Using GMail with a Log4j SMTP Appender in Grails
Wednesday, February 03rd, 2010I saw a plaintive wail on Twitter about using GMail as the smtp server to send error emails using a Log4j
SMTPAppender
in Grails
. It turned out to be a little tricky (and a bigger solution than 140 characters would allow) so I thought I’d describe the process here.
Most of the properties are configurable as appender attributes (e.g. server name, auth username, etc.) but two important ones aren’t. SMTPAppender
creates a Properties
instance with System.getProperties()
as the default values and adds smtp properties to that. But you need to specify the smtp port (it will default to 25 otherwise) and you need to tell it to send a STARTTLS
command. Both are configurable via system properties:
System.setProperty 'mail.smtp.port', '587' System.setProperty 'mail.smtp.starttls.enable', 'true'
and if you add those calls to Config.groovy
before the appender is instantiated then it will have the values available when it configures its JavaMail Session
:
import org.apache.log4j.Level import org.apache.log4j.net.SMTPAppender ... mail.error.server = 'smtp.gmail.com' mail.error.port = 587 mail.error.username = 'your.email@gmail.com' mail.error.password = 'yourpassword' mail.error.to = 'to@yourapp.com' mail.error.from = 'from@yourapp.com' mail.error.subject = '[Application Error]' mail.error.starttls = true mail.error.debug = false environments { production { grails.serverURL = "http://www.changeme.com" } development { grails.serverURL = "http://localhost:8080/${appName}" } test { grails.serverURL = "http://localhost:8080/${appName}" } } log4j = { System.setProperty 'mail.smtp.port', mail.error.port.toString() System.setProperty 'mail.smtp.starttls.enable', mail.error.starttls.toString() appenders { appender new SMTPAppender(name: 'smtp', to: mail.error.to, from: mail.error.from, subject: mail.error.subject, threshold: Level.ERROR, SMTPHost: mail.error.server, SMTPUsername: mail.error.username, SMTPDebug: mail.error.debug.toString(), SMTPPassword: mail.error.password, layout: pattern(conversionPattern: '%d{[ dd.MM.yyyy HH:mm:ss.SSS]} [%t] %n%-5p %n%c %n%C %n %x %n %m%n')) } error 'org.codehaus.groovy.grails.web.servlet', // controllers 'org.codehaus.groovy.grails.web.pages', // GSP 'org.codehaus.groovy.grails.web.sitemesh', // layouts 'org.codehaus.groovy.grails.web.mapping.filter', // URL mapping 'org.codehaus.groovy.grails.web.mapping', // URL mapping 'org.codehaus.groovy.grails.commons', // core / classloading 'org.codehaus.groovy.grails.plugins', // plugins 'org.codehaus.groovy.grails.orm.hibernate', // hibernate integration 'org.springframework', 'org.hibernate', 'net.sf.ehcache.hibernate' warn 'org.mortbay.log' root { error 'stdout', 'smtp' additivity = true } }
I’ve parameterized the properties to make them configurable for each environment or using an external configuration file.
Note that GMail has a limit of 500 emails per day, so if you generate a lot of errors in your app you could hit that limit.