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NAME | SYNOPSIS | DESCRIPTION | OPTIONS | EXAMPLES | ENVIRONMENT VARIABLES | FILES | EXIT STATUS | BUGS | RESOURCES | AUTHORS | COPYRIGHT | SEE ALSO | COLOPHON |
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BABELTRACE2-RUN(1) Babeltrace 2 manual BABELTRACE2-RUN(1)
babeltrace2-run - Create a Babeltrace 2 trace processing graph and
run it
babeltrace2 [GENERAL OPTIONS] run [--retry-duration=TIME-US]
[--allowed-mip-versions=VERSION]
--connect=CONN-RULE... COMPONENTS
The run command creates a Babeltrace 2 trace processing graph and
runs it.
See babeltrace2-intro(7) to learn more about the Babeltrace 2
project and its core concepts.
The run command dynamically loads Babeltrace 2 plugins which
supply component classes. With the run command, you specify which
component classes to instantiate as components and how to connect
them.
The steps to write a babeltrace2 run command line are:
1. Specify which component classes to instantiate as components
with many --component options and how to configure them.
This is the COMPONENTS part of the synopsis. See “Create
components” to learn more.
2. Specify how to connect components together with one or more
--connect options.
See “Connect components” to learn more.
Note
The babeltrace2-convert(1) command is a specialization of the
run command for the very common case of converting one or more
traces: it generates a run command line and executes it. You
can use its --run-args or --run-args-0 option to make it print
the equivalent run command line instead.
Create components
To create a component, use the --component option. This option
specifies:
• The name of the component, unique amongst all the component
names of the trace processing graph.
• The type of the component class to instantiate: source,
filter, or sink.
• The name of the plugin in which to find the component class to
instantiate.
• The name of the component class to instantiate.
Use the --component option multiple times to create multiple
components. You can instantiate the same component class multiple
times as different components.
At any point in the command line, the --base-params sets the
current base initialization parameters and the --reset-base-params
resets them. When you specify a --component option, its initial
initialization parameters are a copy of the current base
initialization parameters.
Immediately following a --component option on the command line,
the created component is known as the current component (until the
next --component option).
The --params=PARAMS option adds parameters to the initialization
parameters of the current component. If PARAMS contains a key
which exists in the initialization parameters of the current
component, then this parameter is replaced.
Connect components
The components which you create from component classes with the
--component option (see “Create components”) add input and output
ports depending on their type. An output port is from where
messages, like trace events, are sent. An input port is where
messages are received. For a given component, each port has a
unique name.
The purpose of the run command is to create a trace processing
graph, that is, to know which component ports to connect together.
The command achieves this with the help of the connection rules
that you provide with one or more --connect=CONN-RULE options.
The format of CONN-RULE is:
UP-COMP-PAT[.UP-PORT-PAT]:DOWN-COMP-PAT[.DOWN-PORT-PAT]
UP-COMP-PAT
Upstream component name pattern.
UP-PORT-PAT
Upstream (output) port name pattern.
DOWN-COMP-PAT
Downstream component name pattern.
DOWN-PORT-PAT
Downstream (input) port name pattern.
When a source or filter component adds a new output port within
the processing graph, the run command does the following to find
an input port to connect it to:
For each connection rule (--connect options, in order):
If the component name of the output port matches UP-COMP-PAT and the
output port name matches UP-PORT-PAT:
For each component COMP in the trace processing graph:
If the name of COMP matches DOWN-COMP-PAT:
Select the first input port of COMP of which the name matches
DOWN-PORT-PAT, or fail with no match.
No possible connection: fail with no match.
UP-COMP-PAT, UP-PORT-PAT, DOWN-COMP-PAT, and DOWN-PORT-PAT are
globbing patterns where only the wildcard character, *, is
special: it matches zero or more characters. You must escape the
*, ?, [, ., :, and \ characters with \.
