From be197caba6282260ca53112f1f5c7ab4a6675ca9 Mon Sep 17 00:00:00 2001
From: kbalk <7536198+kbalk@users.noreply.github.com>
Date: Fri, 19 Nov 2021 08:57:54 -0500
Subject: [PATCH] Add support for filters for list_resolver_endpoints (#4598)

---
 moto/route53resolver/models.py                |  80 +++++++++++-
 moto/route53resolver/responses.py             |   2 +-
 .../test_route53resolver_endpoint.py          | 115 ++++++++++++++++++
 3 files changed, 192 insertions(+), 5 deletions(-)

diff --git a/moto/route53resolver/models.py b/moto/route53resolver/models.py
index 36254c0f0..c6315b624 100644
--- a/moto/route53resolver/models.py
+++ b/moto/route53resolver/models.py
@@ -2,6 +2,7 @@
 from collections import defaultdict
 from datetime import datetime, timezone
 from ipaddress import ip_address, ip_network
+import re
 
 from boto3 import Session
 
@@ -25,6 +26,8 @@ from moto.route53resolver.validations import validate_args
 from moto.utilities.paginator import paginate
 from moto.utilities.tagging_service import TaggingService
 
+CAMEL_TO_SNAKE_PATTERN = re.compile(r"(?<!^)(?=[A-Z])")
+
 
 class ResolverEndpoint(BaseModel):  # pylint: disable=too-many-instance-attributes
     """Representation of a fake Route53 Resolver Endpoint."""
@@ -32,6 +35,18 @@ class ResolverEndpoint(BaseModel):  # pylint: disable=too-many-instance-attribut
     MAX_TAGS_PER_RESOLVER_ENDPOINT = 200
     MAX_ENDPOINTS_PER_REGION = 4
 
+    # There are two styles of filter names and either will be transformed
+    # into lowercase snake.
+    FILTER_NAMES = [
+        "creator_request_id",
+        "direction",
+        "host_vpc_id",
+        "ip_address_count",
+        "name",
+        "security_group_ids",
+        "status",
+    ]
+
     def __init__(
         self,
         region,
@@ -328,14 +343,71 @@ class Route53ResolverBackend(BaseBackend):
         endpoint = self.resolver_endpoints[resolver_endpoint_id]
         return endpoint.ip_descriptions()
 
+    @staticmethod
+    def _add_field_name_to_filter(filters):
+        """Convert both styles of filter names to lowercase snake format.
+
+        "IP_ADDRESS_COUNT" or "IpAddressCount" will become "ip_address_count".
+        However, "HostVPCId" doesn't fit the pattern, so that's treated
+        special.
+        """
+        for rr_filter in filters:
+            filter_name = rr_filter["Name"]
+            if "_" not in filter_name:
+                if filter_name == "HostVPCId":
+                    filter_name = "host_vpc_id"
+                elif filter_name == "HostVpcId":
+                    filter_name = "WRONG"
+                elif not filter_name.isupper():
+                    filter_name = CAMEL_TO_SNAKE_PATTERN.sub("_", filter_name)
+            rr_filter["Field"] = filter_name.lower()
+
+    @staticmethod
+    def _validate_filters(filters, allowed_filter_names):
+        """Raise exception if filter names are not as expected."""
+        for rr_filter in filters:
+            if rr_filter["Field"] not in allowed_filter_names:
+                raise InvalidParameterException(
+                    f"The filter '{rr_filter['Name']}' is invalid"
+                )
+            if "Values" not in rr_filter:
+                raise InvalidParameterException(
+                    f"No values specified for filter {rr_filter['Name']}"
+                )
+
+    @staticmethod
+    def _matches_all_filters(entity, filters):
+        """Return True if this entity has fields matching all the filters."""
+        for rr_filter in filters:
+            field_value = getattr(entity, rr_filter["Field"])
+
+            if isinstance(field_value, list):
+                if not set(field_value).intersection(rr_filter["Values"]):
+                    return False
+            elif isinstance(field_value, int):
+                if str(field_value) not in rr_filter["Values"]:
+                    return False
+            elif field_value not in rr_filter["Values"]:
+                return False
+
+        return True
+
     @paginate(pagination_model=PAGINATION_MODEL)
     def list_resolver_endpoints(
-        self, filters=None, next_token=None, max_results=None,
+        self, filters, next_token=None, max_results=None,
     ):  # pylint: disable=unused-argument
         """List all resolver endpoints, using filters if specified."""
-        # TODO - check subsequent filters
-        # TODO - validate name, values for filters
-        return sorted(self.resolver_endpoints.values(), key=lambda x: x.name)
+        if not filters:
+            filters = []
+
+        self._add_field_name_to_filter(filters)
+        self._validate_filters(filters, ResolverEndpoint.FILTER_NAMES)
+
+        endpoints = []
+        for endpoint in sorted(self.resolver_endpoints.values(), key=lambda x: x.name):
+            if self._matches_all_filters(endpoint, filters):
+                endpoints.append(endpoint)
+        return endpoints
 
