fix(terraform): apply job fails if lock file has not been commited

[hknutsen]

Cache functionality currently breaks the workflow if the dependency lock file (.terraform.lock.hcl) has not been commited.

While it's recommended to commit the lock file, it's not required. It should be okay to skip caching plugins if lock file has not been commited.

Implementation

Check if lock file exists:

• If yes, enable plugin cache.
• If no, don't enable plugin cache and skip all cache related steps.

Testing

• Tested and verified to work when lock file has been commited.
• Tested and verified to work when lock file has not been commited.

(see results in comments)

[hknutsen]

Lock file commited

Both Plan and Apply jobs run successfully:

During the Plan job, cache was both restored and saved:

During the Apply job, cache was restored:

[hknutsen]

Lock file NOT commited

Both Plan and Apply jobs run successfully:

During the Plan job, cache was NOT restored and/or saved:

During the Apply job, cache was NOT restored: