Add autoscaling load balancer methods (#1265)

* add attach_load_balancers, detach_load_balancers,
describe_load_balancers methods

* prefer using amzn_request_id decorator to generate unique request ids

moto/autoscaling/models.py

@@ -539,6 +539,24 @@ class AutoScalingBackend(BaseBackend):
 
             group.tags = new_tags
 
+    def attach_load_balancers(self, group_name, load_balancer_names):
+        group = self.autoscaling_groups[group_name]
+        group.load_balancers.extend(load_balancer_names)
+        self.update_attached_elbs(group_name)
+
+    def describe_load_balancers(self, group_name):
+        return self.autoscaling_groups[group_name].load_balancers
+
+    def detach_load_balancers(self, group_name, load_balancer_names):
+        group = self.autoscaling_groups[group_name]
+        group_instance_ids = set(
+            state.instance.id for state in group.instance_states)
+        elbs = self.elb_backend.describe_load_balancers(names=group.load_balancers)
+        for elb in elbs:
+            self.elb_backend.deregister_instances(
+                elb.name, group_instance_ids)
+        group.load_balancers = [x for x in group.load_balancers if x not in load_balancer_names]
+
 
 autoscaling_backends = {}
 for region, ec2_backend in ec2_backends.items():

moto/autoscaling/responses.py

@@ -1,6 +1,7 @@
 from __future__ import unicode_literals
 
 from moto.core.responses import BaseResponse
+from moto.core.utils import amz_crc32, amzn_request_id
 from .models import autoscaling_backends
 
 
@@ -87,6 +88,8 @@ class AutoScalingResponse(BaseResponse):
         template = self.response_template(CREATE_AUTOSCALING_GROUP_TEMPLATE)
         return template.render()
 
+    @amz_crc32
+    @amzn_request_id
     def attach_instances(self):
         group_name = self._get_param('AutoScalingGroupName')
         instance_ids = self._get_multi_param("InstanceIds.member")
@@ -95,6 +98,8 @@ class AutoScalingResponse(BaseResponse):
         template = self.response_template(ATTACH_INSTANCES_TEMPLATE)
         return template.render()
 
+    @amz_crc32
+    @amzn_request_id
     def detach_instances(self):
         group_name = self._get_param('AutoScalingGroupName')
         instance_ids = self._get_multi_param("InstanceIds.member")
@@ -207,6 +212,34 @@ class AutoScalingResponse(BaseResponse):
         template = self.response_template(EXECUTE_POLICY_TEMPLATE)
         return template.render()
 
+    @amz_crc32
+    @amzn_request_id
+    def attach_load_balancers(self):
+        group_name = self._get_param('AutoScalingGroupName')
+        load_balancer_names = self._get_multi_param("LoadBalancerNames.member")
+        self.autoscaling_backend.attach_load_balancers(
+            group_name, load_balancer_names)
+        template = self.response_template(ATTACH_LOAD_BALANCERS_TEMPLATE)
+        return template.render()
+
+    @amz_crc32
+    @amzn_request_id
+    def describe_load_balancers(self):
+        group_name = self._get_param('AutoScalingGroupName')
+        load_balancers = self.autoscaling_backend.describe_load_balancers(group_name)
+        template = self.response_template(DESCRIBE_LOAD_BALANCERS_TEMPLATE)
+        return template.render(load_balancers=load_balancers)
+
+    @amz_crc32
+    @amzn_request_id
+    def detach_load_balancers(self):
+        group_name = self._get_param('AutoScalingGroupName')
+        load_balancer_names = self._get_multi_param("LoadBalancerNames.member")
+        self.autoscaling_backend.detach_load_balancers(
+            group_name, load_balancer_names)
+        template = self.response_template(DETACH_LOAD_BALANCERS_TEMPLATE)
+        return template.render()
+
 
 CREATE_LAUNCH_CONFIGURATION_TEMPLATE = """<CreateLaunchConfigurationResponse xmlns="http://autoscaling.amazonaws.com/doc/2011-01-01/">
 <ResponseMetadata>
@@ -309,7 +342,7 @@ ATTACH_INSTANCES_TEMPLATE = """<AttachInstancesResponse xmlns="http://autoscalin
 <AttachInstancesResult>
 </AttachInstancesResult>
 <ResponseMetadata>
-<RequestId>8d798a29-f083-11e1-bdfb-cb223EXAMPLE</RequestId>
+<RequestId>{{ requestid }}</RequestId>
 </ResponseMetadata>
 </AttachInstancesResponse>"""
 
