Add state filter to aws_availability_zones data source. (#7965)

* Add state filter to aws_availability_zones data source.

This commit adds an ability to filter Availability Zones based on state, where
by default it would only list available zones.

Be advised that this does not always works reliably for an older accounts which
have been created in the pre-VPC era of EC2. These accounts tends to retrieve
availability zones that are not VPC-enabled, thus creation of a custom subnet
within such Availability Zone would result in a failure.

Signed-off-by: Krzysztof Wilczynski <krzysztof.wilczynski@linux.com>

* Update documentation for aws_availability_zones data source.

Signed-off-by: Krzysztof Wilczynski <krzysztof.wilczynski@linux.com>

* Do not filter on state by default.

This commit makes the state filter applicable only when set.

Signed-off-by: Krzysztof Wilczynski <krzysztof.wilczynski@linux.com>

builtin/providers/aws/data_source_availability_zones.go

@@ -21,6 +21,11 @@ func dataSourceAwsAvailabilityZones() *schema.Resource {
 				Computed: true,
 				Elem:     &schema.Schema{Type: schema.TypeString},
 			},
+			"state": &schema.Schema{
+				Type:         schema.TypeString,
+				Optional:     true,
+				ValidateFunc: validateStateType,
+			},
 		},
 	}
 }
@@ -28,25 +33,55 @@ func dataSourceAwsAvailabilityZones() *schema.Resource {
 func dataSourceAwsAvailabilityZonesRead(d *schema.ResourceData, meta interface{}) error {
 	conn := meta.(*AWSClient).ec2conn
 
-	log.Printf("[DEBUG] Reading availability zones")
+	log.Printf("[DEBUG] Reading Availability Zones.")
 	d.SetId(time.Now().UTC().String())
 
-	req := &ec2.DescribeAvailabilityZonesInput{DryRun: aws.Bool(false)}
-	azresp, err := conn.DescribeAvailabilityZones(req)
-	if err != nil {
-		return fmt.Errorf("Error listing availability zones: %s", err)
+	request := &ec2.DescribeAvailabilityZonesInput{}
+
+	if v, ok := d.GetOk("state"); ok {
+		request.Filters = []*ec2.Filter{
+			&ec2.Filter{
+				Name:   aws.String("state"),
+				Values: []*string{aws.String(v.(string))},
+			},
+		}
 	}
 
-	raw := make([]string, len(azresp.AvailabilityZones))
-	for i, v := range azresp.AvailabilityZones {
+	log.Printf("[DEBUG] Availability Zones request options: %#v", *request)
+
+	resp, err := conn.DescribeAvailabilityZones(request)
+	if err != nil {
+		return fmt.Errorf("Error fetching Availability Zones: %s", err)
+	}
+
+	raw := make([]string, len(resp.AvailabilityZones))
+	for i, v := range resp.AvailabilityZones {
 		raw[i] = *v.ZoneName
 	}
 
 	sort.Strings(raw)
 
 	if err := d.Set("names", raw); err != nil {
-		return fmt.Errorf("[WARN] Error setting availability zones")
+		return fmt.Errorf("[WARN] Error setting Availability Zones: %s", err)
 	}
 
 	return nil
 }
+
+func validateStateType(v interface{}, k string) (ws []string, errors []error) {
+	value := v.(string)
+
+	validState := map[string]bool{
+		"available":   true,
+		"information": true,
+		"impaired":    true,
+		"unavailable": true,
+	}
+
+	if !validState[value] {
+		errors = append(errors, fmt.Errorf(
+			"%q contains an invalid Availability Zone state %q. Valid states are: %q, %q, %q and %q.",
+			k, value, "available", "information", "impaired", "unavailable"))
+	}
+	return
+}