When you don’t specify UP-PORT-PAT or DOWN-PORT-PAT, they’re
equivalent to *.
You can leverage this connection mechanism to specify fallbacks
with a careful use of wildcards, as the order of the --connect
options on the command line is significant. For example:
--connect='A.out*:B.in*' --connect=A:B --connect='*:C'
With those connection rules, the run command connects:
• Any output port of which the name starts with out of component
A to the first input port of which the name starts with in of
component B.
• Any other output port of component A to the first available
input port of component B.
• Any other output port (of any component except A) to the first
available input port of component C.
The run command fails when it cannot find an input port to which
to connect a given output port using the provided connection
rules.
See “EXAMPLES” for more examples.
General
You can use those options before the command name.
See babeltrace2(1) for more details.
-d, --debug
Legacy option: this is equivalent to --log-level=TRACE.
-l LVL, --log-level=LVL
Set the log level of all known Babeltrace 2 loggers to LVL.
--omit-home-plugin-path
Don’t search for plugins in
$HOME/.local/lib/babeltrace2/plugins.
--omit-system-plugin-path
Don’t search for plugins in
/usr/local/lib/babeltrace2/plugins.
--plugin-path=PATH[:PATH]...
Add PATH to the list of paths in which plugins can be found.
-v, --verbose
Legacy option: this is equivalent to --log-level=INFO.
Component creation
See “Create components” for more details.
-b PARAMS, --base-params=PARAMS
Set the current base parameters to PARAMS.
You can reset the current base parameters with the --reset-
base-params option.
See the --params option for the format of PARAMS.
-c NAME:COMP-CLS-TYPE.PLUGIN-NAME.COMP-CLS-NAME,
--component=NAME:COMP-CLS-TYPE.PLUGIN-NAME.COMP-CLS-NAME
Create a component named NAME from the component class of type
COMP-CLS-TYPE named COMP-CLS-NAME found in the plugin named
PLUGIN-NAME, and set it as the current component.
The available values for TYPE are:
source, src
Source component class.
filter, flt
Filter component class.
sink
Sink component class.
The initial initialization parameters of this component are
copied from the current base initialization parameters (see
the --base-params option).
-l LVL, --log-level=LVL
Set the log level of the current component to LVL.
The available values for LVL are:
NONE, N
Logging is disabled.
FATAL, F
Severe errors that lead the execution to abort
immediately.
This level should be enabled in production.
ERROR, E
Errors that might still allow the execution to continue.
Usually, once one or more errors are reported at this
level, the application, plugin, or library won’t perform
any more useful task, but it should still exit cleanly.
This level should be enabled in production.
WARN, WARNING, W
Unexpected situations which still allow the execution to
continue.
This level should be enabled in production.
INFO, I
Informational messages that highlight progress or
important states of the application, plugins, or library.
This level can be enabled in production.
DEBUG, D
Debugging information, with a higher level of details than
the TRACE level.
This level should NOT be enabled in production.
TRACE, T
Low-level debugging context information.
This level should NOT be enabled in production.
-p PARAMS, --params=PARAMS
Add PARAMS to the initialization parameters of the current
component.
If PARAMS contains a key which exists in the initialization
parameters of the current component, then replace the
parameter.
The format of PARAMS is a comma-separated list of NAME=VALUE
assignments:
NAME=VALUE[,NAME=VALUE]...
NAME
Parameter name (C identifier plus the :, ., and -
characters).
VALUE
One of:
• null, nul, NULL: null value.
• true, TRUE, yes, YES: true boolean value.
• false, FALSE, no, NO: false boolean value.
• Binary (0b prefix), octal (0 prefix), decimal, or
hexadecimal (0x prefix) unsigned (with + prefix) or
signed 64-bit integer.
• Double precision floating point number (scientific
notation is accepted).
• Unquoted string with no special characters, and not
matching any of the null and boolean value symbols
above.
• Double-quoted string (accepts escape characters).
