lsstDebug¶

lsstDebug is a tool to help with live debugging of Science Pipelines packages. Many Tasks are configured to show debugging information when certain parameters are set in lsstDebug, for example display might show some Task-specific images and plots.

Contributing¶

lsstDebug is developed at https://github.com/lsst/base. You can find Jira issues for this module under the base component.

Using lsstDebug to control debugging output¶

The lsstDebug module is used to turn on debugging output and plots without changing the code being executed. For example, the variable lsstDebug.Info("lsst.meas.astrom.astrometry").debug is used to control debugging output from the lsst.meas.astrom.astrometry module.

You may interrogate lsstDebug for any string in sys.modules, i.e. for the __name__ of any package that has been imported; for example, if the lsst.meas.algorithms package is loaded then lsstDebug.Info("lsst.meas.algorithms").parameter will return False unless parameter has been set to True elsewhere.

The convention is that the name (e.g. lsst.meas.astrom.astrometry) is the __name__ of the module, so that in astrometry.py you can check whether display was set like this:

import lsstDebug

print(lsstDebug.Info(__name__).display)

which will print False unless lsstDebug.Info(__name__).display has somehow been set to True.

You can use this to turn on debug parameters in specific packages, by creating a debug.py file that is available in the PYTHONPATH:

import lsstDebug

def DebugInfo(name):
    di = lsstDebug.getInfo(name)  # N.b. lsstDebug.Info(name) would call us recursively
    if name == "debugExample":
        di.display = True

    return di


lsstDebug.Info = DebugInfo

Then, if you have a debugExample.py module like this:

import lsstDebug

print("display is", lsstDebug.Info(__name__).display)

Running without importing debug.py will result in display==False:

$ python -c "import foo"
display is False

while importing debug.py will show:

$ python -c "import debug; import foo"
display is True

The pipetask run command line interface supports a flag --debug to import debug.py from your PYTHONPATH.

Python API reference¶

lsstDebug Module¶

Functions¶

getDebugFrame(debugDisplay, name)

Attempt to extract a frame for displaying a product called name from the debugDisplay variable.

Classes¶

Info(modname)

An object cognisant of debugging parameters appropriate for module modname.

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