## Changes
- Print warnings and errors by default.
- Fix ErrAlreadyPrinted not to be logged at Error level.
- Format log messages as "Warn: message" instead of "WARN" to make it
more readable and in-line with the rest of the output.
- Only print attributes (pid, mutator, etc) and time when the overall
level is debug (so --debug output has not changed much).
## Tests
- Existing acceptance tests show how warning messages appear in various
test case.
- Added new test for `--debug` output.
- Add sort_lines.py helper to avoid dependency on 'sort' which is
locale-sensitive.
## Changes
All these validators will return warnings as part of `bundle validate`
run
Added 2 mutators:
1. To check that if tasks use job_cluster_key it is actually defined
2. To check if there are any files to sync as part of deployment
Also added `bundle.Parallel` to run them in parallel
To make sure mutators under bundle.Parallel do not mutate config,
introduced new `ReadOnlyMutator`, `ReadOnlyBundle` and `ReadOnlyConfig`.
Example
```
databricks bundle validate -p deco-staging
Warning: unknown field: new_cluster
at resources.jobs.my_job
in bundle.yml:24:7
Warning: job_cluster_key high_cpu_workload_job_cluster is not defined
at resources.jobs.my_job.tasks[0].job_cluster_key
in bundle.yml:35:28
Warning: There are no files to sync, please check your your .gitignore and sync.exclude configuration
at sync.exclude
in bundle.yml:18:5
Name: test
Target: default
Workspace:
Host: https://acme.databricks.com
User: andrew.nester@databricks.com
Path: /Users/andrew.nester@databricks.com/.bundle/test/default
Found 3 warnings
```
## Tests
Added unit tests