Coverage for cc_modules/cc_alembic.py : 45%

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1#!/usr/bin/env python
3"""
4camcops_server/cc_modules/cc_alembic.py
6===============================================================================
8 Copyright (C) 2012-2020 Rudolf Cardinal (rudolf@pobox.com).
10 This file is part of CamCOPS.
12 CamCOPS is free software: you can redistribute it and/or modify
13 it under the terms of the GNU General Public License as published by
14 the Free Software Foundation, either version 3 of the License, or
15 (at your option) any later version.
17 CamCOPS is distributed in the hope that it will be useful,
18 but WITHOUT ANY WARRANTY; without even the implied warranty of
19 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 GNU General Public License for more details.
22 You should have received a copy of the GNU General Public License
23 along with CamCOPS. If not, see <https://www.gnu.org/licenses/>.
25===============================================================================
27**Functions to talk to Alembic; specifically, those functions that may be used
28by users/administrators, such as to upgrade a database.**
30If you're a developer and want to create a new database migration, see
31``tools/create_database_migration.py`` instead.
33"""
35import logging
36from typing import TYPE_CHECKING
37import os
39# from alembic import command
40from alembic.config import Config
41from cardinal_pythonlib.fileops import preserve_cwd
42from cardinal_pythonlib.logs import BraceStyleAdapter
43from cardinal_pythonlib.sqlalchemy.alembic_func import (
44 # get_current_and_head_revision,
45 downgrade_database,
46 upgrade_database,
47 stamp_allowing_unusual_version_table,
48)
50from camcops_server.cc_modules.cc_baseconstants import (
51 ALEMBIC_BASE_DIR,
52 ALEMBIC_CONFIG_FILENAME,
53 ALEMBIC_VERSION_TABLE,
54)
55from camcops_server.cc_modules.cc_sqlalchemy import Base
57if TYPE_CHECKING:
58 from sqlalchemy.sql.schema import MetaData
59 from camcops_server.cc_modules.cc_config import CamcopsConfig
61log = BraceStyleAdapter(logging.getLogger(__name__))
64def import_all_models():
65 """
66 Imports all SQLAlchemy models. (This has side effects including setting up
67 the SQLAlchemy metadata properly.)
68 """
69 # noinspection PyUnresolvedReferences
70 import camcops_server.cc_modules.cc_all_models # delayed import # import side effects (ensure all models registered) # noqa
73def upgrade_database_to_head(show_sql_only: bool = False) -> None:
74 """
75 The primary upgrade method. Modifies the database structure from where it
76 is, stepwise through revisions, to the head revision.
78 Args:
79 show_sql_only: just show the SQL; don't execute it
80 """
81 upgrade_database_to_revision(revision="head", show_sql_only=show_sql_only)
84def upgrade_database_to_revision(revision: str,
85 show_sql_only: bool = False) -> None:
86 """
87 Upgrades the database to a specific revision. Modifies the database
88 structure from where it is, stepwise through revisions, to the specified
89 revision.
91 Args:
92 revision: destination revision
93 show_sql_only: just show the SQL; don't execute it
94 """
95 import_all_models() # delayed, for command-line interfaces
96 upgrade_database(alembic_base_dir=ALEMBIC_BASE_DIR,
97 alembic_config_filename=ALEMBIC_CONFIG_FILENAME,
98 destination_revision=revision,
99 version_table=ALEMBIC_VERSION_TABLE,
100 as_sql=show_sql_only)
101 # ... will get its config information from the OS environment; see
102 # run_alembic() in alembic/env.py
105def downgrade_database_to_revision(revision: str,
106 show_sql_only: bool = False,
107 confirm_downgrade_db: bool = False) -> None:
108 """
109 Developer option. Takes the database to a specific revision.
111 Args:
112 revision: destination revision
113 show_sql_only: just show the SQL; don't execute it
114 confirm_downgrade_db: has the user confirmed? Necessary for the
115 (destructive) database operation.
116 """
117 if not show_sql_only and not confirm_downgrade_db:
118 log.critical("Destructive action not confirmed! Refusing.")
119 return
120 if show_sql_only:
121 log.warning("Current Alembic v1.0.0 bug in downgrading with "
122 "as_sql=True; may fail")
123 import_all_models() # delayed, for command-line interfaces
124 downgrade_database(alembic_base_dir=ALEMBIC_BASE_DIR,
125 alembic_config_filename=ALEMBIC_CONFIG_FILENAME,
126 destination_revision=revision,
127 version_table=ALEMBIC_VERSION_TABLE,
128 as_sql=show_sql_only)
129 # ... will get its config information from the OS environment; see
130 # run_alembic() in alembic/env.py
133@preserve_cwd
134def create_database_from_scratch(cfg: "CamcopsConfig") -> None:
135 """
136 Takes the database from nothing to the "head" revision in one step, by
137 bypassing Alembic's revisions and taking the state directly from the
138 SQLAlchemy ORM metadata.
140 See
141 https://alembic.zzzcomputing.com/en/latest/cookbook.html#building-an-up-to-date-database-from-scratch
143 This function ASSUMES that the head revision "frozen" into the latest
144 ``alembic/version/XXX.py`` file MATCHES THE STATE OF THE SQLALCHEMY ORM
145 METADATA as judged by ``Base.metadata``. If that's not the case, things
146 will go awry later! (Alembic will think the database is at the state of its
147 "head" revision, but it won't be.)
149 It also ASSUMES (as many things do) that importing ``.cc_all_models``
150 imports all the models (or ``Base.metadata`` will be incomplete).
151 """ # noqa
152 import_all_models() # delayed, for command-line interfaces
154 log.warning("Performing one-step database creation.")
155 metadata = Base.metadata # type: MetaData
156 engine = cfg.get_sqla_engine()
157 metadata.create_all(engine)
159 alembic_cfg = Config(ALEMBIC_CONFIG_FILENAME)
160 os.chdir(ALEMBIC_BASE_DIR)
161 # command.stamp(alembic_cfg, "head")
162 stamp_allowing_unusual_version_table(alembic_cfg, "head",
163 version_table=ALEMBIC_VERSION_TABLE)
164 log.info("One-step database creation complete.")