Go Plugin System

Private linters can be added through Go's plugin system.

For a private linter (which acts as a plugin) to work properly, the plugin as well as the golangci-lint binary needs to be built for the same environment.

CGO_ENABLED is another requirement.

This means that golangci-lint needs to be built for whatever machine you intend to run it on (cloning the golangci-lint repository and running a CGO_ENABLED=1 make build should do the trick for your machine).

Create a Plugin

Your linter must provide one or more golang.org/x/tools/go/analysis.Analyzer structs.

Your project should also use go.mod.

All versions of libraries that overlap golangci-lint (including replaced libraries) MUST be set to the same version as golangci-lint. You can see the versions by running go version -m golangci-lint.

You'll also need to create a Go file like plugin/example.go.

This file MUST be in the package main, and MUST define an exposed function called New with the following signature:

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func New(conf any) ([]*analysis.Analyzer, error) {
    // ...
}

See plugin/example.go for more info.

To build the plugin, from the root project directory, run:

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go build -buildmode=plugin plugin/example.go

This will create a plugin *.so file that can be copied into your project or another well known location for usage in golangci-lint.

Configure a Plugin

If you already have a linter plugin available, you can follow these steps to define its usage in a projects .golangci.yml file.

An example linter can be found at here.

If you're looking for instructions on how to configure your own custom linter, they can be found further down.

1. If the project you want to lint does not have one already, copy the .golangci.yml to the root directory.
2. Adjust the yaml to appropriate linters-settings.custom entries as so:

   .golangci.yml
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   linters-settings:
     custom:
       example:
         path: /example.so
         description: The description of the linter
         original-url: github.com/golangci/example-linter
         settings: # Settings are optional.
           one: Foo
           two:
             - name: Bar
           three:
             name: Bar

That is all the configuration that is required to run a custom linter in your project.

Custom linters are enabled by default, but abide by the same rules as other linters.

If the disable all option is specified either on command line or in .golang.yml files linters.disable-all: true, custom linters will be disabled; they can be re-enabled by adding them to the linters.enable list, or providing the enabled option on the command line, golangci-lint run -Eexample.

The configuration inside the settings field of linter have some limitations (there are NOT related to the plugin system itself): we use Viper to handle the configuration but Viper put all the keys in lowercase, and . cannot be used inside a key.