Drains the channel by getting all elements from it until nothing is left to get.

Initializes operations logging by starting a separate thread listening for log messages on a channel which is shared with a generated reporting function using lexical closure.

The writer (:writer) should be a function taking the following arguments: id (will be used to pass a configuration key k), db (will be used to pass a database connection (a data source), if set under :db configuration key), table (will be set to a table name, if set under the :table configuration key), messages (will be set to a queue of messages to be written). If there is no :writer option given in the configuration map, the initializer will try to find one by using k with a string -writer attached (and the converted to a symbol).

The reporter (:reporter) should be a function taking the following arguments: id (will be used to pass a configuration key k), channel (will be used to pass a channel for sending messages to the listening thread), message (will be used to pass a message. The responsibility for handling the message is delegated to the writer function, with the exception that a message cannot be nil (such messages should be ignored).

A call of the reporter function is wrapped into anonymous function which closes over initialized k and channel values, providing the call with two first arguments. This new function is exposed under :fn/reporter configuration key associated by the initializer within a returned map.

So, if no :reporter nor :writer is set in configuration, and the configuration key is :amelinium.common.oplog.auth/log then the defaults would be: amelinium.common.oplog.auth/log-reporter (reporting) and amelinium.common.oplog.auth/log-writer (writing). Both must be defined.

Creates new FIFO queue. If coll is given, new queue will be initialized with elements from it.

Starts logger thread which waits for new data to be put on queue whenever there are any on communication channel (:channel/messages key of the config). If the timeout is exceeded (:timeout key) or if the queue holds more messages than a number under :buffered-max configuration key, will run the function passed under the :writer key of the configuration map to actually insert all of the accumulated messages into a database. The thread will finish its work (after draining the channel and flushing queue) when there is any value received on its kill channel (:channel/kill).

Stops the operations logger by sending a message via the given kill channel (:channel/kill configuration key) and waiting for the listening thread to finish its work.