BABELTRACE2-SINK.(7) Babeltrace 2 manual BABELTRACE2-SINK.(7)
NAME
babeltrace2-sink.ctf.fs - Babeltrace 2's file system CTF sink component
class
DESCRIPTION
A Babeltrace 2 sink.ctf.fs component writes the messages it consumes to
one or more CTF (see ) 1.8 traces on the file
system.
+-------------+
| sink.ctf.fs |
| +--> CTF trace(s) on
Messages -->@ in | the file system
+-------------+
See babeltrace2-intro(7) to learn more about the Babeltrace 2 project
and its core concepts.
A sink.ctf.fs component does not merge traces: it writes the messages
of different input traces to different output traces.
Special trace IR to CTF translations
A sink.ctf.fs component makes a best effort to write CTF traces that
are semantically equivalent to the input traces. As of this version,
the component writes CTF 1.8 traces, so the following field class
translations can occur:
o The component translates a boolean field class to a CTF unsigned
8-bit integer field class.
The unsigned integer field's value is 0 when the boolean field's
value is false and 1 when the boolean field's value is true.
o The component translates a bit array field to a CTF unsigned
integer field class having the same length.
o The component translates an option field class to a CTF variant
field class where the options are an empty structure field class
and the optional field class itself.
The empty structure field is selected when the option field has no
field.
In all the cases above, the component adds a comment in the metadata
stream, above the field class, to indicate that a special translation
occurred.
Input message constraints
Because of limitations in CTF 1.8 regarding how discarded events and
packets are encoded:
o If a stream class supports discarded events and the ignore-
discarded-events parameter is NOT true:
o The stream class must support packets.
o Discarded events messages must have times.
o Any discarded events message must occur between a packet end
and a packet beginning message.
o The beginning time of a discarded events message must be the
same as the time of the last packet end message.
o The end time of a discarded events message must be the same as
the time of the next packet end message.
o Time ranges of discarded events messages must not overlap.
o If a stream class supports discarded packets and the ignore-
discarded-packets parameter is NOT true:
o The stream class must support packets.
o Discarded packets messages must have times.
o The beginning time of a discarded events message must be the
same as the time of the last packet end message.
o The end time of a discarded events message must be the same as
the time of the next packet beginning message.
o Time ranges of discarded packets messages must not overlap.
The messages which a source.ctf.fs component creates satisfy all the
requirements above.
If a discarded events or packets message has no events/packets count,
the sink.ctf.fs component adds 1 to the corresponding CTF stream's
counter.
Alignment and byte order
A sink.ctf.fs component always aligns data fields as such:
Integer fields with a size which is not a multiple of 8
1-bit.
All other scalar fields (integer, enumeration, real, string)
8-bit.
The component writes fields using the machine's native byte order. As
of this version, there's no way to force a custom byte order.
Output path
The path of a CTF trace is the directory which directly contains the
metadata and data stream files.
The current strategy to build a path in which to write the streams of a
given input trace is, in this order:
1. If the assume-single-trace parameter is true, then the output trace
path to use for the single input trace is the directory specified
by the path parameter.
2. If the component recognizes the input trace as an LTTng (2.11 or
greater) trace, then it checks specific trace environment values to
build a trace path relative to the directory specified by the path
parameter:
Linux kernel domain
HOST/SNAME-STIME/kernel
User space domain, per-UID buffering
HOST/SNAME-STIME/ust/uid/UID/ARCHW-bit
User space domain, per-PID buffering
HOST/SNAME-STIME/ust/pid/PNAME-PID-PTIME
With:
HOST
Target's hostname.
SNAME
Tracing session name.
STIME
Tracing session creation date/time.
UID
User ID.
ARCHW
Architecture's width (32 or 64).
PNAME
Process name.
PID
Process ID.
PTIME
Process's date/time.
3. If the input trace has a name, then the component sanitizes this
name and uses it as a relative path to the directory specified by
the path parameter.
The trace name sanitization operation:
o Replaces . subdirectories with _.
o Replaces .. subdirectories with __.
o Removes any trailing / character.
4. The component uses the subdirectory trace relative to the directory
specified by the path parameter.
In all the cases above, if the effective output trace path already
exists on the file system, the component appends a numeric suffix to
the name of the last subdirectory. The suffix starts at 0 and
increments until the path does not exist.
INITIALIZATION PARAMETERS
assume-single-trace=yes [optional boolean]
Assume that the component only receives messages related to a
single input trace.
This parameter affects how the component builds the output trace
path (see "Output path").
ignore-discarded-events=yes [optional boolean]
Ignore discarded events messages.
ignore-discarded-packets=yes [optional boolean]
Ignore discarded packets messages.
path=PATH [string]
Base output path.
See "Output path" to learn how the component uses this parameter to
build the output path for a given input trace.
quiet=yes [optional boolean]
Do not write anything to the standard output.
PORTS
+-------------+
| sink.ctf.fs |
| |
@ in |
+-------------+
Input
in
Single input port.
BUGS
If you encounter any issue or usability problem, please report it on
the Babeltrace bug tracker (see
).
RESOURCES
The Babeltrace project shares some communication channels with the
LTTng project (see ).
o Babeltrace website (see )
o Mailing list (see ) for support and
development: lttng-dev@lists.lttng.org
o IRC channel (see ): #lttng on
irc.oftc.net
o Bug tracker (see )
o Git repository (see )
o GitHub project (see )
o Continuous integration (see
)
o Code review (see )
AUTHORS
The Babeltrace 2 project is the result of hard work by many regular
developers and occasional contributors.
The current project maintainer is Jeremie Galarneau
.
COPYRIGHT
This component class is part of the Babeltrace 2 project.
Babeltrace is distributed under the MIT license (see
).
SEE ALSO
babeltrace2-intro(7), babeltrace2-plugin-ctf(7)
Babeltrace 2.0.4 14 September 2019 BABELTRACE2-SINK.(7)