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Clean up prepare_database.py a bit and add comments

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This commit is contained in:
Erik Johnston 2019-10-22 18:43:31 +01:00
parent 6cc497f99b
commit 23d62eded2
1 changed files with 30 additions and 7 deletions
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37
synapse/storage/prepare_database.py
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@ -97,7 +97,8 @@ def prepare_database(db_conn, database_engine, config):
def _setup_new_database(cur, database_engine, data_stores):
"""Sets up the database by finding a base set of "full schemas" and then
applying any necessary deltas.
applying any necessary deltas, including schemas from the given data
stores.
The "full_schemas" directory has subdirectories named after versions. This
function searches for the highest version less than or equal to
@ -122,6 +123,15 @@ def _setup_new_database(cur, database_engine, data_stores):
In the example foo.sql and bar.sql would be run, and then any delta files
for versions strictly greater than 11.
Note: we apply the full schemas and deltas from the top level `schema/`
folder as well those in the data stores specified.
Args:
cur (Cursor): a database cursor
database_engine (DatabaseEngine)
data_stores (list[str]): The names of the data stores to instantiate
on the given database.
"""
current_dir = os.path.join(dir_path, "schema", "full_schemas")
directory_entries = os.listdir(current_dir)
@ -245,6 +255,10 @@ def _upgrade_existing_database(
only if `upgraded` is True. Then `foo.sql` and `bar.py` would be run in
some arbitrary order.
Note: we apply the delta files from the specified data stores as well as
those in the top-level schema. We apply all delta files across data stores
for a version before applying those in the next version.
Args:
cur (Cursor)
current_version (int): The current version of the schema.
@ -254,6 +268,14 @@ def _upgrade_existing_database(
applied deltas or from full schema file. If `True` the function
will never apply delta files for the given `current_version`, since
the current_version wasn't generated by applying those delta files.
database_engine (DatabaseEngine)
config (synapse.config.homeserver.HomeServerConfig|None):
application config, or None if we are connecting to an existing
database which we expect to be configured already
data_stores (list[str]): The names of the data stores to instantiate
on the given database.
is_empty (bool): Is this a blank database? I.e. do we need to run the
upgrade portions of the delta scripts.
"""
if current_version > SCHEMA_VERSION:
@ -305,21 +327,19 @@ def _upgrade_existing_database(
# Data stores can have empty entries for a given version delta.
pass
except OSError:
logger.exception("Could not open delta dir for version %d", v)
raise UpgradeDatabaseException(
"Could not open delta dir for version %d" % (v,)
"Could not open delta dir for version %d: %s" % (v, directory)
)
if not directory_entries:
continue
# We sort to ensure that we apply the delta files in a consistent
# order (to avoid bugs caused by inconsistent directory listing order)
directory_entries.sort()
for entry in directory_entries:
file_name = entry.file_name
relative_path = os.path.join(str(v), file_name)
absolute_path = entry.absolute_path
logger.debug("Found file: %s", relative_path)
logger.debug("Found file: %s (%s)", relative_path, absolute_path)
if relative_path in applied_delta_files:
continue
@ -511,6 +531,9 @@ def _get_or_create_schema_state(txn, database_engine):
class _DirectoryListing(object):
"""Helper class to store schema file name and the
absolute path to it.
These entries get sorted, so for consistency we want to ensure that
`file_name` attr is kept first.
"""
file_name = attr.ib()