Add temp dir cleanup on startup

Adding a reliable way of cleaning up the contents of temp dir to make
sure it doesn't pile up terraform binaries and grow in size with every
restart.

main.go

@@ -5,6 +5,7 @@ import (
 	"crypto/sha256"
 	"fmt"
 	"io"
+	"log"
 	"os"
 	"os/signal"
 	"path/filepath"
@@ -411,6 +412,22 @@ preferences: {}
 
 }
 
+func cleanupTmpDir() {
+	tmpDir := os.TempDir()
+
+	files, err := os.ReadDir(tmpDir)
+	if err != nil {
+		log.Fatalf("Error reading directory: %v", err)
+	}
+
+	for _, file := range files {
+		filePath := fmt.Sprintf("%s/%s", tmpDir, file.Name())
+		if err := os.RemoveAll(filePath); err != nil {
+			log.Printf("Error deleting file %s: %v", filePath, err)
+		}
+	}
+}
+
 func main() {
 	app := &cli.App{
 		Name: "terraform-applier",
@@ -482,6 +499,8 @@ func run(c *cli.Context) {
 		}
 	}
 
+	cleanupTmpDir()
+
 	// Find the requested version of terraform and log the version
 	// information
 	execPath, cleanup, err := findTerraformExecPath(ctx, terraformPath, terraformVersion)