(proposal) Make bundle accessible to a cluster

Author: tkashem

doc/contributors/design-proposals/pull-bundle-on-a-cluster.md

@@ -0,0 +1,80 @@
+# Pull Bundle on a Cluster
+
+## Store a bundle in a `ConfigMap`
+Below is the directory layout of the operator bundle inside the image.
+```bash
+$ tree
+/
+├── manifests
+│   ├── testbackup.crd.yaml
+│   ├── testcluster.crd.yaml
+│   ├── testoperator.v0.1.0.clusterserviceversion.yaml
+│   └── testrestore.crd.yaml
+└── metadata
+    └── annotations.yaml
+    
+$ cat /annotations.yaml
+annotations:
+  operators.coreos.com.bundle.resources: "manifests+metadata"
+  operators.coreos.com.bundle.mediatype: "operator-registry+v1"
+```
+
+The following `ConfigMap` maps to the above operator bundle
+```yaml
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: test
+  namespace: test
+  annotations:
+    operators.coreos.com.bundle.resources: "manifests+metadata"
+    operators.coreos.com.bundle.mediatype: "registry+v1"
+data:
+  testbackup.crd.yaml: content of testbackup.crd.yaml
+  testcluster.crd.yaml: content of testcluster.crd.yaml
+  testoperator.v0.1.0.clusterserviceversion.yaml: content oftestoperator.v0.1.0.clusterserviceversion.yaml
+  testrestore.crd.yaml: content of testrestore.crd.yaml
+```
+
+The `key` of a `ConfigMap` has the following format
+```go
+	// Data contains the configuration data.
+	// Each key must consist of alphanumeric characters, '-', '_' or '.'.
+	// Values with non-UTF-8 byte sequences must use the BinaryData field.
+	// The keys stored in Data must not overlap with the keys in
+	// the BinaryData field, this is enforced during validation process.
+	// +optional
+	Data map[string]string `json:"data,omitempty" protobuf:"bytes,2,rep,name=data"`
+```
+
+Notes:
+* The resource file name needs to be manipulated if it contains special characters.
+* The consumer of the `ConfigMap` does will not use the key name in `Data` section to identify the type of resource. It should inspect the content.
+* The consumer will iterate through the `Data` section and and add each resource to the bundle.
+* The annotations from the `annotations.yaml` file is copied to `metadata.annotations` to the `ConfigMap`
+* The `ConfigMap` may have a resource that contains a `PackageManifest` resource. The consumer needs to handle this properly.
+
+
+## Build a Bundle from ConfigMap
+```go
+import (
+	"github.com/operator-framework/operator-registry/pkg/registry"
+	corev1 "k8s.io/api/core/v1"
+)
+
+// Manifest contains a bundle and a PackageManifest.
+type Manifest struct {
+	Bundle          *registry.Bundle
+	PackageManifest *registry.PackageManifest
+}
+
+type Loader interface {
+	Load(cm *corev1.ConfigMap) (manifest *Manifest, err error)
+}
+```
+
+## Managing Lifecycle of the `ConfigMap`
+
+## Things that Happen after reading the configmap
+
+