Add sqlite connector support (#733)

Configurable choice to setup the sqlalchemy engine with SQLite rather than PostgreSQL. This is set in the security configuration. The database name in the database credentials file should be the path to the SQLite database.

Author: d-j-hatton

src/murfey/server/murfey_db.py

@@ -15,6 +15,8 @@ def url(security_config: Security | None = None) -> str:
     security_config = security_config or get_security_config()
     with open(security_config.murfey_db_credentials, "r") as stream:
         creds = yaml.safe_load(stream)
+    if security_config.db == "sqlite":
+        return f"sqlite:///{creds['database']}"
     f = Fernet(security_config.crypto_key.encode("ascii"))
     p = f.decrypt(creds["password"].encode("ascii"))
     return f"postgresql+psycopg2://{creds['username']}:{p.decode()}@{creds['host']}:{creds['port']}/{creds['database']}"

src/murfey/util/config.py

@@ -228,6 +228,7 @@ class Security(BaseModel):
     # Murfey database settings
     murfey_db_credentials: Path
     crypto_key: str
+    db: str = "postgres"
     sqlalchemy_pooling: bool = True
 
     # ISPyB settings