Refactor the sahara.service.api module

https://blueprints.launchpad.net/sahara/+spec/v2-api-experimental-impl

The HTTP API calls that sahara receives are processed by the sahara.api package, the functions of this module then call upon the sahara.service.api and sahara.service.edp.api modules to perform processing before being passed to the conductor. To help accommodate future API changes, these modules should be refactored to create a more unified package for future implementors.

Problem description

The current state of the API service level modules can be confusing when comparing it to the API route level modules. This confusion can lead to misunderstandings in the way the service code interacts with the routing and conductor modules. To improve the state of readability, and expansion, this spec defines a new layout for these modules.

More than confusion, as the API is being reworked for the new version 2 features there will need to be additions in the service layer to assist the endpoint and JSON notational changes. Refactoring these modules will create a more clear pathway for adding to the sahara API.

Proposed change

This change will create a new package named sahara.service.api which will contain all the service level API modules. This new package will create a unified location for service level API changes, and provide a clear path for those wishing to make said changes. The new package will also contain the base service level files for the v2 API.

The new package layout will be as follows:

sahara/service/api/__init__.py
                   v10.py
                   v11.py
                   v2/__init__.py
                      clusters.py
                      cluster_templates.py
                      data_sources.py
                      images.py
                      job_binaries.py
                      job_executions.py
                      jobs.py
                      job_types.py
                      node_group_templates.py
                      plugins.py

This new layout will provide a clean, singular, location for all service level API code. The files created for the sahara.service.api.v2 package will be simple copies of the current functionality.

Alternatives

One alternative is to do nothing and leave the sahara.service.api and sahara.service.edp.api modules as they are and create new code for v2 either in those locations or a new file. A downside to this approach is that it will be less clear where the boundaries between the different versions will exist. This will also leave a larger questions as to where the new v2 code will live.

Data model impact

None

REST API impact

None

Other end user impact

None

Deployer impact

None

Developer impact

This change should improve the developer experience with regard to creating and maintaining the API code as it will be more clear which modules control each version.

Sahara-image-elements impact

None

Sahara-dashboard / Horizon impact

None

Implementation

Assignee(s)

Primary assignee:

Michael McCune (elmiko)

Work Items

• create new package

• move current implementations into new package

• add v2 related service files

• fix outstanding references

• add documentation to v2 developer docs

Dependencies

None

Testing

As these changes will leave the interfaces largely intact, they will be tested through our current unit and tempest tests. The will not require new tests specifically for this change.

Documentation Impact

A new section in the API v2 developer docs will be added to help inform about the purpose of these files and how they will be used in the work to implement features like JSON payload changes.

References

None