Logging Email Appender

by Tim Pease

Description

The Logging email appender provides a way to send log messages via email from a Ruby application. This is useful if you wish to be notified of exceptions or fatal errors as they arise.

The email appender was originally part of the Logging framework proper, but with the release of Logging 2.0.0, it has been extracted into its own gem.

Installation

The Logging framework uses the little-plugger gem based plugin system. All that needs to be done to start using the email appender is to install the gem.

gem install logging-email

The plugin system will automatically detect and load the plugin when the Logging framework is first initialized.

Examples

The example below configures an email appender and gives it the name "gmail". This name will be used later to add the appender to our logger.

The appender itself is configured to send email via the Google's Gmail servers. This requires a user name and password; we load these from environment variables. The Gmail SMTP servers also require STARTTLS to be enabled so that TLS or SSL encryption can be used for communication.

The email appender is configured to buffer log messages. The log messages will be sent in a single email when either 20 log messages have been buffered or one minute has passed since the first log message was buffered. This helps reduce the overall volume of email. The caveat here is that if there is a fatal error and the application crashes, these log message will not be sent out via email; they will be lost.

require 'logging'
Logging.init      # initialize the framework and load plugins

Logger.appenders.email 'gmail',
    :from       => "[email protected]",
    :to         => "[email protected]",
    :subject    => "Application Error [#{%x(uname -n).strip}]",
    :address    => "smtp.gmail.com",
    :port       => 443,
    :domain     => "gmail.com",
    :user_name  => ENV["GMAIL_USER"],
    :password   => ENV["GMAIL_PASS"],
    :authentication => :plain,
    :enable_starttls_auto => true,
    :auto_flushing => 20,      # send an email after 20 messages have been buffered
    :flush_period  => 60,      # send an email after one minute
    :level         => :error   # only process log events that are "error" or "fatal"

logger = Logging.logger['example_logger']
logger.level = :info

logger.add_appenders \
    Logging.appenders['gmail'],             # lookup the gmail email appender
    Logging.appenders.file('example.log')

logger.debug "this debug message will not be output by the logger"
logger.info "just some friendly advice"
logger.error exception                      # this `exception` will be emailed

Development

The logging-email source code relies on the Mr Bones project for default rake tasks. You will need to install the Mr Bones gem if you want to build or test the logging-email gem. Conveniently there is a bootstrap script that you can run to setup your development environment.

script/bootstrap

This will install the Mr Bones gem and the required Ruby gems for development. After this is done you can rake rake -T to see the available rake tasks.

License

The MIT License

Copyright (c) 2015 Tim Pease

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the 'Software'), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.