Allow overriding formatter used by default monolog.handler service.
feature #908 Allow overriding formatter used by default monolog.handler service. (gunnarlium)

This PR was merged into the 2.0.x-dev branch.

Discussion
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Allow overriding formatter used by default monolog.handler service.

This PR adds a new service, `monolog.formatter`, which is read by the default `monolog.handler` in order to allow easy override of the default formatter to use.

Commits
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d77204c Allow overriding formatter used by default monolog.handler service.