more

Dockerfile

@@ -0,0 +1,7 @@
+FROM ubuntu:latest
+
+COPY goenv /usr/local/bin
+
+RUN \
+    apt-get update \
+    && apt-get install -y ca-certificates

Makefile

@@ -0,0 +1,15 @@
+BUILD_METADATA=+$(shell git rev-parse --short HEAD)
+PRERELEASE=
+SEMVER=0.0.1
+
+build:
+	@go build -ldflags="-X 'github.com/drewgonzales360/goenv/version.Semver=${SEMVER}${PRERELEASE}${BUILD_METADATA}'"
+
+image: build
+	@docker build -t goenv .
+
+run-image:
+	@docker run --rm -it goenv bash -c 'goenv install 1.18; go version'
+
+tty:
+	@docker run --rm -it goenv bash

cmd/install.go

@@ -2,12 +2,11 @@ package cmd
 
 import (
 	"fmt"
-	"os"
 
 	"github.com/Masterminds/semver"
-	"github.com/urfave/cli/v2"
-
 	"github.com/drewgonzales360/goenv/pkg"
+	"github.com/pkg/errors"
+	"github.com/urfave/cli/v2"
 )
 
 const (
@@ -28,17 +27,14 @@ func Install(c *cli.Context) error {
 	downloadURL := pkg.FormatDownloadURL(*goVersion)
 	filePath, err := pkg.DownloadFile(downloadURL)
 	if err != nil {
-		return fmt.Errorf("could not download go")
+		return errors.Wrap(err, "could not download go")
 	}
 
 	err = pkg.ExtractTarGz(filePath, InstallDirectory+goVersion.Original())
 	if err != nil {
-		return fmt.Errorf("could not extract go")
-	}
-
-	if err := os.Symlink("/usr/local/bin/go", InstallDirectory+goVersion.Original()+"/bin/go"); err != nil {
-		return fmt.Errorf("could not link go")
+		return errors.Wrap(err, "could not extract go")
 	}
 
+	Use(c)
 	return nil
 }

cmd/use.go

@@ -2,11 +2,38 @@ package cmd
 
 import (
 	"fmt"
+	"os"
+	"os/exec"
 
+	"github.com/Masterminds/semver"
+	"github.com/pkg/errors"
 	"github.com/urfave/cli/v2"
 )
 
 func Use(c *cli.Context) error {
-	fmt.Println("Hello world!")
+	version := ""
+	if c.NArg() > 0 {
+		version = c.Args().Get(0)
+	}
+
+	goVersion, err := semver.NewVersion(version)
+	if err != nil {
+		return fmt.Errorf("could not parse version as a semver")
+	}
+
+	if err := os.Symlink(InstallDirectory+goVersion.Original()+"/bin/go", "/usr/local/bin/go"); err != nil {
+		return errors.Wrap(err, "could not link go")
+	}
+
+	if err := os.Symlink(InstallDirectory+goVersion.Original()+"/bin/gofmt", "/usr/local/bin/gofmt"); err != nil {
+		return errors.Wrap(err, "could not link gofmt")
+	}
+
+	output, _ := exec.Command("go version").Output()
+	if err != nil {
+		fmt.Println(err.Error())
+	}
+	fmt.Println(string(output))
+
 	return nil
 }

main.go

@@ -13,27 +13,31 @@ func main() {
 	app := &cli.App{
 		Name:    version.AppName,
 		Usage:   "Manages multiple go versions for linux",
-		Version: version.Version,
+		Version: version.Version().Original(),
 		Commands: []*cli.Command{
 			{
-				Name:   "install",
-				Usage:  "install a go version",
-				Action: cmd.Install,
+				Name:    "install",
+				Usage:   "install a go version",
+				Aliases: []string{"i"},
+				Action:  cmd.Install,
 			},
 			{
-				Name:   "uninstall",
-				Usage:  "uninstall a go version",
-				Action: cmd.Uninstall,
+				Name:    "uninstall",
+				Usage:   "uninstall a go version",
+				Aliases: []string{"rm"},
+				Action:  cmd.Uninstall,
 			},
 			{
-				Name:   "use",
-				Usage:  "use a go version",
-				Action: cmd.Use,
+				Name:    "use",
+				Usage:   "use a go version",
+				Aliases: []string{"u"},
+				Action:  cmd.Use,
 			},
 			{
-				Name:   "list",
-				Usage:  "list all available go versions",
-				Action: cmd.List,
+				Name:    "list",
+				Usage:   "list all available go versions",
+				Aliases: []string{"ls", "l"},
+				Action:  cmd.List,
 			},
 		},
 	}

pkg/util.go

@@ -11,9 +11,8 @@ import (
 	"strings"
 	"time"
 
-	"github.com/pkg/errors"
-
 	"github.com/Masterminds/semver"
+	"github.com/pkg/errors"
 )
 
 const (
@@ -37,7 +36,13 @@ func RandomString() string {
 }
 
 func FormatDownloadURL(v semver.Version) string {
-	return fmt.Sprintf("https://go.dev/dl/go%s.linux-amd64.tar.gz", v.String())
+	urlVersion := v.String()
+	// If we have 1.18, we'd parse the version to 1.18.0, but the URL doesn't
+	// actually inclued the last .0
+	if v.Patch() == 0 {
+		urlVersion = strings.TrimSuffix(urlVersion, ".0")
+	}
+	return fmt.Sprintf("https://go.dev/dl/go%s.linux-amd64.tar.gz", urlVersion)
 }
 
 // DownloadFile will download a url to a local file. It's efficient because it will
@@ -105,6 +110,12 @@ func ExtractTarGz(tarballPath, destinationPath string) error {
 			if _, err := io.Copy(outFile, tarReader); err != nil {
 				return errors.Wrap(err, "could not write to file")
 			}
+
+			err = os.Chmod(outFile.Name(), header.FileInfo().Mode())
+			if err != nil {
+				return errors.Wrap(err, "could not set extracted file permissions")
+			}
+
 			outFile.Close()
 
 		default:

version/version.go

@@ -1,7 +1,15 @@
 package version
 
+import (
+	"github.com/Masterminds/semver"
+)
+
 // AppName represents the name of the application
-const AppName = "app-name"
+const AppName = "goenv"
 
 // Version semvers the app
-const Version = "0.0.1"
+var Semver string = "unknown; please create an issue for the maintainers"
+
+func Version() *semver.Version {
+	return semver.MustParse(Semver)
+}