Split out the schema preparation and update logic into its own module

1 files changed, 3 insertions, 375 deletions

diff --git a/synapse/storage/__init__.py b/synapse/storage/__init__.py
index 340e59afcb..4be629bff8 100644
--- a/synapse/storage/__init__.py
+++ b/synapse/storage/__init__.py
@@ -41,23 +41,16 @@ from .end_to_end_keys import EndToEndKeyStore
 
 from .receipts import ReceiptsStore
 
+from ._schema_prepare import UpgradeDatabaseException
+
+__all__ = [UpgradeDatabaseException]
 
-import fnmatch
-import imp
 import logging
-import os
-import re
 
 
 logger = logging.getLogger(__name__)
 
 
-# Remember to update this number every time a change is made to database
-# schema files, so the users will be informed on server restarts.
-SCHEMA_VERSION = 24
-
-dir_path = os.path.abspath(os.path.dirname(__file__))
-
 # Number of msec of granularity to store the user IP 'last seen' time. Smaller
 # times give more inserts into the database even for readonly API hits
 # 120 seconds == 2 minutes
@@ -158,371 +151,6 @@ class DataStore(RoomMemberStore, RoomStore,
         )
 
 
-def read_schema(path):
-    """ Read the named database schema.
-
-    Args:
-        path: Path of the database schema.
-    Returns:
-        A string containing the database schema.
-    """
-    with open(path) as schema_file:
-        return schema_file.read()
-
-
-class PrepareDatabaseException(Exception):
-    pass
-
-
-class UpgradeDatabaseException(PrepareDatabaseException):
-    pass
-
-
-def prepare_database(db_conn, database_engine):
-    """Prepares a database for usage. Will either create all necessary tables
-    or upgrade from an older schema version.
-    """
-    try:
-        cur = db_conn.cursor()
-        version_info = _get_or_create_schema_state(cur, database_engine)
-
-        if version_info:
-            user_version, delta_files, upgraded = version_info
-            _upgrade_existing_database(
-                cur, user_version, delta_files, upgraded, database_engine
-            )
-        else:
-            _setup_new_database(cur, database_engine)
-
-        # cur.execute("PRAGMA user_version = %d" % (SCHEMA_VERSION,))
-
-        cur.close()
-        db_conn.commit()
-    except:
-        db_conn.rollback()
-        raise
-
-
-def _setup_new_database(cur, database_engine):
-    """Sets up the database by finding a base set of "full schemas" and then
-    applying any necessary deltas.
-
-    The "full_schemas" directory has subdirectories named after versions. This
-    function searches for the highest version less than or equal to
-    `SCHEMA_VERSION` and executes all .sql files in that directory.
-
-    The function will then apply all deltas for all versions after the base
-    version.
-
-    Example directory structure:
-
-        schema/
-            delta/
-                ...
-            full_schemas/
-                3/
-                    test.sql
-                    ...
-                11/
-                    foo.sql
-                    bar.sql
-                ...
-
-    In the example foo.sql and bar.sql would be run, and then any delta files
-    for versions strictly greater than 11.
-    """
-    current_dir = os.path.join(dir_path, "schema", "full_schemas")
-    directory_entries = os.listdir(current_dir)
-
-    valid_dirs = []
-    pattern = re.compile(r"^\d+(\.sql)?$")
-    for filename in directory_entries:
-        match = pattern.match(filename)
-        abs_path = os.path.join(current_dir, filename)
-        if match and os.path.isdir(abs_path):
-            ver = int(match.group(0))
-            if ver <= SCHEMA_VERSION:
-                valid_dirs.append((ver, abs_path))
-        else:
-            logger.warn("Unexpected entry in 'full_schemas': %s", filename)
-
-    if not valid_dirs:
-        raise PrepareDatabaseException(
-            "Could not find a suitable base set of full schemas"
-        )
-
-    max_current_ver, sql_dir = max(valid_dirs, key=lambda x: x[0])
-
-    logger.debug("Initialising schema v%d", max_current_ver)
-
-    directory_entries = os.listdir(sql_dir)
-
-    for filename in fnmatch.filter(directory_entries, "*.sql"):
-        sql_loc = os.path.join(sql_dir, filename)
-        logger.debug("Applying schema %s", sql_loc)
-        executescript(cur, sql_loc)
-
-    cur.execute(
-        database_engine.convert_param_style(
-            "INSERT INTO schema_version (version, upgraded)"
-            " VALUES (?,?)"
