fix(dataset): handle missing sqla uri in migration

[villebro]

SUMMARY

When running the migration a9422eeaae74_new_dataset_models_take_2.py from #19421 I ran into a problem where some old faulty database metadata caused the migration to fail. This adds a check for the truthiness of drivername similar to what's done a few rows above:

superset/superset/migrations/versions/a9422eeaae74_new_dataset_models_take_2.py

Line 577 in 1c3c3ae

if is_physical and drivername and expression:

to ensure that the the migration completes even if the metadata is corrupted.

BEFORE

Traceback (most recent call last):
  File "/Users/ville/src/superset/venv/bin/superset", line 33, in <module>
    sys.exit(load_entry_point('apache-superset', 'console_scripts', 'superset')())
  File "/Users/ville/src/superset/venv/lib/python3.8/site-packages/click/core.py", line 1128, in __call__
    return self.main(*args, **kwargs)
  File "/Users/ville/src/superset/venv/lib/python3.8/site-packages/flask/cli.py", line 601, in main
    return super().main(*args, **kwargs)
  File "/Users/ville/src/superset/venv/lib/python3.8/site-packages/click/core.py", line 1053, in main
    rv = self.invoke(ctx)
  File "/Users/ville/src/superset/venv/lib/python3.8/site-packages/click/core.py", line 1659, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
  File "/Users/ville/src/superset/venv/lib/python3.8/site-packages/click/core.py", line 1659, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
  File "/Users/ville/src/superset/venv/lib/python3.8/site-packages/click/core.py", line 1395, in invoke
    return ctx.invoke(self.callback, **ctx.params)
  File "/Users/ville/src/superset/venv/lib/python3.8/site-packages/click/core.py", line 754, in invoke
    return __callback(*args, **kwargs)
  File "/Users/ville/src/superset/venv/lib/python3.8/site-packages/click/decorators.py", line 26, in new_func
    return f(get_current_context(), *args, **kwargs)
  File "/Users/ville/src/superset/venv/lib/python3.8/site-packages/flask/cli.py", line 445, in decorator
    return __ctx.invoke(f, *args, **kwargs)
  File "/Users/ville/src/superset/venv/lib/python3.8/site-packages/click/core.py", line 754, in invoke
    return __callback(*args, **kwargs)
  File "/Users/ville/src/superset/venv/lib/python3.8/site-packages/flask_migrate/cli.py", line 149, in upgrade
    _upgrade(directory, revision, sql, tag, x_arg)
  File "/Users/ville/src/superset/venv/lib/python3.8/site-packages/flask_migrate/__init__.py", line 98, in wrapped
    f(*args, **kwargs)
  File "/Users/ville/src/superset/venv/lib/python3.8/site-packages/flask_migrate/__init__.py", line 185, in upgrade
    command.upgrade(config, revision, sql=sql, tag=tag)
  File "/Users/ville/src/superset/venv/lib/python3.8/site-packages/alembic/command.py", line 294, in upgrade
    script.run_env()
  File "/Users/ville/src/superset/venv/lib/python3.8/site-packages/alembic/script/base.py", line 490, in run_env
    util.load_python_file(self.dir, "env.py")
  File "/Users/ville/src/superset/venv/lib/python3.8/site-packages/alembic/util/pyfiles.py", line 97, in load_python_file
    module = load_module_py(module_id, path)
  File "/Users/ville/src/superset/venv/lib/python3.8/site-packages/alembic/util/compat.py", line 184, in load_module_py
    spec.loader.exec_module(module)
  File "<frozen importlib._bootstrap_external>", line 843, in exec_module
  File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
  File "/Users/ville/src/superset/superset/extensions/../migrations/env.py", line 126, in <module>
    run_migrations_online()
  File "/Users/ville/src/superset/superset/extensions/../migrations/env.py", line 118, in run_migrations_online
    context.run_migrations()
  File "<string>", line 8, in run_migrations
  File "/Users/ville/src/superset/venv/lib/python3.8/site-packages/alembic/runtime/environment.py", line 813, in run_migrations
    self.get_context().run_migrations(**kw)
  File "/Users/ville/src/superset/venv/lib/python3.8/site-packages/alembic/runtime/migration.py", line 561, in run_migrations
    step.migration_fn(**kw)
  File "/Users/ville/src/superset/superset/migrations/versions/a9422eeaae74_new_dataset_models_take_2.py", line 885, in upgrade
    postprocess_datasets(session)
  File "/Users/ville/src/superset/superset/migrations/versions/a9422eeaae74_new_dataset_models_take_2.py", line 603, in postprocess_datasets
    expression, get_dialect_name(drivername), show_warning=False
  File "/Users/ville/src/superset/superset/utils/memoized.py", line 50, in __call__
    value = self.func(*args, **kwargs)
  File "/Users/ville/src/superset/superset/connectors/sqla/utils.py", line 185, in get_dialect_name
    return SqlaURL(drivername).get_dialect().name
  File "/Users/ville/src/superset/venv/lib/python3.8/site-packages/sqlalchemy/engine/url.py", line 189, in get_dialect
    entrypoint = self._get_entrypoint()
  File "/Users/ville/src/superset/venv/lib/python3.8/site-packages/sqlalchemy/engine/url.py", line 172, in _get_entrypoint
    cls = registry.load(name)
  File "/Users/ville/src/superset/venv/lib/python3.8/site-packages/sqlalchemy/util/langhelpers.py", line 277, in load
    raise exc.NoSuchModuleError(
sqlalchemy.exc.NoSuchModuleError: Can't load plugin: sqlalchemy.dialects:

