Clean up GoDoc for API types

The GoDoc strings for the API types are used to generate user visible
documentation, for example the API documentation and CRD fields. This commit
ensures the GoDoc is complete, and makes sense in the context of user facing
documentation.

Signed-off-by: Nic Cope <negz@rk0n.org>

apis/core/v1alpha1/bindingphase.go

@@ -38,9 +38,14 @@ const (
 	BindingPhaseBound BindingPhase = "Bound"
 )
 
-// A BindingStatus represents the bindability and binding of a resource.
+// A BindingStatus represents the bindability and binding status of a resource.
 type BindingStatus struct {
-	// Phase represents the binding phase of the resource.
+	// Phase represents the binding phase of a managed resource or claim.
+	// Unbindable resources cannot be bound, typically because they are
+	// currently unavailable, or still being created. Unbound resource are
+	// available for binding, and Bound resources have successfully bound to
+	// another resource.
+	// +optional
 	// +kubebuilder:validation:Enum=Unbindable;Unbound;Bound
 	Phase BindingPhase `json:"bindingPhase,omitempty"`
 }

apis/core/v1alpha1/condition.go

@@ -56,7 +56,7 @@ const (
 // A Condition that may apply to a managed resource.
 type Condition struct {
 	// Type of this condition. At most one of each condition type may apply to
-	// a managed resource at any point in time.
+	// a resource at any point in time.
 	Type ConditionType `json:"type"`
 
 	// Status of this condition; is it currently True, False, or Unknown?
@@ -71,6 +71,7 @@ type Condition struct {
 
 	// A Message containing details about this condition's last transition from
 	// one status to another, if any.
+	// +optional
 	Message string `json:"message,omitempty"`
 }
 
@@ -88,11 +89,13 @@ func (c Condition) Equal(other Condition) bool {
 // marshalled to a JSON array, but doing so confuses the CRD schema generator.
 // https://github.com/kubernetes/community/blob/9bf8cd/contributors/devel/sig-architecture/api-conventions.md#lists-of-named-subobjects-preferred-over-maps
 
+// NOTE(negz): Do not manipulate Conditions directly. Use the Set method.
+
 // A ConditionedStatus reflects the observed status of a managed resource. Only
-// one condition of each type may exist. Do not manipulate Conditions directly -
+// one condition of each type may exist.
-// use the Set method.
 type ConditionedStatus struct {
-	// Conditions of the managed resource.
+	// Conditions of the resource.
+	// +optional
 	Conditions []Condition `json:"conditions,omitempty"`
 }
 

apis/core/v1alpha1/resource.go

@@ -37,64 +37,121 @@ const (
 	ResourceCredentialsTokenKey = "token"
 )
 
-// ResourceClaimSpec contains standard fields that all resource claims should
+// A ResourceClaimSpec defines the desired state of a resource claim.
-// include in their spec. Unlike ResourceClaimStatus, ResourceClaimSpec should
-// typically be embedded in a claim specific struct.
 type ResourceClaimSpec struct {
+	// WriteConnectionSecretToReference specifies the name of a Secret, in the
+	// same namespace as this resource claim, to which any connection details
+	// for this resource claim should be written. Connection details frequently
+	// include the endpoint, username, and password required to connect to the
+	// managed resource bound to this resource claim.
+	// +optional
 	WriteConnectionSecretToReference corev1.LocalObjectReference `json:"writeConnectionSecretToRef,omitempty"`
 
 	// TODO(negz): Make the below references immutable once set? Doing so means
 	// we don't have to track what provisioner was used to create a resource.
 
-	// PortableClassReference is a reference to a portable class by name.
+	// A PortableClassReference specifies the name of a portable resource class,
+	// in the same namespace as this resource claim, that will be used to
+	// dynamically provision a managed resource when the resource claim is
+	// created. The specified class kind must be aligned with the resource
+	// claim; e.g. a MySQLInstance kind resource claim always refers to a
+	// MySQLInstanceClass kind portable resource class. Omit the portable class
+	// reference if you wish to bind to a specific managed resource (known as
+	// static binding), or to use the default portable class for the resource
+	// claim's namespace (if any).
+	// +optional
 	PortableClassReference *corev1.LocalObjectReference `json:"classRef,omitempty"`
+
+	// A ResourceReference specifies an existing managed resource, in any
+	// namespace, to which this resource claim should attempt to bind. Omit the
+	// resource reference to enable dynamic provisioning using a portable
+	// resource class; the resource reference will be automatically populated by
+	// Crossplane.
+	// +optional
 	ResourceReference *corev1.ObjectReference `json:"resourceRef,omitempty"`
 }
 
