Template creation using context

[mgodwan]

Description

• Adds logic to create index template through the context field
• Adds validation to not allow using system templates in composed_of
• Adds validation to ensure only pre-determined loaders can add system templates
• Updates logic where template data is applied during index creation/simulation.

Status 7/18: Modify and add new tests for the feature.

Related Issues

Resolves #12683

Check List

• Functionality includes testing.
• API changes companion pull request created, if applicable.
• Public documentation issue/PR created, if applicable.

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.
For more information on following Developer Certificate of Origin and signing off your commits, please check here.

[github-actions]

❌ Gradle check result for 8036645: FAILURE

Please examine the workflow log, locate, and copy-paste the failure(s) below, then iterate to green. Is the failure a flaky test unrelated to your change?

[github-actions]

❌ Gradle check result for 7233318: FAILURE

Please examine the workflow log, locate, and copy-paste the failure(s) below, then iterate to green. Is the failure a flaky test unrelated to your change?

[opensearch-trigger-bot]

The backport to 2.x failed:

The process '/usr/bin/git' failed with exit code 128

To backport manually, run these commands in your terminal:

# Navigate to the root of your repository
cd $(git rev-parse --show-toplevel)
# Fetch latest updates from GitHub
git fetch
# Create a new working tree
git worktree add ../.worktrees/OpenSearch/backport-2.x 2.x
# Navigate to the new working tree
pushd ../.worktrees/OpenSearch/backport-2.x
# Create a new branch
git switch --create backport/backport-14811-to-2.x
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x --mainline 1 c76bfebd49c8129b564edc68ce59f01853dc6722
# Push it to GitHub
git push --set-upstream origin backport/backport-14811-to-2.x
# Go back to the original working tree
popd
# Delete the working tree
git worktree remove ../.worktrees/OpenSearch/backport-2.x

Then, create a pull request where the base branch is 2.x and the compare/head branch is backport/backport-14811-to-2.x.

[opensearch-trigger-bot]

The backport to 2.16 failed:

The process '/usr/bin/git' failed with exit code 128

To backport manually, run these commands in your terminal:

# Navigate to the root of your repository
cd $(git rev-parse --show-toplevel)
# Fetch latest updates from GitHub
git fetch
# Create a new working tree
git worktree add ../.worktrees/OpenSearch/backport-2.16 2.16
# Navigate to the new working tree
pushd ../.worktrees/OpenSearch/backport-2.16
# Create a new branch
git switch --create backport/backport-14811-to-2.16
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x --mainline 1 c76bfebd49c8129b564edc68ce59f01853dc6722
# Push it to GitHub
git push --set-upstream origin backport/backport-14811-to-2.16
# Go back to the original working tree
popd
# Delete the working tree
git worktree remove ../.worktrees/OpenSearch/backport-2.16

Then, create a pull request where the base branch is 2.16 and the compare/head branch is backport/backport-14811-to-2.16.

[shwetathareja]

@dblock we have added one new request body parameter in the template API. Can you please help with details on changes to be made OpenAPI spec as well. cc: @mgodwan

[dblock]

@mgodwan Please open a PR that exercises these changes in that repo, see https://github.com/opensearch-project/opensearch-api-specification/blob/main/DEVELOPER_GUIDE.md for details.