terraform/vendor/github.com/cihub/seelog/writers_smtpwriter.go

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// Copyright (c) 2012 - Cloud Instruments Co., Ltd.
//
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice, this
// list of conditions and the following disclaimer.
// 2. Redistributions in binary form must reproduce the above copyright notice,
// this list of conditions and the following disclaimer in the documentation
// and/or other materials provided with the distribution.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
// ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
// LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
// ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
package seelog
import (
"crypto/tls"
"crypto/x509"
"errors"
"fmt"
"io/ioutil"
"net/smtp"
"path/filepath"
"strings"
)
const (
// Default subject phrase for sending emails.
DefaultSubjectPhrase = "Diagnostic message from server: "
// Message subject pattern composed according to RFC 5321.
rfc5321SubjectPattern = "From: %s <%s>\nSubject: %s\n\n"
)
// smtpWriter is used to send emails via given SMTP-server.
type smtpWriter struct {
auth smtp.Auth
hostName string
hostPort string
hostNameWithPort string
senderAddress string
senderName string
recipientAddresses []string
caCertDirPaths []string
mailHeaders []string
subject string
}
// NewSMTPWriter returns a new SMTP-writer.
func NewSMTPWriter(sa, sn string, ras []string, hn, hp, un, pwd string, cacdps []string, subj string, headers []string) *smtpWriter {
return &smtpWriter{
auth: smtp.PlainAuth("", un, pwd, hn),
hostName: hn,
hostPort: hp,
hostNameWithPort: fmt.Sprintf("%s:%s", hn, hp),
senderAddress: sa,
senderName: sn,
recipientAddresses: ras,
caCertDirPaths: cacdps,
subject: subj,
mailHeaders: headers,
}
}
func prepareMessage(senderAddr, senderName, subject string, body []byte, headers []string) []byte {
headerLines := fmt.Sprintf(rfc5321SubjectPattern, senderName, senderAddr, subject)
// Build header lines if configured.
if headers != nil && len(headers) > 0 {
headerLines += strings.Join(headers, "\n")
headerLines += "\n"
}
return append([]byte(headerLines), body...)
}
// getTLSConfig gets paths of PEM files with certificates,
// host server name and tries to create an appropriate TLS.Config.
func getTLSConfig(pemFileDirPaths []string, hostName string) (config *tls.Config, err error) {
if pemFileDirPaths == nil || len(pemFileDirPaths) == 0 {
err = errors.New("invalid PEM file paths")
return
}
pemEncodedContent := []byte{}
var (
e error
bytes []byte
)
// Create a file-filter-by-extension, set aside non-pem files.
pemFilePathFilter := func(fp string) bool {
if filepath.Ext(fp) == ".pem" {
return true
}
return false
}
for _, pemFileDirPath := range pemFileDirPaths {
pemFilePaths, err := getDirFilePaths(pemFileDirPath, pemFilePathFilter, false)
if err != nil {
return nil, err
}
// Put together all the PEM files to decode them as a whole byte slice.
for _, pfp := range pemFilePaths {
if bytes, e = ioutil.ReadFile(pfp); e == nil {
pemEncodedContent = append(pemEncodedContent, bytes...)
} else {
return nil, fmt.Errorf("cannot read file: %s: %s", pfp, e.Error())
}
}
}
config = &tls.Config{RootCAs: x509.NewCertPool(), ServerName: hostName}
isAppended := config.RootCAs.AppendCertsFromPEM(pemEncodedContent)
if !isAppended {
// Extract this into a separate error.
err = errors.New("invalid PEM content")
return
}
return
}
// SendMail accepts TLS configuration, connects to the server at addr,
// switches to TLS if possible, authenticates with mechanism a if possible,
// and then sends an email from address from, to addresses to, with message msg.
func sendMailWithTLSConfig(config *tls.Config, addr string, a smtp.Auth, from string, to []string, msg []byte) error {
c, err := smtp.Dial(addr)
if err != nil {
return err
}
// Check if the server supports STARTTLS extension.
if ok, _ := c.Extension("STARTTLS"); ok {
if err = c.StartTLS(config); err != nil {
return err
}
}
// Check if the server supports AUTH extension and use given smtp.Auth.
if a != nil {
if isSupported, _ := c.Extension("AUTH"); isSupported {
if err = c.Auth(a); err != nil {
return err
}
}
}
// Portion of code from the official smtp.SendMail function,
// see http://golang.org/src/pkg/net/smtp/smtp.go.
if err = c.Mail(from); err != nil {
return err
}
for _, addr := range to {
if err = c.Rcpt(addr); err != nil {
return err
}
}
w, err := c.Data()
if err != nil {
return err
}
_, err = w.Write(msg)
if err != nil {
return err
}
err = w.Close()
if err != nil {
return err
}
return c.Quit()
}
// Write pushes a text message properly composed according to RFC 5321
// to a post server, which sends it to the recipients.
func (smtpw *smtpWriter) Write(data []byte) (int, error) {
var err error
if smtpw.caCertDirPaths == nil {
err = smtp.SendMail(
smtpw.hostNameWithPort,
smtpw.auth,
smtpw.senderAddress,
smtpw.recipientAddresses,
prepareMessage(smtpw.senderAddress, smtpw.senderName, smtpw.subject, data, smtpw.mailHeaders),
)
} else {
config, e := getTLSConfig(smtpw.caCertDirPaths, smtpw.hostName)
if e != nil {
return 0, e
}
err = sendMailWithTLSConfig(
config,
smtpw.hostNameWithPort,
smtpw.auth,
smtpw.senderAddress,
smtpw.recipientAddresses,
prepareMessage(smtpw.senderAddress, smtpw.senderName, smtpw.subject, data, smtpw.mailHeaders),
)
}
if err != nil {
return 0, err
}
return len(data), nil
}
// Close closes down SMTP-connection.
func (smtpw *smtpWriter) Close() error {
// Do nothing as Write method opens and closes connection automatically.
return nil
}