     @paginate(pagination_model=PAGINATION_MODEL)
     def list_tags_for_resource(
diff --git a/moto/route53resolver/responses.py b/moto/route53resolver/responses.py
index 3a4d8af6a..4b1863c7b 100644
--- a/moto/route53resolver/responses.py
+++ b/moto/route53resolver/responses.py
@@ -88,7 +88,7 @@ class Route53ResolverResponse(BaseResponse):
                 endpoints,
                 next_token,
             ) = self.route53resolver_backend.list_resolver_endpoints(
-                filters=filters, next_token=next_token, max_results=max_results
+                filters, next_token=next_token, max_results=max_results
             )
         except InvalidToken as exc:
             raise InvalidNextTokenException() from exc
diff --git a/tests/test_route53resolver/test_route53resolver_endpoint.py b/tests/test_route53resolver/test_route53resolver_endpoint.py
index bca5d270b..dc3f70440 100644
--- a/tests/test_route53resolver/test_route53resolver_endpoint.py
+++ b/tests/test_route53resolver/test_route53resolver_endpoint.py
@@ -670,6 +670,121 @@ def test_route53resolver_list_resolver_endpoints():
         assert endpoint["Name"].startswith(f"A{idx + 1}")
 
 
+@mock_ec2
+@mock_route53resolver
+def test_route53resolver_list_resolver_endpoints_filters():
+    """Test good list_resolver_endpoint API calls that use filters."""
+    client = boto3.client("route53resolver", region_name=TEST_REGION)
+    ec2_client = boto3.client("ec2", region_name=TEST_REGION)
+    random_num = get_random_hex(10)
+
+    # Create some endpoints for testing purposes
+    security_group_id = create_security_group(ec2_client)
+    vpc_id = create_vpc(ec2_client)
+    subnet_ids = create_subnets(ec2_client, vpc_id)
+    ip0_values = ["10.0.1.201", "10.0.1.202", "10.0.1.203", "10.0.1.204"]
+    ip1_values = ["10.0.0.21", "10.0.0.22", "10.0.0.23", "10.0.0.24"]
+    endpoints = []
+    for idx in range(1, 5):
+        ip_addrs = [
+            {"SubnetId": subnet_ids[0], "Ip": "10.0.1.200"},
+            {"SubnetId": subnet_ids[1], "Ip": "10.0.0.20"},
+            {"SubnetId": subnet_ids[0], "Ip": ip0_values[idx - 1]},
+            {"SubnetId": subnet_ids[1], "Ip": ip1_values[idx - 1]},
+        ]
+        response = client.create_resolver_endpoint(
+            CreatorRequestId=f"F{idx}-{random_num}",
+            Name=f"F{idx}-{random_num}",
+            SecurityGroupIds=[security_group_id],
+            Direction="INBOUND" if idx % 2 else "OUTBOUND",
+            IpAddresses=ip_addrs,
+        )
+        endpoints.append(response["ResolverEndpoint"])
+
+    # Try all the valid filter names, including some of the old style names.
+    response = client.list_resolver_endpoints(
+        Filters=[{"Name": "CreatorRequestId", "Values": [f"F3-{random_num}"]}]
+    )
+    assert len(response["ResolverEndpoints"]) == 1
+    assert response["ResolverEndpoints"][0]["CreatorRequestId"] == f"F3-{random_num}"
+
+    response = client.list_resolver_endpoints(
+        Filters=[
+            {
+                "Name": "CREATOR_REQUEST_ID",
