Exclude namespaces with regex (#118)

* Add regex match to exclude namespaces

* Modifid default value of exclude namespace to ^kube-system$

* use Pattern object

* mention regex in README

* test CLI option regex mapping

* use Python 3.8

Co-authored-by: Andrea Mercanti <a.mercanti@reply.it>

Author: hjacobs

.travis.yml

@@ -2,7 +2,7 @@ dist: bionic
 sudo: yes
 language: python
 python:
-  - "3.7"
+  - "3.8"
 services:
   - docker
 install:

README.rst

@@ -160,7 +160,7 @@ Available command line options:
 ``--default-downtime``
     Default time range to scale down for (default: never), can also be configured via environment variable ``DEFAULT_DOWNTIME`` or via the annotation ``downscaler/downtime`` on each deployment
 ``--exclude-namespaces``
-    Exclude namespaces from downscaling (default: kube-system), can also be configured via environment variable ``EXCLUDE_NAMESPACES``
+    Exclude namespaces from downscaling (list of regex patterns, default: kube-system), can also be configured via environment variable ``EXCLUDE_NAMESPACES``
 ``--exclude-deployments``
     Exclude specific deployments/statefulsets/cronjobs from downscaling (default: kube-downscaler, downscaler), can also be configured via environment variable ``EXCLUDE_DEPLOYMENTS``.
     Despite its name, this option will match the name of any included resource type (Deployment, StatefulSet, CronJob, ..).

kube_downscaler/cmd.py

@@ -68,7 +68,7 @@ def get_parser():
     )
     parser.add_argument(
         "--exclude-namespaces",
-        help="Exclude namespaces from downscaling (default: kube-system)",
+        help="Exclude namespaces from downscaling, comma-separated list of regex patterns (default: kube-system)",
         default=os.getenv("EXCLUDE_NAMESPACES", "kube-system"),
     )
     parser.add_argument(

kube_downscaler/main.py

@@ -1,5 +1,6 @@
 #!/usr/bin/env python3
 import logging
+import re
 import time
 
 from kube_downscaler import __version__
@@ -69,7 +70,9 @@ def run_loop(
                 default_uptime,
                 default_downtime,
                 include_resources=frozenset(include_resources.split(",")),
-                exclude_namespaces=frozenset(exclude_namespaces.split(",")),
+                exclude_namespaces=frozenset(
+                    re.compile(pattern) for pattern in exclude_namespaces.split(",")
+                ),
                 exclude_deployments=frozenset(exclude_deployments.split(",")),
                 dry_run=dry_run,
                 grace_period=grace_period,

kube_downscaler/scaler.py

@@ -3,6 +3,7 @@
 import logging
 from typing import FrozenSet
 from typing import Optional
+from typing import Pattern
 
 import pykube
 from pykube import CronJob
@@ -317,7 +318,7 @@ def autoscale_resources(
     api,
     kind,
     namespace: str,
-    exclude_namespaces: FrozenSet[str],
+    exclude_namespaces: FrozenSet[Pattern],
     exclude_names: FrozenSet[str],
     upscale_period: str,
     downscale_period: str,
@@ -341,9 +342,11 @@ def autoscale_resources(
 
     for current_namespace, resources in sorted(resources_by_namespace.items()):
 
-        if current_namespace in exclude_namespaces:
+        if any(
+            [pattern.fullmatch(current_namespace) for pattern in exclude_namespaces]
+        ):
             logger.debug(
-                f"Namespace {current_namespace} was excluded (exclusion list matches)"
+                f"Namespace {current_namespace} was excluded (exclusion list regex matches)"
             )
             continue
 
