This new pattern uses the lister support features introduced in swh.scheduler to
replace the database management done in previous iterations of the listers.
Prior to this commit, all listers were instantiated at the same time even if
only one was needed. This commit separates those instantiations.
The only drawback to this is the db model initialization which now happens at
each lister instantiation. This can be dealt with if needed at another time
though.
This allows us to actually run the lister instantiation code instead of relying
on the underlying structure of the lister object. In turn, this allows future
listers to use the scheduler right in their __init__.
Since all the listing tasks accepts an url as first argument (whatever the
argument name is), it makes sense to use a simple common argument name for
this. I've chosen 'url' instead of api_baseurl/forge_url/url.
Also kill now useless `new_lister()` functions.
Add a new register-task-types cli that will create missing task-type entries in the
scheduler according to:
- only create missing task-types (do not update them), but check that the
backend_name field is consistent,
- each SWHTask-based task declared in a module listed in the 'task_modules'
plugin registry field will be checked and added if needed; tasks which name
start wit an underscore will not be added,
- added task-type will have:
- the 'type' field is derived from the task's function name (with underscores
replaced with dashes),
- the description field is the first line of that function's docstring,
- default values as provided by the swh.lister.cli.DEFAULT_TASK_TYPE (with
a simple pattern matching to have decent default values for full/incremental
tasks),
- these default values can be overloaded via the 'task_type' plugin registry
entry.
For this, we had to rename all tasks names (eg. `cran_lister` -> `list_cran`).
Comes with some tests.
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).
Simplify the code:
- do only inherit from ListerBase
- implement HTTP queries directly using requests
- get rid of convoluted code
Make the origin_url gathered from the git repo's "project" page instead of
building it from the 'url_prefix' hack. Now, the lister WILL make substancially
more requests, since it will make one request per listed git repo, but
the provided origin_url should be pretty reliable now.
When several url are provided as clonable URLs, choose the http/https one first,
otherwise, choose the first one of the list.
Add proper tests for the cgit lister.
Also, get rid of the 'time_updated' column in the model.
