migrate from deprecated sqlalchemy methods (#7864)

### Summary & Motivation
noticed this in a BK run
```
[2022-05-12T18:55:29Z]   /workdir/python_modules/dagster/dagster/core/storage/alembic/versions/002_cascade_run_deletion_postgres.py:23: SADeprecationWarning: The from_engine() method on Inspector is deprecated and will be removed in a future release.  Please use the sqlalchemy.inspect() function on an Engine or Connection in order to acquire an Inspector. (deprecated since: 1.4)
[2022-05-12T18:55:29Z]     inspector = reflection.Inspector.from_engine(bind)
```

migrate to the recommended methods

### How I Tested These Changes

bk

python_modules/dagster/dagster/core/storage/alembic/versions/001_initial_1.py

@@ -11,8 +11,7 @@
 
 import sqlalchemy as sa
 from alembic import context, op
-from sqlalchemy import Column
-from sqlalchemy.engine import reflection
+from sqlalchemy import Column, inspect
 
 from dagster.core.storage.event_log import SqlEventLogStorageTable
 
@@ -27,9 +26,7 @@ def upgrade():
     # This is our root migration, and we don't have a common base. Before this revision, sqlite- and
     # postgres-based event logs had different schemas. The conditionality below is to deal with dev
     # databases that might not have been stamped by Alembic.
-    bind = op.get_context().bind
-
-    inspector = reflection.Inspector.from_engine(bind)
+    inspector = inspect(op.get_bind())
     has_tables = inspector.get_table_names()
 
     if "event_log" not in has_tables:

python_modules/dagster/dagster/core/storage/alembic/versions/002_cascade_run_deletion_postgres.py

@@ -6,7 +6,7 @@
 
 """
 from alembic import op
-from sqlalchemy.engine import reflection
+from sqlalchemy import inspect
 
 # pylint: disable=no-member
 # alembic dynamically populates the alembic.context module
@@ -19,8 +19,7 @@
 
 
 def upgrade():
-    bind = op.get_context().bind
-    inspector = reflection.Inspector.from_engine(bind)
+    inspector = inspect(op.get_bind())
     has_tables = inspector.get_table_names()
 
     if "runs" in has_tables and "run_tags" in has_tables:
@@ -36,8 +35,7 @@ def upgrade():
 
 
 def downgrade():
-    bind = op.get_context().bind
-    inspector = reflection.Inspector.from_engine(bind)
+    inspector = inspect(op.get_bind())
     has_tables = inspector.get_table_names()
 
     if "runs" in has_tables and "run_tags" in has_tables:

python_modules/dagster/dagster/core/storage/alembic/versions/002_cascade_run_deletion_sqlite.py

@@ -6,7 +6,7 @@
 
 """
 from alembic import op
-from sqlalchemy.engine import reflection
+from sqlalchemy import inspect
 
 # pylint: disable=no-member
 
@@ -18,8 +18,7 @@
 
 
 def upgrade():
-    bind = op.get_context().bind
-    inspector = reflection.Inspector.from_engine(bind)
+    inspector = inspect(op.get_bind())
     has_tables = inspector.get_table_names()
 
     if "runs" in has_tables and "run_tags" in has_tables:

python_modules/dagster/dagster/core/storage/alembic/versions/003_add_step_key_pipeline_name_postgres.py

@@ -7,7 +7,7 @@
 """
 import sqlalchemy as sa
 from alembic import op
-from sqlalchemy.engine import reflection
+from sqlalchemy import inspect
 
 # pylint: disable=no-member
 
@@ -19,8 +19,7 @@
 
 
 def upgrade():
-    bind = op.get_context().bind
-    inspector = reflection.Inspector.from_engine(bind)
+    inspector = inspect(op.get_bind())
     has_tables = inspector.get_table_names()
     if "event_logs" in has_tables:
         columns = [x.get("name") for x in inspector.get_columns("event_logs")]
@@ -29,8 +28,7 @@ def upgrade():
 
 
 def downgrade():
-    bind = op.get_context().bind
-    inspector = reflection.Inspector.from_engine(bind)
+    inspector = inspect(op.get_bind())
     has_tables = inspector.get_table_names()
     if "event_logs" in has_tables:
         columns = [x.get("name") for x in inspector.get_columns("event_logs")]

python_modules/dagster/dagster/core/storage/alembic/versions/003_add_step_key_pipeline_name_sqlite.py

@@ -7,7 +7,7 @@
 """
 import sqlalchemy as sa
 from alembic import op
-from sqlalchemy.engine import reflection
+from sqlalchemy import inspect
 
