Adjust lacre.dbschema to reflect original schema.sql

- Set nullability of columns.
- Set up primary keys and auto-increment where necessary.
- Add missing 'lacre_locks' table.
- Implement a function to create tables.

lacre/dbschema.py

@@ -7,6 +7,8 @@ This definition includes:
 
 - 'lacre_identities' -- identity catalogue, used by encryption logic to match
   emails with corresponding keys.
+
+- 'lacre_locks' -- used only by the frontend.
 """
 
 import sqlalchemy
@@ -23,23 +25,40 @@ CO_CONFIRMED = ''
 _meta = sqlalchemy.MetaData()
 
 LACRE_KEYS = sqlalchemy.Table('lacre_keys', _meta,
-                              sqlalchemy.Column('id', sqlalchemy.Integer, primary_key=True),
+                              sqlalchemy.Column('id', sqlalchemy.Integer, primary_key=True, autoincrement='auto'),
                               sqlalchemy.Column('email', sqlalchemy.String(256), index=True),
                               # ASCII-armored key
                               sqlalchemy.Column('publickey', sqlalchemy.Text),
                               # Empty string means this key has been confirmed.
                               sqlalchemy.Column('confirm', sqlalchemy.String(32)),
                               # Status: see ST_* constants at the top of the file.
-                              sqlalchemy.Column('status', sqlalchemy.Integer),
+                              sqlalchemy.Column('status', sqlalchemy.Integer, nullable=False),
                               sqlalchemy.Column('time', sqlalchemy.DateTime))
 
+LACRE_LOCKS = sqlalchemy.Table('lacre_locks', _meta,
+                               sqlalchemy.Column('id', sqlalchemy.Integer, primary_key=True, nullable=False, autoincrement='auto'),
+                               sqlalchemy.Column('ip', sqlalchemy.String(16)),
+                               sqlalchemy.Column('time', sqlalchemy.Integer),
+                               sqlalchemy.Column('action', sqlalchemy.String(16)),
+                               sqlalchemy.Column('num', sqlalchemy.Integer),
+                               )
+
 LACRE_IDENTITIES = sqlalchemy.Table('lacre_identities', _meta,
-                                    sqlalchemy.Column('email', sqlalchemy.String(256), index=True),
+                                    sqlalchemy.Column('email', sqlalchemy.String(256), index=True, nullable=False),
                                     # Key fingerprint
-                                    sqlalchemy.Column('fingerprint', sqlalchemy.String(64), index=True))
+                                    sqlalchemy.Column('fingerprint', sqlalchemy.String(64), index=True, nullable=False))
 
 def init_identities_table() -> sqlalchemy.Table:
     return LACRE_IDENTITIES
 
+def init_locks_table() -> sqlalchemy.Table:
+    return LACRE_LOCKS
+
+def init_keys_table() -> sqlalchemy.Table:
+    return LACRE_KEYS
+
+def create_tables(engine):
+    _meta.create_all(engine)
+
 def table_metadata():
     return _meta