Add support to google_compute_target_pool for health checks self_link (#702)

- Accepts self_link in addition of health check name
- Removes the need for an API call to generate the self link
- Improves the documentation to mention that only the legacy google_compute_http_health_check is supported. This will prevent our user from being stuck like mentioned here: #300.
- Adds a MaxItems:1 in the schema. You can't have more than one. The API will fail. The official docs also says so.
- Adds a check to the acceptance test to ensure the health checks are properly setup.

Author: rosbo

google/field_helpers.go

@@ -25,6 +25,10 @@ func ParseSslCertificateFieldValue(sslCertificate string, d TerraformResourceDat
 	return parseGlobalFieldValue("sslCertificates", sslCertificate, "project", d, config, false)
 }
 
+func ParseHttpHealthCheckFieldValue(healthCheck string, d TerraformResourceData, config *Config) (*GlobalFieldValue, error) {
+	return parseGlobalFieldValue("httpHealthChecks", healthCheck, "project", d, config, false)
+}
+
 func ParseDiskFieldValue(disk string, d TerraformResourceData, config *Config) (*ZonalFieldValue, error) {
 	return parseZonalFieldValue("disks", disk, "project", "zone", d, config, false)
 }

google/resource_compute_target_pool.go

@@ -51,7 +51,11 @@ func resourceComputeTargetPool() *schema.Resource {
 				Type:     schema.TypeList,
 				Optional: true,
 				ForceNew: false,
-				Elem:     &schema.Schema{Type: schema.TypeString},
+				MaxItems: 1,
+				Elem: &schema.Schema{
+					Type:             schema.TypeString,
+					DiffSuppressFunc: compareSelfLinkOrResourceName,
+				},
 			},
 
 			"instances": {
@@ -111,17 +115,17 @@ func resourceComputeTargetPool() *schema.Resource {
 }
 
 // Healthchecks need to exist before being referred to from the target pool.
-func convertHealthChecks(config *Config, project string, names []string) ([]string, error) {
-	urls := make([]string, len(names))
-	for i, name := range names {
-		// Look up the healthcheck
-		res, err := config.clientCompute.HttpHealthChecks.Get(project, name).Do()
-		if err != nil {
-			return nil, fmt.Errorf("Error reading HealthCheck: %s", err)
-		}
-		urls[i] = res.SelfLink
+func convertHealthChecks(healthChecks []interface{}, d *schema.ResourceData, config *Config) ([]string, error) {
+	if healthChecks == nil || len(healthChecks) == 0 {
+		return []string{}, nil
 	}
-	return urls, nil
+
+	hc, err := ParseHttpHealthCheckFieldValue(healthChecks[0].(string), d, config)
+	if err != nil {
+		return nil, err
+	}
+
+	return []string{hc.RelativeLink()}, nil
 }
 
 // Instances do not need to exist yet, so we simply generate URLs.
@@ -158,8 +162,7 @@ func resourceComputeTargetPoolCreate(d *schema.ResourceData, meta interface{}) e
 		return err
 	}
 
-	hchkUrls, err := convertHealthChecks(
-		config, project, convertStringArr(d.Get("health_checks").([]interface{})))
+	hchkUrls, err := convertHealthChecks(d.Get("health_checks").([]interface{}), d, config)
 	if err != nil {
 		return err
 	}
@@ -247,13 +250,11 @@ func resourceComputeTargetPoolUpdate(d *schema.ResourceData, meta interface{}) e
 	if d.HasChange("health_checks") {
 
 		from_, to_ := d.GetChange("health_checks")
-		from := convertStringArr(from_.([]interface{}))
-		to := convertStringArr(to_.([]interface{}))
-		fromUrls, err := convertHealthChecks(config, project, from)
+		fromUrls, err := convertHealthChecks(from_.([]interface{}), d, config)
 		if err != nil {
 			return err
 		}
-		toUrls, err := convertHealthChecks(config, project, to)
+		toUrls, err := convertHealthChecks(to_.([]interface{}), d, config)
 		if err != nil {
 			return err
 		}
@@ -376,16 +377,6 @@ func convertInstancesFromUrls(urls []string) []string {
 	return result
 }
 
-func convertHealthChecksFromUrls(urls []string) []string {
-	result := make([]string, 0, len(urls))
-	for _, url := range urls {
-		urlArray := strings.Split(url, "/")
-		healthCheck := fmt.Sprintf("%s", urlArray[len(urlArray)-1])
-		result = append(result, healthCheck)
-	}
-	return result
-}
-
 func resourceComputeTargetPoolRead(d *schema.ResourceData, meta interface{}) error {
 	config := meta.(*Config)
 
