Context history in Orion

问题

I am interested in knowing more about the context history feature of Orion, which is mentioned here: https://forge.fi-ware.org/plugins/mediawiki/wiki/fiware/index.php/FIWARE.OpenSpecification.Data.PubSub#Context_history

I cannot figure:

1. whether context history is implemented and how in the current ORION
2. if it is implemented, I cannot figure how to tap into it, that is, I don't see it covered by APIs etc.

Thanks for any help!

回答1:

By design, Orion doesn't store historic data itself: its purpose is to have always the current context information view of the system. However, Orion can be easly integrated with persistence backends implementing such historic through Cygnus (HDFS, MySQL and CKAN by the time being).

For example, this post explains how to use Cygnus to persist Orion context in Cosmos (HDFS-bases storage).

来源：https://stackoverflow.com/questions/25157215/context-history-in-orion