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Diffstat (limited to 'synapse/storage/schema_prepare.py')
| -rw-r--r-- | synapse/storage/schema_prepare.py | 395 |
1 files changed, 395 insertions, 0 deletions
diff --git a/synapse/storage/schema_prepare.py b/synapse/storage/schema_prepare.py new file mode 100644 index 0000000000..1ddf55be4d --- /dev/null +++ b/synapse/storage/schema_prepare.py @@ -0,0 +1,395 @@ +# -*- coding: utf-8 -*- +# Copyright 2014, 2015 OpenMarket Ltd +# +# Licensed under the Apache License, Version 2.0 (the "License"); +# you may not use this file except in compliance with the License. +# You may obtain a copy of the License at +# +# http://www.apache.org/licenses/LICENSE-2.0 +# +# Unless required by applicable law or agreed to in writing, software +# distributed under the License is distributed on an "AS IS" BASIS, +# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +# See the License for the specific language governing permissions and +# limitations under the License. + +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__)) + + +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) + ) |