add podSpecPath into workloadDefinition, fixes #233

Signed-off-by: 天元 <jianbo.sjb@alibaba-inc.com>

apis/core/v1alpha2/core_types.go

@@ -97,6 +97,11 @@ type TraitDefinitionSpec struct {
 	// +optional
 	WorkloadRefPath string `json:"workloadRefPath,omitempty"`
 
+	// PodSpecPath indicates where/if this workload has K8s podSpec field
+	// if one workload has podSpec, trait can do lot's of assumption such as port, env, volume fields.
+	// +optional
+	PodSpecPath string `json:"podSpecPath,omitempty"`
+
 	// AppliesToWorkloads specifies the list of workload kinds this trait
 	// applies to. Workload kinds are specified in kind.group/version format,
 	// e.g. server.core.oam.dev/v1alpha2. Traits that omit this field apply to
@@ -189,9 +194,7 @@ type ComponentParameter struct {
 	// paths without a leading dot, for example 'spec.replicas'.
 	FieldPaths []string `json:"fieldPaths"`
 
-	// TODO(negz): Use +kubebuilder:default marker to default Required to false
-	// once we're generating v1 CRDs.
-
+	// +kubebuilder:default:=false
 	// Required specifies whether or not a value for this parameter must be
 	// supplied when authoring an ApplicationConfiguration.
 	// +optional
@@ -231,9 +234,7 @@ type ComponentStatus struct {
 	// +optional
 	LatestRevision *Revision `json:"latestRevision,omitempty"`
 
-	// TODO(negz): Maintain references to any ApplicationConfigurations that
-	// reference this component? Doing so would allow us to queue a reconcile
-	// for consuming ApplicationConfigurations when this Component changed.
+	// One Component should only be used by one AppConfig
 }
 
 // Revision has name and revision number

charts/oam-kubernetes-runtime/crds/core.oam.dev_components.yaml

@@ -72,6 +72,7 @@ spec:
                         will specify parameter values using this name.
                       type: string
                     required:
+                      default: false
                       description: Required specifies whether or not a value for this
                         parameter must be supplied when authoring an ApplicationConfiguration.
                       type: boolean

charts/oam-kubernetes-runtime/crds/core.oam.dev_traitdefinitions.yaml

@@ -69,6 +69,11 @@ spec:
                   builders
                 type: object
                 x-kubernetes-preserve-unknown-fields: true
+              podSpecPath:
+                description: PodSpecPath indicates where/if this workload has K8s
+                  podSpec field if one workload has podSpec, trait can do lot's of
+                  assumption such as port, env, volume fields.
+                type: string
               revisionEnabled:
                 description: Revision indicates whether a trait is aware of component
                   revision

design/one-pager-podspecable-workload.md

@@ -0,0 +1,76 @@
+# Indicate Workload has PodSpec field
+
+- Owner: Jianbo Sun (@wonderflow)
+- Date: 05/17/2020
+- Status: Implemented
+
+## Background
+
+Since we have added labels like [`workload.oam.dev/podspecable`](https://github.com/oam-dev/spec/blob/master/4.workload_definitions.md#labels)
+into OAM Spec to indicate the workload will contain 'podSpec' in its spec.
+
+In most famous workload like `Deployment`, `StatefulSet`, `Job`, the `podSpec` field will always be `spec.template.spec`. 
+But it's hard to know which field is podSpec for K8s CRD. For example, we write a workload named [`PodSpecWorkload`](https://github.com/oam-dev/kubevela/blob/master/charts/vela-core/crds/standard.oam.dev_podspecworkloads.yaml).
+It has `podSpec` in `spec.podSpec`, this is different with `spec.template.spec`. In this case, we need a field to indicate
+which field is `podSpec`. 
+
+## Proposal
+
+So I propose we add a field 'podSpecPath' and a label `workload.oam.dev/podspecable: true` into WorkloadDefinition.
+
+The 'podSpecPath' field and the label are both optional fields, they could have following behaviors:
+
+### No label and No `podSpecPath` field
+
+```
+apiVersion: core.oam.dev/v1alpha2
+kind: WorkloadDefinition
+metadata:
+  name: webservice
+spec:
+  definitionRef:
+    name: podspecworkloads.standard.oam.dev
+   ...
+```
+
+In this case, we can't do any podSpec assumption for this workload.
+
+### label specified with No `podSpecPath` field
+
+```
+apiVersion: core.oam.dev/v1alpha2
+kind: WorkloadDefinition
+metadata:
+  name: webservice
+  labels:
+     workload.oam.dev/podspecable: true
+spec:
+  definitionRef:
+    name: podspecworkloads.standard.oam.dev
+   ...
+```
+
+In this case, we will always regard `spec.template.spec` as the `podSpecPath`. 
+This will work for most famous workloads like K8s `Deployment`/`StatefulSet`/`Job` and many other CRD Objects like
+`OpenKruise CloneSet`/`Knative Service`.
+
+### Has `podSpecPath` field 
+
+```
+apiVersion: core.oam.dev/v1alpha2
+kind: WorkloadDefinition
+metadata:
+  name: webservice
+  labels:
+     workload.oam.dev/podspecable: true
+spec:
+  podSpecPath: "spec.podSpec"
+  definitionRef:
+    name: podspecworkloads.standard.oam.dev
+   ...
+```
+
+If the `podSpecPath` is specified, the `workload.oam.dev/podspecable: true` label will always be automatically added. 
+
+In this case, trait can use `podSpecPath` to get the field of podSpec.
+