make backend block optional

docs/resources/service_v1.md

@@ -236,14 +236,14 @@ $ terraform import fastly_service_v1.demo xxxxxxxxxxxxxxxxxxxx@2
 
 ### Required
 
-- **backend** (Block Set, Min: 1) (see [below for nested schema](#nestedblock--backend))
 - **domain** (Block Set, Min: 1) A set of Domain names to serve as entry points for your Service (see [below for nested schema](#nestedblock--domain))
 - **name** (String) The unique name for the Service to create
 
 ### Optional
 
 - **acl** (Block Set) (see [below for nested schema](#nestedblock--acl))
 - **activate** (Boolean) Conditionally prevents the Service from being activated. The apply step will continue to create a new draft version but will not activate it if this is set to `false`. Default `true`
+- **backend** (Block Set) (see [below for nested schema](#nestedblock--backend))
 - **bigquerylogging** (Block Set) (see [below for nested schema](#nestedblock--bigquerylogging))
 - **blobstoragelogging** (Block Set) (see [below for nested schema](#nestedblock--blobstoragelogging))
 - **cache_setting** (Block Set) (see [below for nested schema](#nestedblock--cache_setting))
@@ -295,6 +295,34 @@ $ terraform import fastly_service_v1.demo xxxxxxxxxxxxxxxxxxxx@2
 - **active_version** (Number) The currently active version of your Fastly Service
 - **cloned_version** (Number) The latest cloned version by the provider
 
+<a id="nestedblock--domain"></a>
+### Nested Schema for `domain`
+
+Required:
+
+- **name** (String) The domain that this Service will respond to. It is important to note that changing this attribute will delete and recreate the resource.
+
+Optional:
+
+- **comment** (String) An optional comment about the Domain.
+
+
+<a id="nestedblock--acl"></a>
+### Nested Schema for `acl`
+
+Required:
+
+- **name** (String) A unique name to identify this ACL. It is important to note that changing this attribute will delete and recreate the ACL, and discard the current items in the ACL
+
+Optional:
+
+- **force_destroy** (Boolean) Allow the ACL to be deleted, even if it contains entries. Defaults to false.
+
+Read-Only:
+
+- **acl_id** (String) The ID of the ACL
+
+
 <a id="nestedblock--backend"></a>
 ### Nested Schema for `backend`
 
@@ -330,34 +358,6 @@ Optional:
 - **weight** (Number) The [portion of traffic](https://docs.fastly.com/en/guides/load-balancing-configuration#how-weight-affects-load-balancing) to send to this Backend. Each Backend receives weight / total of the traffic. Default `100`
 
 
-<a id="nestedblock--domain"></a>
-### Nested Schema for `domain`
-
-Required:
-
-- **name** (String) The domain that this Service will respond to. It is important to note that changing this attribute will delete and recreate the resource.
-
-Optional:
-
-- **comment** (String) An optional comment about the Domain.
-
-
-<a id="nestedblock--acl"></a>
-### Nested Schema for `acl`
-
-Required:
-
-- **name** (String) A unique name to identify this ACL. It is important to note that changing this attribute will delete and recreate the ACL, and discard the current items in the ACL
-
-Optional:
-
-- **force_destroy** (Boolean) Allow the ACL to be deleted, even if it contains entries. Defaults to false.
-
-Read-Only:
-
-- **acl_id** (String) The ID of the ACL
-
-
 <a id="nestedblock--bigquerylogging"></a>
 ### Nested Schema for `bigquerylogging`
 

fastly/block_fastly_service_v1_backend.go

@@ -404,7 +404,12 @@ func (h *BackendServiceAttributeHandler) Register(s *schema.Resource) error {
 		},
 	}
 
