Currently, a lot of interpreter runtime errors, such as an access to
an unset optional record field, cause Bro to abort with an internal
error. This is an experimental branch that turns such errors into
non-fatal runtime errors by internally raising exceptions. These are
caught upstream and processing continues afterwards.
For now, not many errors actually raise exceptions (the example above
does though). We'll need to go through them eventually and adapt the
current Internal() calls (and potentially others). More generally, at
some point we should cleanup the interpreter error handling (unifying
errors reported at parse- and runtime; and switching to exceptions for
all Expr/Stmt/Vals). But that's a larger change and left for later.
The main question for now is if this code is already helpful enough to
go into 2.0. It will quite likely prevent a number of crashes due to
script errors.
The Logger class is now in charge of reporting all errors, warnings,
informational messages, weirds, and syslogs. All other components
route their messages through the global bro_logger singleton.
The Logger class comes with these reporting methods:
void Message(const char* fmt, ...);
void Warning(const char* fmt, ...);
void Error(const char* fmt, ...);
void FatalError(const char* fmt, ...); // Terminate Bro.
void Weird(const char* name);
[ .. some more Weird() variants ... ]
void Syslog(const char* fmt, ...);
void InternalWarning(const char* fmt, ...);
void InternalError(const char* fmt, ...); // Terminates Bro.
See Logger.h for more information on these.
Generally, the reporting now works as follows:
- All non-fatal message are reported in one of two ways:
(1) At startup (i.e., before we start processing packets),
they are logged to stderr.
(2) During processing, they turn into events:
event log_message%(msg: string, location: string%);
event log_warning%(msg: string, location: string%);
event log_error%(msg: string, location: string%);
The script level can then handle them as desired.
If we don't have an event handler, we fall back to
reporting on stderr.
- All fatal errors are logged to stderr and Bro terminates
immediately.
- Syslog(msg) directly syslogs, but doesn't do anything else.
The three main types of messages can also be generated on the
scripting layer via new Log::* bifs:
Log::error(msg: string);
Log::warning(msg: string);
Log::message(msg: string);
These pass through the bro_logger as well and thus are handled in the
same way. Their output includes location information.
More changes:
- Removed the alarm statement and the alarm_hook event.
- Adapted lots of locations to use the bro_logger, including some
of the messages that were previously either just written to
stdout, or even funneled through the alarm mechanism.
- No distinction anymore between Error() and RunTime(). There's
now only one class of errors; the line was quite blurred already
anyway.
- util.h: all the error()/warn()/message()/run_time()/pinpoint()
functions are gone. Use the bro_logger instead now.
- Script errors are formatted a bit differently due to the
changes. What I've seen so far looks ok to me, but let me know
if there's something odd.
Notes:
- The default handlers for the new log_* events are just dummy
implementations for now since we need to integrate all this into
the new scripts anyway.
- I'm not too happy with the names of the Logger class and its
instance bro_logger. We now have a LogMgr as well, which makes
this all a bit confusing. But I didn't have a good idea for
better names so I stuck with them for now.
Perhaps we should merge Logger and LogMgr?
