improve switch-backend command

docs/commands.md

@@ -16,7 +16,8 @@ Run the relay.
 
 ## Setup
 
-Run the setup wizard to configure your relay.
+Run the setup wizard to configure your relay. For the PostgreSQL backend, the database has to be
+created first.
 
 	activityrelay setup
 
@@ -29,6 +30,16 @@ not specified, the config will get backed up as `relay.backup.yaml` before conve
 	activityrelay convert --old-config relaycfg.yaml
 
 
+## Switch Backend
+
+Change the database backend from the current one to the other. The config will be updated after
+running the command.
+
+Note: If switching to PostgreSQL, make sure the database exists first.
+
+	activityrelay switch-backend
+
+
 ## Edit Config
 
 Open the config file in a text editor. If an editor is not specified with `--editor`, the default

relay/database/connection.py

@@ -4,7 +4,7 @@ import secrets
 
 from argon2 import PasswordHasher
 from blib import Date, convert_to_boolean
-from bsql import Connection as SqlConnection, Row, Update
+from bsql import BackendType, Connection as SqlConnection, Row, Update
 from collections.abc import Iterator
 from datetime import datetime, timezone
 from typing import TYPE_CHECKING, Any
@@ -51,6 +51,17 @@ class Connection(SqlConnection):
 				yield instance
 
 
+	def drop_tables(self) -> None:
+		with self.cursor() as cur:
+			for table in self.get_tables():
+				query = f"DROP TABLE IF EXISTS {table}"
+
+				if self.database.backend.backend_type == BackendType.POSTGRESQL:
+					query += " CASCADE"
+
+				cur.execute(query)
+
+
 	def fix_timestamps(self) -> None:
 		for app in self.select('apps').all(schema.App):
 			data = {'created': app.created.timestamp(), 'accessed': app.accessed.timestamp()}

relay/manage.py

@@ -102,34 +102,7 @@ def cli_setup(ctx: click.Context, skip_questions: bool) -> None:
 			)
 
 		elif ctx.obj.config.db_type == 'postgres':
-			ctx.obj.config.pg_name = click.prompt(
-				'What is the name of the database?',
-				default = ctx.obj.config.pg_name
-			)
-
-			ctx.obj.config.pg_host = click.prompt(
-				'What IP address, hostname, or unix socket does the server listen on?',
-				default = ctx.obj.config.pg_host,
-				type = int
-			)
-
-			ctx.obj.config.pg_port = click.prompt(
-				'What port does the server listen on?',
-				default = ctx.obj.config.pg_port,
-				type = int
-			)
-
-			ctx.obj.config.pg_user = click.prompt(
-				'Which user will authenticate with the server?',
-				default = ctx.obj.config.pg_user
-			)
-
-			ctx.obj.config.pg_pass = click.prompt(
-				'User password',
-				hide_input = True,
-				show_default = False,
-				default = ctx.obj.config.pg_pass or ""
-			) or None
+			config_postgresql(ctx.obj.config)
 
 		ctx.obj.config.ca_type = click.prompt(
 			'Which caching backend?',
@@ -344,9 +317,24 @@ def cli_switchbackend(ctx: click.Context) -> None:
 
 	config = Config(ctx.obj.config.path, load = True)
 	config.db_type = "sqlite" if config.db_type == "postgres" else "postgres"
+
+	if config.db_type == "postgres":
+		if click.confirm("Setup PostgreSQL configuration?"):
+			config_postgresql(config)
+
+		order = ("SQLite", "PostgreSQL")
+		click.pause("Make sure the database and user already exist before continuing")
+
+	else:
+		order = ("PostgreSQL", "SQLite")
+
+	click.echo(f"About to convert from {order[0]} to {order[1]}...")
 	database = get_database(config, migrate = False)
 
 	with database.session(True) as new, ctx.obj.database.session(False) as old:
+		if click.confirm("All tables in the destination database will be dropped. Continue?"):
+			new.drop_tables()
+
 		new.create_tables()
 
 		for table in schema.TABLES.keys():
@@ -354,7 +342,7 @@ def cli_switchbackend(ctx: click.Context) -> None:
 				new.insert(table, row).close()
 
 		config.save()
-		click.echo(f"Converted database to {repr(config.db_type)}")
+		click.echo("Done!")
 
 
 @cli.group('config')
@@ -1015,6 +1003,35 @@ def cli_whitelist_import(ctx: click.Context) -> None:
 		click.echo('Imported whitelist from inboxes')
 
 
+def config_postgresql(config: Config) -> None:
+	config.pg_name = click.prompt(
+		'What is the name of the database?',
+		default = config.pg_name
+	)
+
+	config.pg_host = click.prompt(
+		'What IP address, hostname, or unix socket does the server listen on?',
+		default = config.pg_host,
+	)
+
+	config.pg_port = click.prompt(
+		'What port does the server listen on?',
+		default = config.pg_port,
+		type = int
+	)
+
+	config.pg_user = click.prompt(
+		'Which user will authenticate with the server?',
+		default = config.pg_user
+	)
+
+	config.pg_pass = click.prompt(
+		'User password',
+		hide_input = True,
+		show_default = False,
+		default = config.pg_pass or ""
+	) or None
+
 
 def main() -> None:
 	cli(prog_name='activityrelay')