Example Spec - The title of your feature

Include the URL of the feature in storyboard:


Introduction paragraph – why are we doing anything? A single paragraph of prose that operators can understand. The title and this first paragraph should be used as the subject line and body of the commit message respectively.

Some notes about the usage of specs folder:

  • Not all blueprints need a spec. If a new feature is straightforward enough that it doesn’t need any design discussion, then no spec is required. It should be decided on IRC meeting within the whole core team.

  • The aim of this document is first to define the problem we need to solve, and second agree the overall approach to solve that problem.

  • This is not intended to be extensive documentation for a new feature. For example, there is no need to specify the exact configuration changes, nor the exact details of any DB model changes. But you should still define that such changes are required, and be clear on how that will affect upgrades.

  • You should aim to get your spec approved before writing your code. While you are free to write prototypes and code before getting your spec approved, it’s possible that the outcome of the spec review process leads you towards a fundamentally different solution than you first envisaged.

  • But, API changes are held to a much higher level of scrutiny. As soon as an API change merges, we must assume it could be in production somewhere, and as such, we then need to support that API change forever. To avoid getting that wrong, we do want lots of details about API changes upfront.

Some notes about using this template:

  • Your spec should be in ReSTructured text, like this template.

  • Please wrap text at 79 columns.

  • The filename in the git repository should be similar to the title in storyboard but in lower case combined with underscore.

  • Please do not delete any of the sections in this template. If you have nothing to say for a whole section, just write: None.

  • For help with syntax, see http://sphinx-doc.org/rest.html

Problem description

A detailed description of the problem. What problem is this feature addressing?

Proposed change

Here is where you cover the change you propose to make in detail. How do you propose to solve this problem?

If this is one part of a larger effort make it clear where this piece ends. In other words, what’s the scope of this effort?

Data model impact

This section is optional.

Changes which require modifications to the data model often have a wider impact on the system. The community often has strong opinions on how the data model should be evolved, from both a functional and performance perspective. It is therefore important to capture and gain agreement as early as possible on any proposed changes to the data model.

Questions which need to be addressed by this section include:

  • What new database schema changes is this going to require?

  • What database migrations will accompany this change.

  • How will the initial set of new data objects be generated, for example if you need to take into account existing workflow/execution, or modify other existing data, please describe how that will work.

REST API impact

This section is optional.

Each API method which is either added or changed should have the following:

  • Specification for the method.

    • A description of the added or changed method.

    • Method type (POST/PUT/GET/DELETE).

    • Normal http response code(s).

    • Expected error http response code(s).

    • URL for the resource.

    • Parameters which can be passed via the url.

  • Example use case including typical API samples for both data supplied by the caller and the response.

End user impact

This section is optional.

Aside from the API, are there other ways a user will interact with this feature?

  • Does this change have an impact on python-qinlingclient? What does the user interface there look like?

Performance Impact

This section is optional.

Describe any potential performance impact on the system, for example how often will new code be called, and is there a major change to the calling pattern of existing code.

Examples of things to consider here include:

  • A small change in a utility function or a commonly used decorator can have a large impacts on performance.

  • Calls which result in a database queries can have a profound impact on performance when called in critical sections of the code.

  • Will the change include any locking, and if so what considerations are there on holding the lock?

Deployer impact

This section is optional.

Discuss things that will affect how you deploy and configure OpenStack that have not already been mentioned, such as:

  • What config options are being added? Are the default values ones which will work well in real deployments?

  • Is this a change that takes immediate effect after its merged, or is it something that has to be explicitly enabled?

  • If this change is a new binary, how would it be deployed?

  • Please state anything that those doing continuous deployment, or those upgrading from the previous release, need to be aware of. Also describe any plans to deprecate configuration values or features.


This section is optional.

What other ways could we do this thing? Why aren’t we using those? This doesn’t have to be a full literature review, but it should demonstrate that thought has been put into why the proposed solution is an appropriate one.



Who is leading the writing of the code? Or is this a blueprint where you’re throwing it out there to see who picks it up?

If more than one person is working on the implementation, please designate the primary author and contact.

Primary assignee:

<irc nick name and email address>

Other contributors:

<irc nick name and email address>


This section is optional.

  • Include specific references to specs and/or features in Qinling, or in other projects, that this one either depends on or is related to.

  • Does this feature require any new library dependencies or code otherwise not included in Qinling? Or does it depend on a specific version of library?


This section is optional.

Please discuss the important scenarios needed to test here, as well as specific edge cases we should be ensuring work correctly.


This section is optional.

Please add any useful references here. You are not required to have any reference. Moreover, this specification should still make sense when your references are unavailable. Examples of what you could include are:

  • Links to mailing list or IRC discussions

  • Links to notes from a summit session

  • Links to relevant research, if appropriate

  • Anything else you feel it is worthwhile to refer to