Split out the Package type into a first class Kubernetes resource (#295)

Split out the Package type into a first class Kubernetes resource. Before this change, packages were implicitly tied to functions.

This wasn't ideal because:
 * Functions will need to share packages
 * A package storage system may be more generally useful than just
   functions (for example, for storing static assets)

This change does the following:
* Updates the fission and tpr types to add a new Package and PackageSpec.  It also creates a PackageRef type, and a FunctionPackageRef type. The PackageRef simply references a package, but the FunctionPackageRef includes the name of a function within the package. This allows us to share packages between different functions.
* Updates fetcher and other components for first-class packages
* Allows customization of fetcher image pull policy in the helm charts

tpr/package.go

@@ -0,0 +1,119 @@
+/*
+Copyright 2016 The Fission 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 tpr
+
+import (
+	"k8s.io/client-go/1.5/pkg/api"
+	"k8s.io/client-go/1.5/pkg/watch"
+	"k8s.io/client-go/1.5/rest"
+)
+
+type (
+	PackageInterface interface {
+		Create(*Package) (*Package, error)
+		Get(name string) (*Package, error)
+		Update(*Package) (*Package, error)
+		Delete(name string, options *api.DeleteOptions) error
+		List(opts api.ListOptions) (*PackageList, error)
+		Watch(opts api.ListOptions) (watch.Interface, error)
+	}
+
+	packageClient struct {
+		client    *rest.RESTClient
+		namespace string
+	}
+)
+
+func MakePackageInterface(tprClient *rest.RESTClient, namespace string) PackageInterface {
+	return &packageClient{
+		client:    tprClient,
+		namespace: namespace,
+	}
+}
+
+func (c *packageClient) Create(f *Package) (*Package, error) {
+	var result Package
+	err := c.client.Post().
+		Resource("packages").
+		Namespace(c.namespace).
+		Body(f).
+		Do().Into(&result)
+	if err != nil {
+		return nil, err
+	}
+	return &result, nil
+}
+
+func (c *packageClient) Get(name string) (*Package, error) {
+	var result Package
+	err := c.client.Get().
+		Resource("packages").
+		Namespace(c.namespace).
+		Name(name).
+		Do().Into(&result)
+	if err != nil {
+		return nil, err
+	}
+	return &result, nil
+}
+
+func (c *packageClient) Update(f *Package) (*Package, error) {
+	var result Package
+	err := c.client.Put().
+		Resource("packages").
+		Namespace(c.namespace).
+		Name(f.Metadata.Name).
+		Body(f).
+		Do().Into(&result)
+	if err != nil {
+		return nil, err
+	}
+	return &result, nil
+}
+
+func (c *packageClient) Delete(name string, opts *api.DeleteOptions) error {
+	return c.client.Delete().
+		Namespace(c.namespace).
+		Resource("packages").
+		Name(name).
+		Body(opts).
+		Do().
+		Error()
+}
+
+func (c *packageClient) List(opts api.ListOptions) (*PackageList, error) {
+	var result PackageList
+	err := c.client.Get().
+		Namespace(c.namespace).
+		Resource("packages").
+		VersionedParams(&opts, api.ParameterCodec).
+		Do().
+		Into(&result)
+	if err != nil {
+		return nil, err
+	}
+	return &result, nil
+}
+
+func (c *packageClient) Watch(opts api.ListOptions) (watch.Interface, error) {
+	return c.client.Get().
+		Prefix("watch").
+		Namespace(c.namespace).
+		Resource("packages").
+		VersionedParams(&opts, api.ParameterCodec).
+		Watch()
+}