Training Core - Failed to find a reader class for the story file `data`

Hi, I had previously posted Running the Test Command with Multiple Domain Files regarding testing with multiple domain files. I combined my domain files into a single domain file and “rasa test nlu” worked.

However, I am still facing the same error message for “rasa train core” with a single domain.yml file. I was following the documentation on Comparing Policy Configurations Testing Your Assistant. “rasa train” itself works fine with no issues.

This is the full stack trace (omitting the file path):

Traceback (most recent call last):
  File "/omitted/env/bin/rasa", line 8, in <module>
    sys.exit(main())
  File "/omitted/env/lib/python3.8/site-packages/rasa/__main__.py", line 117, in main
    cmdline_arguments.func(cmdline_arguments)
  File "/omitted/env/lib/python3.8/site-packages/rasa/cli/train.py", line 165, in run_core_training
    rasa.utils.common.run_in_loop(
  File "/omitted/env/lib/python3.8/site-packages/rasa/utils/common.py", line 296, in run_in_loop
    result = loop.run_until_complete(f)
  File "uvloop/loop.pyx", line 1456, in uvloop.loop.Loop.run_until_complete
  File "/omitted/env/lib/python3.8/site-packages/rasa/core/train.py", line 147, in do_compare_training
    _, no_stories = await asyncio.gather(
  File "/omitted/env/lib/python3.8/site-packages/rasa/core/train.py", line 138, in get_no_of_stories
    stories = await loading.load_data_from_files([story_file], Domain.load(domain))
  File "/omitted/env/lib/python3.8/site-packages/rasa/shared/core/training_data/loading.py", line 111, in load_data_from_files
    reader = _get_reader(story_file, domain, template_variables, use_e2e)
  File "/omitted/env/lib/python3.8/site-packages/rasa/shared/core/training_data/loading.py", line 35, in _get_reader
    return _guess_reader(filename, domain, template_variables, use_e2e)
  File "/omitted/env/lib/python3.8/site-packages/rasa/shared/core/training_data/loading.py", line 48, in _guess_reader
    raise ValueError(
ValueError: Failed to find a reader class for the story file `data`. Supported formats are .md, .yml, .yaml.

Can you show us the output of the rasa --version and tree /f commands in the root directory of the chatbot?

Rasa --version

rasa --version
Rasa Version      :         2.7.1
Minimum Compatible Version: 2.6.0
Rasa SDK Version  :         2.7.0
Rasa X Version    :         0.41.1
Python Version    :         3.8.3