builtin/providers/aws/data_source_availability_zones_test.go

@@ -22,6 +22,12 @@ func TestAccAWSAvailabilityZones_basic(t *testing.T) {
 					testAccCheckAwsAvailabilityZonesMeta("data.aws_availability_zones.availability_zones"),
 				),
 			},
+			resource.TestStep{
+				Config: testAccCheckAwsAvailabilityZonesStateConfig,
+				Check: resource.ComposeTestCheckFunc(
+					testAccCheckAwsAvailabilityZoneState("data.aws_availability_zones.state_filter"),
+				),
+			},
 		},
 	})
 }
@@ -34,7 +40,7 @@ func testAccCheckAwsAvailabilityZonesMeta(n string) resource.TestCheckFunc {
 		}
 
 		if rs.Primary.ID == "" {
-			return fmt.Errorf("AZ resource ID not set")
+			return fmt.Errorf("AZ resource ID not set.")
 		}
 
 		actual, err := testAccCheckAwsAvailabilityZonesBuildAvailable(rs.Primary.Attributes)
@@ -51,10 +57,33 @@ func testAccCheckAwsAvailabilityZonesMeta(n string) resource.TestCheckFunc {
 	}
 }
 
+func testAccCheckAwsAvailabilityZoneState(n string) resource.TestCheckFunc {
+	return func(s *terraform.State) error {
+		rs, ok := s.RootModule().Resources[n]
+		if !ok {
+			return fmt.Errorf("Can't find AZ resource: %s", n)
+		}
+
+		if rs.Primary.ID == "" {
+			return fmt.Errorf("AZ resource ID not set.")
+		}
+
+		if _, ok := rs.Primary.Attributes["state"]; !ok {
+			return fmt.Errorf("AZs state filter is missing, should be set.")
+		}
+
+		_, err := testAccCheckAwsAvailabilityZonesBuildAvailable(rs.Primary.Attributes)
+		if err != nil {
+			return err
+		}
+		return nil
+	}
+}
+
 func testAccCheckAwsAvailabilityZonesBuildAvailable(attrs map[string]string) ([]string, error) {
 	v, ok := attrs["names.#"]
 	if !ok {
-		return nil, fmt.Errorf("Available AZ list is missing")
+		return nil, fmt.Errorf("Available AZ list is missing.")
 	}
 	qty, err := strconv.Atoi(v)
 	if err != nil {
@@ -67,7 +96,7 @@ func testAccCheckAwsAvailabilityZonesBuildAvailable(attrs map[string]string) ([]
 	for n := range zones {
 		zone, ok := attrs["names."+strconv.Itoa(n)]
 		if !ok {
-			return nil, fmt.Errorf("AZ list corrupt, this is definitely a bug")
+			return nil, fmt.Errorf("AZ list corrupt, this is definitely a bug.")
 		}
 		zones[n] = zone
 	}
@@ -75,6 +104,11 @@ func testAccCheckAwsAvailabilityZonesBuildAvailable(attrs map[string]string) ([]
 }
 
 const testAccCheckAwsAvailabilityZonesConfig = `
-data "aws_availability_zones" "availability_zones" {
+data "aws_availability_zones" "availability_zones" { }
+`
+
+const testAccCheckAwsAvailabilityZonesStateConfig = `
+data "aws_availability_zones" "state_filter" {
+	state = "available"
 }
 `

website/source/docs/providers/aws/d/availability_zones.html.markdown

@@ -3,7 +3,7 @@ layout: "aws"
 page_title: "AWS: aws_availability_zones"
 sidebar_current: "docs-aws-datasource-availability-zones"
 description: |-
-    Provides a list of availability zones which can be used by an AWS account
+    Provides a list of Availability Zones which can be used by an AWS account.
 ---
 
 # aws\_availability\_zones
@@ -35,10 +35,15 @@ resource "aws_subnet" "secondary" {
 
 ## Argument Reference
 
-There are no arguments for this data source.
+The following arguments are supported:
+
+* `state` - (Optional) Allows to filter list of Availability Zones based on their
+current state. Can be either `"available"`, `"information"`, `"impaired"` or
+`"unavailable"`. By default the list includes a complete set of Availability Zones
+to which the underlying AWS account has access, regardless of their state.
 
 ## Attributes Reference
 
 The following attributes are exported:
 
-* `names` - A list of the availability zone names available to the account.
+* `names` - A list of the Availability Zone names available to the account.