* [WiP] improve load_examples
related to #7472, longer term we will generate the examples by exporting
them into tarball as in #7472. In the meantime, we need this subset of
the features:
* allowing specifying an alternate database connection for examples
* allowing a --only-metadata flag to `load_examples` to load only
dashboard and chart definitions, no actual data is loaded
* Improve logging
* Rename data->examples
* Load only if not exist
* By default do not load, add a force flag
* fix build
* set published to true
* Force quotes on non-expression time grains on postgres
* Change to or semantics
* Return lower case column name as unmutated
* Add testcases for postgres time grains
* Make expression MixedCase
Summary: We want to allow grouping by on expressions, including the
ability to select expressions (without group-by). The UI ain't good yet
.. it is not at the feature parity of say adhoc filters/metrics that
come with a nice text-box to edit the SQL. But
this suffices for my usecase for now.
(The UI would have to be redone ... but that would require some refactoring
to merge the AdhocFilter/Metric/Popover stuff such that it can be used
for this use case too.)
Also fixed a bug in the SelectControl freeForm selection.
Allow selecting all columns easily: Added a new Select-All special item
that users can select to make all the options in the selectable show
up.
The ability to group by arbitrary expressions is useful because now two
users don't need to create custom computed-fields for this.
* Use py3's f-strings instead of s.format(**locals())
In light of the bug reported here
https://github.com/apache/incubator-superset/issues/6347, which seems
like an odd `.format()` issue in py3, I greped and replaced all
instances of `.format(**locals())` using py3's f-strings
* lint
* fix tests
* [utils] gathering/refactoring into a "utils/" folder
Moving current utils.py into utils/core.py and moving other *util*
modules under this new "utils/" as well.
Following steps include eroding at "utils/core.py" and breaking it down
into smaller modules.
* Improve tests
* Make loading examples in scope for tests
* Remove test class attrs examples_loaded and requires_examples
* [bugfix] temporal columns with expression fail
error msg: "local variable 'literal' referenced before assignment"
Error occurs [only] when using temporal column defined as a SQL
expression.
Also noticed that examples were using `granularity` instead of using
`granularity_sqla` as they should. Fixed that here.
* Add tests
* Add "Impersonate user" setting to Datasource
* Add tests
* Use g.user.username for all the sync cases
* use uri.username instead of uri.user
* Small refactoring