• Array, formatted as an opening [, a comma-separated
list of VALUE, and a closing ].
• Map, formatted as an opening {, a comma-separated list
of NAME=VALUE assignments, and a closing }.
You may put whitespaces around the individual =
(assignment), , (separator), [ (array beginning), ] (array
end), { (map beginning), and } (map end) characters.
Example:
--params='many=null, fresh=yes, condition=false, squirrel=-782329,
play=+23, observe=3.14, simple=beef,
needs-quotes="some string",
escape.chars-are:allowed="a \" quote",
things=[1, "hello", 2.71828],
frog={slow=2, bath=[bike, 23], blind=NO}'
Important
Like in the example above, make sure to single-quote the
whole argument when you run this command from a shell, as
it can contain many special characters.
-r, --reset-base-params
Reset the current base parameters.
You can set the current base parameters with the --base-params
option.
Component connection
-x CONN-RULE, --connect=CONN-RULE
Add the connection rule CONN-RULE.
The format of CONN-RULE is:
UP-COMP-PAT[.UP-PORT-PAT]:DOWN-COMP-PAT[.DOWN-PORT-PAT]
UP-COMP-PAT
Upstream component name pattern.
UP-PORT-PAT
Upstream (output) port name pattern.
DOWN-COMP-PAT
Downstream component name pattern.
DOWN-PORT-PAT
Downstream (input) port name pattern.
See “Connect components” to learn more.
Graph configuration
-m VERSION, --allowed-mip-versions=VERSION
Only allow the graph to honour version VERSION (0 or 1) of the
Message Interchange Protocol (MIP) instead of allowing both
versions.
--retry-duration=TIME-US
Set the duration of a single retry to TIME-US µs when a sink
component reports "try again later" (busy network or file
system, for example).
Default: 100000 (100 ms).
Command information
-h, --help
Show the command help and quit.
Example 1. Create a single-port source component and a single-port
sink component and connect them.
$ babeltrace2 run --component=A:src.plug.my-src \
--component=B:sink.plug.my-sink \
--connect=A:B
Possible resulting graph:
+-----------------+ +-------------------+
| src.plug.my-src | | sink.plug.my-sink |
| [A] | | [B] |
| | | |
| out @--->@ in |
+-----------------+ +-------------------+
Example 2. Use the --params option to set the initialization
parameters of the current component.
In this example, the --params option only applies to component
the-source.
$ babeltrace2 run --component=the-source:src.my-plugin.my-src \
--params=offset=123,flag=true \
--component=the-sink:sink.my-plugin.my-sink \
--connect=the-source:the-sink
Example 3. Use the --base-params and --reset-base-params options
to set and reset the current base initialization parameters.
In this example, the effective initialization parameters of the
created components are:
Component A
offset=1203, flag=false
Component B
offset=1203, flag=true, type=event
Component C
ratio=0.25
$ babeltrace2 run --base-params=offset=1203,flag=false \
--component=A:src.plugin.compcls \
--component=B:flt.plugin.compcls \
--params=flag=true,type=event \
--reset-base-params \
--component=C:sink.plugin.compcls \
--params=ratio=0.25 \
--connect=A:B --connect=B:C
Example 4. Specify a component connection fallback rule.
In this example, any A output port of which the name starts with
foo is connected to a B input port of which the name starts with
nin. Any other A output port is connected to a B input port of
which the name starts with oth.
The order of the --connect options is important here: the opposite
order would create a system in which the first rule is always
satisfied, and any A output port, whatever its name, would be
connected to a B input port with a name that starts with oth.
