Merge pull request #394 from xiekeyang/feature-panic-hook

Feature: Add Hook for Web Application Panic

docs/handlers/app.go

@@ -9,6 +9,7 @@ import (
 	"os"
 	"time"
 
+	log "github.com/Sirupsen/logrus"
 	"github.com/docker/distribution"
 	"github.com/docker/distribution/configuration"
 	ctxu "github.com/docker/distribution/context"
@@ -101,6 +102,7 @@ func NewApp(ctx context.Context, configuration configuration.Configuration) *App
 
 	app.configureEvents(&configuration)
 	app.configureRedis(&configuration)
+	app.configureLogHook(&configuration)
 
 	// configure storage caches
 	if cc, ok := configuration.Storage["cache"]; ok {
@@ -291,6 +293,31 @@ func (app *App) configureRedis(configuration *configuration.Configuration) {
 	}))
 }
 
+// configureLogHook prepares logging hook parameters.
+func (app *App) configureLogHook(configuration *configuration.Configuration) {
+	logger := ctxu.GetLogger(app).(*log.Entry).Logger
+	for _, configHook := range configuration.Log.Hooks {
+		if !configHook.Disabled {
+			switch configHook.Type {
+			case "mail":
+				hook := &logHook{}
+				hook.LevelsParam = configHook.Levels
+				hook.Mail = &mailer{
+					Addr:     configHook.MailOptions.SMTP.Addr,
+					Username: configHook.MailOptions.SMTP.Username,
+					Password: configHook.MailOptions.SMTP.Password,
+					Insecure: configHook.MailOptions.SMTP.Insecure,
+					From:     configHook.MailOptions.From,
+					To:       configHook.MailOptions.To,
+				}
+				logger.Hooks.Add(hook)
+			default:
+			}
+		}
+	}
+	app.Context = ctxu.WithLogger(app.Context, logger)
+}
+
 func (app *App) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	defer r.Body.Close() // ensure that request body is always closed.
 

docs/handlers/hooks.go

@@ -0,0 +1,53 @@
+package handlers
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+	"strings"
+	"text/template"
+
+	"github.com/Sirupsen/logrus"
+)
+
+// logHook is for hooking Panic in web application
+type logHook struct {
+	LevelsParam []string
+	Mail        *mailer
+}
+
+// Fire forwards an error to LogHook
+func (hook *logHook) Fire(entry *logrus.Entry) error {
+	addr := strings.Split(hook.Mail.Addr, ":")
+	if len(addr) != 2 {
+		return errors.New("Invalid Mail Address")
+	}
+	host := addr[0]
+	subject := fmt.Sprintf("[%s] %s: %s", entry.Level, host, entry.Message)
+
+	html := `
+	{{.Message}}
+
+	{{range $key, $value := .Data}}
+	{{$key}}: {{$value}}
+	{{end}}
+	`
+	b := bytes.NewBuffer(make([]byte, 0))
+	t := template.Must(template.New("mail body").Parse(html))
+	if err := t.Execute(b, entry); err != nil {
+		return err
+	}
+	body := fmt.Sprintf("%s", b)
+
+	return hook.Mail.sendMail(subject, body)
+}
+
+// Levels contains hook levels to be catched
+func (hook *logHook) Levels() []logrus.Level {
+	levels := []logrus.Level{}
+	for _, v := range hook.LevelsParam {
+		lv, _ := logrus.ParseLevel(v)
+		levels = append(levels, lv)
+	}
+	return levels
+}

docs/handlers/mail.go

@@ -0,0 +1,45 @@
+package handlers
+
+import (
+	"errors"
+	"net/smtp"
+	"strings"
+)
+
+// mailer provides fields of email configuration for sending.
+type mailer struct {
+	Addr, Username, Password, From string
+	Insecure                       bool
+	To                             []string
+}
+
+// sendMail allows users to send email, only if mail parameters is configured correctly.
+func (mail *mailer) sendMail(subject, message string) error {
+	addr := strings.Split(mail.Addr, ":")
+	if len(addr) != 2 {
+		return errors.New("Invalid Mail Address")
+	}
+	host := addr[0]
+	msg := []byte("To:" + strings.Join(mail.To, ";") +
+		"\r\nFrom: " + mail.From +
+		"\r\nSubject: " + subject +
+		"\r\nContent-Type: text/plain\r\n\r\n" +
+		message)
+	auth := smtp.PlainAuth(
+		"",
+		mail.Username,
+		mail.Password,
+		host,
+	)
+	err := smtp.SendMail(
+		mail.Addr,
+		auth,
+		mail.From,
+		mail.To,
+		[]byte(msg),
+	)
+	if err != nil {
+		return err
+	}
+	return nil
+}