notifier: Refactor and add client certificate authentification support.

Fixes #23

main.go

@@ -45,8 +45,10 @@ var (
 	cfgDbPath = kingpin.Flag("db-path", "Path to the database to use").String()
 
 	// Notifier configuration
-	cfgNotifierType    = kingpin.Flag("notifier-type", "Type of the notifier to use").Default("none").Enum("none", "http")
+	cfgNotifierEndpoint = kingpin.Flag("notifier-endpoint", "URL that will receive POST notifications").String()
-	cfgNotifierHTTPURL = kingpin.Flag("notifier-http-url", "URL that will receive POST notifications").String()
+	cfgNotifierCertFile = kingpin.Flag("notifier-cert-file", "Path to TLS Cert file").ExistingFile()
+	cfgNotifierKeyFile  = kingpin.Flag("notifier-key-file", "Path to TLS Key file").ExistingFile()
+	cfgNotifierCAFile   = kingpin.Flag("notifier-ca-file", "Path to CA for verifying TLS client certs").ExistingFile()
 
 	// Updater configuration
 	cfgUpdateInterval = kingpin.Flag("update-interval", "Frequency at which the vulnerability updater will run. Use 0 to disable the updater entirely.").Default("1h").Duration()
@@ -75,10 +77,6 @@ func main() {
 		kingpin.Errorf("required flag --db-path not provided, try --help")
 		os.Exit(1)
 	}
-	if *cfgNotifierType == "http" && *cfgNotifierHTTPURL == "" {
-		kingpin.Errorf("required flag --notifier-http-url not provided, try --help")
-		os.Exit(1)
-	}
 
 	// Initialize error/logging system
 	logLevel, err := capnslog.ParseLevel(strings.ToUpper(*cfgLogLevel))
@@ -110,17 +108,16 @@ func main() {
 	defer database.Close()
 
 	// Start notifier
-	var notifierService notifier.Notifier
+	if len(*cfgNotifierEndpoint) > 0 {
-	switch *cfgNotifierType {
+		notifier := notifier.New(notifier.Config{
-	case "http":
+			Endpoint: *cfgNotifierEndpoint,
-		notifierService, err = notifier.NewHTTPNotifier(*cfgNotifierHTTPURL)
+			CertFile: *cfgNotifierCertFile,
-		if err != nil {
+			KeyFile:  *cfgNotifierKeyFile,
-			log.Fatalf("could not initialize HTTP notifier: %s", err)
+			CAFile:   *cfgNotifierCAFile,
-		}
+		})
-	}
+
-	if notifierService != nil {
 		st.Begin()
-		go notifierService.Run(st)
+		go notifier.Serve(st)
 	}
 
 	// Start Main API and Health API

notifier/notifier.go

@@ -24,150 +24,172 @@ import (
 	"time"
 
 	"github.com/coreos/pkg/capnslog"
-	"github.com/coreos/pkg/timeutil"
+	"github.com/pborman/uuid"
+
 	"github.com/coreos/clair/database"
-	cerrors "github.com/coreos/clair/utils/errors"
 	"github.com/coreos/clair/health"
 	"github.com/coreos/clair/utils"
-	"github.com/pborman/uuid"
+	httputils "github.com/coreos/clair/utils/http"
 )
 
-// A Notifier dispatches notifications
-type Notifier interface {
-	Run(*utils.Stopper)
-}
-
 var log = capnslog.NewPackageLogger("github.com/coreos/clair", "notifier")
 
 const (
-	maxBackOff    = 5 * time.Minute
+	checkInterval = 5 * time.Minute
-	checkInterval = 5 * time.Second
 
-	refreshLockAnticipation = time.Minute * 2
+	refreshLockDuration = time.Minute * 2
-	lockDuration            = time.Minute*8 + refreshLockAnticipation
+	lockDuration        = time.Minute*8 + refreshLockDuration
 )
 