@@ -412,7 +415,7 @@ def scale(
     default_uptime: str,
     default_downtime: str,
     include_resources: FrozenSet[str],
-    exclude_namespaces: FrozenSet[str],
+    exclude_namespaces: FrozenSet[Pattern],
     exclude_deployments: FrozenSet[str],
     dry_run: bool,
     grace_period: int,

tests/test_main.py

@@ -1,4 +1,5 @@
 import os.path
+import re
 from unittest.mock import MagicMock
 
 import pytest
@@ -59,3 +60,17 @@ def mock_scale(*args, **kwargs):
     main(["--dry-run", "--interval=0"])
 
     assert len(calls) == 2
+
+
+def test_main_exclude_namespaces(kubeconfig, monkeypatch):
+    monkeypatch.setattr(os.path, "expanduser", lambda x: str(kubeconfig))
+
+    mock_scale = MagicMock()
+    monkeypatch.setattr("kube_downscaler.main.scale", mock_scale)
+
+    main(["--dry-run", "--once", "--exclude-namespaces=foo,.*-infra-.*"])
+
+    mock_scale.assert_called_once()
+    assert mock_scale.call_args.kwargs["exclude_namespaces"] == frozenset(
+        [re.compile("foo"), re.compile(".*-infra-.*")]
+    )

tests/test_scaler.py

@@ -1,5 +1,6 @@
 import datetime
 import json
+import re
 from unittest.mock import MagicMock
 
 from kube_downscaler.scaler import DOWNTIME_REPLICAS_ANNOTATION
@@ -110,7 +111,83 @@ def get(url, version, **kwargs):
         default_uptime="never",
         default_downtime="always",
         include_resources=include_resources,
-        exclude_namespaces=["system-ns"],
+        exclude_namespaces=[re.compile("system-ns")],
+        exclude_deployments=[],
+        dry_run=False,
+        grace_period=300,
+        downtime_replicas=0,
+    )
+
+    assert api.patch.call_count == 1
+
+    # make sure that deploy-2 was updated (namespace of sysdep-1 was excluded)
+    patch_data = {
+        "metadata": {
+            "name": "deploy-2",
+            "namespace": "default",
+            "creationTimestamp": "2019-03-01T16:38:00Z",
+            "annotations": {ORIGINAL_REPLICAS_ANNOTATION: "2"},
+        },
+        "spec": {"replicas": 0},
+    }
+    assert api.patch.call_args[1]["url"] == "/deployments/deploy-2"
+    assert json.loads(api.patch.call_args[1]["data"]) == patch_data
+
+
+def test_scaler_namespace_excluded_regex(monkeypatch):
+    api = MagicMock()
+    monkeypatch.setattr(
+        "kube_downscaler.scaler.helper.get_kube_api", MagicMock(return_value=api)
+    )
+
+    def get(url, version, **kwargs):
+        if url == "pods":
+            data = {"items": []}
+        elif url == "deployments":
+            data = {
+                "items": [
+                    {
+                        "metadata": {
+                            "name": "sysdep-1",
+                            "namespace": "system-ns",
+                            "creationTimestamp": "2019-03-01T16:38:00Z",
+                        },
+                        "spec": {"replicas": 1},
+                    },
+                    {
+                        "metadata": {
+                            "name": "deploy-2",
+                            "namespace": "default",
+                            "creationTimestamp": "2019-03-01T16:38:00Z",
+                        },
+                        "spec": {"replicas": 2},
+                    },
+                ]
+            }
+        elif url == "namespaces/default":
+            data = {"metadata": {}}
+        else:
+            raise Exception(f"unexpected call: {url}, {version}, {kwargs}")
+
+        response = MagicMock()
+        response.json.return_value = data
+        return response
+
+    api.get = get
+
+    include_resources = frozenset(["deployments"])
+    scale(
+        namespace=None,
+        upscale_period="never",
+        downscale_period="never",
+        default_uptime="never",
+        default_downtime="always",
+        include_resources=include_resources,
+        exclude_namespaces=[
+            re.compile("foo.*"),
+            re.compile("syst?em-.*"),
+            re.compile("def"),
+        ],
         exclude_deployments=[],
         dry_run=False,
         grace_period=300,