python.Debugging Namespace Reference

Classes
class	DbgStage

Functions
	hookDebugger ()
	hookStrace (out=None)
	allowPtrace ()
	dumpPythonProfile (filename)
	traceExecution (script, level)

Variables
str	__doc__

Function Documentation

allowPtrace()

python.Debugging.allowPtrace

(

)

On kernels with Yama enabled, ptrace may not work by default on processes
which are not decendants of the tracing process.  Among other things, that
causes the way we attach the debugger to fail.  However, we can disable this
on a per-process basis.  Do that here.

See https://www.kernel.org/doc/Documentation/security/Yama.txt and prctl(2).

Definition at line 68 of file Debugging.py.

def allowPtrace():
    """On kernels with Yama enabled, ptrace may not work by default on processes
which are not decendants of the tracing process.  Among other things, that
causes the way we attach the debugger to fail.  However, we can disable this
on a per-process basis.  Do that here.
 
See https://www.kernel.org/doc/Documentation/security/Yama.txt and prctl(2).
"""
 
    # First test to see if ptrace restrictions are enabled.
    import os
    # Return if this kernel does not support ptrace restrictions.
    if not os.path.exists ('/proc/sys/kernel/yama/ptrace_scope'): return
 
    # Return if ptrace restrictions are disabled.
    with open('/proc/sys/kernel/yama/ptrace_scope') as f:
        if f.readline().strip() == '0':
            return
 
    # Use prctl to try to enable ptrace.
    from ctypes import CDLL
    libc = CDLL("libc.so.6")
    # Args are PTRACE_SET_PTRACER (4HYama) and
    # PR_SET_PTRACER_ANY ((unsigned long)-1).
    libc.prctl (0x59616d61, 0xffffffffffffffff)
 
    return
 
 

dumpPythonProfile()

python.Debugging.dumpPythonProfile

(

filename

)

Save python profile data of the default athena profiler instance
into filename (.txt or .pkl format).

Definition at line 97 of file Debugging.py.

def dumpPythonProfile(filename):
    """Save python profile data of the default athena profiler instance
    into filename (.txt or .pkl format).
    """
    from AthenaCommon.Logging import log
    import cProfile
    import pstats
 
    profiler = cProfile._athena_python_profiler
    profiler.disable()
    if filename.endswith(".txt"):
        stats = pstats.Stats(profiler, stream=open(filename, 'w'))
        stats.strip_dirs().sort_stats("time").print_stats()
        log.info("Python profile summary stored in %s", filename)
    else:
        profiler.dump_stats(filename)
        log.info("Python profile stored in %s", filename)
 
 

hookDebugger()

python.Debugging.hookDebugger

(

)

debugging helper, hooks debugger to running interpreter process
   gdb can be overridden via $ATLAS_DEBUGGER

Definition at line 22 of file Debugging.py.

def hookDebugger():
    """debugging helper, hooks debugger to running interpreter process
       gdb can be overridden via $ATLAS_DEBUGGER
    """
    import os
    debugger = os.environ.get('ATLAS_DEBUGGER', 'gdb')
 
    pid = os.spawnvp(os.P_NOWAIT,
                     debugger, [debugger, '-q', 'python', str(os.getpid())])
 
    # give debugger some time to attach to the python process
    import time
    time.sleep( 1 )
 
    # verify the process' existence (will raise OSError if failed)
    os.waitpid( pid, os.WNOHANG )
    os.kill( pid, 0 )
    return
 

hookStrace()

python.Debugging.hookStrace

(

out = None

)

Same than for hookDebugger: spawn strace and attach to the running
interpreter process

Definition at line 41 of file Debugging.py.

def hookStrace(out=None):
    """Same than for hookDebugger: spawn strace and attach to the running
    interpreter process
    """
    import os
    if out is None: out = 'athena.strace.log.%i' % os.getpid()
    if isinstance(out, io.IOBase):
        out = out.name
    elif not isinstance(out,str):
        raise TypeError('argument 0 needs to be either a file or a filename')
    
    pid = os.spawnvp(os.P_NOWAIT,
                     'strace', ['strace',
                                '-f', # follow children
                                '-p', str(os.getpid()),
                                '-o', out])
 
    # give strace some time to attach to the python process
    import time
    time.sleep( 1 )
 
    # verify the process' existence (will raise OSError if failed)
    os.waitpid( pid, os.WNOHANG )
    os.kill( pid, 0 )
    return
 
 

traceExecution()

python.Debugging.traceExecution	(		script,
			level )

Run script with the given trace level

Definition at line 116 of file Debugging.py.

def traceExecution(script, level):
    """Run script with the given trace level"""
    import sys
    import trace
    ignore_dirs = []
    ignore_mods = []
 
    # exclude system and root libraries
    if level > 0:
        ignore_dirs = [x for x in sys.path if x.find("ROOT")!=-1]
        ignore_dirs.append(sys.prefix)
    if level > 1:
        ignore_mods += ['_db', '__init__', '_configurables', 'GaudiHandles', 'six']
    if level > 2:
        ignore_mods += [
            # Legacy stuff we pull in b/c PythonAlgorithms and such still derive from old-style configurables
            'Configurable','Configurables','PropertyProxy','DataHandle','ConfigurableDb',
            'ConfigurableMeta', 'CfgMgr',
            # Internals of the ComponentAccumulator
            'ComponentAccumulator','Logging','AthConfigFlags','AllConfigFlags','Deduplication',
            'semantics','AccumulatorCache','DebuggingContext','AtlasSemantics','ComponentFactory',
            'LegacySupport','ItemListSemantics'
        ]
 
    # taken from cpython/Lib/trace.py
    tracer = trace.Trace(ignoredirs=ignore_dirs, ignoremods=ignore_mods)
 
    with io.open_code(script) as f:
        code = compile(f.read(), script, 'exec')
    tracer.run(code)

Variable Documentation

__doc__

str python.Debugging.__doc__

private

Initial value:

=  """py-module to hold a few tools and utilities to help debugging
configurables and/or Athena application.
"""

Definition at line 9 of file Debugging.py.