ML policies with missing models causing ensemble not to load

[pheel]

rules:
  - rule: Thank you
    steps:
      - intent: thankyou
      - action: utter_noworries
stories: []

policies:
  - name: TEDPolicy
  - name: RulePolicy

Since no stories are used, training results in log entry Can not train 'TEDPolicy'. No data was provided. Skipping training of the policy.

However, trying to load Core model after training is prevented by exception: Failed to load TED policy model. Path '/var/folders/80/5x0m20sn0bb_r7bg28b6lvt40000gn/T/tmp96oslq6_/core/policy_0_TEDPolicy' doesn't exist.

Ensemble could be allowed to load, minus any ML policies whose training was skipped.

Rasa version: 2.0.x

[sara-tagger]

Thanks for raising this issue, @tttthomasssss will get back to you about it soon✨

Please also check out the docs and the forum in case your issue was raised there too 🤗

[shubhvachher]

Adding that this happens for more complex rule based systems as well. Just, without any stories to train upon.

Quick Fix is to comment out TEDPolicy from your config.yml before training and just rule policy trains on nlu, domain and rules. Further stack trace:

During training:

...
2020-12-28 17:05:30 ERROR    rasa.core.policies.ted_policy  - Can not train 'TEDPolicy'. No data was provided. Skipping training of the policy.
...

Running rasa shell to test the model.

2020-12-28 17:46:55 INFO     root  - Connecting to channel 'cmdline' which was specified by the '--connector' argument. Any other channels will be ignored. To connect to all given channels, omit the '--connector' argument.
2020-12-28 17:46:55 INFO     root  - Starting Rasa server on http://localhost:5005
2020-12-28 17:47:02 ERROR    rasa.core.agent  - Could not load model due to Failed to load TED policy model. Path 'C:\Users\USER\AppData\Local\Temp\tmp8w58l_23\core\policy_1_TEDPolicy' doesn't exist..
.\miniconda3\envs\rasa\lib\site-packages\rasa\shared\utils\io.py:89: UserWarning: The model at 'models' could not be loaded. Error: Failed to load TED policy model. Path 'C:\Users\USER\AppData\Local\Temp\tmp8w58l_23\core\policy_1_TEDPolicy' doesn't exist.   
.\miniconda3\envs\rasa\lib\site-packages\rasa\shared\utils\io.py:89: UserWarning: Agent could not be loaded with the provided 
configuration. Load default agent without any model.
2020-12-28 17:47:02 INFO     root  - Rasa server is up and running.
Bot loaded. Type a message and press enter (use '/stop' to exit): 
Your input ->  hi                                                                                                                    
.\miniconda3\envs\rasa\lib\site-packages\rasa\shared\utils\io.py:89: UserWarning: No policy ensemble or domain set. Skipping action prediction and execution.
  More info at https://rasa.com/docs/rasa/policies