Add option to list releases

config.go

@@ -40,6 +40,7 @@ type ConfigRepository struct {
 	UpgradeOnly  bool     `toml:"upgrade_only"`
 	Verify       string   `toml:"verify_sha256"`
 	DisableSSL   bool     `toml:"disable_ssl"`
+	ListOnly     bool     `toml:"list_only"`
 }
 
 type Config struct {
@@ -247,6 +248,7 @@ func SetGlobalOptionsFromConfig(config *Config, parser *flags.Parser, opts *Flag
 	opts.Verify = update("", cli.Verify)
 	opts.Remove = update(false, cli.Remove)
 	opts.DisableSSL = update(false, cli.DisableSSL)
+	opts.ListOnly = update(false, cli.ListOnly)
 	return nil
 }
 
@@ -271,6 +273,7 @@ func SetProjectOptionsFromConfig(config *Config, parser *flags.Parser, opts *Fla
 			opts.UpgradeOnly = update(repo.UpgradeOnly, cli.UpgradeOnly)
 			opts.Verify = update(repo.Verify, cli.Verify)
 			opts.DisableSSL = update(repo.DisableSSL, cli.DisableSSL)
+			opts.ListOnly = update(repo.ListOnly, cli.ListOnly)
 			break
 		}
 	}

eget.go

@@ -423,6 +423,16 @@ func main() {
 		fatal(err)
 	}
 
+	if opts.ListOnly {
+		releases, err := finder.List()
+		if err != nil {
+			fatal(err)
+		}
+		r := strings.Join(releases, "\n* ")
+		fmt.Fprintf(output, "available releases in %s:\n* %v\n", target, r)
+		os.Exit(0)
+	}
+
 	detector, err := getDetector(&opts)
 	if err != nil {
 		fatal(err)

find.go

@@ -6,13 +6,15 @@ import (
 	"fmt"
 	"io"
 	"net/http"
+	"sort"
 	"strings"
 	"time"
 )
 
 // A Finder returns a list of URLs making up a project's assets.
 type Finder interface {
 	Find() ([]string, error)
+	List() ([]string, error)
 }
 
 // A GithubRelease matches the Assets portion of Github's release API json.
@@ -176,25 +178,47 @@ func (f *GithubAssetFinder) FindMatch() ([]string, error) {
 	return nil, fmt.Errorf("no matching tag for '%s'", tag)
 }
 
-// finds the latest pre-release and returns the tag
-func (f *GithubAssetFinder) getLatestTag() (string, error) {
+func (f *GithubAssetFinder) List() ([]string, error) {
+	releases, err := f.getAllReleases()
+	if err != nil {
+		return nil, fmt.Errorf("list releases: %w", err)
+	}
+	var tags []string
+	sort.Slice(releases, func(i, j int) bool {
+		return releases[i].CreatedAt.After(releases[j].CreatedAt)
+	})
+	for _, r := range releases {
+		tags = append(tags, r.Tag)
+	}
+	return tags, nil
+}
+
+func (f *GithubAssetFinder) getAllReleases() ([]GithubRelease, error) {
 	url := fmt.Sprintf("https://api.github.com/repos/%s/releases", f.Repo)
 	resp, err := Get(url)
 	if err != nil {
-		return "", fmt.Errorf("pre-release finder: %w", err)
+		return nil, fmt.Errorf("release finder: %w", err)
 	}
 
 	var releases []GithubRelease
 
 	body, err := io.ReadAll(resp.Body)
 	if err != nil {
-		return "", fmt.Errorf("pre-release finder: %w", err)
+		return nil, fmt.Errorf("release finder: %w", err)
 	}
 	err = json.Unmarshal(body, &releases)
 	if err != nil {
-		return "", fmt.Errorf("pre-release finder: %w", err)
+		return nil, fmt.Errorf("release finder: %w", err)
 	}
+	return releases, nil
+}
 
+// finds the latest pre-release and returns the tag
+func (f *GithubAssetFinder) getLatestTag() (string, error) {
+	releases, err := f.getAllReleases()
+	if err != nil {
+		return "", fmt.Errorf("pre-release finders: %w", err)
+	}
 	if len(releases) <= 0 {
 		return "", fmt.Errorf("no releases found")
 	}
@@ -210,6 +234,9 @@ type DirectAssetFinder struct {
 func (f *DirectAssetFinder) Find() ([]string, error) {
 	return []string{f.URL}, nil
 }
+func (f *DirectAssetFinder) List() ([]string, error) {
+	return f.Find()
+}
 
 type GithubSourceFinder struct {
 	Tool string
@@ -220,3 +247,6 @@ type GithubSourceFinder struct {
 func (f *GithubSourceFinder) Find() ([]string, error) {
 	return []string{fmt.Sprintf("https://github.com/%s/tarball/%s/%s.tar.gz", f.Repo, f.Tag, f.Tool)}, nil
 }
+func (f *GithubSourceFinder) List() ([]string, error) {
+	return f.Find()
+}

flags.go

@@ -16,6 +16,7 @@ type Flags struct {
 	Verify      string
 	Remove      bool
 	DisableSSL  bool
+	ListOnly    bool
 }
 
 type CliFlags struct {
@@ -38,4 +39,5 @@ type CliFlags struct {
 	Help        bool      `short:"h" long:"help" description:"show this help message"`
 	DownloadAll bool      `short:"D" long:"download-all" description:"download all projects defined in the config file"`
 	DisableSSL  *bool     `short:"k" long:"disable-ssl" description:"disable SSL verification for download requests"`
+	ListOnly    *bool     `short:"l" long:"list-only" description:"only list available releases, don't download any"`
 }