gvm

Version Manager

Version manager allows you to manage and download the latest software versions for your applications from GitHub Releases.

Example use

Creating an instance of Version Manager

First set the archive location

dlPath, _ := ioutil.TempDir("", "")

Then set the options for the GitHub organization and the repository, the architecture and operating system are determined at runtime, you can override these values.

	o := Options{
		Organization: "nicholasjackson",
		Repo:         "fake-service",
		ReleasesPath: dlPath,
		//GOOS:         "linux",
		//GOARCH:       "x64",
	}

To determine the name of the asset you define a function, tools like GoReleaser will use formularic naming for assets added to a release. The asset name may be an archive, in this instance Version Manager will automatically unpack the archive.

	nf := func(goos, goarch string) string {
		baseName := "fake-service"

		switch goos {
		case "darwin":
			return fmt.Sprintf("%s-osx", baseName)
		case "linux":
			return fmt.Sprintf("%s-linux", baseName)
		case "windows":
			return fmt.Sprintf("%s.exe", baseName)
		}

		return ""
	}

	o.AssetNameFunc = nf

In the instance that the release asset is an archive you can define a second function to determine the name of the executable within the archive. In the instance that the asset is a simple binary you can set this to the same function as previously used.

	o.ExeNameFunc = nf

You can now create a new instance of Version Manager

  v := New(o)

Listing Releases on GitHub

To list available releases you can use the ListReleases method, this takes a single parameter of a Semantic Version constraint. For example, to list all the releases >= 1.2.3, < 2.0.0, you would specify a constraint of ^1.2.3. Version manager returns you a map of release name and asset download URL.

r, err := v.ListReleases("^1.2.3")
for version, url := range r {
  fmt.Println("Version:", version, "URL:", url)
}

Downloading the latest version matching the constraint

To download the latest version which matches the given constraint.

tag, url, err := v.GetLatestReleaseURL("~v0.12.0")
assert.NoError(t, err)

dl, err := v.DownloadRelease(tag, url)
assert.NoError(t, err)