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Merge branch 'email-handler'
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‎README.md‎

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## log
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<img align="right" src="https://raw.githubusercontent.com/go-playground/log/master/logo.png">
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![Project status](https://img.shields.io/badge/version-2.2-green.svg)
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![Project status](https://img.shields.io/badge/version-2.3-green.svg)
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[![Build Status](https://semaphoreci.com/api/v1/joeybloggs/log/branches/master/badge.svg)](https://semaphoreci.com/joeybloggs/log)
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[![Coverage Status](https://coveralls.io/repos/github/go-playground/log/badge.svg?branch=master)](https://coveralls.io/github/go-playground/log?branch=master)
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[![Go Report Card](https://goreportcard.com/badge/github.com/go-playground/log)](https://goreportcard.com/report/github.com/go-playground/log)

‎handlers/email/email.go‎

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package email
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import (
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"bytes"
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"html/template"
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stdlog "log"
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"os"
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"time"
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"gopkg.in/gomail.v2"
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"github.com/go-playground/log"
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)
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// FormatFunc is the function that the workers use to create
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// a new Formatter per worker allowing reusable go routine safe
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// variable to be used within your Formatter function.
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type FormatFunc func(email *Email) Formatter
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// Formatter is the function used to format the Email entry
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type Formatter func(e *log.Entry) *gomail.Message
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const (
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gopath = "GOPATH"
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contentType = "text/html"
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defaultTemplate = `<!DOCTYPE html>
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<html>
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<body>
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<h2>{{ .Message }}</h2>
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{{ if ne .ApplicationID "" }}
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<h4>{{ .ApplicationID }}</h4>
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{{ end }}
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<p>{{ .Level.String }}</p>
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<p>{{ ts . }}</p>
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{{ if ne .Line 0 }}
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{{ display_file . }}:{{ .Line }}
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{{ end }}
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{{ range $f := .Fields }}
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<p><b>{{ $f.Key }}</b>: {{ $f.Value }}</p>
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{{ end }}
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</body>
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</html>`
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)
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// Email is an instance of the email logger
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type Email struct {
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buffer uint // channel buffer
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numWorkers uint
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formatFunc FormatFunc
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timestampFormat string
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gopath string
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fileDisplay log.FilenameDisplay
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template *template.Template
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templateHTML string
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host string
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port int
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username string
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password string
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from string
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to []string
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keepalive time.Duration
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}
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// New returns a new instance of the email logger
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func New(host string, port int, username string, password string, from string, to []string) *Email {
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return &Email{
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buffer: 0,
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numWorkers: 1,
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timestampFormat: log.DefaultTimeFormat,
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fileDisplay: log.Lshortfile,
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templateHTML: defaultTemplate,
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host: host,
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port: port,
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username: username,
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password: password,
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from: from,
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to: to,
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keepalive: time.Second * 30,
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formatFunc: defaultFormatFunc,
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}
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}
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// SetKeepAliveTimout tells Email how long to keep the smtp connection
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// open when no messsages are being sent; it will automatically reconnect
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// on next message that is received.
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func (email *Email) SetKeepAliveTimout(keepAlive time.Duration) {
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email.keepalive = keepAlive
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}
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// SetEmailTemplate sets Email's html tempalte to be used for email body
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func (email *Email) SetEmailTemplate(htmlTemplate string) {
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email.templateHTML = htmlTemplate
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}
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// SetFilenameDisplay tells Email the filename, when present, how to display
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func (email *Email) SetFilenameDisplay(fd log.FilenameDisplay) {
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email.fileDisplay = fd
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}
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// SetBuffersAndWorkers sets the channels buffer size and number of concurrent workers.
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// These settings should be thought about together, hence setting both in the same function.
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func (email *Email) SetBuffersAndWorkers(size uint, workers uint) {
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email.buffer = size
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if workers == 0 {
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// just in case no log registered yet
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stdlog.Println("Invalid number of workers specified, setting to 1")
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log.Warn("Invalid number of workers specified, setting to 1")
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workers = 1
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}
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email.numWorkers = workers
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}
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// From returns the Email's From address
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func (email *Email) From() string {
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return email.from
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}
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// To returns the Email's To address
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func (email *Email) To() []string {
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return email.to
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}
