Matterhorn.State.Setup.Threads.Logging

This module implements the logging thread. This thread can optionally write logged messages to an output file. When the thread is created, it is initially not writing to any output file and must be told to do so by issuing a LogCommand using the LogManager interface.

The logging thread has an internal bounded log message buffer. Logged messages always get written to the buffer (potentially evicting old messages to maintain the size bound). If the thread is also writing to a file, such messages also get written to the file. When the thread begins logging to a file, the entire buffer is written to the file so that a historical snapshot of log activity can be saved in cases where logging is turned on at runtime only once a problematic behavior is observed.

Documentation

newLogManager :: BChan MHEvent -> Int -> IO LogManager

Create a new log manager and start a logging thread for it.

shutdownLogManager :: LogManager -> IO ()

Shuts down the log manager and blocks until shutdown is complete.