#15 Added use command.

internal/commands/help_command.go

@@ -20,6 +20,7 @@ Commands:
   list		List terraform versions.
   install	Install terraform version.
   which		Print selected terraform version.
+  use		Change selected version in .terraform-version file.
   uptodate	Check for updates.
   help		Print this usage information.
   version	Print tfvm version.

internal/commands/tfvm_command.go

@@ -23,6 +23,8 @@ func RunTfvmCommand(args []string) error {
 	} else if args[0] == "info" {
 		printInfo()
 		return nil
+	} else if args[0] == "use" {
+		return RunTfvmUseCommand(args[1:])
 	} else if args[0] == "version" {
 		printVersion()
 		return nil

internal/commands/use_command.go

@@ -0,0 +1,65 @@
+package commands
+
+import (
+	"errors"
+	inventoryPkg "github.com/cbuschka/tfvm/internal/inventory"
+	"github.com/cbuschka/tfvm/internal/util"
+	"github.com/cbuschka/tfvm/internal/version"
+	workspacePkg "github.com/cbuschka/tfvm/internal/workspace"
+)
+
+func RunTfvmUseCommand(args []string) error {
+	inventory, err := inventoryPkg.GetInventory()
+	if err != nil {
+		return err
+	}
+
+	err = inventory.Update()
+	if err != nil {
+		return err
+	}
+
+	versionSpec, err := getTfVersionSpecToUse(args)
+	if err != nil {
+		return err
+	}
+
+	_, err = inventory.GetTerraformRelease(versionSpec)
+	if err != nil {
+		if version.IsNoSuchTerraformRelease(err) {
+			util.Die(1, "No matching terraform version for %s.", versionSpec.String())
+			return err
+		}
+		return err
+	}
+
+	workspace, err := workspacePkg.GetWorkspace()
+	if err != nil {
+		return err
+	}
+
+	err = workspace.WriteTerraformVersionSelection(versionSpec.String())
+	if err != nil {
+		if workspacePkg.IsNoConfigExists(err) {
+			util.Die(1, "No .terraform-version found.")
+		}
+		return err
+	}
+
+	return nil
+}
+
+func getTfVersionSpecToUse(args []string) (*version.TerraformVersionSpec, error) {
+	if len(args) != 1 {
+		util.Die(1, "Version to use required.")
+		return nil, errors.New("unreachable code")
+	}
+
+	versionSpec, err := version.ParseTerraformVersionSpec(args[0])
+	if err != nil {
+		util.Die(1, "Invalid version '%s'.", args[0])
+		return nil, errors.New("unreachable code")
+	}
+
+	return versionSpec, nil
+}

internal/workspace/config.go

@@ -11,7 +11,7 @@ import (
 
 const noConfigExistsMsg = "config not exists"
 
-func isNoConfigExists(err error) bool {
+func IsNoConfigExists(err error) bool {
 	return err.Error() == noConfigExistsMsg
 }
 

internal/workspace/workspace.go

@@ -5,6 +5,8 @@ import (
 	"fmt"
 	"github.com/cbuschka/tfvm/internal/util"
 	"github.com/cbuschka/tfvm/internal/version"
+	"io/ioutil"
+	"os"
 )
 
 type Workspace struct {
@@ -51,6 +53,27 @@ func newNoTfVersionSelected() error {
 	return errors.New(noTfVersionSelectedMsg)
 }
 
+func (workspace *Workspace) WriteTerraformVersionSelection(tfVersionSelection string) error {
+	configFile, err := getNearestConfigFileFromCwd()
+	if err != nil {
+		if os.IsNotExist(err) {
+			return newNoConfigExists()
+		}
+
+		return err
+	}
+
+	err = ioutil.WriteFile(configFile, []byte(tfVersionSelection), 0644)
+	if err != nil {
+		return nil
+	}
+
+	util.Print("%s written.", configFile)
+
+	return nil
+
+}
+
 func (workspace *Workspace) GetTerraformVersionSelection() (*TerraformVersionSelection, error) {
 
 	tfVersionEnvVar := util.GetFirstEnv("TFVM_TERRAFORM_VERSION", "TERRAFORM_VERSION")
@@ -66,7 +89,7 @@ func (workspace *Workspace) GetTerraformVersionSelection() (*TerraformVersionSel
 
 	config, err := getConfiguration()
 	if err != nil {
-		if isNoConfigExists(err) {
+		if IsNoConfigExists(err) {
 			return nil, newNoTfVersionSelected()
 		}
 		return nil, err