-// A HTTPNotifier dispatches notifications to an HTTP endpoint with POST requests
+// A Notification represents the structure of the notifications that are sent by a Notifier.
-type HTTPNotifier struct {
+type Notification struct {
-	url string
-}
-
-// NewHTTPNotifier initializes a new HTTPNotifier
-func NewHTTPNotifier(URL string) (*HTTPNotifier, error) {
-	if _, err := url.Parse(URL); err != nil {
-		return nil, cerrors.NewBadRequestError("could not create a notifier with an invalid URL")
-	}
-
-	notifier := &HTTPNotifier{url: URL}
-	health.RegisterHealthchecker("notifier", notifier.Healthcheck)
-
-	return notifier, nil
-}
-
-// Run pops notifications from the database, lock them, send them, mark them as
-// send and unlock them
-//
-// It uses an exponential backoff when POST requests fail
-func (notifier *HTTPNotifier) Run(st *utils.Stopper) {
-	defer st.End()
-
-	whoAmI := uuid.New()
-	log.Infof("HTTP notifier started. URL: %s. Lock Identifier: %s", notifier.url, whoAmI)
-
-	for {
-		node, notification, err := database.FindOneNotificationToSend(database.GetDefaultNotificationWrapper())
-		if notification == nil || err != nil {
-			if err != nil {
-				log.Warningf("could not get notification to send: %s.", err)
-			}
-
-			if !st.Sleep(checkInterval) {
-				break
-			}
-
-			continue
-		}
-
-		// Try to lock the notification
-		hasLock, hasLockUntil := database.Lock(node, lockDuration, whoAmI)
-		if !hasLock {
-			continue
-		}
-
-		for backOff := time.Duration(0); ; backOff = timeutil.ExpBackoff(backOff, maxBackOff) {
-			// Backoff, it happens when an error occurs during the communication
-			// with the notification endpoint
-			if backOff > 0 {
-				// Renew lock before going to sleep if necessary
-				if time.Now().Add(backOff).After(hasLockUntil.Add(-refreshLockAnticipation)) {
-					hasLock, hasLockUntil = database.Lock(node, lockDuration, whoAmI)
-					if !hasLock {
-						log.Warning("lost lock ownership, aborting")
-						break
-					}
-				}
-
-				// Sleep
-				if !st.Sleep(backOff) {
-					return
-				}
-			}
-
-			// Get notification content
-			content, err := notification.GetContent()
-			if err != nil {
-				log.Warningf("could not get content of notification '%s': %s", notification.GetName(), err.Error())
-				break
-			}
-
-			// Marshal the notification content
-			jsonContent, err := json.Marshal(struct {
 	Name, Type string
 	Content    interface{}
-			}{
-				Name:    notification.GetName(),
-				Type:    notification.GetType(),
-				Content: content,
-			})
-			if err != nil {
-				log.Errorf("could not marshal content of notification '%s': %s", notification.GetName(), err.Error())
-				break
-			}
-
-			// Post notification
-			req, _ := http.NewRequest("POST", notifier.url, bytes.NewBuffer(jsonContent))
-			req.Header.Set("Content-Type", "application/json")
-
-			client := &http.Client{}
-			res, err := client.Do(req)
-			if err != nil {
-				log.Warningf("could not post notification '%s': %s", notification.GetName(), err.Error())
-				continue
-			}
-			res.Body.Close()
-
-			if res.StatusCode != 200 && res.StatusCode != 201 {
-				log.Warningf("could not post notification '%s': got status code %d", notification.GetName(), res.StatusCode)
-				continue
-			}
-
-			// Mark the notification as sent
-			database.MarkNotificationAsSent(node)
-
-			log.Infof("sent notification '%s' successfully", notification.GetName())
-			break
-		}
-
-		if hasLock {
-			database.Unlock(node, whoAmI)
-		}
-	}
-
-	log.Info("HTTP notifier stopped")
 }
 
