]*Value{}, mutex: &sync.

You should use the package github.com/pkg/errors instead of errors package for errors in your applications. The default package lacks a few things like: stack trace easy appending message to the error and more It helps with debugging a lot. Below you can find an example error message with the stack trace. An important thing to remember is that you should wrap every error which is from any external library or your freshly created error you want to return.

Golang uses a connection pool to manage opened connections for us. As a result, new connections are used when no free connection left and reuses them when golang finds an idle connection. The most important thing is that when two queries are called one by one it does not mean that the queries will use the same connection. It may be true if not in every case. In the example below, you can find two queries which may seem to be executed in one connection.

Some bugs are very hard to find and to reproduce but easy to fix. To avoid them, it’s helpful to know how the tools we’re using work under the hood. From this article, you’ll learn what shallow and deep copy are and which errors you can avoid thank’s the knowledge about them. Can you find a problem with the code below? q1 := NewQuestion(1, "How to be cool?") q1 = q1.

Channels in golang are referenced type. It means that they are references to a place in the memory. The information can be used to achieve the goal. Firstly, let’s consider using structs as the information carrier. This is the most intuitive choice for the purpose. Below you can find an example of a struct which will be used today. type FuncResult struct { Err error Result int } func NewFuncResult(result int) FuncResult { return FuncResult{Result: result} } The idea is to create a channel from the struct, pass the channel to a function and wait for the result.

In 50′ and 60′ input data for programs from those years were written on paper tapes or punch cards. Writing code, compiling and testing loop took from a few hours to even few days. It was the beginning of programming we know it. At this time Dijkstra started his discovery. He conceived the algorithm called his name. He also noticed that programs become too complicated to be fully understood by one person.

Knowing the basics is the key to understanding more complex concepts. After reading this post you will know what are entities and value objects and find out differences between them. When you pay for something at a shop it’s not important which exactly coin you choose. The most important thing to the shop assistant is their value. It does not matter if you give him coin from the left or right pocket.