Use CircleCI contexts for environment variables

[dbeatty10]

resolves N/A

This is a:

• ci change

All pull requests from community contributors should target the main branch (default).

Description & motivation

CircleCI has a capability of creating a named collection of environment variables called "contexts".

We've created one CircleCI Context per hosted data platform used in our integration tests:

• profile-redshift
• profile-snowflake
• profile-bigquery
• profile-databricks

CircleCI contexts included in a CI workflow take priority over project-level environment variables (according to this order of precedence). So if ENV_VAR_123 is defined both at the project level and within a context, the project-specific one is not utilized.

Checklist

• This code is associated with an Issue which has been triaged and accepted for development.
• I have verified that these changes work locally on the following warehouses (Note: it's okay if you do not have access to all warehouses, this helps us understand what has been covered)
  • BigQuery
  • Postgres
  • Redshift
  • Snowflake
• I followed guidelines to ensure that my changes will work on "non-core" adapters by:
  • dispatching any new macro(s) so non-core adapters can also use them (e.g. the star() source)
  • using the limit_zero() macro in place of the literal string: limit 0
  • using dbt.type_* macros instead of explicit datatypes (e.g. dbt.type_timestamp() instead of TIMESTAMP
• I have updated the README.md (if applicable)
• I have added tests & descriptions to my models (and macros if applicable)
• I have added an entry to CHANGELOG.md

[dave-connors-3]

LGTM!

[joellabes]

This is obviously resolved, but for my enrichment: how is this only additive? What did it replace and where did that go?

[dbeatty10]

This is obviously resolved, but for my enrichment: how is this only additive? What did it replace and where did that go?

This replaces project-level environment variables in the case that the same environment variable is also defined within an imported context. The description above has been updated to add more detail.