-// Healthcheck returns the health of the notifier service
+// A Notifier dispatches notifications to an HTTP endpoint.
-func (notifier *HTTPNotifier) Healthcheck() health.Status {
+type Notifier struct {
+	lockIdentifier string
+	endpoint       string
+	client         *http.Client
+}
+
+// Config represents the configuration of a Notifier.
+// The certificates are optionnals and enables client certificate authentification.
+type Config struct {
+	Endpoint                  string
+	CertFile, KeyFile, CAFile string
+}
+
+// New initializes a new Notifier from the specified configuration.
+func New(cfg Config) *Notifier {
+	if _, err := url.Parse(cfg.Endpoint); err != nil {
+		log.Fatal("could not create a notifier with an invalid endpoint URL")
+	}
+
+	// Initialize TLS
+	tlsConfig, err := httputils.LoadTLSClientConfig(cfg.CertFile, cfg.KeyFile, cfg.CAFile)
+	if err != nil {
+		log.Fatalf("could not initialize client cert authentification: %s\n", err)
+	}
+	if tlsConfig != nil {
+		log.Info("notifier configured with client certificate authentification")
+	}
+
+	httpClient := &http.Client{
+		Transport: &http.Transport{
+			TLSClientConfig: tlsConfig,
+		},
+	}
+
+	return &Notifier{
+		lockIdentifier: uuid.New(),
+		endpoint:       cfg.Endpoint,
+		client:         httpClient,
+	}
+}
+
+// Serve starts the Notifier.
+func (n *Notifier) Serve(stopper *utils.Stopper) {
+	defer stopper.End()
+	health.RegisterHealthchecker("notifier", n.Healthcheck)
+
+	log.Infof("notifier service started. endpoint: %s. lock identifier: %s\n", n.endpoint, n.lockIdentifier)
+
+	for {
+		// Find task.
+		// TODO(Quentin-M): Combine node and notification.
+		node, notification := n.findTask(stopper)
+		if node == "" && notification == nil {
+			break
+		}
+
+		// Handle task.
+		done := make(chan bool, 1)
+		go func() {
+			if n.handleTask(node, notification) {
+				database.MarkNotificationAsSent(node)
+			}
+			database.Unlock(node, n.lockIdentifier)
+			done <- true
+		}()
+
+		// Refresh task lock until done.
+	outer:
+		for {
+			select {
+			case <-done:
+				break outer
+			case <-time.After(refreshLockDuration):
+				database.Lock(node, lockDuration, n.lockIdentifier)
+			}
+		}
+	}
+
+	log.Info("notifier service stopped")
+}
+
+func (n *Notifier) findTask(stopper *utils.Stopper) (string, database.Notification) {
+	for {
+		// Find a notification to send.
+		node, notification, err := database.FindOneNotificationToSend(database.GetDefaultNotificationWrapper())
+		if err != nil {
+			log.Warningf("could not get notification to send: %s", err)
+		}
+
+		// No notification or error: wait.
+		if notification == nil || err != nil {
+			if !stopper.Sleep(checkInterval) {
+				return "", nil
+			}
+			continue
+		}
+
+		// Lock the notification.
+		if hasLock, _ := database.Lock(node, lockDuration, n.lockIdentifier); hasLock {
+			log.Infof("found and locked a notification: %s", notification.GetName())
+			return node, notification
+		}
+	}
+}
+
+func (n *Notifier) handleTask(node string, notification database.Notification) bool {
+	// Get notification content.
+	// TODO(Quentin-M): Split big notifications.
+	notificationContent, err := notification.GetContent()
+	if err != nil {
+		log.Warningf("could not get content of notification '%s': %s", notification.GetName(), err)
+		return false
+	}
+
+	// Create notification.
+	payload := Notification{
+		Name:    notification.GetName(),
+		Type:    notification.GetType(),
+		Content: notificationContent,
+	}
+
+	// Marshal notification.
+	jsonPayload, err := json.Marshal(payload)
+	if err != nil {
+		log.Errorf("could not marshal content of notification '%s': %s", notification.GetName(), err)
+		return false
+	}
+
+	// Send notification.
+	resp, err := n.client.Post(n.endpoint, "application/json", bytes.NewBuffer(jsonPayload))
+	defer resp.Body.Close()
+	if err != nil || (resp.StatusCode != 200 && resp.StatusCode != 201) {
+		log.Errorf("could not send notification '%s': (%d) %s", notification.GetName(), resp.StatusCode, err)
+		return false
+	}
+
+	log.Infof("successfully sent notification '%s'\n", notification.GetName())
+	return true
+}
+
+// Healthcheck returns the health of the notifier service.
+func (n *Notifier) Healthcheck() health.Status {
 	queueSize, err := database.CountNotificationsToSend()
 	return health.Status{IsEssential: false, IsHealthy: err == nil, Details: struct{ QueueSize int }{QueueSize: queueSize}}
 }

utils/http/http.go

@@ -0,0 +1,55 @@
+// Copyright 2015 clair 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 http provides utility functions for HTTP servers and clients.
+package http
+
+import (
+	"crypto/tls"
+	"crypto/x509"
+	"io/ioutil"
+)
+
+// LoadTLSClientConfig initializes a *tls.Config using the given certificates and private key, that
+// can be used to communicate with a server using client certificate authentificate.
+//
+// If no certificates are given, a nil *tls.Config is returned.
+// The CA certificate is optionnal, the system defaults are used if not provided.
+func LoadTLSClientConfig(certFile, keyFile, caFile string) (*tls.Config, error) {
+	if len(certFile) == 0 || len(keyFile) == 0 {
+		return nil, nil
+	}
+
+	cert, err := tls.LoadX509KeyPair(certFile, keyFile)
+	if err != nil {
+		return nil, err
+	}
+
+	var caCertPool *x509.CertPool
+	if len(caFile) > 0 {
+		caCert, err := ioutil.ReadFile(caFile)
+		if err != nil {
+			return nil, err
+		}
+		caCertPool = x509.NewCertPool()
+		caCertPool.AppendCertsFromPEM(caCert)
+	}
+
+	tlsConfig := &tls.Config{
+		Certificates: []tls.Certificate{cert},
+		RootCAs:      caCertPool,
+	}
+
+	return tlsConfig, nil
+}