Add a pluggable step for adding missing gvk information to resources

CHANGELOG.md

@@ -11,6 +11,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 <!-- ### Added | Changed | Deprecated | Removed | Fixed | Security -->
 
+### Added
+
+- A pluggable step for adding missing GVK information to resources - [#184](https://github.com/coryodaniel/bonny/pull/184), [#183](https://github.com/coryodaniel/bonny/issues/183)
+
 <!-- No new entries below this line! -->
 
 ## [1.0.1] - 2023-02-04

guides/the_operator.livemd

@@ -32,13 +32,13 @@ The operator defines custom resources, watch queries and their controllers and s
 
 Overall, an operator has the following responsibilities:
 
-* to provide a wrapper for starting and stopping the
+- to provide a wrapper for starting and stopping the
   operator as part of a supervision tree
-* To define the resources to be watched together with the
+- To define the resources to be watched together with the
   controllers which handle action events on those resources.
-* to define an initial pluggable pipeline containing the step `:delegate_to_controller` for all action events
+- to define an initial pluggable pipeline containing the step `:delegate_to_controller` for all action events
   to pass through
-* To define any custom resources ending up in the manifest
+- To define any custom resources ending up in the manifest
   generated by `mix bonny.gen.manifest`
 
 ```elixir
@@ -104,8 +104,8 @@ crds
 
 In `controllers/2` we define the queries and their event handlers, i.e. controllers. function should return a list where each element of the list is a map with these 2 keys:
 
-* `:query` - A list operation of type `K8s.Operation.t()`. Bonny will watch the cluster with this operation and forward all events to the `:controller`.
-* `:controller` - A controller (See the [controller guide](controllers.livemd)) or any other `Pluggable` step. Accepts a module or a `{controller :: module(), init_opts :: keyword()}` tuple. If a tuple is given, the init_opts are passed to the controller's `init/1` function.
+- `:query` - A list operation of type `K8s.Operation.t()`. Bonny will watch the cluster with this operation and forward all events to the `:controller`.
+- `:controller` - A controller (See the [controller guide](controllers.livemd)) or any other `Pluggable` step. Accepts a module or a `{controller :: module(), init_opts :: keyword()}` tuple. If a tuple is given, the init_opts are passed to the controller's `init/1` function.
 
 If you managed to define a valid `conn` above, you can now run the operator defined above in this livebook. The code below starts the operator and shows the supervision tree. Note how the operator starts an `EventRecorder` and two proceses for each controller defined in `controllers/2`. These two processes are the `Watcher` and the `Reconciler`. The `Watcher` watches for `ADD`, `MODIFY` and `DELETE` events in the cluster. The `Reconciler` regularly creates `:reconcile` events for each resource found in the cluster.
 
@@ -139,8 +139,9 @@ The operator implements a [Pluggable](https://hex.pm/packages/pluggable) pipelin
 
 Bonny comes with a few steps to your convenience. In most caes it makes sense to add at least `Bonny.Pluggable.ApplyDescendants` and `Bonny.Pluggable.ApplyStatus` to the end of your operator pipeline.
 
-* `Bonny.Pluggable.AddManagedByLabelToDescendants` - Adds the `app.kubernetes.io/managed-by` label to all descendants registered within the pipeline.
-* `Bonny.Pluggable.ApplyDescendants` - applies all the descendants added to the `%Bonny.Axn{}` struct.
-* `Bonny.Pluggable.ApplyStatus` - applies the status of the given `%Bonny.Axn{}` struct to the status subresource.
-* `Bonny.Pluggable.Logger`- logs an action event and when status, descendants and events are applied to the cluster. If desired, it makes sense to be placed as first step in your operator pipeline but can also be added to a controller pipeline.
-* `Bonny.Pluggable.SkipObservedGenerations` - halts the pipelines for a defined list of actions if the observed generation equals the resource's generation. You'll find further documentation on this module in the [Controller](controllers.livemd) guide.
+- `Bonny.Pluggable.AddManagedByLabelToDescendants` - Adds the `app.kubernetes.io/managed-by` label to all descendants registered within the pipeline.
+- `Bonny.Pluggable.AddMissingGVK` - Add fields `apiVersion` and `kind` to the resource if they are missing.
+- `Bonny.Pluggable.ApplyDescendants` - applies all the descendants added to the `%Bonny.Axn{}` struct.
+- `Bonny.Pluggable.ApplyStatus` - applies the status of the given `%Bonny.Axn{}` struct to the status subresource.
+- `Bonny.Pluggable.Logger`- logs an action event and when status, descendants and events are applied to the cluster. If desired, it makes sense to be placed as first step in your operator pipeline but can also be added to a controller pipeline.
+- `Bonny.Pluggable.SkipObservedGenerations` - halts the pipelines for a defined list of actions if the observed generation equals the resource's generation. You'll find further documentation on this module in the [Controller](controllers.livemd) guide.

lib/bonny/pluggable/add_missing_gvk.ex

@@ -0,0 +1,37 @@
+defmodule Bonny.Pluggable.AddMissingGVK do
+  @moduledoc """
+  The Kubernetes API sometimes doesn't set the fields `apiVersion` and `kind` on
+  items of a list operation. E.g. if you use `K8s.Client` to get a list of
+  deployments, the deployments won't contains those two fields. This is being
+  discussed on https://github.com/kubernetes/kubernetes/issues/3030.
+
+  Bonny sometimes depends on `apiVersion` and `kind` to be defined on the
+  resource being handled. This is the case for setting the status, e.g. when
+  using `Bonny.Pluggable.SkipObservedGenerations` or `Bonny.Axn.update_status/2`.
+
+  Add this step to your controller in order to set those values on all resources
+  being handled.
+
+
+  ## Examples
+
+      step Bonny.Pluggable.AddMissingGVK,
+        apiVersion: "apps/v1",
+        kind: "Deployment"
+  """
+
+  @behaviour Pluggable
+
+  @impl true
+  def init(opts),
+    do: %{
+      "apiVersion" => Keyword.fetch!(opts, :apiVersion),
+      "kind" => Keyword.fetch!(opts, :kind)
+    }
+
+  @impl true
+  def call(axn, config) do
+    resource = Map.merge(config, axn.resource)
+    struct!(axn, resource: resource)
+  end
+end

test/bonny/pluggable/add_missing_gvk_test.exs

@@ -0,0 +1,26 @@
+defmodule Bonny.Pluggable.AddMissingGVKTest do
+  use ExUnit.Case, async: true
+  use Bonny.Axn.Test
+
+  import YamlElixir.Sigil
+
+  alias Bonny.Pluggable.AddMissingGVK, as: MUT
+
+  test "adds apiVersion and kind fields to the resource" do
+    opts = MUT.init(apiVersion: "v1", kind: "ConfigMap")
+
+    resource = ~y"""
+    metadata:
+      name: foo
+      namespace: default
+    data:
+      key: value
+    """
+
+    result = MUT.call(axn(:add, resource: resource), opts)
+
+    # generation already observed
+    assert "v1" == result.resource["apiVersion"]
+    assert "ConfigMap" == result.resource["kind"]
+  end
+end

test/bonny/pluggable/skip_observed_generations_test.exs

@@ -1,5 +1,5 @@
 defmodule Bonny.Pluggable.SkipObservedGenerationsTest do
-  use ExUnit.Case
+  use ExUnit.Case, async: true
   use Bonny.Axn.Test
 
   alias Bonny.Pluggable.SkipObservedGenerations, as: MUT