add more examples

composite-controller/resync-period/deploy/controller.yaml

@@ -0,0 +1,19 @@
+apiVersion: metacontroller.k8s.io/v1alpha1
+kind: CompositeController
+metadata:
+  name: ping-pong-controller
+spec:
+  generateSelector: true
+  parentResource:
+    apiVersion: example.com/v1
+    resource: pings
+  childResources:
+    - apiVersion: example.com/v1
+      resource: pongs
+      updateStrategy:
+        method: InPlace
+  resyncPeriodSeconds: 10
+  hooks:
+    sync:
+      webhook:
+        url: http://192.168.1.15:8080/sync

composite-controller/resync-period/deploy/crd.yaml

@@ -0,0 +1,29 @@
+apiVersion: apiextensions.k8s.io/v1beta1
+kind: CustomResourceDefinition
+metadata:
+  name: pings.example.com
+spec:
+  group: example.com
+  version: v1
+  names:
+    kind: Ping
+    plural: pings
+    singular: ping
+  scope: Namespaced
+  subresources:
+    status: {}
+---
+apiVersion: apiextensions.k8s.io/v1beta1
+kind: CustomResourceDefinition
+metadata:
+  name: pongs.example.com
+spec:
+  group: example.com
+  version: v1
+  names:
+    kind: Pong
+    plural: pongs
+    singular: pong
+  scope: Namespaced
+  subresources:
+    status: {}

composite-controller/resync-period/deploy/ping.yaml

@@ -0,0 +1,6 @@
+apiVersion: example.com/v1
+kind: Ping
+metadata:
+  name: shovan
+spec:
+  name: Shovan Maity

composite-controller/resync-period/python/sync.py

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+from http.server import BaseHTTPRequestHandler, HTTPServer
+import json
+
+
+class Controller(BaseHTTPRequestHandler):
+
+    def do_POST(self):
+
+        # Observed ping object
+        observed = json.loads(self.rfile.read(
+            int(self.headers.get("content-length"))))
+        ping = observed["parent"]
+
+        name = ping.get("spec", {}).get("name", "Unknown")
+
+        pong = [
+            {
+                "apiVersion": "example.com/v1",
+                "kind": "Pong",
+                "metadata": {
+                    "name": ping["metadata"]["name"]
+                },
+                "spec": {
+                    "message": "Hello %s !!" % (name)
+                }
+            }
+        ]
+
+        # Generate desired children
+        desired = {
+            "children": pong
+        }
+
+        self.send_response(200)
+        self.send_header("Content-type", "application/json")
+        self.end_headers()
+        self.wfile.write(json.dumps(desired).encode())
+
+
+HTTPServer(("", 8080), Controller).serve_forever()

composite-controller/resync-period/readme.md

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+### Concept
+By default, your sync hook will only be called when something changes in one of the resources you’re watching, or when the local cache is flushed. The `resyncPeriodSeconds` value specifies how often to do this. Each time it triggers, Metacontroller will send sync hook requests for all objects of the parent resource type, with the latest observed values of all the necessary objects.
+
+### Prerequisite
+
+Make sure metacontroller is [installed](https://github.com/shovanmaity/metacontroller-by-example/tree/master/metacontroller).
+
+Make sure you are inside `composite-controller/resync-period` directory.
+
+Edit the `deploy/controller.yaml` file and update the webhook URL.
+```yaml
+spec:
+  hooks:
+    sync:
+      webhook:
+        url: http://192.168.1.15:8080/sync
+```
+
+Apply the crd and controller.
+```bash
+kubectl apply -f deploy/crd.yaml
+kubectl apply -f deploy/controller.yaml
+```
+
+Execute python files
+```bash
+python3 python/sync.py
+```
+
+Create a ping cr. Find the sample `Ping` is [here](https://github.com/shovanmaity/metacontroller-by-example/blob/master/composite-controller/resync-period/deploy/ping.yaml).
+```bash
+cat <<EOF | kubectl apply -f -
+apiVersion: example.com/v1
+kind: Ping
+metadata:
+  name: shovan
+spec:
+  name: Shovan Maity
+EOF
+```
+
+Try the below processes -
+
+- Check the logs of python file execution.
+
+### Cleanup
+
+```bash
+kubectl delete ping -A --all
+kubectl delete -f deploy/controller.yaml
+kubectl delete -f deploy/crd.yaml
+# Stop the python files execution.
+```

