Merge pull request #11 from citizensadvice/add-tests

Add tests

README.md

@@ -82,3 +82,13 @@ $ kubectl logs -n kube-schedule-scaler kube-schedule-scaler-844b6d5888-p9tc4 | g
 ```
 
 You can change the log level using the `LOG_LEVEL` environment variable (e.g. `LOG_LEVEL=DEBUG`)
+
+## Testing
+
+To run the tests you will need:
+
+- kube-schedule-scaler installed in a working k8s cluster (e.g. Minikube)
+- pytest (can be installed with pip, in a virtualenv for example)
+
+The tests will create some deployment and hpa resources with the proper annotation and verify that they are scaled properly.
+If you want to test your local build, you can [run it in Minikube](https://stackoverflow.com/a/42564211).

tests/manifest.yml

@@ -0,0 +1,105 @@
+---
+apiVersion: v1
+kind: Namespace
+metadata:
+  name: test-kube-schedule-scaler
+  labels:
+    name: test-kube-schedule-scaler
+    product: test
+    component: kube-schedule-scaler
+---
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: sleep
+  namespace: test-kube-schedule-scaler
+  labels:
+    app: test-kube-schedule-scaler
+    product: test
+    component: sleep
+spec:
+  selector:
+    matchLabels:
+      component: sleep
+  replicas: 1
+  template:
+    metadata:
+      labels:
+        app: test-kube-schedule-scaler
+        product: test
+        component: sleep
+    spec:
+      terminationGracePeriodSeconds: 1
+      securityContext:
+        runAsNonRoot: true
+        runAsUser: 65534 # nobody
+        runAsGroup: 65534
+      containers:
+        - name: sleep
+          image: 979633842206.dkr.ecr.eu-west-1.amazonaws.com/docker-hub/library/busybox:1.33.1
+          imagePullPolicy: IfNotPresent
+          resources:
+            requests:
+              cpu: 100m
+              memory: 16Mi
+            limits:
+              cpu: 100m
+              memory: 32Mi
+          command: ['sleep', 'infinity']
+---
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: sleep-with-autoscaling
+  namespace: test-kube-schedule-scaler
+  labels:
+    app: test-kube-schedule-scaler
+    product: test
+    component: sleep-with-autoscaling
+spec:
+  selector:
+    matchLabels:
+      component: sleep-with-autoscaling
+  replicas: 1
+  template:
+    metadata:
+      labels:
+        app: test-kube-schedule-scaler
+        product: test
+        component: sleep-with-autoscaling
+    spec:
+      terminationGracePeriodSeconds: 1
+      securityContext:
+        runAsNonRoot: true
+        runAsUser: 65534 # nobody
+        runAsGroup: 65534
+      containers:
+        - name: sleep
+          image: 979633842206.dkr.ecr.eu-west-1.amazonaws.com/docker-hub/library/busybox:1.33.1
+          imagePullPolicy: IfNotPresent
+          resources:
+            requests:
+              cpu: 100m
+              memory: 16Mi
+            limits:
+              cpu: 100m
+              memory: 32Mi
+          command: ['sleep', 'infinity']
+---
+apiVersion: autoscaling/v1
+kind: HorizontalPodAutoscaler
+metadata:
+  name: sleep-with-autoscaling
+  namespace: test-kube-schedule-scaler
+  labels:
+    app: test-kube-schedule-scaler
+    product: test
+    component: sleep-with-autoscaling
+spec:
+  minReplicas: 1
+  maxReplicas: 2
+  targetCPUUtilizationPercentage: 75
+  scaleTargetRef:
+    apiVersion: apps/v1
+    kind: Deployment
+    name: sleep-with-autoscaling

tests/test_kube_schedule_scaler.py

@@ -0,0 +1,127 @@
+from collections.abc import Sequence
+import datetime
+import json
+from os import path
+import subprocess
+from time import sleep
+
+
+def run(args: Sequence[str]) -> None:
+    """Runs a subprocess and asserts that the exit code is 0"""
+    assert subprocess.call(args) == 0
+
+
+def setup_module(module):
+    base_dir = path.dirname(path.realpath(__file__))
+    # deploy the manifest
+    run(["kubectl", "apply", "-f", f"{base_dir}/manifest.yml"])
+    # wait for resources to be ready
+    sleep(20)
+
+
+def teardown_module(module):
+    base_dir = path.dirname(path.realpath(__file__))
+    # delete the resources
+    run(["kubectl", "delete", "-f", f"{base_dir}/manifest.yml"])
+
+
+def get_cron_formatted_time():
+    '''Return the cron expr prefix for the next minute, e.g. "43 14"'''
+    now = datetime.datetime.now(datetime.UTC)
+
+    # get the minute and hour of the next minute from now
+    return (now + datetime.timedelta(minutes=1)).strftime("%M %H")
+
+
+def get_json_patch(schedule_actions):
+    """Return the JSON string used to patch the Deployment objects"""
+    return json.dumps(
+        {
+            "metadata": {
+                "annotations": {
+                    # schedule action must be a JSON string, so we encode it here
+                    "zalando.org/schedule-actions": json.dumps(schedule_actions)
+                }
+            }
+        }
+    )
+
+
+def patch_deployment(deployment_name, patch):
+    """Inject the scheduler annotation in the target Deployment"""
+    res = subprocess.run(
+        [
+            "kubectl",
+            "patch",
+            "-n",
+            "test-kube-schedule-scaler",
+            "deployment",
+            deployment_name,
+            "-p",
+            patch,
+        ]
+    )
+    assert res.returncode == 0
+
+
+def test_deployment_scaling():
+    """Check that schedule actions are applied to the Deployment object"""
+    t = get_cron_formatted_time()
+    schedule_actions = [{"schedule": f"{t} * * *", "replicas": "2"}]
+    patch = get_json_patch(schedule_actions)
+    patch_deployment("sleep", patch)
+
+    # wait a minute
+    sleep(60)
+
+    # check the deployment number of replicas
+    res = subprocess.check_output(
+        [
+            "kubectl",
+            "get",
+            "-n",
+            "test-kube-schedule-scaler",
+            "deployment",
+            "sleep",
+            "-o",
+            "json",
+        ]
+    )
+
+    data = json.loads(res)
+
+    # check the number of replicas
+    assert data["spec"]["replicas"] == 2
+
+
+def test_hpa_scaling():
+    """Check that schedule actions are applied to the relevant HPA for the Deployment object"""
+    t = get_cron_formatted_time()
+    schedule_actions = [
+        {"schedule": f"{t} * * *", "minReplicas": "2", "maxReplicas": "3"}
+    ]
+    patch = get_json_patch(schedule_actions)
+    patch_deployment("sleep-with-autoscaling", patch)
+
+    # wait a minute
+    sleep(60)
+
+    # check the deployment number of replicas
+    res = subprocess.check_output(
+        [
+            "kubectl",
+            "get",
+            "-n",
+            "test-kube-schedule-scaler",
+            "hpa",
+            "sleep-with-autoscaling",
+            "-o",
+            "json",
+        ]
+    )
+
+    data = json.loads(res)
+
+    # check the number of replicas
+    assert data["spec"]["minReplicas"] == 2
+    assert data["spec"]["maxReplicas"] == 3