Feat/chatml add system message (#1117)

* add system message to template

* readme update

* added code to register new system message

* register chatml template for test

---------

Co-authored-by: Mads Henrichsen <mads@BrbartiendeMads.lan>
Co-authored-by: Wing Lian <wing.lian@gmail.com>

README.md

@@ -613,6 +613,8 @@ rl:
 # Saves the desired chat template to the tokenizer_config.json for easier inferencing
 # Currently supports chatml and inst (mistral/mixtral)
 chat_template: chatml
+# Changes the default system message
+default_system_message: You are a helpful assistant. Please give a long and detailed answer. # Currently only supports chatml.
 # Axolotl attempts to save the dataset as an arrow after packing the data together so
 # subsequent training attempts load faster, relative path
 dataset_prepared_path: data/last_run_prepared

src/axolotl/cli/preprocess.py

@@ -18,6 +18,7 @@
 )
 from axolotl.common.cli import PreprocessCliArgs
 from axolotl.common.const import DEFAULT_DATASET_PREPARED_PATH
+from axolotl.prompt_strategies.sharegpt import register_chatml_template
 
 LOG = logging.getLogger("axolotl.cli.preprocess")
 
@@ -34,6 +35,12 @@ def do_cli(config: Path = Path("examples/"), **kwargs):
         return_remaining_strings=True
     )
 
+    if parsed_cfg.chat_template == "chatml" and parsed_cfg.default_system_message:
+        LOG.info(
+            f"ChatML set. Adding default system message: {parsed_cfg.default_system_message}"
+        )
+        register_chatml_template(parsed_cfg.default_system_message)
+
     if not parsed_cfg.dataset_prepared_path:
         msg = (
             Fore.RED

src/axolotl/cli/train.py

@@ -18,6 +18,7 @@
     print_axolotl_text_art,
 )
 from axolotl.common.cli import TrainerCliArgs
+from axolotl.prompt_strategies.sharegpt import register_chatml_template
 from axolotl.train import train
 
 LOG = logging.getLogger("axolotl.cli.train")
@@ -37,7 +38,12 @@ def do_train(cfg, cli_args) -> Tuple[PreTrainedModel, PreTrainedTokenizer]:
     print_axolotl_text_art()
     check_accelerate_default_config()
     check_user_token()
-    if cfg.rl:
+    if cfg.chat_template == "chatml" and cfg.default_system_message:
+        LOG.info(
+            f"ChatML set. Adding default system message: {cfg.default_system_message}"
+        )
+        register_chatml_template(cfg.default_system_message)
+
         dataset_meta = load_rl_datasets(cfg=cfg, cli_args=cli_args)
     else:
         dataset_meta = load_datasets(cfg=cfg, cli_args=cli_args)

src/axolotl/prompt_strategies/sharegpt.py

@@ -6,16 +6,19 @@
 from axolotl.prompt_tokenizers import ShareGPTPromptTokenizingStrategy
 from axolotl.prompters import ShareGPTPrompterV2
 
-register_conv_template(
-    Conversation(
-        name="chatml",
-        system_template="<|im_start|>system\n{system_message}",
-        system_message="You are a helpful assistant.",
-        roles=["<|im_start|>user", "<|im_start|>assistant"],
-        sep_style=SeparatorStyle.CHATML,
-        sep="<|im_end|>",
+
+def register_chatml_template(system_message=None):
+    system_message = system_message or "You are a helpful assistant."
+    register_conv_template(
+        Conversation(
+            name="chatml",
+            system_template="<|im_start|>system\n{system_message}",
+            system_message=system_message,
+            roles=["<|im_start|>user", "<|im_start|>assistant"],
+            sep_style=SeparatorStyle.CHATML,
+            sep="<|im_end|>",
+        )
     )
-)
 
 
 def load(tokenizer, cfg, ds_cfg: Optional[Dict[str, Any]] = None):

src/axolotl/utils/chat_templates.py

@@ -20,7 +20,7 @@ def chat_templates(user_choice: str):
 
     templates = {
         "inst": "{{ bos_token }}{% for message in messages %}{% if (message['role'] == 'user') != (loop.index0 % 2 == 0) %}{{ raise_exception('Conversation roles must alternate user/assistant/user/assistant/...') }}{% endif %}{% if message['role'] == 'user' %}{{ '[INST] ' + message['content'] + ' [/INST]' }}{% elif message['role'] == 'assistant' %}{{ message['content'] + eos_token}}{% else %}{{ raise_exception('Only user and assistant roles are supported!') }}{% endif %}{% endfor %}",  # I don't know what this one is called. Used by Mistral/Mixtral.
-        "chatml": "{% if not add_generation_prompt is defined %}{% set add_generation_prompt = false %}{% endif %}{% for message in messages %}{{'<|im_start|>' + message['role'] + '\n' + message['content'] + '<|im_end|>' + '\n'}}{% endfor %}{% if add_generation_prompt %}{{ '<|im_start|>assistant\n' }}{% endif %}",
+        "chatml": "{% if messages[0]['role'] == 'system' %}{% set loop_messages = messages[1:] %}{% set system_message = messages[0]['content'] %}{% else %}{% set loop_messages = messages %}{% set system_message = 'You are a helpful assistant.' %}{% endif %}{% if not add_generation_prompt is defined %}{% set add_generation_prompt = false %}{% endif %}{% for message in loop_messages %}{% if loop.index0 == 0 %}{{'<|im_start|>system\n' + system_message + '<|im_end|>\n'}}{% endif %}{{'<|im_start|>' + message['role'] + '\n' + message['content'] + '<|im_end|>' + '\n'}}{% endfor %}{% if add_generation_prompt %}{{ '<|im_start|>assistant\n' }}{% endif %}",
     }
 
     if user_choice in templates:

src/axolotl/utils/models.py

@@ -219,7 +219,13 @@ def load_tokenizer(cfg):
     LOG.debug(f"UNK: {tokenizer.unk_token_id} / {tokenizer.unk_token}")
 
     if cfg.chat_template:
-        tokenizer.chat_template = chat_templates(cfg.chat_template)
+        chat_template_string = chat_templates(cfg.chat_template)
+        if cfg.default_system_message and cfg.chat_template == "chatml":
+            chat_template_string = chat_template_string.replace(
+                "You are a helpful assistant.", cfg.default_system_message
+            )
+
+        tokenizer.chat_template = chat_template_string
     else:
         LOG.info(
             "No Chat template selected. Consider adding a chat template for easier inference."

tests/prompt_strategies/test_sharegpt.py

@@ -7,9 +7,14 @@
 from transformers import AutoTokenizer
 
 from axolotl.datasets import TokenizedPromptDataset
-from axolotl.prompt_strategies.sharegpt import SimpleShareGPTPromptTokenizingStrategy
+from axolotl.prompt_strategies.sharegpt import (
+    SimpleShareGPTPromptTokenizingStrategy,
+    register_chatml_template,
+)
 from axolotl.prompters import ShareGPTPrompterV2
 
+register_chatml_template()
+
 
 @pytest.fixture(name="sharegpt_dataset")
 def fixture_sharegpt_dataset():