Combining filters in boost log

Question

I use boost log and want to define a composed filter. I use boost::log::init_from_streamto read the configuration from a stream. Filtering on single conditions works fine. I can do

Filter = "%Channel% = A"

to get only log entries from channel A. I can do

Filter = "%Severity% >= warn"

to get only log entries that have a severity which is warning or above.

Here comes the question: I want to do someting like

Filter = "   (%Channel% = A AND %Severity% >= warn)
          OR (%Channel% = B AND %Severity% >= info)"

I was not able to find any documentation regarding such a combination of filters. Is there a way to do this when using boost::log::init_from_stream?

a link to the docs you use would not be remiss – sehe Apr 03 '15 at 10:03 — sehe, Apr 03 '15 at 10:03
It wasn't a long search. See my answer :) – sehe Apr 03 '15 at 10:06 — sehe, Apr 03 '15 at 10:06

score 2 · Accepted Answer · edited Apr 15 '15 at 08:48

2

I've found this documentation page which documents the grammar:

Filter and formatter parsers

filter:
    condition { op condition }

op:
    &
    and
    |
    or

condition:
    !condition
    not condition
    (filter)
    %attribute_name%
    %attribute_name% relation operand

relation:
    >
    <
    =
    !=
    >=
    <=
    begins_with
    ends_with
    contains
    matches

Using this, the example given in the question can be expressed as follows:

Filter = "(%Channel% = A & %Severity% >= warn) | (%Channel% = B & %Severity% >= info)"

edited Apr 15 '15 at 08:48

SebastianK

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answered Apr 03 '15 at 10:05

sehe

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Thank you, how could I have missed it :) – SebastianK Apr 03 '15 at 10:18
If I were to make an educated guess: you were looking for sample filter strings. They're absent :) – sehe Apr 03 '15 at 10:19
Yes, this was what I mostly was looking for :) – SebastianK Apr 03 '15 at 10:21

Combining filters in boost log

1 Answers1