 # pylint: disable=no-member
 
@@ -19,8 +19,7 @@
 
 
 def upgrade():
-    bind = op.get_context().bind
-    inspector = reflection.Inspector.from_engine(bind)
+    inspector = inspect(op.get_bind())
     has_tables = inspector.get_table_names()
     if "event_logs" in has_tables:
         columns = [x.get("name") for x in inspector.get_columns("event_logs")]
@@ -29,8 +28,7 @@ def upgrade():
 
 
 def downgrade():
-    bind = op.get_context().bind
-    inspector = reflection.Inspector.from_engine(bind)
+    inspector = inspect(op.get_bind())
     has_tables = inspector.get_table_names()
     if "event_logs" in has_tables:
         columns = [x.get("name") for x in inspector.get_columns("event_logs")]

python_modules/dagster/dagster/core/storage/alembic/versions/004_add_snapshots_to_run_storage.py

@@ -7,7 +7,7 @@
 """
 import sqlalchemy as sa
 from alembic import op
-from sqlalchemy.engine import reflection
+from sqlalchemy import inspect
 
 from dagster.core.storage.migration.utils import has_column, has_table
 
@@ -22,8 +22,7 @@
 
 
 def upgrade():
-    bind = op.get_context().bind
-    inspector = reflection.Inspector.from_engine(bind)
+    inspector = inspect(op.get_bind())
 
     if not has_table("runs"):
         return
@@ -50,7 +49,8 @@ def upgrade():
                         "snapshot_id",
                         sa.String(255),
                         sa.ForeignKey(
-                            "snapshots.snapshot_id", name="fk_runs_snapshot_id_snapshots_snapshot_id"
+                            "snapshots.snapshot_id",
+                            name="fk_runs_snapshot_id_snapshots_snapshot_id",
                         ),
                     ),
                 )
@@ -63,8 +63,7 @@ def upgrade():
 
 
 def downgrade():
-    bind = op.get_context().bind
-    inspector = reflection.Inspector.from_engine(bind)
+    inspector = inspect(op.get_bind())
 
     if not has_table("runs"):
         return

python_modules/dagster/dagster/core/storage/alembic/versions/005_add_asset_key_postgres.py

@@ -7,7 +7,7 @@
 """
 import sqlalchemy as sa
 from alembic import op
-from sqlalchemy.engine import reflection
+from sqlalchemy import inspect
 
 # pylint: disable=no-member
 
@@ -19,8 +19,7 @@
 
 
 def upgrade():
-    bind = op.get_context().bind
-    inspector = reflection.Inspector.from_engine(bind)
+    inspector = inspect(op.get_bind())
     has_tables = inspector.get_table_names()
     if "event_logs" in has_tables:
         columns = [x.get("name") for x in inspector.get_columns("event_logs")]
@@ -33,8 +32,7 @@ def upgrade():
 
 
 def downgrade():
-    bind = op.get_context().bind
-    inspector = reflection.Inspector.from_engine(bind)
+    inspector = inspect(op.get_bind())
     has_tables = inspector.get_table_names()
     if "event_logs" in has_tables:
         columns = [x.get("name") for x in inspector.get_columns("event_logs")]

python_modules/dagster/dagster/core/storage/alembic/versions/005_add_asset_key_sqlite.py

@@ -7,7 +7,7 @@
 """
 import sqlalchemy as sa
 from alembic import op
-from sqlalchemy.engine import reflection
+from sqlalchemy import inspect
 
 # pylint: disable=no-member
 
@@ -19,8 +19,7 @@
 
 
 def upgrade():
-    bind = op.get_context().bind
-    inspector = reflection.Inspector.from_engine(bind)
+    inspector = inspect(op.get_bind())
     has_tables = inspector.get_table_names()
     if "event_logs" in has_tables:
         columns = [x.get("name") for x in inspector.get_columns("event_logs")]
@@ -33,8 +32,7 @@ def upgrade():
 
 
 def downgrade():
-    bind = op.get_context().bind
-    inspector = reflection.Inspector.from_engine(bind)
+    inspector = inspect(op.get_bind())
     has_tables = inspector.get_table_names()
     if "event_logs" in has_tables:
         columns = [x.get("name") for x in inspector.get_columns("event_logs")]

python_modules/dagster/dagster/core/storage/alembic/versions/006_scheduler_update_postgres.py

@@ -6,7 +6,7 @@
 
 """
 from alembic import op
-from sqlalchemy.engine import reflection
+from sqlalchemy import inspect
 
 from dagster.core.storage.migration.utils import get_currently_upgrading_instance, has_table
 
@@ -22,8 +22,7 @@
 
 
 def upgrade():
-    bind = op.get_context().bind
-    inspector = reflection.Inspector.from_engine(bind)
+    inspector = inspect(op.get_bind())
 
     if "postgresql" not in inspector.dialect.dialect_description:
         return

python_modules/dagster/dagster/core/storage/alembic/versions/007_create_run_id_idx_postgres.py

@@ -6,7 +6,7 @@
 
 """
 from alembic import op
-from sqlalchemy.engine import reflection
+from sqlalchemy import inspect
 