tree -f

├── ./actions
│   ├── ./actions/actions.py
│   ├── ./actions/__init__.py
│   ├── ./actions/__pycache__
│   │   ├── ./actions/__pycache__/actions.cpython-38.pyc
│   │   └── ./actions/__pycache__/__init__.cpython-38.pyc
│   └── ./actions/requirements-actions.txt
├── ./config_roberta.yml
├── ./config_spacy.yml
├── ./config.yml
├── ./credentials.yml
├── ./data
│   ├── ./data/cuisine.yml
│   ├── ./data/dairy.yml
│   ├── ./data/datasets
│   │   ├── ./data/datasets/dairy_dataset.pkl
│   │   ├── ./data/datasets/fruit_dataset.pkl
│   │   ├── ./data/datasets/grains_dataset.pkl
│   │   ├── ./data/datasets/proteins_dataset.pkl
│   │   ├── ./data/datasets/recipes_dataset.pkl
│   │   └── ./data/datasets/veg_dataset.pkl
│   ├── ./data/dish_categories.yml
│   ├── ./data/fruits.yml
│   ├── ./data/grains.yml
│   ├── ./data/nlu_healthy_eating.yml
│   ├── ./data/nlu.yml
│   ├── ./data/proteins.yml
│   ├── ./data/rules.yml
│   ├── ./data/stories.yml
│   └── ./data/vegetables.yml
├── ./docker-compose.yml
├── ./Dockerfile
├── ./domain
│   └── ./domain/domain_healthy_eating.yml
├── ./domain.yml
├── ./endpoints.yml
├── ./events.db
├── ./events.db-shm
├── ./events.db-wal
├── ./models
│   ├── ./models/20210728-223717.tar.gz
│   ├── ./models/20210731-222535.tar.gz
│   ├── ./models/20210801-000419.tar.gz
│   ├── ./models/20210801-003539.tar.gz
│   ├── ./models/20210801-012016.tar.gz
│   ├── ./models/20210801-212804.tar.gz
│   ├── ./models/20210801-230304.tar.gz
│   ├── ./models/20210801-231817.tar.gz
│   ├── ./models/20210802-030644.tar.gz
│   ├── ./models/20210803-022937.tar.gz
│   ├── ./models/20210803-024614.tar.gz
│   ├── ./models/20210803-031802.tar.gz
│   ├── ./models/20210803-034655.tar.gz
│   ├── ./models/20210803-040204.tar.gz
│   ├── ./models/20210803-042745.tar.gz
│   ├── ./models/20210803-145147.tar.gz
│   ├── ./models/20210803-150849.tar.gz
│   ├── ./models/core-20210628-014507.tar.gz
│   ├── ./models/core-20210628-014944.tar.gz
│   ├── ./models/nlu-20210628-012100.tar.gz
│   ├── ./models/nlu-20210628-012352.tar.gz
│   ├── ./models/nlu-20210628-205142.tar.gz
│   ├── ./models/nlu-20210701-191556.tar.gz
│   └── ./models/nlu-20210802-030230.tar.gz
├── ./new
│   ├── ./new/actions (with choose recipes).py
│   ├── ./new/nlu (with recipes).yml
│   ├── ./new/stories_recipes.yml
│   └── ./new/stories (with recipe choice).yml
├── ./old
│   ├── ./old/config_2.yml
│   ├── ./old/config_xlnet.yml
│   ├── ./old/domain_food_safety.yml
│   ├── ./old/domain_healthy_eating (copy).yml
│   ├── ./old/domain.yml
│   ├── ./old/nlu (copy).yml
│   ├── ./old/nlu_food_safety.yml
│   ├── ./old/nlu_healthy_eating (copy).yml
│   ├── ./old/nlu_old.yml
│   ├── ./old/stories_old.yml
│   └── ./old/stories.yml
├── ./preprocess_data
│   ├── ./preprocess_data/cuisine
│   │   ├── ./preprocess_data/cuisine/cuisine_dataset.pkl
│   │   ├── ./preprocess_data/cuisine/cuisine.ipynb
│   │   ├── ./preprocess_data/cuisine/DOHMH_New_York_City_Restaurant_Inspection_Results.csv
│   │   ├── ./preprocess_data/cuisine/Restaurant_Inspection_Open_Data_Dictionary_082214.xlsx
│   │   ├── ./preprocess_data/cuisine/test.json
│   │   └── ./preprocess_data/cuisine/train.json
│   ├── ./preprocess_data/food_list.ipynb
│   └── ./preprocess_data/recipes
│       ├── ./preprocess_data/recipes/dish_categories.txt
│       ├── ./preprocess_data/recipes/epi_r.csv
│       ├── ./preprocess_data/recipes/full_format_recipes.json
│       ├── ./preprocess_data/recipes/recipe.py
│       ├── ./preprocess_data/recipes/recipes.ipynb
│       └── ./preprocess_data/recipes/utils.py
├── ./rasa.db
├── ./README.md
├── ./requirements.txt
├── ./story_graph.dot
├── ./temp
│   ├── ./temp/testing_dataset_v1.json
│   └── ./temp/training_dataset_v1.json
├── ./test.ipynb
├── ./tests
│   └── ./tests/test_stories.yml
└── ./train_test_split
    ├── ./train_test_split/nlg_test_data.yml
    ├── ./train_test_split/nlg_training_data.yml
    ├── ./train_test_split/test_data.yml
    └── ./train_test_split/training_data.yml