docs: Add more info on debugging & seeing component outputs

[TuanaCelik]

Our docs doesn't really yet guide users on how to inspect individual component outputs. This comes up especially in terms of prompts, to see the full created prompt. I can imagine a few sections where we could improve the explanations:

• In the Creating Pipelines section: I can imagine a point 7) Inspect the pipeline (or something along those lines)
• Specifically in the PromptBuilder docs
• Adding more context in the setting the log level docs in terms of inspecting component outputs

These are just some ideas..

[underthesand]

I am currently looking for how to debug with v2, not tested with v1. Knowing that debug_path doesn't seem to do anything in the haystack code

Pipeline(debug_path=Path("debug/"))

and I don't see where to get the debug information after pipeline excec with debug=True, debug folder still empty and no data in the output dictionary, no _debug key ?

pipeline.run(data={"query_embedder": {"text": input_text}, "prompt_builder": {"query": input_text}}, debug=True)

So yes it would be helpful to document this.

[MrDVolk]

I also would like some documentation (or functionality) for debugging pipelines. My previous solution relied heavily on getting _debug information from pipeline's output, but after migration I cannot find anything that could effectively substitute it.

[dfokina]

Hi all, I have added a doc page with currently available methods for debugging in Haystack: https://docs.haystack.deepset.ai/docs/debugging-pipelines

The debug param during execution will be deprecated as it is no longer used in 2.x.