Auto-install a version when it is missing

README.md

@@ -78,6 +78,13 @@ tfversion use --latest --pre-release
 tfversion use --required
 ```
 
+### Automatically install a version when using
+
+```sh
+tfversion use 1.7.4 --install
+tfversion use --latest --install
+```
+
 ### Create and use an alias
 
 ```sh

cmd/use.go

@@ -22,11 +22,16 @@ const (
 		"\n" +
 		"\n" +
 		"# Use the required Terraform version for your current directory\n" +
-		"tfversion use --required"
+		"tfversion use --required\n" +
+		"\n" +
+		"\n" +
+		"# Automatically install the target version if it is missing\n" +
+		"tfversion use 1.7.3 --install"
 )
 
 var (
-	useCmd = &cobra.Command{
+	autoInstall bool
+	useCmd      = &cobra.Command{
 		Use:     "use",
 		Short:   "Activates a given Terraform version",
 		Example: useExample,
@@ -43,7 +48,7 @@ var (
 					err := helpers.ErrorWithHelp("tfversion use -h")
 					helpers.ExitWithError("`--latest` flag does not require specifying a Terraform version", err)
 				}
-				use.UseLatestVersion(preRelease)
+				use.UseLatestVersion(preRelease, autoInstall)
 				os.Exit(0)
 			}
 
@@ -53,7 +58,7 @@ var (
 					err := helpers.ErrorWithHelp("tfversion use -h")
 					helpers.ExitWithError("`--required` flag does not require specifying a Terraform version", err)
 				}
-				use.UseRequiredVersion()
+				use.UseRequiredVersion(autoInstall)
 				os.Exit(0)
 			}
 
@@ -62,7 +67,7 @@ var (
 				err := helpers.ErrorWithHelp("tfversion use -h")
 				helpers.ExitWithError("provide a Terraform version to activate", err)
 			}
-			use.UseVersion(args[0])
+			use.UseVersion(args[0], autoInstall)
 		},
 	}
 )
@@ -72,4 +77,5 @@ func init() {
 	useCmd.Flags().BoolVar(&latest, "latest", false, "use the latest stable Terraform version")
 	useCmd.Flags().BoolVar(&preRelease, "pre-release", false, "When used with --latest, use the latest pre-release version")
 	useCmd.Flags().BoolVar(&required, "required", false, "use the required Terraform version for your current directory")
+	useCmd.Flags().BoolVar(&autoInstall, "install", false, "automatically install if the target version is missing")
 }

pkg/use/use.go

@@ -10,11 +10,12 @@
 	"github.com/tfversion/tfversion/pkg/alias"
 	"github.com/tfversion/tfversion/pkg/download"
 	"github.com/tfversion/tfversion/pkg/helpers"
+	"github.com/tfversion/tfversion/pkg/install"
 	"github.com/tfversion/tfversion/pkg/list"
 )
 
 // UseVersion activates the specified Terraform version or one of the latest versions
-func UseVersion(versionOrAlias string) {
+func UseVersion(versionOrAlias string, autoInstall bool) {
 
 	// find the version (via alias or directly)
 	var version string
@@ -26,14 +27,16 @@
 
 	// check if the version is installed
 	if !download.IsAlreadyDownloaded(version) {
-		err := fmt.Errorf("terraform version %s not found, run %s to install", helpers.ColoredVersion(version), helpers.ColoredInstallHelper(version))
-		helpers.ExitWithError("using", err)
+		if !autoInstall {
+			err := fmt.Errorf("terraform version %s not found, run %s to install", helpers.ColoredVersion(version), helpers.ColoredInstallHelper(version))
+			helpers.ExitWithError("using", err)
+		}
+		install.InstallVersion(version)
 	}
 
-	useLocation := GetUseLocation()
-
 	// inform the user that they need to update their PATH
 	path := os.Getenv("PATH")
+	useLocation := getUseLocation()
 	if !strings.Contains(path, useLocation) {
 		fmt.Printf("%s not found in your shell PATH\n", color.CyanString(useLocation))
 		fmt.Printf("Please run %s to make this version available in your shell\n", color.CyanString("`export PATH=%s:$PATH`", useLocation))
@@ -62,13 +65,13 @@
 }
 
 // UseLatestVersion activates the latest Terraform version
-func UseLatestVersion(preRelease bool) {
+func UseLatestVersion(preRelease bool, autoInstall bool) {
 	version := list.FindLatestVersion(preRelease)
-	UseVersion(version)
+	UseVersion(version, autoInstall)
 }
 
 // UseRequiredVersion activates the required Terraform version from the .tf files in the current directory
-func UseRequiredVersion() {
+func UseRequiredVersion(autoInstall bool) {
 	terraformFiles, err := helpers.FindTerraformFiles()
 	if err != nil {
 		helpers.ExitWithError("finding Terraform files", err)
@@ -93,7 +96,7 @@
 		helpers.ExitWithError("installing required version", err)
 	}
 
-	UseVersion(foundVersion)
+	UseVersion(foundVersion, autoInstall)
 }
 
 func GetUseLocation() string {