[v1] support switch v1 backend (#9226)

src/llamafactory/v1/launcher.py

@@ -0,0 +1,33 @@
+# Copyright 2025 the LlamaFactory team.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+
+def run_train():
+    raise NotImplementedError("Please use `llamafactory-cli sft` or `llamafactory-cli rm`.")
+
+
+def run_chat():
+    from llamafactory.v1.core.chat_sampler import Sampler
+
+    Sampler().cli()
+
+
+def run_sft():
+    from llamafactory.v1.train.sft import SFTTrainer
+
+    SFTTrainer().run()
+
+
+if __name__ == "__main__":
+    run_train()