Add deadLetterPolicy to Pub/Sub Subscription resource (#3305) (#1913)

* Add deadLetterPolicy to Pub/Sub subscription resource

* fix: disable allow_empty_objects, fix docstring, add example

* fix: set max_delivery_attempts

* fix: block and topic name

Signed-off-by: Modular Magician <magic-modules@google.com>

.changelog/3305.txt

@@ -0,0 +1,3 @@
+```release-note:enhancement
+pubsub: Added `dead_letter_policy` support to `google_pubsub_subscription`
+```

google-beta/resource_pubsub_subscription.go

@@ -93,6 +93,54 @@ for the call to the push endpoint.
 If the subscriber never acknowledges the message, the Pub/Sub system
 will eventually redeliver the message.`,
 			},
+			"dead_letter_policy": {
+				Type:     schema.TypeList,
+				Optional: true,
+				Description: `A policy that specifies the conditions for dead lettering messages in
+this subscription. If dead_letter_policy is not set, dead lettering
+is disabled.
+
+The Cloud Pub/Sub service account associated with this subscriptions's
+parent project (i.e.,
+service-{project_number}@gcp-sa-pubsub.iam.gserviceaccount.com) must have
+permission to Acknowledge() messages on this subscription.`,
+				MaxItems: 1,
+				Elem: &schema.Resource{
+					Schema: map[string]*schema.Schema{
+						"dead_letter_topic": {
+							Type:     schema.TypeString,
+							Optional: true,
+							Description: `The name of the topic to which dead letter messages should be published.
+Format is 'projects/{project}/topics/{topic}'.
+
+The Cloud Pub/Sub service\naccount associated with the enclosing subscription's
+parent project (i.e., 
+service-{project_number}@gcp-sa-pubsub.iam.gserviceaccount.com) must have
+permission to Publish() to this topic.
+
+The operation will fail if the topic does not exist.
+Users should ensure that there is a subscription attached to this topic
+since messages published to a topic with no subscriptions are lost.`,
+						},
+						"max_delivery_attempts": {
+							Type:     schema.TypeInt,
+							Optional: true,
+							Description: `The maximum number of delivery attempts for any message. The value must be
+between 5 and 100.
+
+The number of delivery attempts is defined as 1 + (the sum of number of 
+NACKs and number of times the acknowledgement deadline has been exceeded for the message).
+
+A NACK is any call to ModifyAckDeadline with a 0 deadline. Note that
+client libraries may automatically extend ack_deadlines.
+
+This field will be honored on a best effort basis.
+
+If this parameter is 0, a default value of 5 is used.`,
+						},
+					},
+				},
+			},
 			"expiration_policy": {
 				Type:     schema.TypeList,
 				Computed: true,
@@ -290,6 +338,12 @@ func resourcePubsubSubscriptionCreate(d *schema.ResourceData, meta interface{})
 	} else if v, ok := d.GetOkExists("expiration_policy"); ok || !reflect.DeepEqual(v, expirationPolicyProp) {
 		obj["expirationPolicy"] = expirationPolicyProp
 	}
+	deadLetterPolicyProp, err := expandPubsubSubscriptionDeadLetterPolicy(d.Get("dead_letter_policy"), d, config)
+	if err != nil {
+		return err
+	} else if v, ok := d.GetOkExists("dead_letter_policy"); ok || !reflect.DeepEqual(v, deadLetterPolicyProp) {
+		obj["deadLetterPolicy"] = deadLetterPolicyProp
+	}
 
 	obj, err = resourcePubsubSubscriptionEncoder(d, meta, obj)
 	if err != nil {
@@ -418,6 +472,9 @@ func resourcePubsubSubscriptionRead(d *schema.ResourceData, meta interface{}) er
 	if err := d.Set("expiration_policy", flattenPubsubSubscriptionExpirationPolicy(res["expirationPolicy"], d, config)); err != nil {
 		return fmt.Errorf("Error reading Subscription: %s", err)
 	}
+	if err := d.Set("dead_letter_policy", flattenPubsubSubscriptionDeadLetterPolicy(res["deadLetterPolicy"], d, config)); err != nil {
+		return fmt.Errorf("Error reading Subscription: %s", err)
+	}
 
