[BUG] The response definition for the GET /_snapshot/{repository}/{snapshot} endpoint is incorrect.

[hogesako]

What is the bug?

The response from the get snapshot endpoint contains only snapshots.
https://opensearch.org/docs/latest/api-reference/snapshots/get-snapshot/

However, the API definition includes total, responses, and remaining.
https://github.com/opensearch-project/opensearch-api-specification/blob/main/spec/namespaces/snapshot.yaml#L411-L427

Similarly, the definition of SnapshotInfo includes unnecessary duration, index_details, metadata, reason, repository, and feature_states."

opensearch-api-specification/spec/schemas/snapshot._common.yaml

Lines 9 to 63 in 10027be

	SnapshotInfo:
	type: object
	properties:
	data_streams:
	type: array
	items:
	type: string
	duration:
	$ref: '_common.yaml#/components/schemas/Duration'
	duration_in_millis:
	$ref: '_common.yaml#/components/schemas/DurationValueUnitMillis'
	end_time:
	$ref: '_common.yaml#/components/schemas/DateTime'
	end_time_in_millis:
	$ref: '_common.yaml#/components/schemas/EpochTimeUnitMillis'
	failures:
	type: array
	items:
	$ref: '#/components/schemas/SnapshotShardFailure'
	include_global_state:
	type: boolean
	indices:
	type: array
	items:
	$ref: '_common.yaml#/components/schemas/IndexName'
	index_details:
	type: object
	additionalProperties:
	$ref: '#/components/schemas/IndexDetails'
	metadata:
	$ref: '_common.yaml#/components/schemas/Metadata'
	reason:
	type: string
	repository:
	$ref: '_common.yaml#/components/schemas/Name'
	snapshot:
	$ref: '_common.yaml#/components/schemas/Name'
	shards:
	$ref: '_common.yaml#/components/schemas/ShardStatistics'
	start_time:
	$ref: '_common.yaml#/components/schemas/DateTime'
	start_time_in_millis:
	$ref: '_common.yaml#/components/schemas/EpochTimeUnitMillis'
	state:
	type: string
	uuid:
	$ref: '_common.yaml#/components/schemas/Uuid'
	version:
	$ref: '_common.yaml#/components/schemas/VersionString'
	version_id:
	$ref: '_common.yaml#/components/schemas/VersionNumber'
	feature_states:
	type: array
	items:
	$ref: '#/components/schemas/InfoFeatureState'

How can one reproduce the bug?

Compare the actual response with requests made to OpenSearch.

What is the expected behavior?

Match spec to what's in the OpenSearch code.

What is your host/environment?

OpenSearch 2.15.0

Do you have any additional context?

opensearch-project/opensearch-java#420

[dblock]

@hogesako Thanks for opening this, appreciate a PR if you have time!

[hogesako]

Duration, metadata, and reason were described in the source code.
https://github.com/opensearch-project/OpenSearch/blob/main/server/src/main/java/org/opensearch/snapshots/SnapshotInfo.java