Writing to Email
Zend_Log_Writer_Mail writes log entries in an email message
by using Zend_Mail. The Zend_Log_Writer_Mail
constructor takes a Zend_Mail object, and an optional
Zend_Layout object.
The primary use case for Zend_Log_Writer_Mail is notifying
developers, systems administrators, or any concerned parties of errors
that might be occurring with PHP-based scripts.
Zend_Log_Writer_Mail was born out of the idea that if
something is broken, a human being needs to be alerted of it immediately
so they can take corrective action.
Basic usage is outlined below:
setFrom('errors@example.org')
->addTo('project_developers@example.org');
$writer = new Zend_Log_Writer_Mail($mail);
// Set subject text for use; summary of number of errors is appended to the
// subject line before sending the message.
$writer->setSubjectPrependText('Errors with script foo.php');
// Only email warning level entries and higher.
$writer->addFilter(Zend_Log::WARN);
$log = new Zend_Log();
$log->addWriter($writer);
// Something bad happened!
$log->error('unable to connect to database');
// On writer shutdown, Zend_Mail::send() is triggered to send an email with
// all log entries at or above the Zend_Log filter level.
]]>
Zend_Log_Writer_Mail will render the email body as plain
text by default.
One email is sent containing all log entries at or above the filter
level. For example, if warning-level entries an up are to be emailed,
and two warnings and five errors occur, the resulting email will contain
a total of seven log entries.
Zend_Layout Usage
A Zend_Layout instance may be used to generate the
HTML portion of a multipart email. If a
Zend_Layout instance is in use,
Zend_Log_Writer_Mail assumes that it is being used to render
HTML and sets the body HTML for the message as
the Zend_Layout-rendered value.
When using Zend_Log_Writer_Mail with a
Zend_Layout instance, you have the option to set a
custom formatter by using the setLayoutFormatter()
method. If no Zend_Layout-specific entry formatter was
specified, the formatter currently in use will be used. Full usage
of Zend_Layout with a custom formatter is outlined
below.
setFrom('errors@example.org')
->addTo('project_developers@example.org');
// Note that a subject line is not being set on the Zend_Mail instance!
// Use a simple Zend_Layout instance with its defaults.
$layout = new Zend_Layout();
// Create a formatter that wraps the entry in a listitem tag.
$layoutFormatter = new Zend_Log_Formatter_Simple(
'' . Zend_Log_Formatter_Simple::DEFAULT_FORMAT . ''
);
$writer = new Zend_Log_Writer_Mail($mail, $layout);
// Apply the formatter for entries as rendered with Zend_Layout.
$writer->setLayoutFormatter($layoutFormatter);
$writer->setSubjectPrependText('Errors with script foo.php');
$writer->addFilter(Zend_Log::WARN);
$log = new Zend_Log();
$log->addWriter($writer);
// Something bad happened!
$log->error('unable to connect to database');
// On writer shutdown, Zend_Mail::send() is triggered to send an email with
// all log entries at or above the Zend_Log filter level. The email will
// contain both plain text and HTML parts.
]]>
Subject Line Error Level Summary
The setSubjectPrependText() method may be used in place
of Zend_Mail::setSubject() to have the email subject
line dynamically written before the email is sent. For example, if
the subject prepend text reads "Errors from script", the subject of
an email generated by Zend_Log_Writer_Mail with two
warnings and five errors would be "Errors from script (warn = 2;
error = 5)". If subject prepend text is not in use via
Zend_Log_Writer_Mail, the Zend_Mail
subject line, if any, is used.
Caveats
Sending log entries via email can be dangerous. If error conditions
are being improperly handled by your script, or if you're misusing
the error levels, you might find yourself in a situation where you
are sending hundreds or thousands of emails to the recipients
depending on the frequency of your errors.
At this time, Zend_Log_Writer_Mail does not provide any
mechanism for throttling or otherwise batching up the messages.
Such functionality should be implemented by the consumer if
necessary.
Again, Zend_Log_Writer_Mail's primary goal is to
proactively notify a human being of error conditions. If those
errors are being handled in a timely fashion, and safeguards are
being put in place to prevent those circumstances in the future,
then email-based notification of errors can be a valuable tool.