From 06ccdd0ade184a214c261931558d1bad07985a8c Mon Sep 17 00:00:00 2001
From: Ringo Hoffmann <r.hoffmann@b12-gruppe.de>
Date: Thu, 5 Dec 2024 15:59:34 +0100
Subject: [PATCH] add parameter for terraform/tofu executable

---
 cmd/root.go      | 25 +++++++++++++++++++++++++
 cmd/util.go      |  9 ++++++---
 cmd/util_test.go |  4 ++++
 3 files changed, 35 insertions(+), 3 deletions(-)

diff --git a/cmd/root.go b/cmd/root.go
index 86e1ef9..455d562 100644
--- a/cmd/root.go
+++ b/cmd/root.go
@@ -4,7 +4,9 @@ Copyright © 2023 Takafumi Miyanaga miya.org.0309@gmai.com
 package cmd
 
 import (
+	"fmt"
 	"os"
+	"os/exec"
 
 	"github.com/spf13/cobra"
 )
@@ -18,11 +20,34 @@ You can interactivity select resource to ( plan | appply | destroy ) with target
 `,
 }
 
+func init() {
+	executable := os.Getenv("TFTARGET_EXECUTABLE")
+	if executable == "" {
+		if existsInPath("terraform") {
+			executable = "terraform"
+		} else if existsInPath("tofu") {
+			executable = "tofu"
+		} else {
+			fmt.Println("Error: no terraform executable found in PATH")
+			os.Exit(1)
+		}
+	}
+	rootCmd.PersistentFlags().StringP("executable", "e", executable, "The name or path of the terraform executable")
+}
+
+// existsInPath returns true if name is available in any of the paths listed
+// in the PATH variable.
+func existsInPath(name string) bool {
+	_, err := exec.LookPath(name)
+	return err == nil
+}
+
 // Execute adds all child commands to the root command and sets flags appropriately.
 // This is called by main.main(). It only needs to happen once to the rootCmd.
 func Execute() {
 	s.Suffix = " loading ..."
 	s.Color("green")
+
 	err := rootCmd.Execute()
 	if err != nil {
 		os.Exit(1)
diff --git a/cmd/util.go b/cmd/util.go
index 4ce4520..051c040 100644
--- a/cmd/util.go
+++ b/cmd/util.go
@@ -24,10 +24,12 @@ func executePlan(cmd *cobra.Command, option string) ([]string, error) {
 	if err := validateFlagValue(action, validValues); action != "" && err != nil {
 		return nil, err
 	}
+
+	executable, _ := cmd.Flags().GetString("executable")
 	p, _ := cmd.Flags().GetInt("parallel")
-	planCmd := exec.Command("terraform", "plan", "-no-color", fmt.Sprintf("--parallelism=%d", p))
+	planCmd := exec.Command(executable, "plan", "-no-color", fmt.Sprintf("--parallelism=%d", p))
 	if option != "" {
-		planCmd = exec.Command("terraform", "plan", option, "-no-color", fmt.Sprintf("--parallelism=%d", p))
+		planCmd = exec.Command(executable, "plan", option, "-no-color", fmt.Sprintf("--parallelism=%d", p))
 	}
 
 	out, err := planCmd.CombinedOutput()
@@ -103,7 +105,8 @@ func slice2String(slice []string) string {
 
 func genTargetCmd(cmd *cobra.Command, action, target string) bytes.Buffer {
 	var buf bytes.Buffer
-	buf.WriteString("terraform " + action + " -target=" + target)
+	executable, _ := cmd.Flags().GetString("executable")
+	buf.WriteString(executable + " " + action + " -target=" + target)
 	p, _ := cmd.Flags().GetInt("parallel")
 	buf.WriteString(fmt.Sprintf(" --parallelism=%d", p))
 	return buf
diff --git a/cmd/util_test.go b/cmd/util_test.go
index 698115d..c72d57f 100644
--- a/cmd/util_test.go
+++ b/cmd/util_test.go
@@ -210,6 +210,10 @@ func Test_genTargetCmd(t *testing.T) {
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
+			// The --executable flag is a persistent flag set by the root command, but because the default value of it
+			// is not passed to the command because it was not executed through the root command, the flag is set here
+			// as flag with the expected test value set as default value.
+			tt.cmd.Flags().String("executable", "terraform", "")
 			got := genTargetCmd(tt.cmd, tt.action, tt.input)
 			if diff := cmp.Diff(got.String(), tt.want); diff != "" {
 				t.Errorf("genTargetCmd (-got +want):%s", diff)