The Syslog-ng Riak module

The Riak module has three worker thread methods -

  • riak_worker_thread_init : This method does the sanity checks, i.e. checks if the bucket, key or value is NULL and fails if required values are unchecked.
  • riak_worker_thread_deinit : This method deferences all the LogTemplates in the RiakDestDriver structs and also frees th emomory alloted to the char * variables of the structure.
  • riak_worker_insert : This method is spposed to do the bulk of the work i.e. store messages in riak, but right now we have a printf statement in it which is used for making sure that is module enters the insert method.

Then for debuging and testing our module we change the source of the syslog-ng.conf to tcp(ip("") port(12345) flags(no-parse)); .This listens to port 12345 on localhost and is tested by using echo foo | nc 12345 on the terminal. Before this a syslog-ng -Fvde on a different terminal shows all the messages in th foreground and the foo string that was echoed shows itself here. Also the message used a printf in the worker_insert method is displayed here aswell which makes it certain that the insert method is being used when a message is being recieved by Syslog-ng. This leaves us with a syslog-ng module that can parse new config options, set up its internal state, and can even receive and ignore messages!! \o/

Riak Client Library

As mentioned in my proposal, the C libraries of riak client that are present on github are all obsolete and hence I have to write a library that can talk to Riak, and supports enough of the PBC protocol, that our two use cases(set and store) are covered. The library so far recides here. It is licensed under LGPLv3. My mentor was kind enough to give me a few test cases to begin with. As of now client , RpbContent and RpbPutReq have been implemented as much as required for our porpose. also the test coverage is also good for all the functions. A few commands that helped me in debugging are :

  • make check VERBOSE=1 : used to check all the tests and print the error messages on the same screen
  • export CK_FORK=no : used before running gdb checks defaults to using a child process to run the tests themselves, so it can catch segfaults and the like CK_FORK=no turns that off
  • tests/check_libriack && gdb tests/check_libriack to run gdb along with the tests, very helpful

Also since I used dynamically allocated object and not static struct for Proto messages hence i had to use rpb_content_init instead of RPB_CONTENT_INIT and likewise to initialise the protobuf-c structure.

Last but not the least CG_FORK=no valgrind --tool=memcheck --log-file=riack-tes.log --leak-check=full --show-reachable=yes tests/check_libriack used on the tests I wrote gave me the logs of all the memory leaks that are there in the functions which were all fixed.

Now since both the parts of the project are stable in their own basic state, next would be to join those to and then make the riak module use this library and save a few messages in a riak node using the RpbPutReq.