LTTng » Babeltrace

When trying to use a trimmer component with a stream that does not have packets, we get:

CAUSED BY [filter.utils.trimmer: 'filter.utils.trimmer'] (/home/smarchi/src/babeltrace/src/plugins/utils/trimmer/trimmer.c:1315)
  Unsupported stream: packets have no beginning clock snapshot: stream-addr=0x60d000001080, stream-id=0, stream-name="(null)" 

The trimmer component does not yet support packet messages that don't have default clock snapshots, but it should support streams that don't have packet messages at all.

It can be reproduced with the following plugin file:

import bt2

class MyIter(bt2._UserMessageIterator):
    def __init__(self, config, port):
        tc, sc, ec, cc = port.user_data
        trace = sc.trace_class()
        stream = trace.create_stream(sc)

        self._msgs = [
            self._create_stream_beginning_message(stream),
            self._create_event_message(ec, stream, 123),
            self._create_stream_end_message(stream),
        ]
        self._i = 0

    def __next__(self):
        if self._i >= len(self._msgs):
            raise bt2.Stop

        msg = self._msgs[self._i]
        self._i += 1
        return msg

    def _user_can_seek_beginning(self):
        return True

    def _user_seek_beginning(self):
        self._i = 0

@bt2.plugin_component_class
class MySource(bt2._UserSourceComponent, message_iterator_class=MyIter):
    def __init__(self, config, params, obj):
        cc = self._create_clock_class()
        tc = self._create_trace_class()
        sc = tc.create_stream_class(default_clock_class=cc)
        ec = sc.create_event_class(name='hello')

        self._add_output_port('out', (tc, sc, ec, cc))

bt2.register_plugin(
    __name__, "foo",
)

And the command line:

babeltrace2 --plugin-path . -c source.foo.MySource -c filter.utils.trimmer