@@ -410,11 +401,7 @@ func resourceComputeTargetPoolRead(d *schema.ResourceData, meta interface{}) err
 	d.Set("backup_pool", tpool.BackupPool)
 	d.Set("description", tpool.Description)
 	d.Set("failover_ratio", tpool.FailoverRatio)
-	if tpool.HealthChecks != nil {
-		d.Set("health_checks", convertHealthChecksFromUrls(tpool.HealthChecks))
-	} else {
-		d.Set("health_checks", nil)
-	}
+	d.Set("health_checks", tpool.HealthChecks)
 	if tpool.Instances != nil {
 		d.Set("instances", convertInstancesFromUrls(tpool.Instances))
 	} else {

google/resource_compute_target_pool_test.go

@@ -21,7 +21,11 @@ func TestAccComputeTargetPool_basic(t *testing.T) {
 				Config: testAccComputeTargetPool_basic,
 				Check: resource.ComposeTestCheckFunc(
 					testAccCheckComputeTargetPoolExists(
-						"google_compute_target_pool.foobar"),
+						"google_compute_target_pool.foo"),
+					testAccCheckComputeTargetPoolHealthCheck("google_compute_target_pool.foo", "google_compute_http_health_check.foobar"),
+					testAccCheckComputeTargetPoolExists(
+						"google_compute_target_pool.bar"),
+					testAccCheckComputeTargetPoolHealthCheck("google_compute_target_pool.bar", "google_compute_http_health_check.foobar"),
 				),
 			},
 		},
@@ -73,6 +77,27 @@ func testAccCheckComputeTargetPoolExists(n string) resource.TestCheckFunc {
 	}
 }
 
+func testAccCheckComputeTargetPoolHealthCheck(targetPool, healthCheck string) resource.TestCheckFunc {
+	return func(s *terraform.State) error {
+		targetPoolRes, ok := s.RootModule().Resources[targetPool]
+		if !ok {
+			return fmt.Errorf("Not found: %s", targetPool)
+		}
+
+		healthCheckRes, ok := s.RootModule().Resources[healthCheck]
+		if !ok {
+			return fmt.Errorf("Not found: %s", healthCheck)
+		}
+
+		hcLink := healthCheckRes.Primary.Attributes["self_link"]
+		if targetPoolRes.Primary.Attributes["health_checks.0"] != hcLink {
+			return fmt.Errorf("Health check not set up. Expected %q", hcLink)
+		}
+
+		return nil
+	}
+}
+
 var testAccComputeTargetPool_basic = fmt.Sprintf(`
 resource "google_compute_http_health_check" "foobar" {
 	name = "healthcheck-test-%s"
@@ -95,12 +120,20 @@ resource "google_compute_instance" "foobar" {
 	}
 }
 
-resource "google_compute_target_pool" "foobar" {
+resource "google_compute_target_pool" "foo" {
 	description = "Resource created for Terraform acceptance testing"
 	instances = ["${google_compute_instance.foobar.self_link}", "us-central1-b/bar"]
 	name = "tpool-test-%s"
 	session_affinity = "CLIENT_IP_PROTO"
 	health_checks = [
 		"${google_compute_http_health_check.foobar.name}"
 	]
-}`, acctest.RandString(10), acctest.RandString(10), acctest.RandString(10))
+}
+
+resource "google_compute_target_pool" "bar" {
+	description = "Resource created for Terraform acceptance testing"
+	name = "tpool-test-%s"
+	health_checks = [
+		"${google_compute_http_health_check.foobar.self_link}"
+	]
+}`, acctest.RandString(10), acctest.RandString(10), acctest.RandString(10), acctest.RandString(10))

website/docs/r/compute_target_pool.html.markdown

@@ -30,6 +30,13 @@ resource "google_compute_target_pool" "default" {
     "${google_compute_http_health_check.default.name}",
   ]
 }
+
+resource "google_compute_http_health_check" "default" {
+  name               = "default"
+  request_path       = "/"
+  check_interval_sec = 1
+  timeout_sec        = 1
+}
 ```
 
 ## Argument Reference
@@ -49,7 +56,8 @@ The following arguments are supported:
 * `failover_ratio` - (Optional) Ratio (0 to 1) of failed nodes before using the
     backup pool (which must also be set).
 
-* `health_checks` - (Optional) List of zero or one healthcheck names.
+* `health_checks` - (Optional) List of zero or one health check name or self_link. Only
+    legacy `google_compute_http_health_check` is supported.
 
 * `instances` - (Optional) List of instances in the pool. They can be given as
     URLs, or in the form of "zone/name". Note that the instances need not exist