$ babeltrace2 run --component=A:src.plug.my-src \
--component=B:sink.plug.my-sink \
--connect='A.foo*:B:nin*' --connect='A:B.oth*'
Possible resulting graph:
+-----------------+ +-------------------+
| src.plug.my-src | | sink.plug.my-sink |
| [A] | | [B] |
| | | |
| foot @--->@ nine |
| foodies @--->@ ninja |
| some-port @--->@ othello |
| hello @--->@ other |
+-----------------+ +-------------------+
Babeltrace 2 library
BABELTRACE_EXEC_ON_ABORT=CMDLINE
Execute the command line CMDLINE, as parsed like a UNIX 98
shell, when any part of the Babeltrace 2 project unexpectedly
aborts.
The application only aborts when the executed command returns,
ignoring its exit status.
This environment variable is ignored when the application has
the setuid or the setgid access right flag set.
BABELTRACE_TERM_COLOR=(AUTO | NEVER | ALWAYS)
Force the terminal color support for the babeltrace2(1)
program and the project plugins.
The available values are:
AUTO
Only emit terminal color codes when the standard output
and error streams are connected to a color-capable
terminal.
NEVER
Never emit terminal color codes.
ALWAYS
Always emit terminal color codes.
BABELTRACE_TERM_COLOR_BRIGHT_MEANS_BOLD=0
Set to 0 to emit SGR (see
<https://en.wikipedia.org/wiki/ANSI_escape_code>) codes 90
to 97 for bright colors instead of bold (SGR code 1) and
standard color codes (SGR codes 30 to 37).
BABELTRACE_PLUGIN_PATH=PATHS
Set the list of directories, in order, in which dynamic
plugins can be found before other directories are considered
to PATHS (colon-separated, or semicolon on Windows).
LIBBABELTRACE2_DISABLE_PYTHON_PLUGINS=1
Disable the loading of any Babeltrace 2 Python plugin.
LIBBABELTRACE2_INIT_LOG_LEVEL=LVL
Force the initial log level of the Babeltrace 2 library to be
LVL.
If this environment variable is set, then it overrides the log
level set by the --log-level option for the Babeltrace 2
library logger.
The available values for LVL are:
NONE, N
Logging is disabled.
FATAL, F
Severe errors that lead the execution to abort
immediately.
This level should be enabled in production.
ERROR, E
Errors that might still allow the execution to continue.
Usually, once one or more errors are reported at this
level, the application, plugin, or library won’t perform
any more useful task, but it should still exit cleanly.
This level should be enabled in production.
WARN, WARNING, W
Unexpected situations which still allow the execution to
continue.
This level should be enabled in production.
INFO, I
Informational messages that highlight progress or
important states of the application, plugins, or library.
This level can be enabled in production.
DEBUG, D
Debugging information, with a higher level of details than
the TRACE level.
This level should NOT be enabled in production.
TRACE, T
Low-level debugging context information.
This level should NOT be enabled in production.
LIBBABELTRACE2_NO_DLCLOSE=1
Make the Babeltrace 2 library leave any dynamically loaded
modules (plugins and plugin providers) open at exit. This can
be useful for debugging purposes.
LIBBABELTRACE2_PLUGIN_PROVIDER_DIR=DIR
Set the directory from which the Babeltrace 2 library
dynamically loads plugin provider shared objects to DIR.
If this environment variable is set, then it overrides the
default plugin provider directory.
Babeltrace 2 Python bindings
BABELTRACE_PYTHON_BT2_LOG_LEVEL=LVL
Force the Babeltrace 2 Python bindings log level to be LVL.
If this environment variable is set, then it overrides the log
level set by the --log-level option for the Python bindings
logger.
The available values for LVL are:
NONE, N
Logging is disabled.
FATAL, F
Severe errors that lead the execution to abort
immediately.
This level should be enabled in production.
ERROR, E
Errors that might still allow the execution to continue.
Usually, once one or more errors are reported at this
level, the application, plugin, or library won’t perform
any more useful task, but it should still exit cleanly.
This level should be enabled in production.
WARN, WARNING, W
Unexpected situations which still allow the execution to
continue.
This level should be enabled in production.
INFO, I
Informational messages that highlight progress or
important states of the application, plugins, or library.
