How to Configure Monolog to Email Errors
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How to Configure Monolog to Email Errors
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:
mail:
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: buffered
buffered:
type: buffer
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!
level: debugThe mail 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 buffered 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 buffered handler simply keeps all the messages for a request and
then passes them onto the nested handler in one go. If you do not use this
handler then each message will be emailed separately. This is 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 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:
Caution
The default spool setting for swiftmailer is set to memory, which
means that emails are sent at the very end of the request. However, this
does not work with buffered logs at the moment. In order to enable emailing
logs per the example below, you must comment out the spool: { type: memory }
line in the config.yml file.
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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, buffered]
streamed:
type: stream
path: '%kernel.logs_dir%/%kernel.environment%.log'
level: debug
buffered:
type: buffer
handler: swift
swift:
type: swift_mailer
from_email: 'error@example.com'
to_email: 'error@example.com'
subject: An Error Occurred!
level: debugThis uses the group handler to send the messages to the two
group members, the buffered and the stream handlers. The messages will
now be both written to the log file and emailed.
