With the release of Bundler 2.0, things got a bit messy. Since both
bundler and rake are very likely to retain backwards compatibility due
to their wide use in the wild, this is likely safe enough.
In any case, these are "only" development dependencies which do not
affect any production users of Rackstash but merely people running the
tests.
Each flow now has an associated executor which performs all actions
(writing events, closing, reopening) asynchronously by default using a
Concurrent::SingleThreadExecutor.
This improves the responsiveness of the application by performing the
(usually) IO-bound task of writing the logs to a background thread.
By creating a flow with `synchronous: true`, all actions are run in the
calling thread as before, making the flow blocking.
With this, we also drop the ability to define conditions in the filter
itself. When adding a filter, users can still setup a condition using
the common functionality of all filters.
This takes care of edge-cases and ensures that multiple loads of
`lib/rackstash.rb` do not fail on an attempted second initialization of
the UndefinedClass.
We now support two different modes of file rotation at the same time:
* auto_reopen can be used to automatically reopen a logfile at the
original location if the file was moved or deleted from the filesystem
* rotate can be used to write to a rotate file which can be reopened /
created based on Date pattern.
The user can now decide whether they want to use an external logrotate
command or use internal rotation with Rackstash instead.
Instead of defining the specific buffering behavior on a Buffer, we can
now mark individual flows as auto_flushing or now. An auto_flushing Flow
with a buffering Buffer behaves the same as a Buffer with `buffering:
:data` would before.
This allows us to simplify the buffering logic on the Buffer. Also, we
can now use "normal" flows and auto_flushing flows on the same logger in
parallel. Each of them behaves as expected with the same unchanged logger
code.
It is thus easier to define behavior for a development or production
environment of an app since the necessary changes can all be defined on
the logger itself (through the defined flows) without having to adapt
the code which creates suitable Buffers with the Logger#with_buffer
method in any way.
With that, we can lazy-transform the Buffer to the event hash. B using
the common `.to_h` protocol, we can also support various other objects
here instead of just Buffers (including actual raw Hashes).
