AUTH-2587 add config watcher and reload logic for access client forwarder

cmd/cloudflared/config/manager.go

@@ -0,0 +1,101 @@
+package config
+
+import (
+	"errors"
+	"os"
+
+	"github.com/cloudflare/cloudflared/watcher"
+
+	"github.com/sirupsen/logrus"
+	"gopkg.in/yaml.v2"
+)
+
+// Notifier sends out config updates
+type Notifier interface {
+	ConfigDidUpdate(Root)
+}
+
+// Manager is the base functions of the config manager
+type Manager interface {
+	Start(Notifier) error
+	Shutdown()
+}
+
+// FileManager watches the yaml config for changes
+// sends updates to the service to reconfigure to match the updated config
+type FileManager struct {
+	watcher    watcher.Notifier
+	notifier   Notifier
+	configPath string
+	logger     *logrus.Logger
+}
+
+// NewFileManager creates a config manager
+func NewFileManager(watcher watcher.Notifier, configPath string, logger *logrus.Logger) (Manager, error) {
+	m := &FileManager{
+		watcher:    watcher,
+		configPath: configPath,
+		logger:     logger,
+	}
+	err := watcher.Add(configPath)
+	return m, err
+}
+
+// Start starts the runloop to watch for config changes
+func (m *FileManager) Start(notifier Notifier) error {
+	m.notifier = notifier
+
+	// update the notifier with a fresh config on start
+	config, err := m.GetConfig()
+	if err != nil {
+		return err
+	}
+	notifier.ConfigDidUpdate(config)
+
+	m.watcher.Start(m)
+	return nil
+}
+
+// GetConfig reads the yaml file from the disk
+func (m *FileManager) GetConfig() (Root, error) {
+	if m.configPath == "" {
+		return Root{}, errors.New("unable to find config file")
+	}
+
+	file, err := os.Open(m.configPath)
+	if err != nil {
+		return Root{}, err
+	}
+	defer file.Close()
+
+	var config Root
+	if err := yaml.NewDecoder(file).Decode(&config); err != nil {
+		return Root{}, err
+	}
+
+	return config, nil
+}
+
+// Shutdown stops the watcher
+func (m *FileManager) Shutdown() {
+	m.watcher.Shutdown()
+}
+
+// File change notifications from the watcher
+
+// WatcherItemDidChange triggers when the yaml config is updated
+// sends the updated config to the service to reload its state
+func (m *FileManager) WatcherItemDidChange(filepath string) {
+	config, err := m.GetConfig()
+	if err != nil {
+		m.logger.WithError(err).Error("Failed to read new config")
+		return
+	}
+	m.logger.Info("Config file has been updated")
+	m.notifier.ConfigDidUpdate(config)
+}
+
+// WatcherDidError notifies of errors with the file watcher
+func (m *FileManager) WatcherDidError(err error) {
+	m.logger.WithError(err).Error("Config watcher encountered an error")
+}

cmd/cloudflared/config/manager_test.go

@@ -0,0 +1,80 @@
+package config
+
+import (
+	"bufio"
+	"os"
+	"testing"
+	"time"
+
+	"github.com/cloudflare/cloudflared/log"
+	"github.com/cloudflare/cloudflared/watcher"
+	"github.com/stretchr/testify/assert"
+	"gopkg.in/yaml.v2"
+)
+
+type mockNotifier struct {
+	configs []Root
+}
+
+func (n *mockNotifier) ConfigDidUpdate(c Root) {
+	n.configs = append(n.configs, c)
+}
+
+func writeConfig(t *testing.T, f *os.File, c *Root) {
+	f.Sync()
+	b, err := yaml.Marshal(c)
+	assert.NoError(t, err)
+
+	w := bufio.NewWriter(f)
+	_, err = w.Write(b)
+	assert.NoError(t, err)
+
+	err = w.Flush()
+	assert.NoError(t, err)
+}
+
+func TestConfigChanged(t *testing.T) {
+	filePath := "config.yaml"
+	f, err := os.Create(filePath)
+	assert.NoError(t, err)
+	defer func() {
+		f.Close()
+		os.Remove(filePath)
+	}()
+	c := &Root{
+		OrgKey:          "abcd",
+		ConfigType:      "mytype",
+		CheckinInterval: 1,
+		Forwarders: []Forwarder{
+			{
+				URL:      "test.daltoniam.com",
+				Listener: "127.0.0.1:8080",
+			},
+		},
+	}
+	writeConfig(t, f, c)
+
+	w, err := watcher.NewFile()
+	assert.NoError(t, err)
+	logger := log.CreateLogger()
+	service, err := NewFileManager(w, filePath, logger)
+	assert.NoError(t, err)
+
+	n := &mockNotifier{}
+	go service.Start(n)
+
+	c.Forwarders = append(c.Forwarders, Forwarder{URL: "add.daltoniam.com", Listener: "127.0.0.1:8081"})
+	writeConfig(t, f, c)
+
+	// give it time to trigger
+	time.Sleep(10 * time.Millisecond)
+	service.Shutdown()
+
+	assert.Len(t, n.configs, 2, "did not get 2 config updates as expected")
+	assert.Len(t, n.configs[0].Forwarders, 1, "not the amount of forwarders expected")
+	assert.Len(t, n.configs[1].Forwarders, 2, "not the amount of forwarders expected")
+
+	assert.Equal(t, n.configs[0].Forwarders[0].Hash(), c.Forwarders[0].Hash(), "forwarder hashes don't match")
+	assert.Equal(t, n.configs[1].Forwarders[0].Hash(), c.Forwarders[0].Hash(), "forwarder hashes don't match")
+	assert.Equal(t, n.configs[1].Forwarders[1].Hash(), c.Forwarders[1].Hash(), "forwarder hashes don't match")
+}

cmd/cloudflared/config/model.go

@@ -0,0 +1,37 @@
+package config
+
+import (
+	"crypto/md5"
+	"fmt"
+	"io"
+)
+
+// Forwarder represents a client side listener to forward traffic to the edge
+type Forwarder struct {
+	URL      string `json:"url"`
+	Listener string `json:"listener"`
+}
+
+// Tunnel represents a tunnel that should be started
+type Tunnel struct {
+	URL          string `json:"url"`
+	Origin       string `json:"origin"`
+	ProtocolType string `json:"type"`
+}
+
+// Root is the base options to configure the service
+type Root struct {
+	OrgKey          string      `json:"org_key"`
+	ConfigType      string      `json:"type"`
+	CheckinInterval int         `json:"checkin_interval"`
+	Forwarders      []Forwarder `json:"forwarders,omitempty"`
+	Tunnels         []Tunnel    `json:"tunnels,omitempty"`
+}
+
+// Hash returns the computed values to see if the forwarder values change
+func (f *Forwarder) Hash() string {
+	h := md5.New()
+	io.WriteString(h, f.URL)
+	io.WriteString(h, f.Listener)
+	return fmt.Sprintf("%x", h.Sum(nil))
+}