Weaviate: Improve connection check

[hsm207]

Is your feature request related to a problem? Please describe.
The current check makes a random call to check if the weaviate server is reachable:

 # Test connection, it will raise an exception if it fails.
        self._client.schema.get()

Describe the solution you'd like
Encapsulate the client creation in a method that also does exception handling and prints user friendly messages when an exception is raised. For example (credit to @Shah91n):

def establish_connection():
    
    try:
        client = weaviate.connect_to_wcs(
            cluster_url="",
            auth_credentials=weaviate.auth.AuthApiKey(""),
            headers={"X-OpenAI-Api-Key": ""}
        )

        ready = client.is_ready()
        version = weaviate.__version__
        print(f"Weaviate client is ready: {ready}")
        print(f"Weaviate Version: {version}")
        
return client

    except Exception as e:
        print(f"There is a problem: {e}")
        traceback.print_exc()
        return None

Describe alternatives you've considered
do nothing

Additional context
NA

[srini047]

Hi, @hsm207 I would like to take up this issue.

[hsm207]

Hi @srini047,

Great! Thanks for volunteering. I'm not a maintainer so I can't assign this issue to you. Maybe @masci can?

[srini047]

Hi @hsm207 , I see this issue outdated considering weaviate now automatically handles the connection persistence and its incorporated in haystack-integrations/integrations/weaviate/src/haystack_integrations/document_stores/weaviate/document_store.py.

But now the issue lies with closing connection, where resources are not freed up. So I would like to extend this issue to address that and contribute the same. This requires handling at the object destructor scope to ensure proper management.