@@ -335,7 +368,7 @@ DETACH_INSTANCES_TEMPLATE = """<DetachInstancesResponse xmlns="http://autoscalin
   </Activities>
 </DetachInstancesResult>
 <ResponseMetadata>
-<RequestId>8d798a29-f083-11e1-bdfb-cb223EXAMPLE</RequestId>
+<RequestId>{{ requestid }}</RequestId>
 </ResponseMetadata>
 </DetachInstancesResponse>"""
 
@@ -505,3 +538,33 @@ DELETE_POLICY_TEMPLATE = """<DeleteScalingPolicyResponse xmlns="http://autoscali
     <RequestId>70a76d42-9665-11e2-9fdf-211deEXAMPLE</RequestId>
   </ResponseMetadata>
 </DeleteScalingPolicyResponse>"""
+
+ATTACH_LOAD_BALANCERS_TEMPLATE = """<AttachLoadBalancersResponse xmlns="http://autoscaling.amazonaws.com/doc/2011-01-01/">
+<AttachLoadBalancersResult></AttachLoadBalancersResult>
+<ResponseMetadata>
+<RequestId>{{ requestid }}</RequestId>
+</ResponseMetadata>
+</AttachLoadBalancersResponse>"""
+
+DESCRIBE_LOAD_BALANCERS_TEMPLATE = """<DescribeLoadBalancersResponse xmlns="http://autoscaling.amazonaws.com/doc/2011-01-01/">
+<DescribeLoadBalancersResult>
+  <LoadBalancers>
+    {% for load_balancer in load_balancers %}
+      <member>
+        <LoadBalancerName>{{ load_balancer }}</LoadBalancerName>
+        <State>Added</State>
+      </member>
+    {% endfor %}
+  </LoadBalancers>
+</DescribeLoadBalancersResult>
+<ResponseMetadata>
+<RequestId>{{ requestid }}</RequestId>
+</ResponseMetadata>
+</DescribeLoadBalancersResponse>"""
+
+DETACH_LOAD_BALANCERS_TEMPLATE = """<DetachLoadBalancersResponse xmlns="http://autoscaling.amazonaws.com/doc/2011-01-01/">
+<DetachLoadBalancersResult></DetachLoadBalancersResult>
+<ResponseMetadata>
+<RequestId>{{ requestid }}</RequestId>
+</ResponseMetadata>
+</DetachLoadBalancersResponse>"""

tests/test_autoscaling/test_autoscaling.py

@@ -8,7 +8,7 @@ from boto.ec2.autoscale import Tag
 import boto.ec2.elb
 import sure  # noqa
 
-from moto import mock_autoscaling, mock_ec2_deprecated, mock_elb_deprecated, mock_autoscaling_deprecated, mock_ec2
+from moto import mock_autoscaling, mock_ec2_deprecated, mock_elb_deprecated, mock_elb, mock_autoscaling_deprecated, mock_ec2
 from tests.helpers import requires_boto_gte
 
 
@@ -484,6 +484,131 @@ Boto3
 '''
 
