How to Configure Monolog to Email Errors
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Monolog can be configured to send an email when an error occurs with an application. The configuration for this requires a few nested handlers in order to avoid receiving too many emails. This configuration looks complicated at first but each handler is fairly straightforward when it is broken down.
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# app/config/config_prod.yml
monolog:
handlers:
main:
type: fingers_crossed
# 500 errors are logged at the critical level
action_level: critical
# to also log 400 level errors (but not 404's):
# action_level: error
# excluded_404s:
# - ^/
handler: deduplicated
deduplicated:
type: deduplication
handler: swift
swift:
type: swift_mailer
from_email: 'error@example.com'
to_email: 'error@example.com'
# or list of recipients
# to_email: ['dev1@example.com', 'dev2@example.com', ...]
subject: 'An Error Occurred! %%message%%'
level: debug
formatter: monolog.formatter.html
content_type: text/html
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<!-- app/config/config_prod.xml -->
<?xml version="1.0" encoding="UTF-8" ?>
<container xmlns="http://symfony.com/schema/dic/services"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:monolog="http://symfony.com/schema/dic/monolog"
xsi:schemaLocation="http://symfony.com/schema/dic/services
http://symfony.com/schema/dic/services/services-1.0.xsd
http://symfony.com/schema/dic/monolog http://symfony.com/schema/dic/monolog/monolog-1.0.xsd">
<monolog:config>
<!--
500 errors are logged at the critical level,
to also log 400 level errors (but not 404's):
action-level="error"
And add this child inside this monolog:handler
<monolog:excluded-404>^/</monolog:excluded-404>
-->
<monolog:handler
name="main"
type="fingers_crossed"
action-level="critical"
handler="deduplicated"
/>
<monolog:handler
name="deduplicated"
type="deduplication"
handler="swift"
/>
<monolog:handler
name="swift"
type="swift_mailer"
from-email="error@example.com"
subject="An Error Occurred! %%message%%"
level="debug"
formatter="monolog.formatter.html"
content-type="text/html">
<monolog:to-email>error@example.com</monolog:to-email>
<!-- or list of recipients -->
<!--
<monolog:to-email>dev1@example.com</monolog:to-email>
<monolog:to-email>dev2@example.com</monolog:to-email>
...
-->
</monolog:handler>
</monolog:config>
</container>
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// app/config/config_prod.php
$container->loadFromExtension('monolog', array(
'handlers' => array(
'main' => array(
'type' => 'fingers_crossed',
// 500 errors are logged at the critical level
'action_level' => 'critical',
// to also log 400 level errors (but not 404's):
// 'action_level' => 'error',
// 'excluded_404s' => array(
// '^/',
// ),
'handler' => 'deduplicated',
),
'deduplicated' => array(
'type' => 'deduplication',
'handler' => 'swift',
),
'swift' => array(
'type' => 'swift_mailer',
'from_email' => 'error@example.com',
'to_email' => 'error@example.com',
// or a list of recipients
// 'to_email' => array('dev1@example.com', 'dev2@example.com', ...),
'subject' => 'An Error Occurred! %%message%%',
'level' => 'debug',
'formatter' => 'monolog.formatter.html',
'content_type' => 'text/html',
),
),
));
The main
handler is a fingers_crossed
handler which means that
it is only triggered when the action level, in this case critical
is reached.
The critical
level is only triggered for 5xx HTTP code errors. If this level
is reached once, the fingers_crossed
handler will log all messages
regardless of their level. The handler
setting means that the output
is then passed onto the deduplicated
handler.
Tip
If you want both 400 level and 500 level errors to trigger an email,
set the action_level
to error
instead of critical
. See the
code above for an example.
The deduplicated
handler simply keeps all the messages for a request and
then passes them onto the nested handler in one go, but only if the records are
unique over a given period of time (60 seconds by default). If the records are
duplicates they are simply discarded. Adding this handler reduces the amount of
notifications to a manageable level, specially in critical failure scenarios.
