Tutorial projects do not work in Colab because of dependency conflict.

[palle-k]

Describe the bug
When launching the example projects in Google Colab (tested with basic example without elasticsearch and knowledge base example), importing haystack results in a ContextualVersionConflict.

Error message

ContextualVersionConflict                 Traceback (most recent call last)
<ipython-input-7-55c351f0b509> in <module>()
----> 1 from haystack.utils import clean_wiki_text, convert_files_to_dicts, fetch_archive_from_http, print_answers
      2 from haystack.nodes import FARMReader, TransformersReader

15 frames
/usr/local/lib/python3.7/dist-packages/pkg_resources/__init__.py in resolve(self, requirements, env, installer, replace_conflicting, extras)
    775                 # Oops, the "best" so far conflicts with a dependency
    776                 dependent_req = required_by[req]
--> 777                 raise VersionConflict(dist, req).with_context(dependent_req)
    778 
    779             # push the new requirements onto the stack

ContextualVersionConflict: (grpcio 1.42.0 (/usr/local/lib/python3.7/dist-packages), Requirement.parse('grpcio<1.38.0,>=1.22.0'), {'pymilvus'})

Expected behavior
Haystack should import without error.

Additional context
Google Colab with GPU runtime

To Reproduce

1. Open colab example
2. Change runtime type to GPU
3. Run the first few cells of the notebook including the cell that imports haystack.

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System:

• OS: Linux 76012de36819 5.4.144+
• GPU/CPU: Nvidia Tesla K80 / Intel Xeon
• Haystack version (commit or version number): latest master (0b0b968)
• DocumentStore: InMemoryDocumentStore
• Reader: FARMReader
• Retriever: TfidfRetriever

[julian-risch]

Hi @palle-k thanks for creating this issue. It will work after restarting the notebook ("restart and run all" for example).

Unfortunately, this dependency conflict and the need to restart the notebook is something we weren't able to resolve in the last weeks although we are already aware of the problem. We have an open issue for that here: #1806 We will define a reduced set of required dependencies to resolve that version conflict. Feel free to open another issue in case there is anything we can help with! 🙂