Initial commit

This is a FastAPI backend microservice template used with `copier` utility.

Features of applied template are:
- Configuration file processing logic
- Metrics and tracing (both optional) configuration available
- Debug endpoints
- Database migration commands, prepared Alembic environment
- Database usage example in ping_db endpoint
- gitea sanity check pipeline

{{project_slug}}/db/migrator/env.py.jinja

@@ -0,0 +1,96 @@
+# pylint: disable=wrong-import-position
+"""Environment preparation for Alembic is performed here."""
+
+import asyncio
+import os
+from logging.config import fileConfig
+
+from alembic import context
+from dotenv import load_dotenv
+from sqlalchemy import pool
+from sqlalchemy.engine import Connection
+from sqlalchemy.ext.asyncio import async_engine_from_config
+
+from {{project_slug}}.config import {{ProjectName}}Config
+from {{project_slug}}.db import DeclarativeBase
+from {{project_slug}}.db.entities import *  # pylint: disable=wildcard-import,unused-wildcard-import
+
+envfile_path = os.environ.get("ENVFILE", ".env")
+if os.path.isfile(envfile_path):
+    try:
+        load_dotenv(envfile_path)
+    except Exception as exc:
+        print(f"Got an error while loading envfile '{envfile_path}': {exc!r}")
+config = context.config
+section = config.config_ini_section
+
+app_settings = {{ProjectName}}Config.from_file(os.getenv("CONFIG_PATH"))
+
+config.set_section_option(section, "POSTGRES_DB", app_settings.db.master.database)
+config.set_section_option(section, "POSTGRES_HOST", app_settings.db.master.host)
+config.set_section_option(section, "POSTGRES_USER", app_settings.db.master.user)
+config.set_section_option(section, "POSTGRES_PASSWORD", app_settings.db.master.password.get_secret_value())
+config.set_section_option(section, "POSTGRES_PORT", str(app_settings.db.master.port))
+
+
+fileConfig(config.config_file_name, disable_existing_loggers=False)
+target_metadata = DeclarativeBase.metadata
+
+
+def run_migrations_offline() -> None:
+    """Run migrations in 'offline' mode.
+
+    This configures the context with just a URL
+    and not an Engine, though an Engine is acceptable
+    here as well.  By skipping the Engine creation
+    we don't even need a DBAPI to be available.
+
+    Calls to context.execute() here emit the given string to the
+    script output.
+    """
+    url = config.get_main_option("sqlalchemy.url")
+    context.configure(
+        url=url,
+        target_metadata=target_metadata,
+        literal_binds=True,
+        dialect_opts={"paramstyle": "named"},
+    )
+
+    with context.begin_transaction():
+        context.run_migrations()
+
+
+def do_run_migrations(connection: Connection) -> None:
+    context.configure(connection=connection, target_metadata=target_metadata)
+
+    with context.begin_transaction():
+        context.run_migrations()
+
+
+async def run_async_migrations() -> None:
+    """In this scenario we need to create an Engine
+    and associate a connection with the context.
+    """
+
+    connectable = async_engine_from_config(
+        config.get_section(config.config_ini_section, {}),
+        prefix="sqlalchemy.",
+        poolclass=pool.NullPool,
+    )
+
+    async with connectable.connect() as connection:
+        await connection.run_sync(do_run_migrations)
+
+    await connectable.dispose()
+
+
+def run_migrations_online() -> None:
+    """Run migrations in 'online' mode."""
+
+    asyncio.run(run_async_migrations())
+
+
+if context.is_offline_mode():
+    run_migrations_offline()
+else:
+    run_migrations_online()