feat: pass modular input script as parameter to input helper stream_e…

[Benni0]

Summary

Change input helper templates to also pass the modular_input instance (smi.Script) to the stream_events function. This makes it easier to interact with Splunk, because the Splunk service of the modular_input instance can be used.

Changes

Added a additional parameter modular_input to the stream_events function of the input helper. Within the input itself, it is checked, if the stream_events function expects three parameters or not. If three parameters are expected, self will be passed as modular_input.
This is the least intrusive approach to implement this feature, but it has the overhead to check the amount of function parameters on each execution. Due to that, all prior implementation which doesn't have the parameter also work and no additional config parameter is necessary.
If you think an additional config parameter would be the better approach, I can implement this as well.

User experience

The user can access the modular_input within the input helper as well.

Checklist

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• I have performed a self-review of this change
• Changes have been tested
• Changes are documented
• PR title follows conventional commit semantics

[hetangmodi-crest]

The changes are neat, however, can you share the use cases where an add-on developer would require the smi.Script object for?
The existing implementation gives you all the knowledge of inputs and an event_writer to write the events.
Moreover, do we need this parameter for both validate_input and stream_events or just stream_events?

[Benni0]

My usecase is an input, which fetches items from MS using securitycenter and graph API. The authentication response is a bearer token which is valid for a specific time. As I want to reuse the token, I want to store it as secret. To achieve this, I use storage_passwords of the splunklib.client. But for this I need a client instance which the smi.Script instance provides (input.service).
The reason why I've added it to validate_input is, that i execute a test request, which requires authentication, during validation.

[hetangmodi-crest]

To achieve the above-mentioned use case, have you tried using ConfManager from solnlib library? It has CRUD methods supported. Perhaps, using this, you can achieve your use case?

[Benni0]

Sure, it would be possible to use ConfManager, but in my opinion I think it is easier to use the already existing client instance.