This level can be enabled in production.
DEBUG, D
Debugging information, with a higher level of details than
the TRACE level.
This level should NOT be enabled in production.
TRACE, T
Low-level debugging context information.
This level should NOT be enabled in production.
CLI
BABELTRACE_CLI_LOG_LEVEL=LVL
Force the log level of the log level babeltrace2 CLI to be
LVL.
If this environment variable is set, then it overrides the log
level set by the --log-level option for the CLI logger.
The available values for LVL are:
NONE, N
Logging is disabled.
FATAL, F
Severe errors that lead the execution to abort
immediately.
This level should be enabled in production.
ERROR, E
Errors that might still allow the execution to continue.
Usually, once one or more errors are reported at this
level, the application, plugin, or library won’t perform
any more useful task, but it should still exit cleanly.
This level should be enabled in production.
WARN, WARNING, W
Unexpected situations which still allow the execution to
continue.
This level should be enabled in production.
INFO, I
Informational messages that highlight progress or
important states of the application, plugins, or library.
This level can be enabled in production.
DEBUG, D
Debugging information, with a higher level of details than
the TRACE level.
This level should NOT be enabled in production.
TRACE, T
Low-level debugging context information.
This level should NOT be enabled in production.
BABELTRACE_CLI_WARN_COMMAND_NAME_DIRECTORY_CLASH=0
Disable the warning message which babeltrace2-convert(1)
prints when you convert a trace with a relative path that’s
also the name of a babeltrace2 command.
BABELTRACE_DEBUG=1
Legacy variable: equivalent to setting the --log-level option
to TRACE.
BABELTRACE_VERBOSE=1
Legacy variable: equivalent to setting the --log-level option
to INFO.
$HOME/.local/lib/babeltrace2/plugins
User plugin directory.
/usr/local/lib/babeltrace2/plugins
System plugin directory.
/usr/local/lib/babeltrace2/plugin-providers
System plugin provider directory.
0 on success, 1 otherwise.
If you encounter any issue or usability problem, please report it
on the Babeltrace bug tracker (see
<https://bugs.lttng.org/projects/babeltrace>).
The Babeltrace project shares some communication channels with the
LTTng project (see <https://lttng.org/>).
• Babeltrace website (see <https://babeltrace.org/>)
• Mailing list (see <https://lists.lttng.org>) for support and
development: lttng-dev@lists.lttng.org
• IRC channel (see <irc://irc.oftc.net/lttng>): #lttng on
irc.oftc.net
• Bug tracker (see <https://bugs.lttng.org/projects/babeltrace>)
• Git repository (see
<https://git.efficios.com/?p=babeltrace.git>)
• GitHub project (see <https://github.com/efficios/babeltrace>)
• Continuous integration (see
<https://ci.lttng.org/view/Babeltrace/>)
• Code review (see
<https://review.lttng.org/q/project:babeltrace>)
The Babeltrace 2 project is the result of hard work by many
regular developers and occasional contributors.
The current project maintainer is Jérémie Galarneau
<mailto:jeremie.galarneau@efficios.com>.
This command is part of the Babeltrace 2 project.
Babeltrace is distributed under the MIT license (see
<https://opensource.org/licenses/MIT>).
babeltrace2-intro(7), babeltrace2(1), babeltrace2-convert(1)
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 ⟨http://www.efficios.com/babeltrace⟩. If
you have a bug report for this manual page, send it to
lttng-dev@lists.lttng.org. This page was obtained from the
project's upstream Git repository
⟨git://git.efficios.com/babeltrace.git⟩ on 2025-08-11. (At that
time, the date of the most recent commit that was found in the
repository was 2025-06-25.) 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
man-pages@man7.org
Babeltrace 2.2.0rc1 14 September 2019 BABELTRACE2-RUN(1)
Pages that refer to this page: babeltrace2(1), babeltrace2-convert(1), babeltrace2-intro(7)
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HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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