Monasca is the OpenStack project for MONitoring At SCAle.
Monasca also includes a Logging API that supports centralized
logging of logs. The monasca-log-api is a OpenStack based
microservice and supports Keystone (Identity Management) based
authentication. It provides a secure, reliable and multi-tenant
based Logging as a service.

The flow is as follows:
1. Using the monsaca log configuration properties, get a token
   from keystone
2. Cache this token for performance
3. Get the monasca-log-api url from the keystone token service
   catalog. If the monasca_log_hosts is specified in the config,
   that would be used instead of the keystone catalog. This
   config property is a list of host names (or IPs) separated by
   comma
4. If the hosts list is specified, select a random host and form
   an url using that
5. Use the log url thus arrived at and open a HTTP connection.
   If it fails, get another random host. Use retries as well
6. Build the monasca-log-api dimensions, token and content-type
   (HTTP headers) for the request
7. Send the request to the open HTTP connection (using connection
   pools to reuse connections where possible)
8. Batch the requests to avoid network overhead and improve
   throughput

Added unit tests and refactored for better readability