Naming Go Packages: Best Practices and Common Mistakes

When it comes to writing code, one of the most important aspects to consider is naming. This is particularly true when it comes to organizing Go code into packages. Go code is organized into packages, and each package contains exported types, functions, constants, and variables that can be used by clients of the package.

Good package names are short, clear, and provide context for the package’s contents, making it easier for clients to understand what the package is for and how to use it. They also help package maintainers determine what does and does not belong in the package as it evolves. Well-named packages make it easier to find the code you need and ensure that the package is used correctly.

This article will provide practical guidelines and examples for naming Go packages. It will cover package naming conventions, best practices for naming package contents, package path naming conventions, and how to fix common mistakes in package naming. By following these guidelines, you can improve your code organization, readability, and maintainability.

Package Naming Conventions

When it comes to naming packages in Go, there are several conventions that you should follow to ensure that your code is organized and easy to understand. In this section, we’ll cover some of the most important package naming conventions.

Choose Descriptive, Short, and Simple Package Names

Good package names are descriptive, short, and simple. They should provide context for the package’s contents, but not be so long that they become unwieldy. Short names are easier to type and remember, and they make it easier to scan through code and find what you need.

Package names should be lowercase, with no under_scores or mixedCaps. They are often simple nouns that describe the functionality of the package. For example, the time package provides functionality for measuring and displaying time, the list package implements a doubly linked list, and the http package provides HTTP client and server implementations.

Abbreviate Judiciously

You can abbreviate package names when the abbreviation is familiar to the programmer. Widely-used packages often have compressed names like strconv (string conversion), syscall (system call), or fmt (formatted I/O). However, if abbreviating a package name makes it ambiguous or unclear, don’t do it.

Don’t Steal Good Names from the User

Avoid giving a package a name that is commonly used in client code. For example, the buffered I/O package is called bufio, not buf, since buf is a good variable name for a buffer.

Using Meaningful Prefixes

In Go, the package name serves as a prefix for its contents. As such, you don’t need to repeat the package name in the name of its contents. For instance, the HTTP server provided by the http package is called Server, not HTTPServer. Client code refers to this type as http.Server, so there is no ambiguity.

Additionally, if you cannot come up with a package name that’s a meaningful prefix for the package’s contents, the package abstraction boundary may be wrong. In this case, write code that uses your package as a client would, and restructure your packages if the result seems poor.

By following these package naming conventions, you can ensure that your code is organized and easy to understand. In the next section, we’ll cover best practices for naming package contents.

Package Naming Best Practices

While following package naming conventions is important, it’s also essential to consider the package’s contents when naming a package. In this section, we’ll cover best practices for naming package contents.

Avoid Repetition

Since client code uses the package name as a prefix when referring to the package contents, the names for those contents need not repeat the package name. For example, if you have a package named “http” and a type called “HTTPClient,” you should rename the type to “Client” to avoid repetition.

Simplify Function Names

When a function in package pkg returns a value of type pkg.Pkg (or *pkg.Pkg), the function name can often omit the type name without confusion. For example, you can call a function that returns a time.Time value “Now” instead of “TimeNow.” Similarly, you can call a function that returns a net.IP value “FromContext” instead of “UserIPFromContext.”

Use Abbreviations Judiciously

As mentioned earlier, abbreviations should be used judiciously. If you’re using an abbreviation, make sure it’s familiar to the programmer, and avoid abbreviations that make the package name ambiguous or unclear.

Avoid Stealing Good Names from the User

Avoid giving a package a name that is commonly used in client code. For example, if you have a package that provides functionality for working with buffers, don’t call it “Buf.” Instead, consider a more specific name like “BufferIO.”

When naming package contents, it’s also important to consider the client’s point of view. This will help ensure that the package contents are named in a way that makes sense and is easy to use. In the next section, we’ll cover package path naming conventions.

Package Path Naming

In Go, a package has both a name and a path. The package name is specified in the package statement of its source files and is used as the prefix for the package’s exported names. Client code uses the package path when importing the package. In this section, we’ll cover package path naming conventions.

Use Meaningful Package Paths

When choosing a package path, use a meaningful path that describes the functionality of the package. For example, the path “github.com/yourname/projectname/pkg/stringutil” describes a package that provides string manipulation utilities for your project.

By using meaningful package paths, you can make it easier for other developers to understand the purpose of your package and how it fits into the broader ecosystem of your project.

Use a Consistent Structure

To make your code more organized, use a consistent package path structure. For example, you might structure your package paths like this:

github.com/yourname/projectname/pkg/subpackage

In this structure, the “pkg” directory contains all of the packages for your project, and each subdirectory contains a separate subpackage.

Use Directory Names to Group Packages

In Go, packages can be grouped into directories based on related protocols and algorithms. For example, the standard library uses directories like crypto, container, encoding, and image to group related packages.

By grouping packages into directories, you can make it easier to find the package you need and ensure that your code is organized in a logical way.

Avoid Package Name Collisions

To avoid package name collisions, make sure that packages that are frequently used together have distinct names. This will reduce confusion and the need for local renaming in client code. Also, avoid using the same name as popular standard packages like io or http.

By following these package path naming conventions, you can ensure that your code is well-organized, easy to understand, and less prone to naming conflicts. In the next section, we’ll cover common mistakes in package naming and how to fix them.

Fixing Bad Package Names

Bad package names can make your code harder to navigate and maintain. In this section, we’ll cover common mistakes in package naming and how to fix them.

Avoid Meaningless Package Names

Packages named “util,” “common,” or “misc” provide clients with no sense of what the package contains. This makes it harder for clients to use the package and makes it harder for maintainers to keep the package focused. Over time, they accumulate dependencies that can make compilation significantly slower, especially in large programs.

To fix such packages, look for types and functions with common name elements and pull them into their own package. For example, if you have a package named “util” that contains functions like “NewStringSet” and “SortStringSet,” you could create a new package called “stringset” and move these functions into it.

Don’t Use a Single Package for All Your APIs

Many programmers put all the interfaces exposed by their program into a single package named “api,” “types,” or “interfaces,” thinking it makes it easier to find the entry points to their codebase. This is a mistake. Such packages suffer from the same problems as those named “util” or “common,” growing without bound, providing no guidance to users, accumulating dependencies, and colliding with other imports.

To fix such packages, break them up, perhaps using directories to separate public packages from implementation. For example, you might create a separate package for each API and group them into a directory called “api.”

Avoid Unnecessary Package Name Collisions

While packages in different directories may have the same name, packages that are frequently used together should have distinct names. This reduces confusion and the need for local renaming in client code. Also, avoid using the same name as popular standard packages like “io” or “http.”

To fix such packages, rename the package or use a more specific name that accurately describes its contents. For example, if you have a package named “http” that provides an HTTP client and server implementation, you could rename it to “httputil” to avoid collisions with the standard “http” package.

Conclusion

In this article, we’ve covered package naming conventions, best practices, and how to fix bad package names. We’ve seen that good package names make code better by providing context for its contents, making it easier for clients to understand what the package is for and how to use it. A well-named package also helps package maintainers determine what does and does not belong in the package as it evolves.

We’ve seen that good package names are short, clear, and lower case, with no under_scores or mixedCaps. We’ve also seen that it’s important to avoid meaningless package names, using a consistent structure, grouping packages into directories, and avoiding package name collisions.

By following these guidelines, you can make your code more organized, easier to understand, and less prone to naming conflicts. Good package naming is central to good naming in Go programs, and taking the time to choose good package names and organize your code well can make your packages more usable and maintainable.