Base class for command-line tasks: tasks that may be executed from the command-line.
Notes
-----
See :ref:`task-framework-overview` to learn what tasks are and :ref:`creating-a-command-line-task` for
more information about writing command-line tasks.
Subclasses must specify the following class variables:
- ``ConfigClass``: configuration class for your task (a subclass of `lsst.pex.config.Config`, or if your
task needs no configuration, then `lsst.pex.config.Config` itself).
- ``_DefaultName``: default name used for this task (a str).
Subclasses may also specify the following class variables:
- ``RunnerClass``: a task runner class. The default is ``TaskRunner``, which works for any task
with a run method that takes exactly one argument: a data reference. If your task does
not meet this requirement then you must supply a variant of ``TaskRunner``; see ``TaskRunner``
for more information.
- ``canMultiprocess``: the default is `True`; set `False` if your task does not support multiprocessing.
Subclasses must specify a method named ``run``:
- By default ``run`` accepts a single butler data reference, but you can specify an alternate task runner
(subclass of ``TaskRunner``) as the value of class variable ``RunnerClass`` if your run method needs
something else.
- ``run`` is expected to return its data in a `lsst.pipe.base.Struct`. This provides safety for evolution
of the task since new values may be added without harming existing code.
- The data returned by ``run`` must be picklable if your task is to support multiprocessing.
Definition at line 472 of file cmdLineTask.py.
def lsst.pipe.base.cmdLineTask.CmdLineTask.parseAndRun |
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cls, |
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args = None , |
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config = None , |
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log = None , |
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doReturnResults = False |
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) |
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Parse an argument list and run the command.
Parameters
----------
args : `list`, optional
List of command-line arguments; if `None` use `sys.argv`.
config : `lsst.pex.config.Config`-type, optional
Config for task. If `None` use `Task.ConfigClass`.
log : `lsst.log.Log`-type, optional
Log. If `None` use the default log.
doReturnResults : `bool`, optional
If `True`, return the results of this task. Default is `False`. This is only intended for
unit tests and similar use. It can easily exhaust memory (if the task returns enough data and you
call it enough times) and it will fail when using multiprocessing if the returned data cannot be
pickled.
Returns
-------
struct : `lsst.pipe.base.Struct`
Fields are:
- ``argumentParser``: the argument parser.
- ``parsedCmd``: the parsed command returned by the argument parser's
`lsst.pipe.base.ArgumentParser.parse_args` method.
- ``taskRunner``: the task runner used to run the task (an instance of `Task.RunnerClass`).
- ``resultList``: results returned by the task runner's ``run`` method, one entry per invocation.
This will typically be a list of `None` unless ``doReturnResults`` is `True`;
see `Task.RunnerClass` (`TaskRunner` by default) for more information.
Notes
-----
Calling this method with no arguments specified is the standard way to run a command-line task
from the command-line. For an example see ``pipe_tasks`` ``bin/makeSkyMap.py`` or almost any other
file in that directory.
If one or more of the dataIds fails then this routine will exit (with a status giving the
number of failed dataIds) rather than returning this struct; this behaviour can be
overridden by specifying the ``--noExit`` command-line option.
Definition at line 529 of file cmdLineTask.py.
def lsst.pipe.base.cmdLineTask.CmdLineTask.writeConfig |
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self, |
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butler, |
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clobber = False , |
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doBackup = True |
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Write the configuration used for processing the data, or check that an existing
one is equal to the new one if present.
Parameters
----------
butler : `lsst.daf.persistence.Butler`
Data butler used to write the config. The config is written to dataset type
`CmdLineTask._getConfigName`.
clobber : `bool`, optional
A boolean flag that controls what happens if a config already has been saved:
- `True`: overwrite or rename the existing config, depending on ``doBackup``.
- `False`: raise `TaskError` if this config does not match the existing config.
doBackup : bool, optional
Set to `True` to backup the config files if clobbering.
Definition at line 628 of file cmdLineTask.py.
def lsst.pipe.base.cmdLineTask.CmdLineTask.writePackageVersions |
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self, |
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butler, |
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clobber = False , |
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doBackup = True , |
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dataset = "packages" |
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Compare and write package versions.
Parameters
----------
butler : `lsst.daf.persistence.Butler`
Data butler used to read/write the package versions.
clobber : `bool`, optional
A boolean flag that controls what happens if versions already have been saved:
- `True`: overwrite or rename the existing version info, depending on ``doBackup``.
- `False`: raise `TaskError` if this version info does not match the existing.
doBackup : `bool`, optional
If `True` and clobbering, old package version files are backed up.
dataset : `str`, optional
Name of dataset to read/write.
Raises
------
TaskError
Raised if there is a version mismatch with current and persisted lists of package versions.
Notes
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Note that this operation is subject to a race condition.
Definition at line 719 of file cmdLineTask.py.
def lsst.pipe.base.cmdLineTask.CmdLineTask.writeSchemas |
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self, |
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butler, |
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clobber = False , |
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doBackup = True |
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Write the schemas returned by `lsst.pipe.base.Task.getAllSchemaCatalogs`.
Parameters
----------
butler : `lsst.daf.persistence.Butler`
Data butler used to write the schema. Each schema is written to the dataset type specified as the
key in the dict returned by `~lsst.pipe.base.Task.getAllSchemaCatalogs`.
clobber : `bool`, optional
A boolean flag that controls what happens if a schema already has been saved:
- `True`: overwrite or rename the existing schema, depending on ``doBackup``.
- `False`: raise `TaskError` if this schema does not match the existing schema.
doBackup : `bool`, optional
Set to `True` to backup the schema files if clobbering.
Notes
-----
If ``clobber`` is `False` and an existing schema does not match a current schema,
then some schemas may have been saved successfully and others may not, and there is no easy way to
tell which is which.
Definition at line 668 of file cmdLineTask.py.