waterdrink / importas

linter to enforce consistent import aliases

A linter to enforce importing certain packages consistently.

What is this for?

Ideally, go imports should avoid aliasing. Sometimes though, especially with Kubernetes API code, it becomes unavoidable, because many packages are imported as e.g. "[package]/v1alpha1" and you end up with lots of collisions if you use "v1alpha1".

This linter lets you enforce that whenever (for example) "pkg/apis/serving/v1alpha1" is aliased, it is aliased as "servingv1alpha1".

Usage

importas \
  -alias knative.dev/serving/pkg/apis/autoscaling/v1alpha1:autoscalingv1alpha1 \
  -alias knative.dev/serving/pkg/apis/serving/v1:servingv1 \
  ./...

-no-unaliased option

By default, importas allows non-aliased imports, even when the package is specified by -alias flag. With -no-unaliased option, importas does not allow this.

importas -no-unaliased \
  -alias knative.dev/serving/pkg/apis/autoscaling/v1alpha1:autoscalingv1alpha1 \
  -alias knative.dev/serving/pkg/apis/serving/v1:servingv1 \
  ./...

-no-extra-aliases option

By default, importas allows aliases which are not specified by -alias flags. With -no-extra-aliases option, importas does not allow any unspecified aliases.

importas -no-extra-aliases \
  -alias knative.dev/serving/pkg/apis/autoscaling/v1alpha1:autoscalingv1alpha1 \
  -alias knative.dev/serving/pkg/apis/serving/v1:servingv1 \
  ./...

Use regular expression

You can specify the package path by regular expression, and alias by regular expression replacement syntax like following snippet.

importas -alias 'knative.dev/serving/pkg/apis/(\w+)/(v[\w\d]+):$1$2'

$1 represents the text of the first submatch. See detail.

So it will enforce that

"knative.dev/serving/pkg/apis/autoscaling/v1alpha1" is aliased by "autoscalingv1alpha1", and "knative.dev/serving/pkg/apis/serving/v1" is aliased by "servingv1"