-        ),
-        (max_current_ver, False,)
-    )
-
-    _upgrade_existing_database(
-        cur,
-        current_version=max_current_ver,
-        applied_delta_files=[],
-        upgraded=False,
-        database_engine=database_engine,
-    )
-
-
-def _upgrade_existing_database(cur, current_version, applied_delta_files,
-                               upgraded, database_engine):
-    """Upgrades an existing database.
-
-    Delta files can either be SQL stored in *.sql files, or python modules
-    in *.py.
-
-    There can be multiple delta files per version. Synapse will keep track of
-    which delta files have been applied, and will apply any that haven't been
-    even if there has been no version bump. This is useful for development
-    where orthogonal schema changes may happen on separate branches.
-
-    Different delta files for the same version *must* be orthogonal and give
-    the same result when applied in any order. No guarantees are made on the
-    order of execution of these scripts.
-
-    This is a no-op of current_version == SCHEMA_VERSION.
-
-    Example directory structure:
-
-        schema/
-            delta/
-                11/
-                    foo.sql
-                    ...
-                12/
-                    foo.sql
-                    bar.py
-                ...
-            full_schemas/
-                ...
-
-    In the example, if current_version is 11, then foo.sql will be run if and
-    only if `upgraded` is True. Then `foo.sql` and `bar.py` would be run in
-    some arbitrary order.
-
-    Args:
-        cur (Cursor)
-        current_version (int): The current version of the schema.
-        applied_delta_files (list): A list of deltas that have already been
-            applied.
-        upgraded (bool): Whether the current version was generated by having
-            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.
-    """
-
-    if current_version > SCHEMA_VERSION:
-        raise ValueError(
-            "Cannot use this database as it is too " +
-            "new for the server to understand"
-        )
-
-    start_ver = current_version
-    if not upgraded:
-        start_ver += 1
-
-    logger.debug("applied_delta_files: %s", applied_delta_files)
-
-    for v in range(start_ver, SCHEMA_VERSION + 1):
-        logger.debug("Upgrading schema to v%d", v)
-
-        delta_dir = os.path.join(dir_path, "schema", "delta", str(v))
-
-        try:
-            directory_entries = os.listdir(delta_dir)
-        except OSError:
-            logger.exception("Could not open delta dir for version %d", v)
-            raise UpgradeDatabaseException(
-                "Could not open delta dir for version %d" % (v,)
-            )
-
-        directory_entries.sort()
-        for file_name in directory_entries:
-            relative_path = os.path.join(str(v), file_name)
-            logger.debug("Found file: %s", relative_path)
-            if relative_path in applied_delta_files:
-                continue
-
-            absolute_path = os.path.join(
-                dir_path, "schema", "delta", relative_path,
-            )
-            root_name, ext = os.path.splitext(file_name)
-            if ext == ".py":
-                # This is a python upgrade module. We need to import into some
-                # package and then execute its `run_upgrade` function.
-                module_name = "synapse.storage.v%d_%s" % (
-                    v, root_name
-                )
-                with open(absolute_path) as python_file:
-                    module = imp.load_source(
-                        module_name, absolute_path, python_file
-                    )
-                logger.debug("Running script %s", relative_path)
-                module.run_upgrade(cur, database_engine)
-            elif ext == ".pyc":
-                # Sometimes .pyc files turn up anyway even though we've
-                # disabled their generation; e.g. from distribution package
-                # installers. Silently skip it
-                pass
-            elif ext == ".sql":
-                # A plain old .sql file, just read and execute it
-                logger.debug("Applying schema %s", relative_path)
-                executescript(cur, absolute_path)
-            else:
-                # Not a valid delta file.
-                logger.warn(
-                    "Found directory entry that did not end in .py or"
