What are 'Import Side Effects' in Go and Why Are They Used?

Understanding 'import Side Effects' in Go

Importing packages in Go can have side effects, as mentioned in the effective.go resource. What exactly constitutes an 'import side effect'?

In this context, 'import side effects' refer to code or features that execute statically. Simply importing a package can cause code to run at the start of the application, modifying the system's state. Unlike packages used dynamically (e.g., calling functions), these side effects occur solely due to the import.

For instance, an imported package may have an init() method that registers handlers or performs other initialization tasks. These tasks are executed before the main function is called, potentially leading to changes in the system's configuration or resource allocation.

So why might a developer make a blank import (e.g., import _ "somepackageImNotUsingReally")? This approach explicitly indicates that the package is imported for its side effects, such as initializing resources or registering components, without the need to actively use it in the code.

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