-// ResourceClaimStatus represents the status of a resource claim. Claims should
+// A ResourceClaimStatus represents the observed status of a resource claim.
-// typically use this struct as their status.
 type ResourceClaimStatus struct {
 	ConditionedStatus `json:",inline"`
 	BindingStatus     `json:",inline"`
 }
 
-// ResourceSpec contains standard fields that all resources should
+// TODO(negz): Rename Resource* to Managed* to clarify that they enable the
-// include in their spec. ResourceSpec should typically be embedded in a
+// resource.Managed interface.
-// resource specific struct.
+
+// A ResourceSpec defines the desired state of a managed resource.
 type ResourceSpec struct {
+	// WriteConnectionSecretToReference specifies the name of a Secret, in the
+	// same namespace as this managed resource, to which any connection details
+	// for this managed resource should be written. Connection details
+	// frequently include the endpoint, username, and password required to
+	// connect to the managed resource.
+	// +optional
 	WriteConnectionSecretToReference corev1.LocalObjectReference `json:"writeConnectionSecretToRef,omitempty"`
 
+	// ClaimReference specifies the resource claim to which this managed
+	// resource will be bound. ClaimReference is set automatically during
+	// dynamic provisioning. Crossplane does not currently support setting this
+	// field manually, per https://github.com/crossplaneio/crossplane-runtime/issues/19
+	// +optional
 	ClaimReference *corev1.ObjectReference `json:"claimRef,omitempty"`
 
-	// NonPortableClassReference is a reference to a non-portable class.
+	// NonPortableClassReference specifies the non-portable resource class that
+	// was used to dynamically provision this managed resource, if any.
+	// Crossplane does not currently support setting this field manually, per
+	// https://github.com/crossplaneio/crossplane-runtime/issues/20
+	// +optional
 	NonPortableClassReference *corev1.ObjectReference `json:"classRef,omitempty"`
+
+	// ProviderReference specifies the provider that will be used to create,
+	// observe, update, and delete this managed resource.
 	ProviderReference *corev1.ObjectReference `json:"providerRef"`
 
+	// ReclaimPolicy specifies what will happen to the external resource this
+	// managed resource manages when the managed resource is deleted. "Delete"
+	// deletes the external resource, while "Retain" (the default) does not.
+	// Note this behaviour is subtly different from other uses of the
+	// ReclaimPolicy concept within the Kubernetes ecosystem per
+	// https://github.com/crossplaneio/crossplane-runtime/issues/21
+	// +optional
 	ReclaimPolicy ReclaimPolicy `json:"reclaimPolicy,omitempty"`
 }
 
-// NonPortableClassSpecTemplate contains standard fields that all non-portable classes should
+// ResourceStatus represents the observed state of a managed resource.
-// include in their spec template. NonPortableClassSpecTemplate should typically be embedded in a
-// non-portable class specific struct.
-type NonPortableClassSpecTemplate struct {
-	ProviderReference *corev1.ObjectReference `json:"providerRef"`
-
-	ReclaimPolicy ReclaimPolicy `json:"reclaimPolicy,omitempty"`
-}
-
-// ResourceStatus contains standard fields that all resources should
-// include in their status. ResourceStatus should typically be embedded in a
-// resource specific status.
 type ResourceStatus struct {
 	ConditionedStatus `json:",inline"`
 	BindingStatus     `json:",inline"`
 }
 
+// NonPortableClassSpecTemplate defines a template that will be used to create
+// the specifications of managed resources dynamically provisioned using a
+// resource class.
+type NonPortableClassSpecTemplate struct {
+	// ProviderReference specifies the provider that will be used to create,
+	// observe, update, and delete managed resources that are dynamically
+	// provisioned using this resource class.
+	ProviderReference *corev1.ObjectReference `json:"providerRef"`
+
+	// ReclaimPolicy specifies what will happen to external resources when
+	// managed resources dynamically provisioned using this resource class are
+	// deleted. "Delete" deletes the external resource, while "Retain" (the
+	// default) does not. Note this behaviour is subtly different from other
+	// uses of the ReclaimPolicy concept within the Kubernetes ecosystem per
+	// https://github.com/crossplaneio/crossplane-runtime/issues/21
+	// +optional
+	ReclaimPolicy ReclaimPolicy `json:"reclaimPolicy,omitempty"`
+}
+
 // PortableClass contains standard fields that all portable classes should include. Class
 // should typically be embedded in a specific portable class.
+
+// A PortableClass connects a portable resource claim to a non-portable resource
+// class used for dynamic provisioning.
 type PortableClass struct {
 
-	// NonPortableClassReference is a reference to a non-portable class.
+	// NonPortableClassReference is a reference to a resource class kind that is
+	// not portable across cloud providers, such as an RDSInstanceClass.
 	NonPortableClassReference *corev1.ObjectReference `json:"classRef,omitempty"`
 }