OpenStackClient

osc is a CLI for the OpenStack written in Rust. It is relying on the corresponding openstack_sdk crate (library) and is generated using OpenAPI specifications. That means that the maintenance effort for the tool is much lower compared to the fully human written python-openstackclient. Due to the fact of being auto-generated there are certain differences to the python cli but also an enforced UX consistency.

NOTE: As a new tool it tries to solve some issues with the original python-openstackclient. That means that it can not provide seamless migration from one tool to another.

Commands implementation code is being produced by codegenerator what means there is no maintenance required for that code.

Microversions

Initially python-openstackclient was using lowest microversion unless additional argument specifying microversion was passed. Later, during switching commands towards using of the OpenStackSDK a highest possible microversion started being used (again unless user explicitly requested microversion with --XXX-api-version Y.Z). One common thing both approaches use is to give user control over the version what is crucial to guarantee stability. The disadvantage of both approaches is that they come with certain opinions that does not necessarily match what user expects and make expectation on what will happen hard. For the end user reading help page of the command is pretty complex and error prone when certain parameters appear, disappear and re-appear with different types between microversion. Implementing (and using) the command is also both complex and error prone in this case.

osc is trying to get the best of 2 approaches and providing dedicated commands for microversions (i.e. create20, create294). Latest microversion command is always having a general alias (create in the above case) to let user explicitly use latest microversion, what, however, does not guarantee it can be invoked with requested parameters. This approach allows user to be very explicit in the requirement and have a guarantee of the expected parameters. When a newer microversion is required user should explicitly to do "migration" step adapting the invocation to a newer set of parameters. Microversion (or functionality) deprecation is also much simpler this way and is handled by marking the whole command deprecated and/or drop it completely.