Describe your context
This applies to background callbacks using the Celery Background Callback Manager. This should be reproducible using the latest version of dash as well.
dash 3.3.0
dash-ag-grid 33.3.3
dash-iconify 0.1.2
dash-mantine-components 2.5.1
dash-testing-stub 0.0.2
Describe the bug
Celery supports multiple backends that are not a BaseKeyValueStoreBackend:
CassandraBackendDatabaseBackendMongoBackendRPCBackend
However, Dash's CeleryManager assumes the backend to be a BaseKeyValueStoreBackend having the methods set and get.
Configuring any of the backends above will result in an error similar to AttributeError: 'DatabaseBackend' object has no attribute 'get' when triggering a background callback.
Backends that that implement BaseKeyValueStoreBackend might also fail, when the parameters passed to set and get do not comply with the backend's requirements (e.g. the FilesystemBackend expects a byte-like object for the key resulting in an error similar to TypeError: sequence item 1: expected a bytes-like object, str found, also see #3116).
Expected behavior
The CeleryManager should either
- support all Celery backends by using
get_result and store_result from BaseBackend instead of get and set and using byte-like objects for keys or
- make the restriction more explicit by additional documentation and erroring early on when the configured backend does not implement
BaseKeyValueStoreBackend or is otherwise not supported.
Especially the DatabaseBackend and FilesystemBackend would be accessible options without the need for additional infrastructure to execute background callbacks.
Describe your context
This applies to background callbacks using the Celery Background Callback Manager. This should be reproducible using the latest version of dash as well.
Describe the bug
Celery supports multiple backends that are not a
BaseKeyValueStoreBackend:CassandraBackendDatabaseBackendMongoBackendRPCBackendHowever, Dash's
CeleryManagerassumes the backend to be aBaseKeyValueStoreBackendhaving the methodssetandget.Configuring any of the backends above will result in an error similar to
AttributeError: 'DatabaseBackend' object has no attribute 'get'when triggering a background callback.Backends that that implement
BaseKeyValueStoreBackendmight also fail, when the parameters passed tosetandgetdo not comply with the backend's requirements (e.g. theFilesystemBackendexpects a byte-like object for the key resulting in an error similar toTypeError: sequence item 1: expected a bytes-like object, str found, also see #3116).Expected behavior
The
CeleryManagershould eitherget_resultandstore_resultfromBaseBackendinstead ofgetandsetand using byte-like objects for keys orBaseKeyValueStoreBackendor is otherwise not supported.Especially the
DatabaseBackendandFilesystemBackendwould be accessible options without the need for additional infrastructure to execute background callbacks.