OpenSearch/rest-api-spec
Nhat Nguyen 3d69b5c41e Introduce point in time APIs in x-pack basic (#61062)
This commit introduces a new API that manages point-in-times in x-pack
basic. Elasticsearch pit (point in time) is a lightweight view into the
state of the data as it existed when initiated. A search request by
default executes against the most recent point in time. In some cases,
it is preferred to perform multiple search requests using the same point
in time. For example, if refreshes happen between search_after requests,
then the results of those requests might not be consistent as changes
happening between searches are only visible to the more recent point in
time.

A point in time must be opened before being used in search requests. The
`keep_alive` parameter tells Elasticsearch how long it should keep a
point in time around.

```
POST /my_index/_pit?keep_alive=1m
```

The response from the above request includes a `id`, which should be
passed to the `id` of the `pit` parameter of search requests.

```
POST /_search
{
    "query": {
        "match" : {
            "title" : "elasticsearch"
        }
    },
    "pit": {
            "id":  "46ToAwMDaWR4BXV1aWQxAgZub2RlXzEAAAAAAAAAAAEBYQNpZHkFdXVpZDIrBm5vZGVfMwAAAAAAAAAAKgFjA2lkeQV1dWlkMioGbm9kZV8yAAAAAAAAAAAMAWICBXV1aWQyAAAFdXVpZDEAAQltYXRjaF9hbGw_gAAAAA==",
            "keep_alive": "1m"
    }
}
```

Point-in-times are automatically closed when the `keep_alive` is
elapsed. However, keeping point-in-times has a cost; hence,
point-in-times should be closed as soon as they are no longer used in
search requests.

```
DELETE /_pit
{
    "id" : "46ToAwMDaWR4BXV1aWQxAgZub2RlXzEAAAAAAAAAAAEBYQNpZHkFdXVpZDIrBm5vZGVfMwAAAAAAAAAAKgFjA2lkeQV1dWlkMioGbm9kZV8yAAAAAAAAAAAMAWIBBXV1aWQyAAA="
}
```

#### Notable works in this change:

- Move the search state to the coordinating node: #52741
- Allow searches with a specific reader context: #53989
- Add the ability to acquire readers in IndexShard: #54966

Relates #46523
Relates #26472

Co-authored-by: Jim Ferenczi <jimczi@apache.org>
2020-09-10 19:25:47 -04:00
..
src Introduce point in time APIs in x-pack basic (#61062) 2020-09-10 19:25:47 -04:00
.gitignore Initial commit (blank repository) 2013-05-23 17:56:22 +02:00
README.markdown [DOCS] Note doc links should be live in REST API JSON specs (#53871) 2020-03-23 07:42:03 -04:00
build.gradle 7.x - Create plugin for yamlTest task (#56841) (#59090) 2020-07-06 14:16:26 -05:00
keywords.json Update rest-api-spec keyword list 2020-06-25 09:55:13 +01:00

README.markdown

Elasticsearch REST API JSON specification

This repository contains a collection of JSON files which describe the Elasticsearch HTTP API.

Their purpose is to formalize and standardize the API, to facilitate development of libraries and integrations.

Example for the "Create Index" API:

{
  "indices.create": {
    "documentation":{
      "url":"https://www.elastic.co/guide/en/elasticsearch/reference/master/indices-create-index.html"
    },
    "stability": "stable",
    "url":{
      "paths":[
        {
          "path":"/{index}",
          "method":"PUT",
          "parts":{
            "index":{
              "type":"string",
              "description":"The name of the index"
            }
          }
        }
      ]
    },
    "params": {
      "timeout": {
        "type" : "time",
        "description" : "Explicit operation timeout"
      }
    },
    "body": {
      "description" : "The configuration for the index (`settings` and `mappings`)"
    }
  }
}

The specification contains:

  • The name of the API (indices.create), which usually corresponds to the client calls

  • Link to the documentation at the http://elastic.co website.

    IMPORANT: This should be a live link. Several downstream ES clients use this link to generate their documentation. Using a broken link or linking to yet-to-be-created doc pages can break the Elastic docs build.

  • stability indicating the state of the API, has to be declared explicitly or YAML tests will fail

    • experimental highly likely to break in the near future (minor/path), no bwc guarantees. Possibly removed in the future.
    • beta less likely to break or be removed but still reserve the right to do so
    • stable No backwards breaking changes in a minor
  • Request URL: HTTP method, path and parts

  • Request parameters

  • Request body specification

NOTE If an API is stable but it response should be treated as an arbitrary map of key values please notate this as followed

{
  "api.name": {
    "stability" : "stable",
    "response": {
      "treat_json_as_key_value" : true
    }
  }
}

Backwards compatibility

The specification follows the same backward compatibility guarantees as Elasticsearch.

  • Within a Major, additions only.
  • If an item has been documented wrong it should be deprecated instead as removing these might break downstream clients.
  • Major version change, may deprecate pieces or simply remove them given enough deprecation time.

Deprecations

The specification schema allows to codify API deprecations, either for an entire API, or for specific parts of the API, such as paths or parameters.

Entire API:

{
  "api" : {
    "deprecated" : {
      "version" : "7.0.0",
      "description" : "Reason API is being deprecated"
    },
  }
}

Specific paths and their parts:

{
  "api": {
    "url": {
      "paths": [
        {
          "path":"/{index}/{type}/{id}/_create",
          "method":"PUT",
          "parts":{
            "id":{
              "type":"string",
              "description":"Document ID"
            },
            "index":{
              "type":"string",
              "description":"The name of the index"
            },
            "type":{
              "type":"string",
              "description":"The type of the document",
              "deprecated":true
            }
          },
          "deprecated":{
            "version":"7.0.0",
            "description":"Specifying types in urls has been deprecated"
          }
        }
      ]
    }
  }
}

Parameters

{
  "api": {
    "url": {
      "params": {
        "stored_fields": {
          "type": "list",
          "description" : "",
          "deprecated" : {
            "version" : "7.0.0",
            "description" : "Reason parameter is being deprecated"
          }
        }
      }
    }
  }
}

License

This software is licensed under the Apache License, version 2 ("ALv2").