* origin/topic/bernhard/log-threads:
typo
fix CreateBackend function - the way that the right backend was chosen & backends were initialized did not make sense...
backend does not need friend access to manager
move Value and Field from the logging namespace to the threading namespace, because other modules using threading will need them.
send enum instead of string
memleak fix.
make logging framework send the protocol to the writer.
- Data queued at termination wasn't written out completely.
- Fixed some race conditions.
- Fixing IOSource integration.
- Fixing setting thread names on Linux.
- Fixing minor leaks.
All tests now pass for me on Linux in debug and non-debug compiles.
Remaining TODOs:
- Needs leak check.
- Test on MacOS and FreeBSD.
- More testing:
- High volume traffic.
- Different platforms.
Send protocol type to log writers - the ascii writer simply ignores this, but the input reader needs support for this.
Conflicts:
src/LogMgr.h
src/logging/Manager.cc
This is based on Gilbert's code but I ended up refactoring it quite a
bit. That's why I didn't do a direct merge but started with a new
branch and copied things over to adapt. It looks quite a bit different
now as I tried to generalize things a bit more to also support the
Input Framework.
The larger changes code are:
- Moved all logging code into subdirectory src/logging/. Code
here is in namespace "logging".
- Moved all threading code into subdirectory src/threading/. Code
here is in namespace "threading".
- Introduced a central thread manager that tracks threads and is
in charge of termination and (eventually) statistics.
- Refactored logging independent threading code into base classes
BasicThread and MsgThread. The former encapsulates all the
pthread code with simple start/stop methods and provides a
single Run() method to override.
The latter is derived from BasicThread and adds bi-directional
message passing between main and child threads. The hope is that
the Input Framework can reuse this part quite directly.
- A log writer is now split into a general WriterFrontend
(LogEmissary in Gilbert's code) and a type-specific
WriterBackend. Specific writers are implemented by deriving from
the latter. (The plugin interface is almost unchanged compared
to the 2.0 version.).
Frontend and backend communicate via MsgThread's message
passing.
- MsgThread (and thus WriterBackend) has a Heartbeat() method that
a thread can override to execute code on a regular basis. It's
triggered roughly once a second by the main thread.
- Integration into "the rest of Bro". Threads can send messages to
the reporter and do debugging output; they are hooked into the
I/O loop for sending messages back; and there's a new debugging
stream "threading" that logs, well, threading activity.
This all seems to work for the most part, but it's not done yet.
TODO list:
- Not all tests pass yet. In particular, diffs for the external
tests seem to indicate some memory problem (no crashes, just an
occasional weird character).
- Only tested in --enable-debug mode.
- Only tested on Linux.
- Needs leak check.
- Each log write is currently a single inter-thread message. Bring
Gilbert's bulk writes back.
- Code needs further cleanup.
- Document the class API.
- Document the internal structure of the logging framework.
- Check for robustness: live traffic, aborting, signals, etc.
- Add thread statistics to profile.log (most of the code is there).
- Customize the OS-visible thread names on platforms that support it.
