Issue #340 fill null event key

[EvavW]

Description & motivation

Follows discussion in Issue #340

Changes:

• Use array_to_string rather than concat to create event_key
• replace session_key with client_key and session_id in event_key creation
• Add warning for users that this could result in duplicate event_keys in cases where distinction between events depends on one or both of those values being not null.

Rationale:

Generate event_key even when session_key is null (either because of null user_psuedo_id or null ga_session_id). This will improve the usability of event_key as a tool to count unique events.

Use both client_key and session_id in key creation (instead of session_key) so that a null value in either user_pseudo_id or ga_session_id will not nullify the other. This prevents duplicate event_keys. For example:

• In a case where user_pseudo_id is available but ga_session_id is null. This results in a null session_key. If that session_key is used to create event_key for two events for which all other inputs to key generation are identical then there will be duplicates. Using both client_key and session_id in event_key generation prevents this.
• Of course in the case that both user_pseudo_id and ga_session_id are null and all other inputs to key generation are identical there will still be duplicates.

Checklist

• I have verified that these changes work locally
• I have updated the README.md (if applicable)
• I have added tests & descriptions to my models (and macros if applicable)
• I have run dbt test and python -m pytest . to validate existing tests

[adamribaudo-velir]

Looks good. Well-documented as well. Hope to see you contribute more!

[EvavW]

Thanks for the review @adamribaudo-velir! Do you have an idea of when this can be merged and released?

[adamribaudo-velir]

Released https://github.com/Velir/dbt-ga4/releases/tag/6.1.0