Chronos is a distributed, redundant, reliable timer service. It is designed to be generic to allow it to be used as part of any service infrastructure.
Chronos is designed to scale out horizontally to handle large loads on the system and also supports elastic, lossless scaling up and down of the cluster to handle extra load on the service.
The HTTP API is described here, and the procedure for clustering a group of Chronos nodes together is described here.
To develop on Chronos, you'll need to install a few dependencies first.
- General building tools (make/gcc/libc/devscripts)
- libcurl
- libboost-program-options
- libboost-regex
- libevent
- google-mock
- google-test
On Ubuntu most of these can be installed with:
sudo apt-get install git build-essential devscripts debhelper libcurl4-gnutls-dev libboost-program-options-dev libboost-regex-dev libevent-dev google-mock
The only part that doesn't install is the actual gtest library, it does however install the library code to /usr/src. You can build this into the correct library with:
sudo apt-get install cmake
cd /usr/src/gtest
sudo cmake -f CMakeCache.txt
sudo make
sudo mv libgtest.a libgtest_main.a /usr/lib/
To fetch the code, use git and remember to fetch the sub-modules as well:
git clone git@github.com:Metaswitch/chronos.git --recursive
The supplied makefile has a few useful targets:
make- Builds the Chronos executablemake test- Runs the UTsmake coverage- Runs the UTs and generates a code coverage reportmake valgrind- Runs the UTs under valgrind and reports the resultsmake deb- Build a Debian package containing Chronos and a default configuration file.