NAMEDESCRIPTIONINITIALIZATION PARAMETERSPORTSQUERY OBJECTSSEE ALSO

babeltrace2-source.ctf.fs(7)

NAME

babeltrace2-source.ctf.fs — Babeltrace 2's file system CTF source component class

DESCRIPTION

A Babeltrace 2 source.ctf.fs message iterator reads one or more CTF 1.8 streams on the file system and emits corresponding messages.

CTF streams on
the file system
  |
  |   +---------------------+
  |   |      src.ctf.fs     |
  |   |                     |
  '-->|    ...5c847 | 0 | 0 @--> Stream 0 messages
      |    ...5c847 | 0 | 1 @--> Stream 1 messages
      |    ...5c847 | 0 | 2 @--> Stream 2 messages
      +---------------------+

See babeltrace2-intro(7) to learn more about the Babeltrace 2 project and its core concepts.

Input

A source.ctf.fs component opens a single logical CTF trace. A logical CTF trace contains one or more physical CTF traces. A physical CTF trace on the file system is a directory which contains:

If the logical CTF trace to handle contains more than one physical CTF trace, then all the physical CTF traces must have a trace UUID and all UUIDs must be the same. Opening more than one physical CTF trace to constitute a single logical CTF trace is needed to support LTTng’s tracing session rotation feature, for example (see lttng-rotate(1) starting from LTTng 2.11).

You specify which physical CTF traces to open and read with the inputs array parameter. Each entry in this array is the path to a physical CTF trace directory, that is, the directory directly containing the stream files.

A source.ctf.fs component does not recurse into directories to find CTF traces. However, the component class provides the babeltrace.support-info query object which indicates whether or not a given directory looks like a CTF trace directory (see babeltrace.support-info).

The component creates one output port for each logical CTF data stream. More than one physical CTF data stream file can support a single logical CTF data stream (LTTng’s trace file rotation and tracing session rotation can cause this).

Trace quirks

Many tracers produce CTF traces. A source.ctf.fs component makes some effort to support as many CTF traces as possible, even those with malformed streams.

Generally:

A source.ctf.fs component has special quirk handling for some LTTng and barectf traces, depending on the tracer’s version:

All LTTng versions
  • The component sets the monotonic clock class’s origin to the Unix epoch so that different LTTng traces are always correlatable.

    This is the equivalent of setting the force-clock-class-origin-unix-epoch parameter to true.

  • For a given data stream, for all the contiguous last packets of which the timestamp_end context field is 0, the message iterator uses the packet’s last event record’s time as the packet end message’s time.

    This is useful for the traces which lttng-crash(1) generates.

LTTng-UST up to, but excluding, 2.11.0
LTTng-modules up to, but excluding, 2.9.13
LTTng-modules from 2.10.0 to 2.10.9
  • For a given packet, the message iterator uses the packet’s last event record’s time as the packet end message’s time, ignoring the packet context’s timestamp_end field.

barectf up to, but excluding, 2.3.1
  • For a given packet, the message iterator uses the packet’s first event record’s time as the packet beginning message’s time, ignoring the packet context’s timestamp_begin field.

INITIALIZATION PARAMETERS

clock-class-offset-ns=NS [optional signed integer]

Add NS nanoseconds to the offset of all the clock classes that the component creates.

You can combine this parameter with the clock-class-offset-s parameter.

clock-class-offset-s=SEC [optional signed integer]

Add SEC seconds to the offset of all the clock classes that the component creates.

You can combine this parameter with the clock-class-offset-ns parameter.

force-clock-class-origin-unix-epoch=yes [optional boolean]

Force the origin of all clock classes that the component creates to have a Unix epoch origin, whatever the detected tracer.

inputs=DIRS [array of strings]

Open and read the physical CTF traces located in DIRS.

Each element of DIRS is the path to a physical CTF trace directory containing the trace’s stream files.

All the specified physical CTF traces must belong to the same logical CTF trace. See Input to learn more about logical and physical CTF traces.

trace-name=NAME [optional string]

Set the name of the trace object that the component creates to NAME.

PORTS

+--------------------+
|     src.ctf.fs     |
|                    |
|   ...5c847 | 0 | 1 @
|                ... @
+--------------------+

Output

A source.ctf.fs component creates one output port for each logical CTF data stream. See Input to learn more about logical and physical CTF data streams.

Each output port’s name has one of the following forms:

TRACE-ID | STREAM-CLASS-ID | STREAM-ID
TRACE-ID | STREAM-ID

The component uses the second form when the stream class ID is not available.

TRACE-ID

Trace’s UUID if available, otherwise trace’s absolute directory path.

STREAM-CLASS-ID

Stream class ID.

STREAM-ID

Stream ID if available, otherwise stream’s absolute file path.

QUERY OBJECTS

babeltrace.support-info

See babeltrace2-query-babeltrace.support-info(7) to learn more about this query object.

For a directory input which is the path to a CTF trace directory, the result object contains:

weight

0.75

group

Trace’s UUID if available, otherwise the entry does not exist.

You can leverage this query object’s group entry to assemble many physical CTF traces as a single logical CTF trace (see Input to learn more about logical and physical CTF traces). This is how the babeltrace2-convert(1) command makes it possible to specify as non-option arguments the paths to multiple physical CTF traces which belong to the same logical CTF trace and create a single source.ctf.fs component.

babeltrace.trace-infos

See babeltrace2-query-babeltrace.trace-infos(7) to learn more about this query object.

metadata-info

You can query the metadata-info object for a specific CTF trace to get its plain text metadata stream as well as whether or not it is packetized.

Parameters:

path=PATH [string]

Path to the physical CTF trace directory which contains the metadata file.

Result object (map):

is-packetized [boolean]

True if the metadata stream file is packetized.

text [string]

Plain text metadata stream.

SEE ALSO

babeltrace2-intro(7), babeltrace2-plugin-ctf(7), lttng-crash(1)