 	return nil
 }
@@ -467,6 +524,12 @@ func resourcePubsubSubscriptionUpdate(d *schema.ResourceData, meta interface{})
 	} else if v, ok := d.GetOkExists("expiration_policy"); ok || !reflect.DeepEqual(v, expirationPolicyProp) {
 		obj["expirationPolicy"] = expirationPolicyProp
 	}
+	deadLetterPolicyProp, err := expandPubsubSubscriptionDeadLetterPolicy(d.Get("dead_letter_policy"), d, config)
+	if err != nil {
+		return err
+	} else if v, ok := d.GetOkExists("dead_letter_policy"); ok || !reflect.DeepEqual(v, deadLetterPolicyProp) {
+		obj["deadLetterPolicy"] = deadLetterPolicyProp
+	}
 
 	obj, err = resourcePubsubSubscriptionUpdateEncoder(d, meta, obj)
 	if err != nil {
@@ -504,6 +567,10 @@ func resourcePubsubSubscriptionUpdate(d *schema.ResourceData, meta interface{})
 	if d.HasChange("expiration_policy") {
 		updateMask = append(updateMask, "expirationPolicy")
 	}
+
+	if d.HasChange("dead_letter_policy") {
+		updateMask = append(updateMask, "deadLetterPolicy")
+	}
 	// updateMask is a URL parameter but not present in the schema, so replaceVars
 	// won't set it
 	url, err = addQueryParams(url, map[string]string{"updateMask": strings.Join(updateMask, ",")})
@@ -669,6 +736,42 @@ func flattenPubsubSubscriptionExpirationPolicyTtl(v interface{}, d *schema.Resou
 	return v
 }
 
+func flattenPubsubSubscriptionDeadLetterPolicy(v interface{}, d *schema.ResourceData, config *Config) interface{} {
+	if v == nil {
+		return nil
+	}
+	original := v.(map[string]interface{})
+	if len(original) == 0 {
+		return nil
+	}
+	transformed := make(map[string]interface{})
+	transformed["dead_letter_topic"] =
+		flattenPubsubSubscriptionDeadLetterPolicyDeadLetterTopic(original["deadLetterTopic"], d, config)
+	transformed["max_delivery_attempts"] =
+		flattenPubsubSubscriptionDeadLetterPolicyMaxDeliveryAttempts(original["maxDeliveryAttempts"], d, config)
+	return []interface{}{transformed}
+}
+func flattenPubsubSubscriptionDeadLetterPolicyDeadLetterTopic(v interface{}, d *schema.ResourceData, config *Config) interface{} {
+	return v
+}
+
+func flattenPubsubSubscriptionDeadLetterPolicyMaxDeliveryAttempts(v interface{}, d *schema.ResourceData, config *Config) interface{} {
+	// Handles the string fixed64 format
+	if strVal, ok := v.(string); ok {
+		if intVal, err := strconv.ParseInt(strVal, 10, 64); err == nil {
+			return intVal
+		}
+	}
+
+	// number values are represented as float64
+	if floatVal, ok := v.(float64); ok {
+		intVal := int(floatVal)
+		return intVal
+	}
+
+	return v // let terraform core handle it otherwise
+}
+
 func expandPubsubSubscriptionName(v interface{}, d TerraformResourceData, config *Config) (interface{}, error) {
 	return replaceVars(d, config, "projects/{{project}}/subscriptions/{{name}}")
 }
@@ -826,6 +929,40 @@ func expandPubsubSubscriptionExpirationPolicyTtl(v interface{}, d TerraformResou
 	return v, nil
 }
 
