For backward compatibility when reading values, we first check
the ZEEK-prefixed value, and if not set, then check the corresponding
BRO-prefixed value.
This also installs symlinks from "zeek" and "bro-config" to a wrapper
script that prints a deprecation warning.
The btests pass, but this is still WIP. broctl renaming is still
missing.
#239
* origin/topic/johanna/config-framework-fixes:
Fix test that fails now that options are automatically redefable.
Make options redef-able by default.
Ascii formatter: do not complain about port text.
Make parsing of booleans a little bit more lenient.
The ascii formatter already was happy to read ports in the form
"42/tcp"; however it emitted a warning message for each line.
This patch fixes this and adds a bit more testing for the existing
behavior.
Mostly trying to standardize the way tests sleep for arbitrary amounts
of time to make it easier to tell at which particular point the
unit test actually may need the timeout interval increased (or else
debugged further).
This test-case has actually revealed an interesting issue - it works as
is, but as soon as one adds a vector, one gets the fun error-message
fatal error in any: BroType::AsVectorType (any/vector) (any)
This will require a bit more digging :).
This small change allows the empty field separator to be empty. This
means that we can represent an empty list by a empty input string, which
was not possible before.
Before, an empty empty field separator meant that there is no empty
field - to get back to this behavior one now has to set the empty field
separator to a string that is guaranteed to not be part of the input
data. Note that we did not use "empty" empty field separators anywhere
and I am not aware of this being used by anyone - the new behavior seems
like it is much more useful in practice.
This also changes the config framework to interpret empty lists as...
empty, instead of interpreting them as lists that have one zero-length
element; this seems like the saner default.
The configure reader had a small bug that caused the tracking of changed
variables to be incorrect after the second update. This resulted in
change-events for unchanged variables.
The configuration framework consists of three mostly distinct parts:
* option variables
* the config reader
* the script level framework
I will describe the three elements in the following.
Internally, this commit also performs a range of changes to the Input
manager; it marks a lot of functions as const and introduces a new
ValueToVal method (which could in theory replace the already existing
one - it is a bit more powerful).
This also changes SerialTypes to have a subtype for Values, just as
Fields already have it; I think it was mostly an oversight that this was
not introduced from the beginning. This should not necessitate any code
changes for people already using SerialTypes.
option variable
===============
The option keyword allows variables to be specified as run-tine options.
Such variables cannot be changed using normal assignments. Instead, they
can be changed using Option::set. It is possible to "subscribe" to
options and be notified when an option value changes.
Change handlers can also change values before they are applied; this
gives them the opportunity to reject changes. Priorities can be
specified if there are several handlers for one option.
Example script:
option testbool: bool = T;
function option_changed(ID: string, new_value: bool): bool
{
print fmt("Value of %s changed from %s to %s", ID, testbool, new_value);
return new_value;
}
event bro_init()
{
print "Old value", testbool;
Option::set_change_handler("testbool", option_changed);
Option::set("testbool", F);
print "New value", testbool;
}
config reader
=============
The config reader provides a way to read configuration files back into
Bro. Most importantly it automatically converts values to the correct
types. This is important because it is at least inconvenient (and
sometimes near impossible) to perform the necessary type conversions in
Bro scripts themselves. This is especially true for sets/vectors.
Configuration generally look like this:
[option name][tab/spaces][new variable value]
so, for example:
testaddr 2607:f8b0:4005:801::200e
testinterval 60
testtime 1507321987
test_set a b c d erdbeerschnitzel
The reader uses the option name to look up the type that variable has in
the Bro core and automatically converts the value to the correct type.
Example script use:
type Idx: record {
option_name: string;
};
type Val: record {
option_val: string;
};
global currconfig: table[string] of string = table();
event InputConfig::new_value(name: string, source: string, id: string, value: any)
{
print id, value;
}
event bro_init()
{
Input::add_table([$reader=Input::READER_CONFIG, $source="../configfile", $name="configuration", $idx=Idx, $val=Val, $destination=currconfig, $want_record=F]);
}
Script-level config framework
=============================
The script-level framework ties these two features together and makes
them a bit more convenient to use. Configuration files can simply be
specified by placing them into Config::config_files. The framework also
creates a config.log that shows all value changes that took place.
Usage example:
redef Config::config_files += {configfile};
export {
option testbool : bool = F;
}
The file is now monitored for changes; when a change occurs the
respective option values are automatically updated and the value change
is written to config.log.
