Previously, the lister was relying on the use of the CRANtools R module
but it has the drawback to only list the latest version of each registered
package in the CRAN registry.
In order to get all possible versions for each CRAN package, prefer to exploit
the content of the weekly dump of the CRAN database in RDS format.
To read the content of the RDS file from Python, the rpy2 package is used as
it has the advantage to be packaged in debian.
Related to swh/meta#1709.
Legacy Lister classes from the swh.lister.core mdule are no longer
used in swh-lister codebase so it is time to remove them.
Also remove lister CLI options related to legacy Lister API.
As a consequence, the following requirements are no longer needed:
arrow, SQLAlchemy, sqlalchemy-stubs and testing.postgresql.
Closes T2442
The new lister has incremental and full listing capability.
It can request the Bitbucket API in anonymous and HTTP basic authentication
modes. Rate-limiting is not aggressive and is handled.
Listers are declared as plugins via the `swh.workers` entry_point.
As such, the registry function is expected to return a dict with the
`task_modules` field (as for generic worker plugins), plus:
- `lister`: the lister class,
- `models`: list of SQLAlchemy models used by this lister,
- `init` (optionnal): hook (callable) used to initialize the lister's state
(typically, create/initialize the database for this lister).
If not set, the default implementation creates database tables (after
optionally having deleted exisintg ones) according to models declared in
the `models` register field.
There is no need for explicitely add lister task modules in the main
`conftest` module, but any new/extra lister to be tested must be registered
(the tested lister module must be properly installed in the test environment).
Also refactor a bit the cli tools:
- add support for the standard --config-file option at the 'lister' group
level,
- move the --db-url to the 'lister' group,
- drop the --lister option for the `swh lister db-init` cli tool:
initializing (especially with --drop-tables) the database for a single
lister is unreliable, since all tables are created using a sibgle MetaData
(in the same namespace).