You can adjust the time period using the time
option:
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# app/config/config_prod.yml
monolog:
handlers:
# ...
deduplicated:
type: deduplication
# the time in seconds during which duplicate entries are discarded (default: 60)
time: 10
handler: swift
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<!-- app/config/config_prod.xml -->
<!-- time: the time in seconds during which duplicate entries are discarded (default: 60) -->
<monolog:handler name="deduplicated"
type="deduplication"
time="10"
handler="swift" />
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// app/config/config_prod.php
$container->loadFromExtension('monolog', array(
'handlers' => array(
// ...
'deduplicated' => array(
'type' => 'deduplication',
// the time in seconds during which duplicate entries are discarded (default: 60)
'time' => 10,
'handler' => 'swift',
)
The messages are then passed to the swift
handler. This is the handler that
actually deals with emailing you the error. The settings for this are
straightforward, the to and from addresses, the formatter, the content type
and the subject.
You can combine these handlers with other handlers so that the errors still get logged on the server as well as the emails being sent:
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# app/config/config_prod.yml
monolog:
handlers:
main:
type: fingers_crossed
action_level: critical
handler: grouped
grouped:
type: group
members: [streamed, deduplicated]
streamed:
type: stream
path: '%kernel.logs_dir%/%kernel.environment%.log'
level: debug
deduplicated:
type: deduplication
handler: swift
swift:
type: swift_mailer
from_email: 'error@example.com'
to_email: 'error@example.com'
subject: 'An Error Occurred! %%message%%'
level: debug
formatter: monolog.formatter.html
content_type: text/html
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<!-- app/config/config_prod.xml -->
<container xmlns="http://symfony.com/schema/dic/services"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:monolog="http://symfony.com/schema/dic/monolog"
xsi:schemaLocation="http://symfony.com/schema/dic/services
http://symfony.com/schema/dic/services/services-1.0.xsd
http://symfony.com/schema/dic/monolog http://symfony.com/schema/dic/monolog/monolog-1.0.xsd">
<monolog:config>
<monolog:handler
name="main"
type="fingers_crossed"
action_level="critical"
handler="grouped"
/>
<monolog:handler
name="grouped"
type="group"
>
<member type="stream"/>
<member type="deduplicated"/>
</monolog:handler>
<monolog:handler
name="stream"
path="%kernel.logs_dir%/%kernel.environment%.log"
level="debug"
/>
<monolog:handler
name="deduplicated"
type="deduplication"
handler="swift"
/>
<monolog:handler
name="swift"
type="swift_mailer"
from-email="error@example.com"
subject="An Error Occurred! %%message%%"
level="debug"
formatter="monolog.formatter.html"
content-type="text/html">
<monolog:to-email>error@example.com</monolog:to-email>
<!-- or list of recipients -->
<!--
<monolog:to-email>dev1@example.com</monolog:to-email>
<monolog:to-email>dev2@example.com</monolog:to-email>
...
-->
</monolog:handler>
</monolog:config>
</container>
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// app/config/config_prod.php
$container->loadFromExtension('monolog', array(
'handlers' => array(
'main' => array(
'type' => 'fingers_crossed',
'action_level' => 'critical',
'handler' => 'grouped',
),
'grouped' => array(
'type' => 'group',
'members' => array('streamed', 'deduplicated'),
),
'streamed' => array(
'type' => 'stream',
'path' => '%kernel.logs_dir%/%kernel.environment%.log',
'level' => 'debug',
),
'deduplicated' => array(
'type' => 'deduplication',
'handler' => 'swift',
),
'swift' => array(
'type' => 'swift_mailer',
'from_email' => 'error@example.com',
'to_email' => 'error@example.com',
// or a list of recipients
// 'to_email' => array('dev1@example.com', 'dev2@example.com', ...),
'subject' => 'An Error Occurred! %%message%%',
'level' => 'debug',
'formatter' => 'monolog.formatter.html',
'content_type' => 'text/html',
),
),
));
This uses the group
handler to send the messages to the two
group members, the deduplicated
and the stream
handlers. The messages will
now be both written to the log file and emailed.