This makes the data_stream timestamp field specification optional when
defining a composable template.
When there isn't one specified it will default to `@timestamp`.
Limit the creation of data streams only for namespaces that have a composable template with a data stream definition.
This way we ensure that mappings/settings have been specified and will be used at data stream creation and data stream rollover.
Also remove `timestamp_field` parameter from create data stream request and
let the create data stream api resolve the timestamp field
from the data stream definition snippet inside a composable template.
Relates to #53100
This PR changes the name of the Index Template V2 classes to "Composable Templates", it also ensures there are no mentions of "V2" in the documentation or error/warning messages. V1 templates are referred to as "legacy" templates.
Resolves#56609
This adds an API for simulating template composition with or without an index template.
It looks like:
```
POST /_index_template/_simulate/my-template
```
To simulate a template named `my-template` that already exists, or, to simulate a template that does
not already exist:
```
POST /_index_template/_simulate
{
"index_patterns": ["my-index"]
"composed_of": ["ct1", "ct2"],
}
```
This is related to #55686, which adds an API to simulate composition based on an index name (hence
the `_simulate_index` vs `_simulate`).
This commit also adds reference documentation for both simulation APIs.
Relates to #53101Resolves#56390Resolves#56255
This commit removes the ability to put V2 index templates that reference missing component templates.
It also prevents removing component templates that are being referenced by an existing V2 index
template.
Relates to #53101Resolves#56314
This commit removes the `prefer_v2_templates` flag and setting. This was a brief setting that
allowed specifying whether V1 or V2 template should be used when an index is created. It has been
removed in favor of V2 templates always having priority.
Relates to #53101Resolves#56528
This is not a breaking change because this flag was never in a released version.
This also fixes an issue where a `null` priority was treated as below a 0 priority. `null` is now
treated as 0 priority when it comes to comparing V2 templates.
Relates to #53101
This commit adds the initial document for version two index templates. Since these are intended to
be used in favor of V1 index templates, this re-uses the anchors for index templates to point to the
V2 APIs, renaming the V1 template docs' anchors (this was a suggestion from the docs team).
There is more documentation that can be written, but this is a start.
Relates to #53101
debadair
Julie Tibshirani
James Rodewig
Andrei Dan
Lisa Cawley
Martijn van Groningen
Lee Hinman