## Changes
This pull request extends the templating support in preparation of a
new, default template (WIP, https://github.com/databricks/cli/pull/686):
* builtin templates that can be initialized using e.g. `databricks
bundle init default-python`
* builtin templates are embedded into the executable using go's `embed`
functionality, making sure they're co-versioned with the CLI
* new helpers to get the workspace name, current user name, etc. help
craft a complete template
* (not enabled yet) when the user types `databricks bundle init` they
can interactively select the `default-python` template
And makes two tangentially related changes:
* IsServicePrincipal now uses the "users" API rather than the
"principals" API, since the latter is too slow for our purposes.
* mode: prod no longer requires the 'target.prod.git' setting. It's hard
to set that from a template. (Pieter is planning an overhaul of warnings
support; this would be one of the first warnings we show.)
The actual `default-python` template is maintained in a separate PR:
https://github.com/databricks/cli/pull/686
## Tests
Unit tests, manual testing
## Changes
The `.tmpl` extension is only meant as a qualifier for whether the file
content is executed as a template. All file paths in the `template`
directory should be treated as valid go text templates.
Before only paths with the `.tmpl` extensions would be resolved as
templates, after this change, all file paths are interpreted as
templates.
## Tests
Unit test. The newly added unit tests also asserts that the file path is
correct, even when the `.tmpl` extension is missing.
## Changes
In a world before this PR, all files would be treated as `go text
templates`, making the content in these files quake in fear since they
would be executed (as a template).
This PR makes it so that only files with the `.tmpl` extension are
understood to be templates. This is useful for avoiding ambiguity in
cases like where a binary file could be interpreted as a go text
template otherwise.
In order to do so, we introduce the `copyFile` struct which does a copy
of the source file from the template without loading it into memory.
## Tests
Unit tests