+func expandPubsubSubscriptionDeadLetterPolicy(v interface{}, d TerraformResourceData, config *Config) (interface{}, error) {
+	l := v.([]interface{})
+	if len(l) == 0 || l[0] == nil {
+		return nil, nil
+	}
+	raw := l[0]
+	original := raw.(map[string]interface{})
+	transformed := make(map[string]interface{})
+
+	transformedDeadLetterTopic, err := expandPubsubSubscriptionDeadLetterPolicyDeadLetterTopic(original["dead_letter_topic"], d, config)
+	if err != nil {
+		return nil, err
+	} else if val := reflect.ValueOf(transformedDeadLetterTopic); val.IsValid() && !isEmptyValue(val) {
+		transformed["deadLetterTopic"] = transformedDeadLetterTopic
+	}
+
+	transformedMaxDeliveryAttempts, err := expandPubsubSubscriptionDeadLetterPolicyMaxDeliveryAttempts(original["max_delivery_attempts"], d, config)
+	if err != nil {
+		return nil, err
+	} else if val := reflect.ValueOf(transformedMaxDeliveryAttempts); val.IsValid() && !isEmptyValue(val) {
+		transformed["maxDeliveryAttempts"] = transformedMaxDeliveryAttempts
+	}
+
+	return transformed, nil
+}
+
+func expandPubsubSubscriptionDeadLetterPolicyDeadLetterTopic(v interface{}, d TerraformResourceData, config *Config) (interface{}, error) {
+	return v, nil
+}
+
+func expandPubsubSubscriptionDeadLetterPolicyMaxDeliveryAttempts(v interface{}, d TerraformResourceData, config *Config) (interface{}, error) {
+	return v, nil
+}
+
 func resourcePubsubSubscriptionEncoder(d *schema.ResourceData, meta interface{}, obj map[string]interface{}) (map[string]interface{}, error) {
 	delete(obj, "name")
 	return obj, nil

google-beta/resource_pubsub_subscription_generated_test.go

@@ -75,6 +75,52 @@ resource "google_pubsub_subscription" "example" {
 `, context)
 }
 
+func TestAccPubsubSubscription_pubsubSubscriptionDeadLetterExample(t *testing.T) {
+	t.Parallel()
+
+	context := map[string]interface{}{
+		"random_suffix": acctest.RandString(10),
+	}
+
+	resource.Test(t, resource.TestCase{
+		PreCheck:     func() { testAccPreCheck(t) },
+		Providers:    testAccProviders,
+		CheckDestroy: testAccCheckPubsubSubscriptionDestroy,
+		Steps: []resource.TestStep{
+			{
+				Config: testAccPubsubSubscription_pubsubSubscriptionDeadLetterExample(context),
+			},
+			{
+				ResourceName:      "google_pubsub_subscription.example",
+				ImportState:       true,
+				ImportStateVerify: true,
+			},
+		},
+	})
+}
+
+func testAccPubsubSubscription_pubsubSubscriptionDeadLetterExample(context map[string]interface{}) string {
+	return Nprintf(`
+resource "google_pubsub_topic" "example" {
+  name = "tf-test-example-topic%{random_suffix}"
+}
+
+resource "google_pubsub_topic" "example_dead_letter" {
+  name = "tf-test-example-topic%{random_suffix}-dead-letter"
+}
+
+resource "google_pubsub_subscription" "example" {
+  name  = "tf-test-example-subscription%{random_suffix}"
+  topic = google_pubsub_topic.example.name
+
+  dead_letter_policy {
+    dead_letter_topic = google_pubsub_topic.example_dead_letter.id
+    max_delivery_attempts = 10
+  }
+}
+`, context)
+}
+
 func testAccCheckPubsubSubscriptionDestroy(s *terraform.State) error {
 	for name, rs := range s.RootModule().Resources {
 		if rs.Type != "google_pubsub_subscription" {

