bindings/python/examples/babeltrace_and_lttng.py

   1 # babeltrace_and_lttng.py
   2 #
   3 # Babeltrace and LTTng example script
   4 #
   5 # Copyright 2012 EfficiOS Inc.
   6 #
   7 # Author: Danny Serres <danny.serres@efficios.com>
   8 #
   9 # Permission is hereby granted, free of charge, to any person obtaining a copy
  10 # of this software and associated documentation files (the "Software"), to deal
  11 # in the Software without restriction, including without limitation the rights
  12 # to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  13 # copies of the Software, and to permit persons to whom the Software is
  14 # furnished to do so, subject to the following conditions:
  15 #
  16 # The above copyright notice and this permission notice shall be included in
  17 # all copies or substantial portions of the Software.
  18
  19
  20 # This script uses both lttng-tools and babeltrace
  21 # python modules.  It creates a session, enables
  22 # events, starts tracing for 2 seconds, stops tracing,
  23 # destroys the session and outputs the trace in the
  24 # specified output file.
  25 #
  26 # WARNING: will destroy any existing trace having
  27 #          the same name as ses_name
  28
  29
  30 # ------------------------------------------------------
  31 ses_name =      "babeltrace-lttng-test"
  32 trace_path =    "/lttng-traces/babeltrace-lttng-trace/"
  33 out_file =      "babeltrace-lttng-trace-text-output.txt"
  34 # ------------------------------------------------------
  35
  36
  37 import time
  38 try:
  39         import babeltrace, lttng
  40 except ImportError:
  41         raise ImportError(      "both babeltrace and lttng-tools "
  42                                 "python modules must be installed" )
  43
  44
  45 # Errors to raise if something goes wrong
  46 class LTTngError(Exception):
  47         pass
  48 class BabeltraceError(Exception):
  49         pass
  50
  51
  52 # LTTNG-TOOLS
  53
  54 # Making sure session does not already exist
  55 lttng.destroy(ses_name)
  56
  57 # Creating a new session and handle
  58 ret = lttng.create(ses_name,trace_path)
  59 if ret < 0:
  60         raise LTTngError(lttng.strerror(ret))
  61
  62 han = None
  63 han = lttng.Handle(ses_name, lttng.Domain())
  64 if han is None:
  65         raise LTTngError("Handle not created")
  66
  67
  68 # Enabling all events
  69 ret = lttng.enable_event(han, lttng.Event(), None)
  70 if ret < 0:
  71         raise LTTngError(lttng.strerror(ret))
  72
  73
  74 # Start, wait, stop
  75 ret = lttng.start(ses_name)
  76 if ret < 0:
  77         raise LTTngError(lttng.strerror(ret))
  78 print("Tracing...")
  79 time.sleep(2)
  80 print("Stopped.")
  81 ret = lttng.stop(ses_name)
  82 if ret < 0:
  83         raise LTTngError(lttng.strerror(ret))
  84
  85
  86 # Destroying tracing session
  87 ret = lttng.destroy(ses_name)
  88 if ret < 0:
  89         raise LTTngError(lttng.strerror(ret))
  90
  91
  92 # BABELTRACE
  93
  94 # Create context and add trace:
  95 ctx = babeltrace.Context()
  96 ret = ctx.add_trace(trace_path + "/kernel", "ctf")
  97 if ret is None:
  98         raise BabeltraceError("Error adding trace")
  99
 100 # Iterator setup
 101 bp = babeltrace.IterPos(babeltrace.SEEK_BEGIN)
 102 ctf_it = babeltrace.ctf.Iterator(ctx,bp)
 103
 104 # Reading events from trace
 105 # and outputting timestamps and event names
 106 # in out_file
 107 print("Writing trace file...")
 108 output = open(out_file, "wt")
 109
 110 event = ctf_it.read_event()
 111 while(event is not None):
 112         output.write("TS: {}, {} : {}\n".format(event.get_timestamp(),
 113                 event.get_cycles(), event.get_name()))
 114
 115         # Next event
 116         ret = ctf_it.next()
 117         if ret < 0:
 118                 break
 119         event = ctf_it.read_event()
 120
 121 # Closing file
 122 output.close()
 123
 124 # Destroying dynamic elements
 125 del ctf_it, han
 126 print("Done.")