add "config format" command

Makefile

@@ -8,19 +8,19 @@ bin/bindownloader: gobuildcache
 bins += bin/bindownloader
 
 bin/golangci-lint: bin/bindownloader
-	bin/bindownloader $@
+	bin/bindownloader download $@
 bins += bin/golangci-lint
 
 bin/gobin: bin/bindownloader
-	bin/bindownloader $@
+	bin/bindownloader download $@
 bins += bin/gobin
 
 bin/goreleaser: bin/bindownloader
-	bin/bindownloader $@
+	bin/bindownloader download $@
 bins += bin/goreleaser
 
 bin/semver-next: bin/bindownloader
-	bin/bindownloader $@
+	bin/bindownloader download $@
 bins += bin/semver-next
 
 GOIMPORTS_REF := 8aaa1484dc108aa23dcf2d4a09371c0c9e280f6b

cmd/bindownloader/main.go

@@ -1,7 +1,9 @@
 package main
 
 import (
+	"encoding/json"
 	"fmt"
+	"io/ioutil"
 	"os"
 	"path"
 	"runtime"
@@ -11,23 +13,26 @@ import (
 )
 
 var kongVars = kong.Vars{
-	"arch_help":       `download for this architecture`,
-	"arch_default":    runtime.GOARCH,
-	"os_help":         `download for this operating system`,
-	"os_default":      runtime.GOOS,
-	"config_help":     `file with tool definitions`,
-	"config_default":  `buildtools.json`,
-	"force_help":      `force download even if it already exists`,
-	"cellar_dir_help": `directory where downloads will be cached`,
+	"arch_help":          `download for this architecture`,
+	"arch_default":       runtime.GOARCH,
+	"os_help":            `download for this operating system`,
+	"os_default":         runtime.GOOS,
+	"configfile_help":    `file with tool definitions`,
+	"configfile_default": `buildtools.json`,
+	"force_help":         `force download even if it already exists`,
+	"cellar_dir_help":    `directory where downloads will be cached`,
+	"config_format_help": `formats the config file`,
+	"download_help":      `download a bin`,
 }
 
 var version = "unknown"
 
 var cli struct {
-	Version   versionCmd  `kong:"cmd"`
-	Download  downloadCmd `kong:"cmd"`
-	Config    string      `kong:"type=path,help=${config_help},default=${config_default}"`
-	CellarDir string      `kong:"type=path,help=${cellar_dir_help}"`
+	Version    versionCmd  `kong:"cmd"`
+	Download   downloadCmd `kong:"cmd,help=${download_help}"`
+	Config     configCmd   `kong:"cmd"`
+	Configfile string      `kong:"type=path,help=${configfile_help},default=${configfile_default}"`
+	CellarDir  string      `kong:"type=path,help=${cellar_dir_help}"`
 }
 
 type versionCmd struct{}
@@ -45,9 +50,9 @@ type downloadCmd struct {
 }
 
 func (d *downloadCmd) Run(*kong.Context) error {
-	config, err := bindownloader.LoadConfigFile(cli.Config)
+	config, err := bindownloader.LoadConfigFile(cli.Configfile)
 	if err != nil {
-		return fmt.Errorf("error loading config from %q\n", cli.Config)
+		return fmt.Errorf("error loading config from %q", cli.Configfile)
 	}
 	binary := path.Base(d.TargetFile)
 	binDir := path.Dir(d.TargetFile)
@@ -57,8 +62,7 @@ func (d *downloadCmd) Run(*kong.Context) error {
 		return fmt.Errorf(`no downloader configured for:
 bin: %s
 os: %s
-arch: %s
-`, binary, d.OS, d.Arch)
+arch: %s`, binary, d.OS, d.Arch)
 	}
 
 	installOpts := bindownloader.InstallOpts{
@@ -71,6 +75,24 @@ arch: %s
 	return downloader.Install(installOpts)
 }
 
+type configCmd struct {
+	Format configFmtCmd `kong:"cmd,help=${config_format_help}"`
+}
+
+type configFmtCmd struct{}
+
+func (c configFmtCmd) Run() error {
+	config, err := bindownloader.LoadConfigFile(cli.Configfile)
+	if err != nil {
+		return err
+	}
+	b, err := json.MarshalIndent(&config, "", "  ")
+	if err != nil {
+		return err
+	}
+	return ioutil.WriteFile(cli.Configfile, b, 0600)
+}
+
 func main() {
 	parser := kong.Must(&cli, kongVars, kong.UsageOnError())
 

downloader.go

@@ -16,16 +16,16 @@ import (
 
 // Downloader downloads a binary
 type Downloader struct {
-	URL         string `json:"url"`
-	Checksum    string `json:"checksum"`
-	BinName     string `json:"bin"`
-	ArchivePath string `json:"archive_path"`
-	Link        bool   `json:"link"`
 	OS          string `json:"os"`
 	Arch        string `json:"arch"`
+	URL         string `json:"url"`
+	Checksum    string `json:"checksum,omitempty"`
+	ArchivePath string `json:"archive_path,omitempty"`
+	Link        bool   `json:"link,omitempty"`
+	BinName     string `json:"bin,omitempty"`
 
 	// Deprecated: use ArchivePath
-	MoveFrom string `json:"move-from"`
+	MoveFrom string `json:"move-from,omitempty"`
 
 	// Deprecated: use ArchivePath and Link
 	LinkSource string `json:"symlink,omitempty"`