+	required := true
+
 	if h.GetServiceMetadata().serviceType == ServiceTypeVCL {
+		// backend is optional in VCL service
+		required = false
+
 		blockAttributes["request_condition"] = &schema.Schema{
 			Type:        schema.TypeString,
 			Optional:    true,
@@ -415,7 +420,8 @@ func (h *BackendServiceAttributeHandler) Register(s *schema.Resource) error {
 
 	s.Schema[h.GetKey()] = &schema.Schema{
 		Type:     schema.TypeSet,
-		Required: true,
+		Required: required,
+		Optional: !required,
 		Elem: &schema.Resource{
 			Schema: blockAttributes,
 		},

fastly/resource_fastly_service_v1_test.go

@@ -349,6 +349,62 @@ func TestAccFastlyServiceV1_updateInvalidBackend(t *testing.T) {
 	})
 }
 
+func TestAccFastlyServiceV1_createServiceWithStaticBackend(t *testing.T) {
+	var service gofastly.ServiceDetail
+	name := fmt.Sprintf("tf-test-%s", acctest.RandString(10))
+	domain := fmt.Sprintf("fastly-test.tf-%s.com", acctest.RandString(10))
+	snippet1 := `
+	backend F_httpbin_org {
+		.always_use_host_header = true;
+		.between_bytes_timeout = 1s;
+		.connect_timeout = 1s;
+		.dynamic = true;
+		.first_byte_timeout = 1s;
+		.host = "httpbin.org";
+		.host_header = "httpbin.org";
+		.max_connections = 200;
+		.port = "443";
+		.share_key = "foo";
+		.ssl = true;
+		.ssl_cert_hostname = "httpbin.org";
+		.ssl_check_cert = always;
+		.ssl_sni_hostname = "httpbin.org";
+		.probe = {
+			.dummy = true;
+			.initial = 5;
+			.request = "HEAD / HTTP/1.1"  "Host: httpbin.org" "Connection: close";
+			.threshold = 1;
+			.timeout = 2s;
+			.window = 5;
+		  }
+	}
+	`
+	snippet2 := "# just a comment line"
+
+	resource.ParallelTest(t, resource.TestCase{
+		PreCheck:          func() { testAccPreCheck(t) },
+		ProviderFactories: testAccProviders,
+		CheckDestroy:      testAccCheckServiceV1Destroy,
+		Steps: []resource.TestStep{
+			{
+				Config: testAccServiceV1Config_staticBackend(name, domain, snippet1),
+				Check: resource.ComposeTestCheckFunc(
+					testAccCheckServiceV1Exists("fastly_service_v1.foo", &service),
+					testAccCheckFastlyServiceV1Attributes_backends(&service, name, []string{}),
+					resource.TestCheckResourceAttr(
+						"fastly_service_v1.foo", "active_version", "1"),
+					resource.TestCheckResourceAttr(
+						"fastly_service_v1.foo", "backend.#", "0"),
+				),
+			},
+			{
+				Config:      testAccServiceV1Config_staticBackend(name, domain, snippet2),
+				ExpectError: regexp.MustCompile("No backends"),
+			},
+		},
+	})
+}
+
 func TestAccFastlyServiceV1_basic(t *testing.T) {
 	var service gofastly.ServiceDetail
 	name := fmt.Sprintf("tf-test-%s", acctest.RandString(10))
@@ -847,6 +903,27 @@ resource "fastly_service_v1" "foo" {
 }`, name, domain, backend)
 }
 
+func testAccServiceV1Config_staticBackend(name, domain, snippet string) string {
+	return fmt.Sprintf(`
+resource "fastly_service_v1" "foo" {
+    name           = "%s"
+    force_destroy = true
+
+    domain {
+        name = "%s"
+    }
+
+    snippet {
+        content  = <<-EOT
+            %s
+        EOT
+        name     = "vcl_init"
+        priority = 50
+        type     = "init"
+    }
+}`, name, domain, snippet)
+}
+
 func testAccServiceV1Config_backendTTL(name, domain, backend string, ttl uint) string {
 	return fmt.Sprintf(`
 resource "fastly_service_v1" "foo" {