composite-controller/sync-finalize-hook/deploy/controller.yaml

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+apiVersion: metacontroller.k8s.io/v1alpha1
+kind: CompositeController
+metadata:
+  name: ping-pong-controller
+spec:
+  generateSelector: true
+  parentResource:
+    apiVersion: example.com/v1
+    resource: pings
+  childResources:
+    - apiVersion: example.com/v1
+      resource: pongs
+      updateStrategy:
+        method: InPlace
+  resyncPeriodSeconds: 10
+  hooks:
+    sync:
+      webhook:
+        url: http://192.168.1.15:8080/sync
+    finalize:
+      webhook:
+        url: http://192.168.1.15:9090/sync

composite-controller/sync-finalize-hook/deploy/crd.yaml

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+apiVersion: apiextensions.k8s.io/v1beta1
+kind: CustomResourceDefinition
+metadata:
+  name: pings.example.com
+spec:
+  group: example.com
+  version: v1
+  names:
+    kind: Ping
+    plural: pings
+    singular: ping
+  scope: Namespaced
+  subresources:
+    status: {}
+---
+apiVersion: apiextensions.k8s.io/v1beta1
+kind: CustomResourceDefinition
+metadata:
+  name: pongs.example.com
+spec:
+  group: example.com
+  version: v1
+  names:
+    kind: Pong
+    plural: pongs
+    singular: pong
+  scope: Namespaced
+  subresources:
+    status: {}

composite-controller/sync-finalize-hook/deploy/ping.yaml

@@ -0,0 +1,6 @@
+apiVersion: example.com/v1
+kind: Ping
+metadata:
+  name: shovan
+spec:
+  name: Shovan Maity

composite-controller/sync-finalize-hook/python/finalize.py

@@ -0,0 +1,24 @@
+from http.server import BaseHTTPRequestHandler, HTTPServer
+import json
+
+
+class Controller(BaseHTTPRequestHandler):
+
+    def do_POST(self):
+        observed = json.loads(self.rfile.read(
+            int(self.headers.get("content-length"))))
+        observed_pong_map = observed["children"].get(
+            "Pong.example.com/v1", {})
+
+        finalized = len(observed_pong_map) == 0
+        desired = {
+            "finalized": finalized
+        }
+
+        self.send_response(200)
+        self.send_header("Content-type", "application/json")
+        self.end_headers()
+        self.wfile.write(json.dumps(desired).encode())
+
+
+HTTPServer(("", 9090), Controller).serve_forever()

composite-controller/sync-finalize-hook/python/sync.py

@@ -0,0 +1,40 @@
+from http.server import BaseHTTPRequestHandler, HTTPServer
+import json
+
+
+class Controller(BaseHTTPRequestHandler):
+
+    def do_POST(self):
+
+        # Observed ping object
+        observed = json.loads(self.rfile.read(
+            int(self.headers.get("content-length"))))
+        ping = observed["parent"]
+
+        name = ping.get("spec", {}).get("name", "Unknown")
+
+        pong = [
+            {
+                "apiVersion": "example.com/v1",
+                "kind": "Pong",
+                "metadata": {
+                    "name": ping["metadata"]["name"]
+                },
+                "spec": {
+                    "message": "Hello %s !!" % (name)
+                }
+            }
+        ]
+
+        # Generate desired children
+        desired = {
+            "children": pong
+        }
+
+        self.send_response(200)
+        self.send_header("Content-type", "application/json")
+        self.end_headers()
+        self.wfile.write(json.dumps(desired).encode())
+
+
+HTTPServer(("", 8080), Controller).serve_forever()

