add modify_rules to elbv2

moto/elbv2/exceptions.py

@@ -150,3 +150,11 @@ class InvalidDescribeRulesRequest(ELBClientError):
         super(InvalidDescribeRulesRequest, self).__init__(
             "ValidationError", msg
         )
+
+
+class RuleNotFoundError(ELBClientError):
+
+    def __init__(self):
+        super(RuleNotFoundError, self).__init__(
+            "RuleNotFound",
+            "The specified rule does not exist.")

moto/elbv2/models.py

@@ -19,7 +19,8 @@ from .exceptions import (
     InvalidConditionValueError,
     InvalidActionTypeError,
     ActionTargetGroupNotFoundError,
-    InvalidDescribeRulesRequest
+    InvalidDescribeRulesRequest,
+    RuleNotFoundError
 )
 
 
@@ -406,6 +407,49 @@ class ELBv2Backend(BaseBackend):
                 return listener
         raise ListenerNotFoundError()
 
+    def modify_rule(self, rule_arn, conditions, actions):
+        rules = self.describe_rules(listener_arn=None, rule_arns=[rule_arn])
+        if not rules:
+            raise RuleNotFoundError()
+        rule = rules[0]
+
+        # validate conditions
+        for condition in conditions:
+            field = condition['field']
+            if field not in ['path-pattern', 'host-header']:
+                raise InvalidConditionFieldError(field)
+
+            values = condition['values']
+            if len(values) == 0:
+                raise InvalidConditionValueError('A condition value must be specified')
+            if len(values) > 1:
+                raise InvalidConditionValueError(
+                    "The '%s' field contains too many values; the limit is '1'" % field
+                )
+
+            # TODO: check pattern of value for 'host-header'
+            # TODO: check pattern of value for 'path-pattern'
+
+        # validate Actions
+        target_group_arns = [target_group.arn for target_group in self.target_groups.values()]
+        for i, action in enumerate(actions):
+            index = i + 1
+            action_type = action['type']
+            if action_type not in ['forward']:
+                raise InvalidActionTypeError(action_type, index)
+            action_target_group_arn = action['target_group_arn']
+            if action_target_group_arn not in target_group_arns:
+                raise ActionTargetGroupNotFoundError(action_target_group_arn)
+
+        # TODO: check for error 'TooManyRegistrationsForTargetId'
+        # TODO: check for error 'TooManyRules'
+
+        # modify rule
+        rule.conditions = conditions
+        rule.actions = actions
+        return [rule]
+
+
     def register_targets(self, target_group_arn, instances):
         target_group = self.target_groups.get(target_group_arn)
         if target_group is None:

moto/elbv2/responses.py

@@ -196,6 +196,28 @@ class ELBV2Response(BaseResponse):
         template = self.response_template(DELETE_LISTENER_TEMPLATE)
         return template.render()
 
+    def modify_rule(self):
+        rule_arn = self._get_param('RuleArn')
+        _conditions = self._get_list_prefix('Conditions.member')
+        conditions = []
+        for _condition in _conditions:
+            condition = {}
+            condition['field'] = _condition['field']
+            values = sorted(
+                [e for e in _condition.items() if e[0].startswith('values.member')],
+                key=lambda x: x[0]
+            )
+            condition['values'] = [e[1] for e in values]
+            conditions.append(condition)
+        actions = self._get_list_prefix('Actions.member')
+        rules = self.elbv2_backend.modify_rule(
+            rule_arn=rule_arn,
+            conditions=conditions,
+            actions=actions
+        )
+        template = self.response_template(MODIFY_RULE_TEMPLATE)
+        return template.render(rules=rules)
+
     def modify_target_group_attributes(self):
         target_group_arn = self._get_param('TargetGroupArn')
         target_group = self.elbv2_backend.target_groups.get(target_group_arn)
@@ -678,6 +700,43 @@ CONFIGURE_HEALTH_CHECK_TEMPLATE = """<ConfigureHealthCheckResponse xmlns="http:/
   </ResponseMetadata>
 </ConfigureHealthCheckResponse>"""
 
+MODIFY_RULE_TEMPLATE = """<ModifyRuleResponse xmlns="http://elasticloadbalancing.amazonaws.com/doc/2015-12-01/">
+  <ModifyRuleResult>
+    <Rules>
+      {% for rule in rules %}
+      <member>
+        <IsDefault>{{ "true" if rule.is_default else "false" }}</IsDefault>
+        <Conditions>
+          {% for condition in rule.conditions %}
+          <member>
+            <Field>{{ condition["field"] }}</Field>
+            <Values>
+              {% for value in condition["values"] %}
+              <member>{{ value }}</member>
+              {% endfor %}
+            </Values>
+          </member>
+          {% endfor %}
+        </Conditions>
+        <Priority>{{ rule.priority }}</Priority>
+        <Actions>
+          {% for action in rule.actions %}
+          <member>
+            <Type>{{ action["type"] }}</Type>
+            <TargetGroupArn>{{ action["target_group_arn"] }}</TargetGroupArn>
+          </member>
+          {% endfor %}
+        </Actions>
+        <RuleArn>{{ rule.arn }}</RuleArn>
+      </member>
+      {% endfor %}
+    </Rules>
+  </ModifyRuleResult>
+  <ResponseMetadata>
+    <RequestId>c5478c83-f397-11e5-bb98-57195a6eb84a</RequestId>
+  </ResponseMetadata>
+</ModifyRuleResponse>"""
+
 MODIFY_TARGET_GROUP_ATTRIBUTES_TEMPLATE = """<ModifyTargetGroupAttributesResponse xmlns="http://elasticloadbalancing.amazonaws.com/doc/2015-12-01/">
   <ModifyTargetGroupAttributesResult>
     <Attributes>

tests/test_elbv2/test_elbv2.py

@@ -615,10 +615,10 @@ def test_create_listener_rules():
     priorities.should.equal(['50', '100', 'default'])
 
     # test for describe listeners
-    first_rule = rules['Rules'][0]
     obtained_rules = conn.describe_rules(ListenerArn=http_listener_arn)
     obtained_rules['Rules'].should.equal(rules['Rules'])
 
+    first_rule = obtained_rules['Rules'][0]
     obtained_rules = conn.describe_rules(RuleArns=[first_rule['RuleArn']])
     obtained_rules['Rules'].should.equal([first_rule])
 
@@ -638,6 +638,28 @@ def test_create_listener_rules():
             RuleArns=[first_rule['RuleArn']]
         )
 
+    # modify
+    new_host = 'new.example.com'
+    new_path_pattern = 'new_path'
+    modified_rule = conn.modify_rule(
+        RuleArn=first_rule['RuleArn'],
+        Conditions=[{
+                'Field': 'host-header',
+                'Values': [ new_host ]
+            },
+            {
+                'Field': 'path-pattern',
+                'Values': [ new_path_pattern ]
+            }],
+            Actions=[{
+                'TargetGroupArn': target_group.get('TargetGroupArn'),
+                'Type': 'forward'
+            }]
+
+    )['Rules'][0]
+    rules = conn.describe_rules(ListenerArn=http_listener_arn)
+    modified_rule.should.equal(rules['Rules'][0])
+
     # delete
     arn = first_rule['RuleArn']
     conn.delete_rule(RuleArn=arn)