How to play nicely with other plugins

There are several namespace considerations to keep in mind when developing QIIME 2 plugins or actions.

• Plugin names are unique, and collisions are not tolerated by the framework. This means if you want to name your plugin dada2, users will not be able to have your plugin and the DADA2 plugin installed in the same deployment at the same time.

• Action names are not globally unique, but rather are namespaced within a plugin’s domain.

• Semantic types, artifact classes, formats, and transformers are registered globally, like plugins, again, if you choose to use an existing name, this will prevent users from deploying both offending plugins concurrently.

There are a few strategies the QIIME 2 developers have employed to work within these limits:

• Most semantic types, artifact classes, formats, and transformers are registered in a single plugin: q2-types. This prevents circular imports. For many 3rd-party plugin developers, this means most typical types and formats are available within a single import. If you’re creating new types in your plugins, avoid re-using type names. Generally types are well established before being added to q2-types, since we commit to backward compability of q2-types (so it’s hard to make changes to type names, for example).

• Plugin naming takes one of two approaches, typically:

  • The name matches the source tool being wrapped (e.g. cutadapt).

  • The name is some generic descriptor, like diversity or taxa.

• Action naming typically takes one of two approaches:

  • The name matches a subcommand or method on the source tool being wrapped.

  • The name is a generic descriptor, and typically is written as a verb (but not exclusively).