BABELTRACE2-SOURCE() BABELTRACE2-SOURCE()
NAME
babeltrace2-source.ctf.lttng-live - Babeltrace 2's LTTng live source
component class
DESCRIPTION
A Babeltrace 2 source.ctf.lttng-live message iterator connects to a
local or remote LTTng (see ) relay daemon, receives
the streams of a specific tracing session, and emits corresponding
messages.
CTF streams over
LTTng live (TCP)
|
| +--------------------+
| | src.ctf.lttng-live |
'-->| |
| out @--> Sorted messages of one
+--------------------+ or more streams
More information about LTTng live is available in the LTTng
Documentation (see ).
See babeltrace2-intro(7) to learn more about the Babeltrace 2 project
and its core concepts.
A source.ctf.lttng-live component has a single output port: its message
iterator muxes (sorts) the messages from the various CTF data streams
internally.
A source.ctf.lttng-live message iterator handles the messages of one,
and only one LTTng tracing session. A single LTTng tracing session can
contain one or more traces, depending on the active tracing domains and
the configured user space buffering scheme.
The component connects to an LTTng relay daemon using the inputs
parameter. This is an array of exactly one string which is the URL of
the LTTng relay daemon to connect to.
By default, if the remote tracing session name does not exist, the
message iterator returns "try again later". This default mode makes the
message iterator never end: even if the remote tracing session is
destroyed, the message iterator keeps on waiting for a tracing session
with the same name to exist. You can change this behaviour with the
session-not-found-action initialization parameter.
Note
As of this version, you can only create one message iterator per
source.ctf.lttng-live component. This is because the LTTng live
protocol accepts at most one client per tracing session per LTTng
relay daemon.
INITIALIZATION PARAMETERS
inputs=URL [array of one string]
Use URL to connect to the LTTng relay daemon.
URL is an array of exactly one string of which the format is:
net[4]://RDHOST[:RDPORT]/host/TGTHOST/SESSION
RDHOST
LTTng relay daemon's host name or IP address.
RDPORT
LTTng relay daemon's listening port.
If not specified, the component uses the default port (5344).
TGTHOST
Target's host name or IP address.
SESSION
Name of the LTTng tracing session from which to receive data.
session-not-found-action=(continue | fail | end) [optional string]
When the message iterator does not find the specified remote
tracing session (SESSION part of the inputs parameter), do one of:
continue (default)
Keep on trying, returning "try again later" to the downstream
user until the tracing session exists.
With this action, the message iterator never ends, as the LTTng
live protocol cannot currently indicate that a tracing session
will never exist.
fail
Fail.
end
End.
PORTS
+--------------------+
| src.ctf.lttng-live |
| |
| out @
+--------------------+
Output
out
Single output port.
QUERY OBJECTS
babeltrace.support-info
See babeltrace2-query-babeltrace.support-info(7) to learn more about
this query object.
For a string input which honors the LTTng live URL format (see the
inputs parameter), the result object is 0.75.
sessions
You can query the sessions object to get a list of available LTTng
tracing sessions for a given LTTng relay daemon URL.
Parameters:
url=URL [string]
Use URL to connect to the LTTng relay daemon.
The format of URL is:
net[4]://RDHOST[:RDPORT]
RDHOST
LTTng relay daemon's host name or IP address.
RDPORT
LTTng relay daemon's listening port.
If not specified, the query operation uses the default port
(5344).
Result object (array of maps, one element for each available tracing
session):
client-count [unsigned integer]
Current number of LTTng live clients connected to the relay daemon
to receive data from this tracing session.
session-name [string]
Tracing session's name.
stream-count [unsigned integer]
Current number of CTF streams in this tracing sessions, including
the metadata streams.
target-hostname [string]
Hostname of the tracing session.
This is not necessarily the relay daemon's hostname.
timer-us [unsigned integer]
Tracing session's configured live timer's period (s) (see
lttng-create(1)).
url [string]
URL to use as the first element of the inputs parameter to connect
to the same LTTng relay daemon and receive data from this tracing
session.
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), lttng-relayd(8),
lttng-create(1)
BABELTRACE2-SOURCE()