 # pylint: disable=no-member
 
@@ -18,8 +18,7 @@
 
 
 def upgrade():
-    bind = op.get_context().bind
-    inspector = reflection.Inspector.from_engine(bind)
+    inspector = inspect(op.get_bind())
     has_tables = inspector.get_table_names()
     if "event_logs" in has_tables:
         indices = [x.get("name") for x in inspector.get_indexes("event_logs")]
@@ -28,8 +27,7 @@ def upgrade():
 
 
 def downgrade():
-    bind = op.get_context().bind
-    inspector = reflection.Inspector.from_engine(bind)
+    inspector = inspect(op.get_bind())
     has_tables = inspector.get_table_names()
     if "event_logs" in has_tables:
         indices = [x.get("name") for x in inspector.get_indexes("event_logs")]

python_modules/dagster/dagster/core/storage/alembic/versions/007_create_run_id_idx_sqlite.py

@@ -6,7 +6,7 @@
 
 """
 from alembic import op
-from sqlalchemy.engine import reflection
+from sqlalchemy import inspect
 
 # pylint: disable=no-member
 
@@ -18,8 +18,7 @@
 
 
 def upgrade():
-    bind = op.get_context().bind
-    inspector = reflection.Inspector.from_engine(bind)
+    inspector = inspect(op.get_bind())
     has_tables = inspector.get_table_names()
     if "event_logs" in has_tables:
         indices = [x.get("name") for x in inspector.get_indexes("event_logs")]
@@ -28,8 +27,7 @@ def upgrade():
 
 
 def downgrade():
-    bind = op.get_context().bind
-    inspector = reflection.Inspector.from_engine(bind)
+    inspector = inspect(op.get_bind())
     has_tables = inspector.get_table_names()
     if "event_logs" in has_tables:
         indices = [x.get("name") for x in inspector.get_indexes("event_logs")]

python_modules/dagster/dagster/core/storage/alembic/versions/008_add_run_tags_index_postgres.py

@@ -6,7 +6,7 @@
 
 """
 from alembic import op
-from sqlalchemy.engine import reflection
+from sqlalchemy import inspect
 
 # pylint: disable=no-member
 
@@ -18,8 +18,7 @@
 
 
 def upgrade():
-    bind = op.get_context().bind
-    inspector = reflection.Inspector.from_engine(bind)
+    inspector = inspect(op.get_bind())
     has_tables = inspector.get_table_names()
     if "run_tags" in has_tables:
         indices = [x.get("name") for x in inspector.get_indexes("run_tags")]
@@ -28,8 +27,7 @@ def upgrade():
 
 
 def downgrade():
-    bind = op.get_context().bind
-    inspector = reflection.Inspector.from_engine(bind)
+    inspector = inspect(op.get_bind())
     has_tables = inspector.get_table_names()
     if "run_tags" in has_tables:
         indices = [x.get("name") for x in inspector.get_indexes("run_tags")]

python_modules/dagster/dagster/core/storage/alembic/versions/008_add_run_tags_index_sqlite.py

@@ -6,7 +6,7 @@
 
 """
 from alembic import op
-from sqlalchemy.engine import reflection
+from sqlalchemy import inspect
 
 # pylint: disable=no-member
 
@@ -18,8 +18,7 @@
 
 
 def upgrade():
-    bind = op.get_context().bind
-    inspector = reflection.Inspector.from_engine(bind)
+    inspector = inspect(op.get_bind())
     has_tables = inspector.get_table_names()
     if "run_tags" in has_tables:
         indices = [x.get("name") for x in inspector.get_indexes("run_tags")]
@@ -28,8 +27,7 @@ def upgrade():
 
 
 def downgrade():
-    bind = op.get_context().bind
-    inspector = reflection.Inspector.from_engine(bind)
+    inspector = inspect(op.get_bind())
     has_tables = inspector.get_table_names()
     if "run_tags" in has_tables:
         indices = [x.get("name") for x in inspector.get_indexes("run_tags")]

python_modules/dagster/dagster/core/storage/alembic/versions/009_add_partition_column_postgres.py

@@ -7,7 +7,7 @@
 """
 import sqlalchemy as sa
 from alembic import op
-from sqlalchemy.engine import reflection
+from sqlalchemy import inspect
 
 # pylint: disable=no-member
 
@@ -19,8 +19,7 @@
 
 
 def upgrade():
-    bind = op.get_context().bind
-    inspector = reflection.Inspector.from_engine(bind)
+    inspector = inspect(op.get_bind())
     has_tables = inspector.get_table_names()
     if "event_logs" in has_tables:
         columns = [x.get("name") for x in inspector.get_columns("event_logs")]
@@ -32,8 +31,7 @@ def upgrade():
 
 
 def downgrade():
-    bind = op.get_context().bind
-    inspector = reflection.Inspector.from_engine(bind)
+    inspector = inspect(op.get_bind())
     has_tables = inspector.get_table_names()
     if "event_logs" in has_tables:
         columns = [x.get("name") for x in inspector.get_columns("event_logs")]