Pull common functionality into driver superclass, including data transformation¶
Include the URL of your launchpad blueprint:
https://blueprints.launchpad.net/congress/+spec/refactor-drivers
Currently, each datasource driver contains code to convert data from the API call response to the Congress data tables. This change will make it easier for a developer to add each incremental data source driver.
Problem description¶
Today, it takes more code than necessary to write a data source driver.
The code is also more difficult to write than necessary. Some of these API responses (like in neutron list networks) contain nested data, for example in the list of networks, each network can contain a sub-list of subnets. The driver populates a separate table for subnets and the creates a key to link between the network table and the subnet table.
Proposed change¶
To generalize the driver, this change will allow a driver class to specify how to extract data from the API response, and into which table/field to put the response data.
To handle the sublist conversion, the driver class will specify if a field is a sublist, and then also specify a key, so that the main table can link to the subtable. This sublist relationship will be recursive, so that a sublist can also contain another sublist.
Alternatives¶
None
Policy¶
None
Policy Actions¶
None
Data Sources¶
None
Data model impact¶
None
REST API impact¶
None
Security impact¶
None
Notifications impact¶
None
Other end user impact¶
None
Performance impact¶
None
Other deployer impact¶
This change will have an effect as soon as it is merged, but Congress should behave exactly as it did without the change.
Developer impact¶
The new refactoring will change how programmers write datasource drivers. The new way should be easier, require less code, and be less bug prone. To take advantage of the new refactoring, we’ll need to rewrite the existing drivers, but this need not happen at the same time as writing the new datasource driver superclass.
Implementation¶
Assignee(s)¶
ayip
Work items¶
Write new superclass.
Rewrite Nova driver.
Rewrite Neutron driver.
Rewrite Keystone driver.
Dependencies¶
None
Testing¶
Unit tests for superclass, and modify existing test cases for individual drivers.
Documentation impact¶
This change will include new documentation for how to use the new datasource driver superclass.
References¶
None
