recreate database tables only if necessary

mc_backend/mcserver/app/__init__.py

@@ -5,7 +5,7 @@ import sys
 from logging.handlers import RotatingFileHandler
 from threading import Thread
 from time import strftime
-from typing import Type
+from typing import Type, List
 import connexion
 import flask
 from connexion import FlaskApp
@@ -91,6 +91,9 @@ def init_app_common(cfg: Type[Config] = Config, is_csm: bool = False) -> Flask:
     if is_csm:
         from mcserver.app.services.databaseService import DatabaseService
         DatabaseService.init_db_alembic()
+    tables: List[str] = [Config.DATABASE_TABLE_ALEMBIC, Config.DATABASE_TABLE_CORPUS, Config.DATABASE_TABLE_EXERCISE,
+                         Config.DATABASE_TABLE_UPDATEINFO]
+    if any(not db.engine.dialect.has_table(db.engine, x) for x in tables):
         db.create_all()
     from mcserver.app.services.textService import TextService
     TextService.init_proper_nouns_list()

mc_backend/mcserver/app/services/databaseService.py

@@ -42,7 +42,7 @@ class DatabaseService:
     @staticmethod
     def init_db_corpus() -> None:
         """Initializes the corpus list if it is not already there and up to date."""
-        if db.engine.dialect.has_table(db.engine, "Corpus"):
+        if db.engine.dialect.has_table(db.engine, Config.DATABASE_TABLE_CORPUS):
             CorpusService.existing_corpora = db.session.query(Corpus).all()
             db.session.commit()
             urn_dict: Dict[str, int] = {v.source_urn: i for i, v in enumerate(CorpusService.existing_corpora)}
@@ -66,7 +66,7 @@ class DatabaseService:
     @staticmethod
     def init_db_update_info() -> None:
         """Initializes update entries for all resources that have not yet been created."""
-        if db.engine.dialect.has_table(db.engine, "UpdateInfo"):
+        if db.engine.dialect.has_table(db.engine, Config.DATABASE_TABLE_UPDATEINFO):
             for rt in ResourceType:
                 ui_cts: UpdateInfo = db.session.query(UpdateInfo).filter_by(resource_type=rt.name).first()
                 if ui_cts is None:
@@ -93,7 +93,7 @@ class DatabaseService:
     @staticmethod
     def update_exercises(is_csm: bool) -> None:
         """Deletes old exercises."""
-        if db.engine.dialect.has_table(db.engine, "Exercise"):
+        if db.engine.dialect.has_table(db.engine, Config.DATABASE_TABLE_EXERCISE):
             exercises: List[Exercise] = db.session.query(Exercise).all()
             now: datetime = datetime.utcnow()
             for exercise in exercises:

mc_backend/mcserver/config.py

@@ -58,6 +58,9 @@ class Config(object):
     CUSTOM_CORPUS_VIVA_URN = "urn:custom:latinLit:viva.lat"
     CUSTOM_CORPUS_PROIEL_URN_TEMPLATE = "urn:custom:latinLit:proiel.{0}.lat"
     DATABASE_TABLE_ALEMBIC = "alembic_version"
+    DATABASE_TABLE_CORPUS = "Corpus"
+    DATABASE_TABLE_EXERCISE = "Exercise"
+    DATABASE_TABLE_UPDATEINFO = "UpdateInfo"
     DATABASE_URL_DOCKER = "postgresql://postgres@db:5432/"
     DATABASE_URL_LOCAL = "postgresql://postgres@0.0.0.0:5432/postgres"
     DATABASE_URL_SQLITE = f"sqlite:///{os.path.join(basedir, 'app.db')}"