## Changes
This PR now allows you to define variables in the bundle config and set
them in three ways
1. command line args
2. process environment variable
3. in the bundle config itself
## Tests
manually, unit, and black box tests
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Co-authored-by: Miles Yucht <miles@databricks.com>
## Changes
Traverses the variables referred in a depth first manner to resolve
string fields.
Errors out if a cycle is detected
## Tests
Manually and unit/blackbox tests
By specifying a function typed `LookupFunction` the caller can customize
which path expressions to interpolate and which ones to skip. When we
express dependencies between resources their values are known by
Terraform at deploy time. Therefore, we have to skip interpolation for
`${resources.jobs.my_job.id}` and instead rewrite it to
`${databricks_job.my_job.id}` before passing it along to Terraform.
Performs interpolation on string field.
It looks for patterns `${foo.bar}` where `foo.bar` points to a string
field in the configuration data model.
It does not support traversal (e.g. `${foo}` with `foo` equal
to`${bar}`), hence "rudimentary".
shreyas-goenka
Pieter Noordhuis