projects / lttng-tools.git / blame
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|---|---|---|
| 36907cb5 DS |
1 | PYTHON BINDINGS |
| 2 | ---------------- | |
| 3 | ||
| 4 | This is a brief howto for using the lttng-tools Python module. | |
| 5 | ||
| 6 | By default, the Python bindings are not installed. | |
| 7 | If you wish the Python bindings, you can configure with the | |
| 8 | --enable-python-bindings option during the installation procedure: | |
| 9 | ||
| 10 | $ ./configure --enable-python-bindings | |
| 11 | ||
| 12 | The Python module is automatically generated using SWIG, therefore the | |
| 13 | swig2.0 package on Debian/Ubuntu is requied. | |
| 14 | ||
| 15 | Once installed, the Python module can be used by importing it in Python. | |
| 16 | In the Python interpreter: | |
| 17 | ||
| 18 | >>> import lttng | |
| 19 | ||
| 20 | Example: | |
| 21 | ---------------- | |
| 22 | ||
| 23 | Quick example using Python to trace with LTTng. | |
| 24 | ||
| 25 | 1) Run python | |
| 26 | ||
| 27 | $ python | |
| 28 | ||
| 29 | 2) Import the lttng module | |
| 30 | ||
| 31 | >>> import lttng | |
| 32 | ||
| 33 | 3) Create a session | |
| 34 | ||
| 35 | >>> lttng.create("session-name", "path/to/trace") | |
| 36 | ||
| 37 | 4) Create a handle for the tracing session and domain | |
| 38 | ||
| 39 | >>> domain = lttng.Domain() | |
| 40 | >>> domain.type = lttng.DOMAIN_KERNEL * | |
| 41 | >>> handle = lttng.Handle("session-name", domain) | |
| 42 | ||
| 43 | * This line is somewhat useless since domain.type is set to 0 | |
| 44 | by default, the corresponding value of lttng.DOMAIN_KERNEL | |
| 45 | ||
| 46 | 5) Enable all Kernel events | |
| 47 | ||
| 48 | >>> event = lttng.Event() | |
| 49 | >>> event.type = lttng.EVENT_TRACEPOINT * | |
| 50 | >>> event.loglevel_type = lttng.EVENT_LOGLEVEL_ALL * | |
| 51 | >>> lttng.enable_event(handle, event, None) | |
| 52 | ||
| 53 | * These two lines are somewhat useless since event.type | |
| 54 | and event.loglevel_type are by default set to 0, the | |
| 55 | corresponding value of lttng.EVENT_TRACEPOINT and | |
| 56 | lttng.EVENT_LOGLEVEL_ALL | |
| 57 | ||
| 58 | 5) Start tracing | |
| 59 | ||
| 60 | >>> lttng.start("session-name") | |
| 61 | ||
| 62 | 6) Stop tracing | |
| 63 | ||
| 64 | >>> lttng.stop("session-name") | |
| 65 | ||
| 66 | 7) Destroy the tracing session | |
| 67 | ||
| 68 | >>> lttng.destroy("session-name") | |
| 69 | ||
| 70 | For an example script with more details, see extras/bindings/swig/python/tests/example.py |