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BABELTRACE2-QUERY-(7)      Babeltrace 2 manual     BABELTRACE2-QUERY-(7)

NAME         top - Babeltrace 2's
       support info query object

DESCRIPTION         top

       The Babeltrace 2 query object indicates,
       for a given source component class, whether or not its instance
       can handle a given input, and if so, what’s the confidence of
       this support.

       Said input can be a simple string, an existing file path, or an
       existing directory path. Components which expect some form of URI
       can handle a string input, while components which expect an
       existing file or directory can handle a file/directory path

       When the source component class’s query method replies that its
       component can handle a given input, it can also specify the name
       of a group in which to put that input. All the inputs of a given
       group, for a given component class, should be passed when
       instantiating the component class as its inputs initialization
       parameter (array of strings).

       The babeltrace2-convert(1) command queries this object from
       specific source component classes to find the most appropriate
       for a given non-option argument.

PARAMETERS         top

       input=INPUT [string]
           Check input INPUT.

           Depending on the type parameter, this is a simple string, a
           file path, or a directory path.

       type=(string | file | directory) [string]
           Input type, one of:

               input parameter is a simple string.

               input parameter is a file path.

               input parameter is a directory path.

               It is expected that the query method does not recurse
               into this directory: the result object indicates whether
               or not the component class supports this specific
               directory (input).

RESULT OBJECT         top

       The result object can be one of:

       •   A simple real value which is the weight, between 0 and 1, of
           the support by the component class for the given input.

           A weight of 0 means the input is unsupported while a weight
           of 1 means it’s fully supported. Any value in between shows
           how confident the component class is about the support of the
           given input.

       •   A map with a weight and an optional group name.

       When it’s a map, the expected entries are:

       group=GROUP-NAME [optional string]
           Put the given input into a group named GROUP-NAME for this
           component class.

           If this entry is missing, then the given input gets its own,
           unique group.

       weight=WEIGHT [real]
           Weight, between 0 and 1, of the support by the component
           class for the given input.

           The semantics are the same as when the result object is a
           simple real value.

EXAMPLES         top

   Query parameters
       Example 1. String input.

           input: net://relayd177/host/node23/active
           type: string

       Example 2. File path input.

           input: /home/user/traces/2019-08-26/
           type: file

   Result object
       Example 3. Simple weight (unique group).


       Example 4. Weight and specific group.

           group: 63a4b7e5-37f0-4254-a048-a0cff9e5b761
           weight: 0.75

       Example 5. Weight within a map (unique group).

           weight: 0.6

BUGS         top

       If you encounter any issue or usability problem, please report it
       on the Babeltrace bug tracker (see

RESOURCES         top

       The Babeltrace project shares some communication channels with
       the LTTng project (see <>).

       •   Babeltrace website (see <>)

       •   Mailing list (see <>) for support and

       •   IRC channel (see <irc://>): #lttng on

       •   Bug tracker (see

       •   Git repository (see

       •   GitHub project (see <>)

       •   Continuous integration (see

       •   Code review (see

AUTHORS         top

       The Babeltrace 2 project is the result of hard work by many
       regular developers and occasional contributors.

       The current project maintainer is Jérémie Galarneau

COPYRIGHT         top

       This query object is part of the Babeltrace 2 project.

       Babeltrace is distributed under the MIT license (see

SEE ALSO         top

       babeltrace2-intro(7), babeltrace2-query(1),

COLOPHON         top

       This page is part of the babeltrace (trace read and write
       libraries and a trace converter) project.  Information about the
       project can be found at ⟨⟩.  If
       you have a bug report for this manual page, send it to  This page was obtained from the
       project's upstream Git repository
       ⟨git://⟩ on 2021-04-01.  (At that
       time, the date of the most recent commit that was found in the
       repository was 2021-03-25.)  If you discover any rendering
       problems in this HTML version of the page, or you believe there
       is a better or more up-to-date source for the page, or you have
       corrections or improvements to the information in this COLOPHON
       (which is not part of the original manual page), send a mail to

Babeltrace 2.1.0-rc1        14 September 2019      BABELTRACE2-QUERY-(7)

Pages that refer to this page: babeltrace2-convert(1)babeltrace2-source.ctf.fs(7)babeltrace2-source.ctf.lttng-live(7)