Add minion registry

pkg/registry/minion_registry.go

@@ -0,0 +1,148 @@
+/*
+Copyright 2014 Google Inc. All rights reserved.
+
+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 registry
+
+import (
+	"encoding/json"
+	"fmt"
+	"sort"
+	"sync"
+
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/apiserver"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/labels"
+)
+
+var ErrDoesNotExist = fmt.Errorf("The requested resource does not exist.")
+
+// Keep track of a set of minions. Safe for concurrent reading/writing.
+type MinionRegistry interface {
+	List() (currentMinions []string, err error)
+	Insert(minion string) error
+	Delete(minion string) error
+	Contains(minion string) (bool, error)
+}
+
+// Initialize a minion registry with a list of minions.
+func MakeMinionRegistry(minions []string) MinionRegistry {
+	m := &minionList{
+		minions: stringSet{},
+	}
+	for _, minion := range minions {
+		m.minions.insert(minion)
+	}
+	return m
+}
+
+type empty struct{}
+type stringSet map[string]empty
+
+func (s stringSet) insert(item string) {
+	s[item] = empty{}
+}
+
+func (s stringSet) delete(item string) {
+	delete(s, item)
+}
+
+func (s stringSet) has(item string) bool {
+	_, contained := s[item]
+	return contained
+}
+
+type minionList struct {
+	minions stringSet
+	lock    sync.Mutex
+}
+
+func (m *minionList) List() (currentMinions []string, err error) {
+	m.lock.Lock()
+	defer m.lock.Unlock()
+	// Make a copy to avoid any threading issues
+	for minion := range m.minions {
+		currentMinions = append(currentMinions, minion)
+	}
+	sort.StringSlice(currentMinions).Sort()
+	return
+}
+
+func (m *minionList) Insert(newMinion string) error {
+	m.lock.Lock()
+	defer m.lock.Unlock()
+	m.minions.insert(newMinion)
+	return nil
+}
+
+func (m *minionList) Delete(minion string) error {
+	m.lock.Lock()
+	defer m.lock.Unlock()
+	m.minions.delete(minion)
+	return nil
+}
+
+func (m *minionList) Contains(minion string) (bool, error) {
+	m.lock.Lock()
+	defer m.lock.Unlock()
+	return m.minions.has(minion), nil
+}
+
+// MinionRegistryStorage implements the RESTStorage interface, backed by a MinionRegistry.
+type MinionRegistryStorage struct {
+	registry MinionRegistry
+}
+
+func MakeMinionRegistryStorage(m MinionRegistry) apiserver.RESTStorage {
+	return &MinionRegistryStorage{
+		registry: m,
+	}
+}
+
+func (storage *MinionRegistryStorage) List(selector labels.Selector) (interface{}, error) {
+	return storage.registry.List()
+}
+
+func (storage *MinionRegistryStorage) Get(id string) (interface{}, error) {
+	exists, err := storage.registry.Contains(id)
+	if !exists {
+		return nil, ErrDoesNotExist
+	}
+	return id, err
+}
+
+func (storage *MinionRegistryStorage) Extract(body string) (interface{}, error) {
+	var minion string
+	err := json.Unmarshal([]byte(body), &minion)
+	return minion, err
+}
+
+func (storage *MinionRegistryStorage) Create(minion interface{}) (<-chan interface{}, error) {
+	return apiserver.MakeAsync(func() interface{} { return minion }), storage.registry.Insert(minion.(string))
+}
+
+func (storage *MinionRegistryStorage) Update(minion interface{}) (<-chan interface{}, error) {
+	return nil, fmt.Errorf("Minions can only be created (inserted) and deleted.")
+}
+
+func (storage *MinionRegistryStorage) Delete(id string) (<-chan interface{}, error) {
+	exists, err := storage.registry.Contains(id)
+	if !exists {
+		return nil, ErrDoesNotExist
+	}
+	if err != nil {
+		return nil, err
+	}
+	return apiserver.MakeAsync(func() interface{} { return apiserver.Status{Success: true} }), storage.registry.Delete(id)
+}

pkg/registry/minion_registry_test.go

@@ -0,0 +1,98 @@
+/*
+Copyright 2014 Google Inc. All rights reserved.
+
+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 registry
+
+import (
+	"reflect"
+	"testing"
+
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/labels"
+)
+
+func TestMinionRegistry(t *testing.T) {
+	m := MakeMinionRegistry([]string{"foo", "bar"})
+	if has, err := m.Contains("foo"); !has || err != nil {
+		t.Errorf("missing expected object")
+	}
+	if has, err := m.Contains("bar"); !has || err != nil {
+		t.Errorf("missing expected object")
+	}
+	if has, err := m.Contains("baz"); has || err != nil {
+		t.Errorf("has unexpected object")
+	}
+
+	if err := m.Insert("baz"); err != nil {
+		t.Errorf("insert failed")
+	}
+	if has, err := m.Contains("baz"); !has || err != nil {
+		t.Errorf("insert didn't actually insert")
+	}
+
+	if err := m.Delete("bar"); err != nil {
+		t.Errorf("delete failed")
+	}
+	if has, err := m.Contains("bar"); has || err != nil {
+		t.Errorf("delete didn't actually delete")
+	}
+
+	list, err := m.List()
+	if err != nil {
+		t.Errorf("got error calling List")
+	}
+	if !reflect.DeepEqual(list, []string{"baz", "foo"}) {
+		t.Errorf("Unexpected list value: %#v", list)
+	}
+}
+
+func TestMinionRegistryStorage(t *testing.T) {
+	m := MakeMinionRegistry([]string{"foo", "bar"})
+	ms := MakeMinionRegistryStorage(m)
+
+	if obj, err := ms.Get("foo"); err != nil || obj.(string) != "foo" {
+		t.Errorf("missing expected object")
+	}
+	if obj, err := ms.Get("bar"); err != nil || obj.(string) != "bar" {
+		t.Errorf("missing expected object")
+	}
+	if _, err := ms.Get("baz"); err != ErrDoesNotExist {
+		t.Errorf("has unexpected object")
+	}
+
+	if _, err := ms.Create("baz"); err != nil {
+		t.Errorf("insert failed")
+	}
+	if obj, err := ms.Get("baz"); err != nil || obj.(string) != "baz" {
+		t.Errorf("insert didn't actually insert")
+	}
+
+	if _, err := ms.Delete("bar"); err != nil {
+		t.Errorf("delete failed")
+	}
+	if _, err := ms.Get("bar"); err != ErrDoesNotExist {
+		t.Errorf("delete didn't actually delete")
+	}
+	if _, err := ms.Delete("bar"); err != ErrDoesNotExist {
+		t.Errorf("delete returned wrong error")
+	}
+
+	list, err := ms.List(labels.Everything())
+	if err != nil {
+		t.Errorf("got error calling List")
+	}
+	if !reflect.DeepEqual(list.(string), []string{"baz", "foo"}) {
+		t.Errorf("Unexpected list value: %#v", list)
+	}
+}