bindings/python/examples/babeltrace_and_lttng.py

   1 #!/usr/bin/env python3
   2 # babeltrace_and_lttng.py
   3 #
   4 # Babeltrace and LTTng example script
   5 #
   6 # Copyright 2012 EfficiOS Inc.
   7 #
   8 # Author: Danny Serres <danny.serres@efficios.com>
   9 #
  10 # Permission is hereby granted, free of charge, to any person obtaining a copy
  11 # of this software and associated documentation files (the "Software"), to deal
  12 # in the Software without restriction, including without limitation the rights
  13 # to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  14 # copies of the Software, and to permit persons to whom the Software is
  15 # furnished to do so, subject to the following conditions:
  16 #
  17 # The above copyright notice and this permission notice shall be included in
  18 # all copies or substantial portions of the Software.
  19
  20
  21 # This script uses both lttng-tools and babeltrace
  22 # python modules.  It creates a session, enables
  23 # events, starts tracing for 2 seconds, stops tracing,
  24 # destroys the session and outputs the trace in the
  25 # specified output file.
  26 #
  27 # WARNING: will destroy any existing trace having
  28 #          the same name as ses_name
  29
  30
  31 # ------------------------------------------------------
  32 ses_name =      "babeltrace-lttng-test"
  33 trace_path =    "/lttng-traces/babeltrace-lttng-trace/"
  34 out_file =      "babeltrace-lttng-trace-text-output.txt"
  35 # ------------------------------------------------------
  36
  37
  38 import time
  39 try:
  40         import babeltrace, lttng
  41 except ImportError:
  42         raise ImportError(      "both babeltrace and lttng-tools "
  43                                 "python modules must be installed" )
  44
  45
  46 # Errors to raise if something goes wrong
  47 class LTTngError(Exception):
  48         pass
  49 class BabeltraceError(Exception):
  50         pass
  51
  52
  53 # LTTNG-TOOLS
  54
  55 # Making sure session does not already exist
  56 lttng.destroy(ses_name)
  57
  58 # Creating a new session and handle
  59 ret = lttng.create(ses_name,trace_path)
  60 if ret < 0:
  61         raise LTTngError(lttng.strerror(ret))
  62
  63 domain = lttng.Domain()
  64 domain.type = lttng.DOMAIN_KERNEL
  65
  66 han = None
  67 han = lttng.Handle(ses_name, domain)
  68 if han is None:
  69         raise LTTngError("Handle not created")
  70
  71
  72 # Enabling all events
  73 event = lttng.Event()
  74 event.type = lttng.EVENT_ALL
  75 event.loglevel_type = lttng.EVENT_LOGLEVEL_ALL
  76 ret = lttng.enable_event(han, event, None)
  77 if ret < 0:
  78         raise LTTngError(lttng.strerror(ret))
  79
  80 # Start, wait, stop
  81 ret = lttng.start(ses_name)
  82 if ret < 0:
  83         raise LTTngError(lttng.strerror(ret))
  84 print("Tracing...")
  85 time.sleep(2)
  86 print("Stopped.")
  87 ret = lttng.stop(ses_name)
  88 if ret < 0:
  89         raise LTTngError(lttng.strerror(ret))
  90
  91
  92 # Destroying tracing session
  93 ret = lttng.destroy(ses_name)
  94 if ret < 0:
  95         raise LTTngError(lttng.strerror(ret))
  96
  97
  98 # BABELTRACE
  99
 100 # Create context and add trace:
 101 ctx = babeltrace.Context()
 102 ret = ctx.add_trace(trace_path + "/kernel", "ctf")
 103 if ret is None:
 104         raise BabeltraceError("Error adding trace")
 105
 106 # Iterator setup
 107 bp = babeltrace.IterPos(babeltrace.SEEK_BEGIN)
 108 ctf_it = babeltrace.CTFReader.Iterator(ctx,bp)
 109
 110 # Reading events from trace
 111 # and outputting timestamps and event names
 112 # in out_file
 113 print("Writing trace file...")
 114 output = open(out_file, "wt")
 115
 116 event = ctf_it.read_event()
 117 while(event is not None):
 118         output.write("TS: {}, {} : {}\n".format(event.get_timestamp(),
 119                 event.get_cycles(), event.get_name()))
 120
 121         # Next event
 122         ret = ctf_it.next()
 123         if ret < 0:
 124                 break
 125         event = ctf_it.read_event()
 126
 127 # Closing file
 128 output.close()
 129
 130 # Destroying dynamic elements
 131 del ctf_it, han
 132 print("Done.")