-                    " .sql: %s",
-                    relative_path,
-                )
-                continue
-
-            # Mark as done.
-            cur.execute(
-                database_engine.convert_param_style(
-                    "INSERT INTO applied_schema_deltas (version, file)"
-                    " VALUES (?,?)",
-                ),
-                (v, relative_path)
-            )
-
-            cur.execute("DELETE FROM schema_version")
-            cur.execute(
-                database_engine.convert_param_style(
-                    "INSERT INTO schema_version (version, upgraded)"
-                    " VALUES (?,?)",
-                ),
-                (v, True)
-            )
-
-
-def get_statements(f):
-    statement_buffer = ""
-    in_comment = False  # If we're in a /* ... */ style comment
-
-    for line in f:
-        line = line.strip()
-
-        if in_comment:
-            # Check if this line contains an end to the comment
-            comments = line.split("*/", 1)
-            if len(comments) == 1:
-                continue
-            line = comments[1]
-            in_comment = False
-
-        # Remove inline block comments
-        line = re.sub(r"/\*.*\*/", " ", line)
-
-        # Does this line start a comment?
-        comments = line.split("/*", 1)
-        if len(comments) > 1:
-            line = comments[0]
-            in_comment = True
-
-        # Deal with line comments
-        line = line.split("--", 1)[0]
-        line = line.split("//", 1)[0]
-
-        # Find *all* semicolons. We need to treat first and last entry
-        # specially.
-        statements = line.split(";")
-
-        # We must prepend statement_buffer to the first statement
-        first_statement = "%s %s" % (
-            statement_buffer.strip(),
-            statements[0].strip()
-        )
-        statements[0] = first_statement
-
-        # Every entry, except the last, is a full statement
-        for statement in statements[:-1]:
-            yield statement.strip()
-
-        # The last entry did *not* end in a semicolon, so we store it for the
-        # next semicolon we find
-        statement_buffer = statements[-1].strip()
-
-
-def executescript(txn, schema_path):
-    with open(schema_path, 'r') as f:
-        for statement in get_statements(f):
-            txn.execute(statement)
-
-
-def _get_or_create_schema_state(txn, database_engine):
-    # Bluntly try creating the schema_version tables.
-    schema_path = os.path.join(
-        dir_path, "schema", "schema_version.sql",
-    )
-    executescript(txn, schema_path)
-
-    txn.execute("SELECT version, upgraded FROM schema_version")
-    row = txn.fetchone()
-    current_version = int(row[0]) if row else None
-    upgraded = bool(row[1]) if row else None
-
-    if current_version:
-        txn.execute(
-            database_engine.convert_param_style(
-                "SELECT file FROM applied_schema_deltas WHERE version >= ?"
-            ),
-            (current_version,)
-        )
-        applied_deltas = [d for d, in txn.fetchall()]
-        return current_version, applied_deltas, upgraded
-
-    return None
-
-
-def prepare_sqlite3_database(db_conn):
-    """This function should be called before `prepare_database` on sqlite3
-    databases.
-
-    Since we changed the way we store the current schema version and handle
-    updates to schemas, we need a way to upgrade from the old method to the
-    new. This only affects sqlite databases since they were the only ones
-    supported at the time.
-    """
-    with db_conn:
-        schema_path = os.path.join(
-            dir_path, "schema", "schema_version.sql",
-        )
-        create_schema = read_schema(schema_path)
-        db_conn.executescript(create_schema)
-
-        c = db_conn.execute("SELECT * FROM schema_version")
-        rows = c.fetchall()
-        c.close()
-
-        if not rows:
-            c = db_conn.execute("PRAGMA user_version")
-            row = c.fetchone()
-            c.close()
-
-            if row and row[0]:
-                db_conn.execute(
-                    "REPLACE INTO schema_version (version, upgraded)"
-                    " VALUES (?,?)",
-                    (row[0], False)
-                )
-
-
 def are_all_users_on_domain(txn, database_engine, domain):
     sql = database_engine.convert_param_style(
         "SELECT COUNT(*) FROM users WHERE name NOT LIKE ?"