Items filtering in Mistral

https://blueprints.launchpad.net/mistral/+spec/mistral-items-filtering

Problem description

Currently, we don’t have any support for items filtering on the server side which affects performance badly. In future, we may have thousands of actions. So, we should be able to filter items before transferring them over the network. Also, it is very difficult to find specific data in the list of returned items. For example, we have a lot of ‘standard’ OpenStack actions. So it is not very convenient to look through all of them to find actions for nova.

Use Cases

As a user, I want to have an ability to filter data.

Proposed change

To solve this problem, I would like to implement customized filter for database. This filter will support “in”, “nin”, “>”, “>=”, “<” and “<=” operations. Also, new parameters will be allowed in REST API. These parameters are the name of columns by which users are allowed to filter data.

Alternatives

None

Data model impact

None

REST API impact

  1. Gets only those actions which have ‘<some_value>’ as <column_name> value.

GET http://127.0.0.1:8989/v2/actions?<column_name>=<some_value>

  1. Gets only those actions which have ‘<some_value_1>’ or ‘<some_value_2>’ as <column_name> value.

GET http://127.0.0.1:8989/v2/actions?<column_name>=in:<some_value_1>,<some_value_2>

  1. Gets only those actions which have not ‘<some_value_1>’ or ‘<some_value_2>’ as <column_name> value.

GET http://127.0.0.1:8989/v2/actions?<column_name>=nin:<some_value_1>,<some_value_2>

  1. Gets only those actions which have not <some_value> as <column_name> value.

GET http://127.0.0.1:8989/v2/actions?<column_name>=neq:<some_value>

  1. Gets only those actions which have greater value than <some_value> as <column_name> value.

GET http://127.0.0.1:8989/v2/actions?<column_name>=gt:<some_value>

  1. Gets only those actions which have greater than or equal to <some_value> as <column_name> value.

GET http://127.0.0.1:8989/v2/actions?<column_name>=gte:<some_value>

  1. Gets only those actions which have less value than <some_value> as <column_name> value.

GET http://127.0.0.1:8989/v2/actions?<column_name>=lt:<some_value>

  1. Gets only those actions which have less than or equal to <some_value> as <column_name> value.

GET http://127.0.0.1:8989/v2/actions?<column_name>=lte:<some_value>

Same changes are proposed for workflows, workbooks, cron triggers, executions, tasks etc.

End user impact

User can add new option in CLI. For instance

mistral action-list --filter <column-name>=<op>:<some_value>

Here ‘<op>’ can be “eq”, “neq”, “gt”, “gte”, “lt”, “lte”, “in” or “nin”. Multiple values can be provided by using “;” separator.

Performance Impact

Only requested/filtered data will be fetched from database and transmitted over network. So, it will improve the response time for the request.

Deployer impact

None

Implementation

Assignee(s)

hardik <hardik.parekh@nectechnologies.in>

Work Items

  • Add new parameter to REST api.

  • Add new option for CLI.

Dependencies

None

Testing

Tests should cover all the scenarios memtioned in use cases section.