Backend/S3: Add support for use_path_style (#787)

Signed-off-by: Marcin Białoń <mbialon@spacelift.io>

CHANGELOG.md

@@ -60,6 +60,7 @@ S3 BACKEND:
 * Adds support for `ec2_metadata_service_endpoint` and `ec2_metadata_service_endpoint_mode` arguments to enable overriding the EC2 metadata service (IMDS) endpoint. ([#693](https://github.com/opentofu/opentofu/issues/693))
 * Adds support for the `retry_mode` attribute. ([#698](https://github.com/opentofu/opentofu/issues/698))
 * Adds support for the `http_proxy`, `insecure`, `use_dualstack_endpoint`, and `use_fips_endpoint` attributes. ([#694](https://github.com/opentofu/opentofu/issues/694))
+* Adds support for the `use_path_style` argument and deprecates the `force_path_style` argument. ([#783](https://github.com/opentofu/opentofu/issues/783))
 
 ## Previous Releases
 

internal/backend/remote-state/s3/backend.go

@@ -223,7 +223,13 @@ func (b *Backend) ConfigSchema(context.Context) *configschema.Block {
 			"force_path_style": {
 				Type:        cty.Bool,
 				Optional:    true,
-				Description: "Force s3 to use path style api.",
+				Description: "Force s3 to use path style api. Use `use_path_style` instead.",
+				Deprecated:  true,
+			},
+			"use_path_style": {
+				Type:        cty.Bool,
+				Optional:    true,
+				Description: "Enable path-style S3 URLs.",
 			},
 			"retry_mode": {
 				Type:        cty.String,
@@ -490,6 +496,24 @@ func (b *Backend) PrepareConfig(ctx context.Context, obj cty.Value) (cty.Value,
 			attrPath))
 	}
 
+	if val := obj.GetAttr("force_path_style"); !val.IsNull() {
+		attrPath := cty.GetAttrPath("force_path_style")
+		detail := fmt.Sprintf(
+			`Parameter "%s" is deprecated. Use "%s" instead.`,
+			pathString(attrPath),
+			pathString(cty.GetAttrPath("use_path_style")))
+
+		diags = diags.Append(attributeWarningDiag(
+			"Deprecated Parameter",
+			detail,
+			attrPath))
+	}
+
+	validateAttributesConflict(
+		cty.GetAttrPath("force_path_style"),
+		cty.GetAttrPath("use_path_style"),
+	)(obj, cty.Path{}, &diags)
+
 	var assumeRoleDeprecatedFields = map[string]string{
 		"role_arn":                        "assume_role.role_arn",
 		"session_name":                    "assume_role.session_name",
@@ -769,6 +793,9 @@ func getS3Config(obj cty.Value) func(options *s3.Options) {
 		if v, ok := boolAttrOk(obj, "force_path_style"); ok {
 			options.UsePathStyle = v
 		}
+		if v, ok := boolAttrOk(obj, "use_path_style"); ok {
+			options.UsePathStyle = v
+		}
 	}
 }
 

internal/backend/remote-state/s3/backend_test.go

@@ -766,6 +766,47 @@ func TestBackendConfig_PrepareConfigValidation(t *testing.T) {
 	}
 }
 
+func TestBackendConfig_PrepareConfigValidationWarnings(t *testing.T) {
+	cases := map[string]struct {
+		config       cty.Value
+		expectedWarn string
+	}{
+		"deprecated force path style": {
+			config: cty.ObjectVal(map[string]cty.Value{
+				"bucket":           cty.StringVal("test"),
+				"key":              cty.StringVal("test"),
+				"region":           cty.StringVal("us-west-2"),
+				"force_path_style": cty.BoolVal(false),
+			}),
+			expectedWarn: `Deprecated Parameter: Parameter "force_path_style" is deprecated. Use "use_path_style" instead.`,
+		},
+	}
+
+	for name, tc := range cases {
+		t.Run(name, func(t *testing.T) {
+			oldEnv := servicemocks.StashEnv()
+			defer servicemocks.PopEnv(oldEnv)
+
+			b := New()
+
+			ctx := context.Background()
+
+			_, diags := b.PrepareConfig(ctx, populateSchema(t, b.ConfigSchema(ctx), tc.config))
+			if tc.expectedWarn != "" {
+				if err := diags.ErrWithWarnings(); err != nil {
+					if !strings.Contains(err.Error(), tc.expectedWarn) {
+						t.Fatalf("unexpected validation result: %v", err)
+					}
+				} else {
+					t.Fatal("expected a warning, got none")
+				}
+			} else if err := diags.ErrWithWarnings(); err != nil {
+				t.Fatalf("expected no warnings, got %s", err)
+			}
+		})
+	}
+}
+
 func TestBackendConfig_PrepareConfigWithEnvVars(t *testing.T) {
 	cases := map[string]struct {
 		config      cty.Value

website/docs/language/settings/backends/s3.mdx

@@ -315,7 +315,8 @@ The following configuration is optional:
 * `acl` - (Optional) [Canned ACL](https://docs.aws.amazon.com/AmazonS3/latest/userguide/acl-overview.html#canned-acl) to be applied to the state file.
 * `encrypt` - (Optional) Enable [server side encryption](https://docs.aws.amazon.com/AmazonS3/latest/userguide/UsingServerSideEncryption.html) of the state file.
 * `endpoint` - (Optional) Custom endpoint for the AWS S3 API. This can also be sourced from the `AWS_S3_ENDPOINT` environment variable.
-* `force_path_style` - (Optional) Enable path-style S3 URLs (`https://<HOST>/<BUCKET>` instead of `https://<BUCKET>.<HOST>`).
+* `force_path_style` - (Optional) **Deprecated** Enable path-style S3 URLs (`https://<HOST>/<BUCKET>` instead of `https://<BUCKET>.<HOST>`). Use `use_path_style` instead.
+* `use_path_style` - (Optional) Enable path-style S3 URLs (`https://<HOST>/<BUCKET>` instead of `https://<BUCKET>.<HOST>`).
 * `kms_key_id` - (Optional) Amazon Resource Name (ARN) of a Key Management Service (KMS) Key to use for encrypting the state. Note that if this value is specified, OpenTofu will need `kms:Encrypt`, `kms:Decrypt` and `kms:GenerateDataKey` permissions on this KMS key.
 * `sse_customer_key` - (Optional) The key to use for encrypting state with [Server-Side Encryption with Customer-Provided Keys (SSE-C)](https://docs.aws.amazon.com/AmazonS3/latest/userguide/ServerSideEncryptionCustomerKeys.html). This is the base64-encoded value of the key, which must decode to 256 bits. This can also be sourced from the `AWS_SSE_CUSTOMER_KEY` environment variable, which is recommended due to the sensitivity of the value. Setting it inside an OpenTofu file will cause it to be persisted to disk in `terraform.tfstate`.
 * `workspace_key_prefix` - (Optional) Prefix applied to the state path inside the bucket. This is only relevant when using a non-default workspace. Defaults to `env:`.