Use lock to prevent simultaneous file access

terraform-provider-openstack · Jun 20, 2023 · 3d8b9f1 · 3d8b9f1
1 parent 9054e67
commit 3d8b9f1
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Showing 2 changed files with 14 additions and 6 deletions.
diff --git a/openstack/images_image_v2.go b/openstack/images_image_v2.go
@@ -15,12 +15,14 @@ import (
 	"regexp"
 	"strings"
 
-	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/resource"
-	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/schema"
-
 	"github.com/gophercloud/gophercloud"
 	"github.com/gophercloud/gophercloud/openstack/imageservice/v2/images"
 	"github.com/gophercloud/gophercloud/openstack/imageservice/v2/members"
+	"github.com/gophercloud/utils/terraform/mutexkv"
+
+	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/resource"
+	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/schema"
+
 	"github.com/ulikunitz/xz"
 )
 
@@ -86,7 +88,7 @@ func resourceImagesImageV2FileProps(filename string) (int64, string, error) {
 	return filesize, filechecksum, nil
 }
 
-func resourceImagesImageV2File(client *gophercloud.ServiceClient, d *schema.ResourceData) (string, error) {
+func resourceImagesImageV2File(client *gophercloud.ServiceClient, d *schema.ResourceData, mutexKV *mutexkv.MutexKV) (string, error) {
 	if filename := d.Get("local_file_path").(string); filename != "" {
 		return filename, nil
 	}
@@ -101,7 +103,12 @@ func resourceImagesImageV2File(client *gophercloud.ServiceClient, d *schema.Reso
 		return "", fmt.Errorf("unable to create dir %s: %s", dir, err)
 	}
 
-	filename := filepath.Join(dir, fmt.Sprintf("%x.img", md5.Sum([]byte(furl))))
+	// calculate the hashsum and create a lock to prevent simultaneous file access
+	md5sum := fmt.Sprintf("%x", md5.Sum([]byte(furl)))
+	mutexKV.Lock(md5sum)
+	defer mutexKV.Unlock(md5sum)
+
+	filename := filepath.Join(dir, fmt.Sprintf("%s.img", md5sum))
 	// a cleanup func to delete a failed file
 	delFile := func() {
 		if err := os.Remove(filename); err != nil {
@@ -115,6 +122,7 @@ func resourceImagesImageV2File(client *gophercloud.ServiceClient, d *schema.Reso
 	}
 
 	// check if the file size is zero
+	// it could be a leftoever from older provider versions
 	if info != nil {
 		if info.Size() != 0 {
 			log.Printf("[DEBUG] File exists %s", filename)

diff --git a/openstack/resource_openstack_images_image_v2.go b/openstack/resource_openstack_images_image_v2.go
@@ -302,7 +302,7 @@ func resourceImagesImageV2Create(ctx context.Context, d *schema.ResourceData, me
 		var imgFile *os.File
 
 		// downloading/getting image file props
-		imgFilePath, err = resourceImagesImageV2File(imageClient, d)
+		imgFilePath, err = resourceImagesImageV2File(imageClient, d, config.MutexKV)
 		if err != nil {
 			return diag.Errorf("Error opening file for Image: %s", err)
 		}