Add an interface for test Apps. (#379)

pkg/app/app.go

@@ -0,0 +1,83 @@
+// Copyright 2019 The Kanister Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package app
+
+import (
+	"context"
+	"time"
+
+	crv1alpha1 "github.com/kanisterio/kanister/pkg/apis/cr/v1alpha1"
+)
+
+// App represents an application we can install into a namespace.
+type App interface {
+	// Init instantiates the app based on the environemnt configuration,
+	// including environement variables and state in the Kubernetes cluster. If
+	// any required configuration is not discoverable, Init will return an
+	// error.
+	Init(context.Context) error
+	// Install will install the app into a specified namespace. Install should
+	// be called after Init.
+	Install(ctx context.Context, namespace string) error
+	// IsReady returns true once an app is running. If we detect a failure state
+	// that will not recover from on it's own, then IsReady will return an
+	// error.
+	IsReady(context.Context) (bool, error)
+	// Object returns a reference to this app to be used by ActionSets.
+	Object() crv1alpha1.ObjectReference
+	// Uninstall deletes an app and all it's components from a Namespace.
+	Uninstall(context.Context) error
+}
+
+// DatabaseApp inherits methods from App, but also includes method to add, read
+// and remove entries stored byt the App.
+type DatabaseApp interface {
+	App
+	// Ping will issue trivial request to the database to see if it is
+	// accessable.
+	Ping(context.Context) error
+	// Insert adds n entries to the database.
+	Insert(ctx context.Context, n int) error
+	// Count returns the number of entries in the database.
+	Count(context.Context) (int, error)
+	// Reset Removes all entries from the database.
+	Reset(context.Context) error
+}
+
+// ConfigApp describes an App installs additional configuration that can be
+// referenced from an ActionSet and used in a Blueprint. Not all apps will
+// create this additional configuration.
+type ConfigApp interface {
+	App
+	// ConfigMaps returns named references to ConfigMaps when installing App.
+	ConfigMaps() map[string]crv1alpha1.ObjectReference
+	// Secrets returns named references to Secrets when installing App.
+	Secrets() map[string]crv1alpha1.ObjectReference
+}
+
+// Blueprinter is the interface used to create a Blueprint.
+type Blueprinter interface {
+	// Blueprint returns a new non-namespaced Blueprint.
+	Blueprint() *crv1alpha1.Blueprint
+}
+
+// PITRBlueprinter is optionally implemented if a Blueprint supports
+// point-in-time recovery.
+type PITRBlueprinter interface {
+	Blueprinter
+	// FormatPITR takes a time.Time struct and returns a string for use by a
+	// Blueprint that supports PITR.
+	FormatPITR(time.Time) string
+}