Merge pull request #3036 from hashicorp/b-aws-eip-computed-instance

provider/aws: Allow Instance to be computed in EIPs

builtin/providers/aws/resource_aws_eip.go

@@ -30,13 +30,13 @@ func resourceAwsEip() *schema.Resource {
 			"instance": &schema.Schema{
 				Type:     schema.TypeString,
 				Optional: true,
+                                Computed: true,
 			},
 
 			"network_interface": &schema.Schema{
-				Type:          schema.TypeString,
-				Optional:      true,
-				Computed:      true,
-				ConflictsWith: []string{"instance"},
+                                Type:     schema.TypeString,
+                                Optional: true,
+                                Computed: true,
 			},
 
 			"allocation_id": &schema.Schema{

website/source/docs/providers/aws/r/eip.html.markdown

@@ -27,6 +27,11 @@ The following arguments are supported:
 * `instance` - (Optional) EC2 instance ID.
 * `network_interface` - (Optional) Network interface ID to associate with.
 
+~> **NOTE:** You can specify either the `instance` ID or the `network_interface` ID, 
+but not both. Including both will **not** return an error from the AWS API, but will
+have undefined behavior. See the relevant [AssociateAddress API Call][1] for
+more information.
+
 ## Attributes Reference
 
 The following attributes are exported:
@@ -36,3 +41,5 @@ The following attributes are exported:
 * `instance` - Contains the ID of the attached instance.
 * `network_interface` - Contains the ID of the attached network interface.
 
+
+[1]: http://docs.aws.amazon.com/fr_fr/AWSEC2/latest/APIReference/API_AssociateAddress.html