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// SetTimestampFormat sets Email's timestamp output format
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// Default is : "2006-01-02T15:04:05.000000000Z07:00"
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func (email *Email) SetTimestampFormat(format string) {
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email.timestampFormat = format
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}
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// SetFormatFunc sets FormatFunc each worker will call to get
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// a Formatter func
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func (email *Email) SetFormatFunc(fn FormatFunc) {
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email.formatFunc = fn
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}
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// Run starts the logger consuming on the returned channed
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func (email *Email) Run() chan<- *log.Entry {
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// pre-setup
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if email.fileDisplay == log.Llongfile {
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// gather $GOPATH for use in stripping off of full name
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// if not found still ok as will be blank
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email.gopath = os.Getenv(gopath)
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if len(email.gopath) != 0 {
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email.gopath += string(os.PathSeparator) + "src" + string(os.PathSeparator)
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}
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}
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// parse email htmlTemplate, will panic if fails
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email.template = template.Must(template.New("email").Funcs(
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template.FuncMap{
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"display_file": func(e *log.Entry) (file string) {
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file = e.File
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if email.fileDisplay == log.Lshortfile {
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for i := len(file) - 1; i > 0; i-- {
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if file[i] == '/' {
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file = file[i+1:]
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break
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}
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}
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} else {
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file = file[len(email.gopath):]
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}
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return
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},
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"ts": func(e *log.Entry) (ts string) {
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ts = e.Timestamp.Format(email.timestampFormat)
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return
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},
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},
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).Parse(email.templateHTML))
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ch := make(chan *log.Entry, email.buffer)
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for i := 0; i <= int(email.numWorkers); i++ {
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go email.handleLog(ch)
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}
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return ch
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}
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func defaultFormatFunc(email *Email) Formatter {
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var err error
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b := new(bytes.Buffer)
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message := gomail.NewMessage()
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message.SetHeader("From", email.from)
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message.SetHeader("To", email.to...)
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return func(e *log.Entry) *gomail.Message {
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b.Reset()
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if err = email.template.ExecuteTemplate(b, "email", e); err != nil {
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log.WithFields(log.F("error", err)).Error("Error parsing Email handler template")
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}
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message.SetHeader("Subject", e.Message)
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message.SetBody(contentType, b.String())
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return message
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}
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}
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func (email *Email) handleLog(entries <-chan *log.Entry) {
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var e *log.Entry
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var s gomail.SendCloser
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var err error
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var open bool
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var alreadyTriedSending bool
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var message *gomail.Message
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var count uint8
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formatter := email.formatFunc(email)
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d := gomail.NewDialer(email.host, email.port, email.username, email.password)
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for {
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select {
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case e = <-entries:
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count = 0
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alreadyTriedSending = false
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message = formatter(e)
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REOPEN:
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// check if smtp connection open
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if !open {
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count++
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if s, err = d.Dial(); err != nil {
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log.WithFields(log.F("error", err)).Warn("ERROR connection to smtp server")
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if count == 3 {
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// we tried to reconnect...
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e.Consumed()
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break
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}
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goto REOPEN
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}
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count = 0
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open = true
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}
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RESEND:
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count++
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if err = gomail.Send(s, message); err != nil {
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log.WithFields(log.F("error", err)).Warn("ERROR sending to smtp server, retrying")
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if count == 3 && !alreadyTriedSending {
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// maybe we got disconnected...
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alreadyTriedSending = true
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open = false
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s.Close()
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goto REOPEN
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} else if alreadyTriedSending {
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// we reopened and tried 2 more times, can;t say we didn't try
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log.WithFields(log.F("error", err)).Alert("ERROR sending log via EMAIL, RETRY and REOPEN failed")
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e.Consumed()
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break
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}
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goto RESEND
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}
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e.Consumed()
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case <-time.After(email.keepalive):
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if open {
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s.Close()
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open = false
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}
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}
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}
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}

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