 
+@mock_autoscaling
+@mock_elb
+def test_describe_load_balancers():
+    INSTANCE_COUNT = 2
+
+    elb_client = boto3.client('elb', region_name='us-east-1')
+    elb_client.create_load_balancer(
+        LoadBalancerName='my-lb',
+        Listeners=[
+            {'Protocol': 'tcp', 'LoadBalancerPort': 80, 'InstancePort': 8080}],
+        AvailabilityZones=['us-east-1a', 'us-east-1b']
+    )
+
+    client = boto3.client('autoscaling', region_name='us-east-1')
+    _ = client.create_launch_configuration(
+        LaunchConfigurationName='test_launch_configuration'
+    )
+    _ = client.create_auto_scaling_group(
+        AutoScalingGroupName='test_asg',
+        LaunchConfigurationName='test_launch_configuration',
+        LoadBalancerNames=['my-lb'],
+        MinSize=0,
+        MaxSize=INSTANCE_COUNT,
+        DesiredCapacity=INSTANCE_COUNT,
+        Tags=[{
+            "ResourceId": 'test_asg',
+            "Key": 'test_key',
+            "Value": 'test_value',
+            "PropagateAtLaunch": True
+        }]
+    )
+
+    response = client.describe_load_balancers(AutoScalingGroupName='test_asg')
+    list(response['LoadBalancers']).should.have.length_of(1)
+    response['LoadBalancers'][0]['LoadBalancerName'].should.equal('my-lb')
+
+
+@mock_autoscaling
+@mock_elb
+def test_attach_load_balancer():
+    INSTANCE_COUNT = 2
+
+    elb_client = boto3.client('elb', region_name='us-east-1')
+    elb_client.create_load_balancer(
+        LoadBalancerName='my-lb',
+        Listeners=[
+            {'Protocol': 'tcp', 'LoadBalancerPort': 80, 'InstancePort': 8080}],
+        AvailabilityZones=['us-east-1a', 'us-east-1b']
+    )
+
+    client = boto3.client('autoscaling', region_name='us-east-1')
+    _ = client.create_launch_configuration(
+        LaunchConfigurationName='test_launch_configuration'
+    )
+    _ = client.create_auto_scaling_group(
+        AutoScalingGroupName='test_asg',
+        LaunchConfigurationName='test_launch_configuration',
+        MinSize=0,
+        MaxSize=INSTANCE_COUNT,
+        DesiredCapacity=INSTANCE_COUNT,
+        Tags=[{
+            "ResourceId": 'test_asg',
+            "Key": 'test_key',
+            "Value": 'test_value',
+            "PropagateAtLaunch": True
+        }]
+    )
+
+    response = client.attach_load_balancers(
+        AutoScalingGroupName='test_asg',
+        LoadBalancerNames=['my-lb'])
+    response['ResponseMetadata']['HTTPStatusCode'].should.equal(200)
+
+    response = elb_client.describe_load_balancers(
+        LoadBalancerNames=['my-lb']
+    )
+    list(response['LoadBalancerDescriptions'][0]['Instances']).should.have.length_of(INSTANCE_COUNT)
+
+
+@mock_autoscaling
+@mock_elb
+def test_detach_load_balancer():
+    INSTANCE_COUNT = 2
+
+    elb_client = boto3.client('elb', region_name='us-east-1')
+    elb_client.create_load_balancer(
+        LoadBalancerName='my-lb',
+        Listeners=[
+            {'Protocol': 'tcp', 'LoadBalancerPort': 80, 'InstancePort': 8080}],
+        AvailabilityZones=['us-east-1a', 'us-east-1b']
+    )
+
+    client = boto3.client('autoscaling', region_name='us-east-1')
+    _ = client.create_launch_configuration(
+        LaunchConfigurationName='test_launch_configuration'
+    )
+    _ = client.create_auto_scaling_group(
+        AutoScalingGroupName='test_asg',
+        LaunchConfigurationName='test_launch_configuration',
+        LoadBalancerNames=['my-lb'],
+        MinSize=0,
+        MaxSize=INSTANCE_COUNT,
+        DesiredCapacity=INSTANCE_COUNT,
+        Tags=[{
+            "ResourceId": 'test_asg',
+            "Key": 'test_key',
+            "Value": 'test_value',
+            "PropagateAtLaunch": True
+        }]
+    )
+
+    response = client.detach_load_balancers(
+        AutoScalingGroupName='test_asg',
+        LoadBalancerNames=['my-lb'])
+    response['ResponseMetadata']['HTTPStatusCode'].should.equal(200)
+
+    response = elb_client.describe_load_balancers(
+        LoadBalancerNames=['my-lb']
+    )
+    list(response['LoadBalancerDescriptions'][0]['Instances']).should.have.length_of(0)
+
+    response = client.describe_load_balancers(AutoScalingGroupName='test_asg')
+    list(response['LoadBalancers']).should.have.length_of(0)
+
+
 @mock_autoscaling
 def test_create_autoscaling_group_boto3():
     client = boto3.client('autoscaling', region_name='us-east-1')