distgen

Overview ¶

A simple generator for creating easily distributable Go packages.

This automation provides an easy way to generate variables that can be configured globally across multiple go packages, such as trademarks, product names, websites, etc. This generator should be defined as a "go:generate" comment and run at build time, using the "go generate" command.

Single Package Example ¶

Our first example involves a simple use within a single main package. First, create a file called dist_gen.go with the following command:

package main
//go:generate go run github.com/chef/go-libs/distgen

The automation will deploy a file called dist.go with all the variables defined inside the JSON file glob_dist.json inside this repository.

Multi-package Example ¶

In our second example involving multi-package, create a go package called "dist" with a file called gen.go with the following command:

package dist
//go:generate go run github.com/chef/go-libs/distgen global.go dist

This usage is for go projects that has multiple packages. By creating a single "dist" package inside your repository, you can import the generated package in any other packages. (See a real example at [example-multi-pkg/](example-multi-pkg).)

Custom JSON File Example ¶

To fully customize this automation, a user can provide a URL pointing to a custom JSON file as a third parameter of the "go:generate" directive. This custom JSON file should contain the global variables to generate. (See an example of a JSON file at [glob_dist.json](glob_dist.json).)

package dist
//go:generate go run github.com/chef/go-libs/distgen global.go dist https://example.com/path/to/glob_dist.json

Using an Environment Variable ¶

Using an environmental variable gives you more flexibility with CI systems. As we saw in the custom JSON file example, passing a URI to `go run` in the third argument overrides the default JSON file for `distgen`. The `DIST_FILE` environment performs the same function by overloading the default JSON file. The usage inside of your dist files will not change, but you can pass ENV as a part of your `go generate` command.

DIST_FILE="https://raw.githubusercontent.com/chef/go-libs/master/distgen/tiny_glob_dist.json" go generate