Blkin is a project that allows you to trace applications with LTTng following the tracing semantics described in Google's Dapper Paper.
According to this paper, the logged information is called Annotation, and
belongs to a specific span and trace. Each trace is comprised of multiple spans
which are related with each other with causal relationships. The Blkin
library gives the user the API to easily instrument C/C++ applications according
to the Dapper specification. In order to instrument applications, you should take
a look at blkin-lib/tests for some testcases and at the blkin-lib/zipkin_c.h
file.
Blkin uses LTTng as a tracing backend, so you must have LTTng installed.
In order to build and install the Blkin library, go to blkin-lib folder and run:
cmake .
make
make install
You should take a look at the examples to find out how to link the blkin lib with your instrumented application.
In order to visualize the aggregated information you can use Twitter's Zipkin and send the data that you created by running the equivalent babeltrace plugin. In order to do so, you can run:
$> ./zipkin/src/babeltrace_zipkin.py </path/to/lttng/traces> -s <server_ip> -p <port_number>
within the babeltrace-plugins directory. Note that you'll need facebook-scribe
and python-thrift installed.
In case you have not used the blkin-lib to instrument your application, you can still send your data to a Scribe server. To do so, you can use another Babeltrace plugin. This plugin tranforms LTTng trace data to a JSON format and sends them to a Scribe sever. In order to do so, you can run:
$> ./json/src/babeltrace_json.py </path/to/lttng/traces> -s <server_ip> -p <port_number>
within the babeltrace-plugins directory.
You might need to enable Scribe support in Zipkin.
Both of these plugins require that you have installed Babeltrace with its Python bindings enabled, which is not the case with the packages provided by many Linux distributions (see here for more details). The path to the lttng traces should not be the root directory but the directory where the channel directories are included.
- libboost-all-dev
- lttng-tools
Note that Blkin is tested only with LTTng2.4