NAME

babeltrace2-query - Query an object from a Babeltrace 2 component class

SYNOPSIS

babeltrace2 [GENERAL OPTIONS] query [--params=PARAMS]
             COMP-CLS-TYPE.PLUGIN-NAME.COMP-CLS-NAME OBJECT

DESCRIPTION

The query command queries the object named OBJECT from the component class named COMP-CLS-NAME of the type COMP-CLS-TYPE found in the Babeltrace 2 plugin named PLUGIN-NAME and prints the results.
 
See babeltrace2-intro(7) to learn more about the Babeltrace 2 project and its core concepts.
 
The available values for COMP-CLS-TYPE are:
source, src
Source component class.
filter, flt
Filter component class.
sink
Sink component class.
 
The exact object names and the parameters that a given component class expects are described in its own documentation. babeltrace2-help(1) can generally provide this information.
 
You can use the --params option to pass parameters to the component class’s query operation.
 
The output of the query command can look like YAML (see <https://yaml.org/>), but it’s not guaranteed to be YAML-compliant.
 
See “EXAMPLES” for usage examples.

OPTIONS

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
Do not search for plugins in $HOME/.local/lib/babeltrace2/plugins.
--omit-system-plugin-path
Do not search for plugins in /usr/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.

Query parameters

-p PARAMS, --params=PARAMS
Set the query parameters to PARAMS.
 
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.
 

Command information

-h, --help
Show the command’s help and quit.

EXAMPLES

Example 1. Query the available tracing sessions of a local LTTng relay daemon.
 
$ babeltrace2 query src.ctf.lttng-live sessions \
                    --params='url="net://localhost"'
Example 2. Query the metadata info (includes the decoded plain text) of a CTF trace located on the local file system.
 
$ babeltrace2 query src.ctf.fs metadata-info \
                    --params='path="/path/to/trace"'
Example 3. Query the trace infos of a CTF trace located on the local file system.
 
$ babeltrace2 query src.ctf.fs babeltrace.trace-infos \
                    --params='path="/path/to/trace"'
Example 4. Query some object from a sink component class without parameters.
 
$ babeltrace2 query sink.my-plugin.my-sink some-object

ENVIRONMENT VARIABLES

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’s 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 Babeltrace 2 library’s initial log level to be LVL.
 
If this environment variable is set, 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, 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, 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 babeltrace2 CLI’s log level to be LVL.
 
If this environment variable is set, 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.

FILES

$HOME/.local/lib/babeltrace2/plugins
User plugin directory.
/usr/lib/babeltrace2/plugins
System plugin directory.
/usr/lib/babeltrace2/plugin-providers
System plugin provider directory.

EXIT STATUS

0 on success, 1 otherwise.

BUGS

If you encounter any issue or usability problem, please report it on the Babeltrace bug tracker (see <https://bugs.lttng.org/projects/babeltrace>).

RESOURCES

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: [email protected]
 
•IRC channel (see <irc://irc.oftc.net/lttng>): #lttng on irc.oftc.net
 
 
 
•GitHub project (see <https://github.com/efficios/babeltrace>)
 
•Continuous integration (see <https://ci.lttng.org/view/Babeltrace/>)
 

AUTHORS

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:[email protected]>. This command is part of the Babeltrace 2 project.
 
Babeltrace is distributed under the MIT license (see <https://opensource.org/licenses/MIT>).

SEE ALSO

babeltrace2-intro(7), babeltrace2(1)

Recommended readings

Pages related to babeltrace2-query you should read also:
babeltrace2-convert(1) babeltrace2-help(1) babeltrace2-intro(7) babeltrace2(1)

Questions & Answers

Helpful answers and articles about babeltrace2-query you may found on these sites:
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