Merge pull request #54 from flavio/tilt

Introduce Tilt to simplify the development process

.gitignore

@@ -1,3 +1,4 @@
+tilt-settings.yaml
 
 # Binaries for programs and plugins
 *.exe

CONTRIBUTING.md

@@ -0,0 +1,63 @@
+# Contributing
+
+## Building
+
+Pre-requisites:
+
+- make
+- Go compiler
+
+To build the controller use the following command:
+
+```console
+make all
+```
+
+To run the unit tests:
+
+```console
+make test
+```
+
+## Development
+
+To run the controller for development purposes, you can use [Tilt](https://tilt.dev/).
+
+### Pre-requisites
+
+Please follow the [Tilt installation documentation](https://docs.tilt.dev/install.html) to install the command line tool.
+
+A development Kubernetes cluster is needed to run the controller.
+You can use [k3d](https://k3d.io/) to create a local cluster for development purposes.
+
+### Settings
+
+The `tilt-settings.yaml.example` acts as a template for the `tilt-settings.yaml` file that you need to create in the root of this repository.
+Copy the example file and edit it to match your environment.
+The `tilt-settings.yaml` file is ignored by git, so you can safely edit it without worrying about committing it by mistake.
+
+The following settings can be configured:
+
+- `registry`: the container registry where the controller image will be pushed.
+  If you don't have a private registry, you can use `ghcr.io` as long as your
+  cluster has access to it.
+
+Example:
+
+```yaml
+registry: ghcr.io/your-gh-username/kwasm-operator
+```
+
+### Running the controller
+
+The `Tiltfile` included in this repository will take care of the following:
+
+- Create the `kwasm` namespace and install the controller helm-chart in it.
+- Inject the development image in the deployment.
+- Automatically reload the controller when you make changes to the code.
+
+To run the controller, you just need to run the following command against an empty cluster:
+
+```console
+$ tilt up --stream
+```

Tiltfile

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+# -*- mode: Python -*-
+
+tilt_settings_file = "./tilt-settings.yaml"
+settings = read_yaml(tilt_settings_file)
+
+kubectl_cmd = "kubectl"
+
+# verify kubectl command exists
+if str(local("command -v " + kubectl_cmd + " || true", quiet = True)) == "":
+    fail("Required command '" + kubectl_cmd + "' not found in PATH")
+
+# Create the kwasm namespace
+# This is required since the helm() function doesn't support the create_namespace flag
+load('ext://namespace', 'namespace_create')
+namespace_create('kwasm')
+
+# Install kwasm-operator helm chart
+install = helm(
+    './charts/kwasm-operator/', 
+    name='kwasm-operator', 
+    namespace='kwasm', 
+    set=['image.repository=' + settings.get('registry')]
+)
+
+objects = decode_yaml_stream(install)
+for o in objects:
+    # Update the root security group. Tilt requires root access to update the
+    # running process.
+    if o.get('kind') == 'Deployment' and o.get('metadata').get('name') == 'kwasm-operator':
+        o['spec']['template']['spec']['securityContext']['runAsNonRoot'] = False
+        # Disable the leader election to speed up the startup time.
+        o['spec']['template']['spec']['containers'][0]['args'].remove('--leader-elect')
+        break
+updated_install = encode_yaml_stream(objects)
+k8s_yaml(updated_install)
+
+# enable hot reloading by doing the following:
+# - locally build the whole project
+# - create a docker imagine using tilt's hot-swap wrapper
+# - push that container to the local tilt registry
+# Once done, rebuilding now should be a lot faster since only the relevant
+# binary is rebuilt and the hot swat wrapper takes care of the rest.
+local_resource(
+    'manager',
+    "CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build -o bin/manager ./",
+    deps = [
+        "main.go",
+        "go.mod",
+        "go.sum",
+        "controllers",
+    ],
+)
+
+# Build the docker image for our controller. We use a specific Dockerfile
+# since tilt can't run on a scratch container.
+entrypoint = ['/manager', '-zap-devel']
+dockerfile = 'tilt.dockerfile'
+
+load('ext://restart_process', 'docker_build_with_restart')
+docker_build_with_restart(
+    settings.get('registry'),
+    '.',
+    dockerfile = dockerfile,
+    entrypoint = entrypoint,
+    # `only` here is important, otherwise, the container will get updated
+    # on _any_ file change.
+    only=[
+      './bin',
+    ],
+    live_update = [
+        sync('./bin/manager', '/manager'),
+    ],
+)
+

charts/kwasm-operator/templates/deployment.yaml

@@ -27,6 +27,8 @@ spec:
         {{- toYaml .Values.podSecurityContext | nindent 8 }}
       containers:
         - name: {{ .Chart.Name }}
+          args:
+          - --leader-elect
           env:
           - name: CONTROLLER_NAMESPACE
             value: {{ .Release.Namespace }}

tilt-settings.yaml.example

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+# Replace with a development registry that offers pull & push access
+registry: ghcr.io/<your github handle>/kwasm-operator

tilt.dockerfile

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+FROM alpine
+WORKDIR /
+COPY ./bin/manager /manager
+
+ENTRYPOINT ["/manager"]