Fix: defined default var for langchain cache path to enable custom path (issue 987)

[m10mi5]

When defining lc_cache_path and enabling cache in config:

# Enable third parties caching (e.g LangChain cache)
cache = true
lc_cache_path = './.custom-cache-path.db'

TypeError is thrown:

TypeError: chainlit.config.ProjectSettings() got multiple values for keyword argument 'lc_cache_path'

[tpatel]

Thanks for your code, I've added two comments.

[tpatel]

I believe you're missing something to change the project_config["lc_cache_path"] value, like:

Suggested change

	project_settings = ProjectSettings(
	project_config["lc_cache_path"] = project_config.get("lc_cache_path", lc_cache_path)
	project_settings = ProjectSettings(

[m10mi5]

the way i understand it and tested it locally, possible custom path will be picked up by toml_dict module here:

project_config = toml_dict.get("project", {})

or will default to default value as proposed by my PR here

# default to "{config_dir}/.langchain.db"
lc_cache_path: Optional[str] = os.path.join(config_dir, ".langchain.db")

[dokterbob]

I think @necjamahim is right on this one. Could you please have another look @tpatel?

[tpatel]

I'm not sure to understand why you've removed this?

[m10mi5]

it is because previous line st_llm_cache generates sqlite db file at path

set_llm_cache(SQLiteCache(database_path=config.project.lc_cache_path))

consequently in next line we want to inform cache was generated by testing if path exists and not the opposite. I hope I was clear - was trying not to use too many "if", "not" in the explaination

[dokterbob]

Thanks for your contribution @necjamahim!

I see where you're coming from; current config doesn't allow overriding the langchain cache configured through lc_cache_path, which seems hardcoded to {config_dir}/.langchain.db.

So this patch keeps the previously hardcoded value as a default and makes it configurable.

However, I don't see how your changes to set_chat_profiles come in. Could you please remove this from your patch and resolve any merge conflicts?

As soon as that's done I'll do a final manual test and I think we're good to go!

[dokterbob]

How is this relevant to the issue at hand?

[dokterbob]

If this is a default config option, it seems better to uncomment it, in line with other default config options.

[dokterbob]

I think @necjamahim is right on this one. Could you please have another look @tpatel?