+                "Values": [f"F2-{random_num}", f"F4-{random_num}"],
+            }
+        ]
+    )
+    assert len(response["ResolverEndpoints"]) == 2
+    assert response["ResolverEndpoints"][0]["CreatorRequestId"] == f"F2-{random_num}"
+    assert response["ResolverEndpoints"][1]["CreatorRequestId"] == f"F4-{random_num}"
+
+    response = client.list_resolver_endpoints(
+        Filters=[{"Name": "Direction", "Values": ["INBOUND"]}]
+    )
+    assert len(response["ResolverEndpoints"]) == 2
+    assert response["ResolverEndpoints"][0]["CreatorRequestId"] == f"F1-{random_num}"
+    assert response["ResolverEndpoints"][1]["CreatorRequestId"] == f"F3-{random_num}"
+
+    response = client.list_resolver_endpoints(
+        Filters=[{"Name": "HostVPCId", "Values": [vpc_id]}]
+    )
+    assert len(response["ResolverEndpoints"]) == 4
+
+    response = client.list_resolver_endpoints(
+        Filters=[{"Name": "IpAddressCount", "Values": ["4"]}]
+    )
+    assert len(response["ResolverEndpoints"]) == 4
+
+    response = client.list_resolver_endpoints(
+        Filters=[{"Name": "Name", "Values": [f"F1-{random_num}"]}]
+    )
+    assert len(response["ResolverEndpoints"]) == 1
+    assert response["ResolverEndpoints"][0]["Name"] == f"F1-{random_num}"
+
+    response = client.list_resolver_endpoints(
+        Filters=[
+            {"Name": "HOST_VPC_ID", "Values": [vpc_id]},
+            {"Name": "DIRECTION", "Values": ["INBOUND"]},
+            {"Name": "NAME", "Values": [f"F3-{random_num}"]},
+        ]
+    )
+    assert len(response["ResolverEndpoints"]) == 1
+    assert response["ResolverEndpoints"][0]["Name"] == f"F3-{random_num}"
+
+    response = client.list_resolver_endpoints(
+        Filters=[{"Name": "SecurityGroupIds", "Values": [security_group_id]}]
+    )
+    assert len(response["ResolverEndpoints"]) == 4
+
+    response = client.list_resolver_endpoints(
+        Filters=[{"Name": "Status", "Values": ["OPERATIONAL"]}]
+    )
+    assert len(response["ResolverEndpoints"]) == 4
+    response = client.list_resolver_endpoints(
+        Filters=[{"Name": "Status", "Values": ["CREATING"]}]
+    )
+    assert len(response["ResolverEndpoints"]) == 0
+
+
+@mock_route53resolver
+def test_route53resolver_bad_list_resolver_endpoints_filters():
+    """Test bad list_resolver_endpoint API calls that use filters."""
+    client = boto3.client("route53resolver", region_name=TEST_REGION)
+
+    # botocore barfs on an empty "Values":
+    # TypeError: list_resolver_endpoints() only accepts keyword arguments.
+    # client.list_resolver_endpoints([{"Name": "Direction", "Values": []}])
+    # client.list_resolver_endpoints([{"Values": []}])
+
+    with pytest.raises(ClientError) as exc:
+        client.list_resolver_endpoints(Filters=[{"Name": "foo", "Values": ["bar"]}])
+    err = exc.value.response["Error"]
+    assert err["Code"] == "InvalidParameterException"
+    assert "The filter 'foo' is invalid" in err["Message"]
+
+
 @mock_ec2
 @mock_route53resolver
 def test_route53resolver_bad_list_resolver_endpoints():