website/docs/r/pubsub_subscription.html.markdown

@@ -107,6 +107,33 @@ resource "google_pubsub_subscription" "example" {
   topic   = google_pubsub_topic.example.name
 }
 ```
+<div class = "oics-button" style="float: right; margin: 0 0 -15px">
+  <a href="https://console.cloud.google.com/cloudshell/open?cloudshell_git_repo=https%3A%2F%2Fgit.luolix.top%2Fterraform-google-modules%2Fdocs-examples.git&cloudshell_working_dir=pubsub_subscription_dead_letter&cloudshell_image=gcr.io%2Fgraphite-cloud-shell-images%2Fterraform%3Alatest&open_in_editor=main.tf&cloudshell_print=.%2Fmotd&cloudshell_tutorial=.%2Ftutorial.md" target="_blank">
+    <img alt="Open in Cloud Shell" src="//gstatic.com/cloudssh/images/open-btn.svg" style="max-height: 44px; margin: 32px auto; max-width: 100%;">
+  </a>
+</div>
+## Example Usage - Pubsub Subscription Dead Letter
+
+
+```hcl
+resource "google_pubsub_topic" "example" {
+  name = "example-topic"
+}
+
+resource "google_pubsub_topic" "example_dead_letter" {
+  name = "example-topic-dead-letter"
+}
+
+resource "google_pubsub_subscription" "example" {
+  name  = "example-subscription"
+  topic = google_pubsub_topic.example.name
+
+  dead_letter_policy {
+    dead_letter_topic = google_pubsub_topic.example_dead_letter.id
+    max_delivery_attempts = 10
+  }
+}
+```
 
 ## Argument Reference
 
@@ -181,6 +208,16 @@ The following arguments are supported:
   resource never expires.  The minimum allowed value for expirationPolicy.ttl
   is 1 day.  Structure is documented below.
 
+* `dead_letter_policy` -
+  (Optional)
+  A policy that specifies the conditions for dead lettering messages in
+  this subscription. If dead_letter_policy is not set, dead lettering
+  is disabled.
+  The Cloud Pub/Sub service account associated with this subscriptions's
+  parent project (i.e.,
+  service-{project_number}@gcp-sa-pubsub.iam.gserviceaccount.com) must have
+  permission to Acknowledge() messages on this subscription.  Structure is documented below.
+
 * `project` - (Optional) The ID of the project in which the resource belongs.
     If it is not provided, the provider project is used.
 
@@ -248,6 +285,31 @@ The `expiration_policy` block supports:
   A duration in seconds with up to nine fractional digits, terminated by 's'.
   Example - "3.5s".
 
+The `dead_letter_policy` block supports:
+
+* `dead_letter_topic` -
+  (Optional)
+  The name of the topic to which dead letter messages should be published.
+  Format is `projects/{project}/topics/{topic}`.
+  The Cloud Pub/Sub service\naccount associated with the enclosing subscription's
+  parent project (i.e., 
+  service-{project_number}@gcp-sa-pubsub.iam.gserviceaccount.com) must have
+  permission to Publish() to this topic.
+  The operation will fail if the topic does not exist.
+  Users should ensure that there is a subscription attached to this topic
+  since messages published to a topic with no subscriptions are lost.
+
+* `max_delivery_attempts` -
+  (Optional)
+  The maximum number of delivery attempts for any message. The value must be
+  between 5 and 100.
+  The number of delivery attempts is defined as 1 + (the sum of number of 
+  NACKs and number of times the acknowledgement deadline has been exceeded for the message).
+  A NACK is any call to ModifyAckDeadline with a 0 deadline. Note that
+  client libraries may automatically extend ack_deadlines.
+  This field will be honored on a best effort basis.
+  If this parameter is 0, a default value of 5 is used.
+
 ## Attributes Reference
 
 In addition to the arguments listed above, the following computed attributes are exported: