1 | #!/usr/bin/env python
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2 | from __future__ import print_function
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3 | """
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4 | pytrace.py
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5 | """
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6 |
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7 | import cStringIO
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8 | import os
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9 | import struct
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10 | import sys
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11 |
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12 | # TODO: Two kinds of tracing?
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13 | # - FullTracer -> Chrome trace?
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14 | # - ReservoirSamplingTracer() -- flame graph that is deterministic?
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15 |
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16 | # TODO: Check this in but just go ahead and fix wild.sh instead.
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17 |
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18 |
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19 | class Tracer(object):
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20 | # Limit to 10M events by default.
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21 | def __init__(self, max_events=10e6):
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22 | self.pid = os.getpid()
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23 | # append
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24 | self.event_strs = cStringIO.StringIO()
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25 |
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26 | # After max_events we stop recording
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27 | self.max_events = max_events
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28 | self.num_events = 0
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29 | self.depth = 0
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30 |
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31 | # Python VM callback
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32 | def OnEvent(self, frame, event_type, arg):
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33 | # Test overhead
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34 | # 7.5 seconds. Geez. That's crazy high.
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35 | # The baseline is 2.7 seconds, and _lsprof takes 3.8 seconds.
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36 |
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37 | # I guess that's why pytracing is a decorator and only works on one part of
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38 | # the program.
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39 | # pytracing isn't usable with large programs. It can't run abuild -h.
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40 |
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41 | # What I really want is the nicer visualization. I don't want the silly
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42 | # cProfile output.
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43 |
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44 | self.num_events += 1
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45 | name = frame.f_code.co_name
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46 | filename = frame.f_code.co_filename
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47 | if event_type in ('call', 'c_call'):
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48 | self.depth += 1
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49 |
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50 | record = '%s%s\t%s\t%s\t%s\t%s\n' % (' ' * self.depth,
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51 | event_type, filename, frame.f_lineno, name, arg)
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52 | self.event_strs.write(record)
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53 |
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54 | if event_type in ('return', 'c_return'):
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55 | self.depth -= 1
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56 |
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57 | return
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58 |
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59 | # NOTE: Do we want a struct.pack version eventually?
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60 | #self.event_strs.write('')
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61 |
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62 | def Start(self):
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63 | sys.setprofile(self.OnEvent)
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64 |
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65 | def Stop(self, path):
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66 | sys.setprofile(None)
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67 | # Only one process should write out the file!
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68 | if os.getpid() != self.pid:
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69 | return
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70 |
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71 | # TODO:
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72 | # - report number of events?
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73 | # - report number of bytes?
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74 | print('num_events: %d' % self.num_events, file=sys.stderr)
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75 | print('Writing to %r' % path, file=sys.stderr)
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76 | with open(path, 'w') as f:
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77 | f.write(self.event_strs.getvalue())
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78 |
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79 |
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80 | def main(argv):
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81 | t = Tracer()
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82 | import urlparse
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83 | t.Start()
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84 | print(urlparse.urlparse('http://example.com/foo'))
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85 | t.Stop('demo.pytrace')
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86 |
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87 |
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88 | if __name__ == '__main__':
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89 | try:
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90 | main(sys.argv)
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91 | except RuntimeError as e:
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92 | print >>sys.stderr, 'FATAL: %s' % e
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93 | sys.exit(1)
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