AFTER

INFO  [alembic.runtime.migration] Running upgrade ad07e4fdbaba -> a9422eeaae74, new_dataset_models_take_2
>> Copy 35 physical tables to sl_tables...
>> Copy 91 SqlaTable to sl_datasets...
   Copy dataset owners...
   Link physical datasets with tables...
>> Copy 1,033 table columns to sl_columns...
   Link all columns to sl_datasets...
>> Copy 101 metrics to sl_columns...
   Link metric columns to datasets...
>> Run postprocessing on 1,134 columns
   [Column 1 to 1,134] 1,011 may be updated
   Assign table column relations...
>> Run postprocessing on 91 datasets
   Process dataset 1~91...
>> Assign new UUIDs to tables...

Adding uuids for `sl_tables`...
Done. Assigned 34 uuids in 0.012s.

>> Drop intermediate columns...
INFO  [alembic.runtime.migration] Running upgrade a9422eeaae74 -> cbe71abde154, fix report schedule and execution log
Revision ID: 6f139c533bea
Revises: cbe71abde154
Create Date: 2021-05-27 16:10:59.567684

TESTING INSTRUCTIONS

ADDITIONAL INFORMATION

• Has associated issue:
• Required feature flags:
• Changes UI
• Includes DB Migration (follow approval process in SIP-59)
  • Migration is atomic, supports rollback & is backwards-compatible
  • Confirm DB migration upgrade and downgrade tested
  • Runtime estimates and downtime expectations provided
• Introduces new feature or API
• Removes existing feature or API

[codecov]

Codecov Report

Merging #20073 (388c15c) into master (1c3c3ae) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master   #20073   +/-   ##
=======================================
  Coverage   66.37%   66.37%           
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  Files        1715     1715           
  Lines       64179    64179           
  Branches     6753     6753           
=======================================
  Hits        42602    42602           
  Misses      19859    19859           
  Partials     1718     1718           

Flag	Coverage Δ
hive	53.70% <ø> (ø)
mysql	82.04% <ø> (ø)
postgres	82.10% <ø> (ø)
presto	53.56% <ø> (ø)
python	82.53% <ø> (ø)
sqlite	81.84% <ø> (ø)
unit	49.14% <ø> (ø)

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[zhaoyongjie]

LGTM! Thanks for the fix.