composite-controller/sync-finalize-hook/readme.md

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+### Concept
+
+`CompositeController` contains 2 hooks `sync` and `finalize`.
+
+The `sync` hook is how you specify which children to create/maintain for a given parent – in other words, your desired state. After you return your desired state, Metacontroller begins to take action to converge towards it – creating, deleting, and updating objects as appropriate.
+
+Sync Hook Request
+- `controller` - The whole `CompositeController` cr, like - `kubectl get compositecontroller <name> -o json`.
+- `parent` - The parent object, like `kubectl get <parent-resource> <parent-name> -o json`.
+- `children` - An associative array of child objects that already exist.
+- `finalizing` - This is always false for the sync hook.
+
+Sync Hook Response
+- `status` - A JSON object that will completely replace the status field within the parent object.
+- `children` - A list of JSON objects representing all the desired children for this parent object.
+- `resyncAfterSeconds` - Set the delay (in seconds, as a float) before an optional, one-time, per-object resync.
+
+The `finalize` hook is useful for doing ordered teardown of children. Metacontroller will add a finalizer to the parent object, which will prevent it from being deleted until your hook has had a chance to run and the response indicates that you’re done cleaning up. To perform ordered teardown, you can generate children just like you would for sync, but omit some children from the desired state depending on the observed set of children that are left. For example, if you observe [A,B,C], generate only [A,B] as your desired state; if you observe [A,B], generate only [A]; if you observe [A], return an empty desired list [].
+
+Finalize Hook Request
+- `controller` - The whole `CompositeController` cr, like - `kubectl get compositecontroller <name> -o json`.
+- `parent` - The parent object, like `kubectl get <parent-resource> <parent-name> -o json`.
+- `children` - An associative array of child objects that already exist.
+- `finalizing` - This is always true for the sync hook.
+
+Finalize Hook Response
+- `status` - A JSON object that will completely replace the status field within the parent object.
+- `children` - A list of JSON objects representing all the desired children for this parent object.
+- `resyncAfterSeconds` - Set the delay (in seconds, as a float) before an optional, one-time, per-object resync.
+- `finalized` - A boolean indicating whether you are done finalizing.
+
+### Prerequisite
+
+Make sure metacontroller is [installed](https://github.com/shovanmaity/metacontroller-by-example/tree/master/metacontroller).
+
+Make sure you are inside `composite-controller/sync-finalize-hook` directory.
+
+Edit the `deploy/controller.yaml` file and update the webhook URL.
+```yaml
+spec:
+  hooks:
+    sync:
+      webhook:
+        url: http://192.168.1.15:8080/sync
+    finalize:
+      webhook:
+        url: http://192.168.1.15:9090/sync
+```
+
+Apply the crd and controller.
+```bash
+kubectl apply -f deploy/crd.yaml
+kubectl apply -f deploy/controller.yaml
+```
+
+Execute python files
+```bash
+python3 python/sync.py
+python3 python/finalize.py
+```
+
+Create a ping cr. Find the sample `Ping` is [here](https://github.com/shovanmaity/metacontroller-by-example/blob/master/composite-controller/sync-finalize-hook/deploy/ping.yaml).
+```bash
+cat <<EOF | kubectl apply -f -
+apiVersion: example.com/v1
+kind: Ping
+metadata:
+  name: shovan
+spec:
+  name: Shovan Maity
+EOF
+```
+
+Try the below processes -
+
+- Get the `metadata.finalizers` of the ping cr using `kubectl get ping -o=jsonpath='{range .items[*]}{@.metadata.finalizers}{"\n"}{end}'`.
+- Delete the `Ping` cr using `kubectl delete ping -A --all`.
+- List `Pong` cr using `kubectl get ping -A`.
+
+### Cleanup
+
+```bash
+kubectl delete -f deploy/controller.yaml
+kubectl delete -f deploy/crd.yaml
+# Stop the python files execution.
+```

composite-controller/target-status/deploy/controller.yaml

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+apiVersion: metacontroller.k8s.io/v1alpha1
+kind: CompositeController
+metadata:
+  name: ping-pong-controller
+spec:
+  generateSelector: true
+  parentResource:
+    apiVersion: example.com/v1
+    resource: pings
+  childResources:
+    - apiVersion: example.com/v1
+      resource: pongs
+      updateStrategy:
+        method: InPlace
+  hooks:
+    sync:
+      webhook:
+        url: http://192.168.1.15:8080/sync