Allow associating WAF Policy to Application Gateway

Fixes hashicorp#4667.

Signed-off-by: Sune Keller <absukl@almbrand.dk>

azurerm/internal/services/network/resource_arm_application_gateway.go

@@ -1276,6 +1276,21 @@ func resourceArmApplicationGateway() *schema.Resource {
  },
  },
 
+ "firewall_policy": {
+ Type: schema.TypeList,
+ Optional: true,
+ MaxItems: 1,
+ Elem: &schema.Resource{
+ Schema: map[string]*schema.Schema{
+ "id": {
+ Type: schema.TypeString,
+ Required: true,
+ ValidateFunc: validation.NoZeroValues,
+ },
+ },
+ },
+ },
+
  "custom_error_configuration": {
  Type: schema.TypeList,
  Optional: true,
@@ -1430,6 +1445,15 @@ func resourceArmApplicationGatewayCreateUpdate(d *schema.ResourceData, meta inte
  gateway.ApplicationGatewayPropertiesFormat.WebApplicationFirewallConfiguration = expandApplicationGatewayWafConfig(d)
  }
 
+ if res, ok := d.GetOk("firewall_policy"); ok {
+ vs := res.([]interface{})
+ v := vs[0].(map[string]interface{})
+ id := v["id"].(string)
+ gateway.ApplicationGatewayPropertiesFormat.FirewallPolicy = &network.SubResource{
+ ID: &id,
+ }
+ }
+
  if stopApplicationGateway {
  future, err := client.Stop(ctx, resGroup, name)
  if err != nil {
@@ -1608,6 +1632,10 @@ func resourceArmApplicationGatewayRead(d *schema.ResourceData, meta interface{})
  if setErr := d.Set("waf_configuration", flattenApplicationGatewayWafConfig(props.WebApplicationFirewallConfiguration)); setErr != nil {
  return fmt.Errorf("Error setting `waf_configuration`: %+v", setErr)
  }
+
+ if setErr := d.Set("firewall_policy", flattenApplicationGatewayFirewallPolicy(props.FirewallPolicy)); setErr != nil {
+ return fmt.Errorf("Error setting `firewall_policy`: %+v", setErr)
+ }
  }
 
  return tags.FlattenAndSet(d, applicationGateway.Tags)
@@ -3591,6 +3619,20 @@ func flattenApplicationGatewayWafConfig(input *network.ApplicationGatewayWebAppl
  return results
 }
 
+func flattenApplicationGatewayFirewallPolicy(input *network.SubResource) []interface{} {
+ results := make([]interface{}, 0)
+ if input == nil {
+ return results
+ }
+
+ output := make(map[string]interface{})
+
+ output["id"] = input.ID
+ results = append(results, output)
+
+ return results
+}
+
 func expandApplicationGatewayFirewallDisabledRuleGroup(d []interface{}) *[]network.ApplicationGatewayFirewallDisabledRuleGroup {
  if len(d) == 0 {
  return nil