Elasticsearch Java Client Request Converter

Experimental converter from elasticsearch json requests to Java client requests, as seen in the api docs.

Usage

The converter does not work on its own, it relies on the common request-converter to perform an intermediate conversion from the Elasticsearch json request to a more structured/typed request, then converts the intermediate format to a java request. The common request-converter is a node library, so the easier way to use both libraries is to write a simple js/typescript script which calls the request-converter first and then calls the java request converter .jar. A full example of a javascript script is provided in this repo at usage.js

Full Example

First of all generate the jar file by running gradle jar.

Starting from a json request:

GET /my-index-000001/_search?size=20
  {
    "query": {
      "term": {
        "user.id": "kimchy"
      }
    }
  }

it needs to be passed to the .parseRequest() method of the request-converter, which will return this:

[
  {
    params: { index: 'my-index-000001' },
    method: 'GET',
    url: '/my-index-000001/_search?size=20',
    path: '/my-index-000001/_search',
    rawPath: '/my-index-000001/_search',
    query: { size: '20' },
    body: { query: [Object] },
    api: 'search',
    request: {
      attachedBehaviors: [Array],
      body: [Object],
      description: 'Returns search hits that match the query defined in the request.\n' +
        'You can provide search queries using the `q` query string parameter or the request body.\n' +
        'If both are specified, only the query parameter is used.',
      inherits: [Object],
      kind: 'request',
      name: [Object],
      path: [Array],
      query: [Array],
      specLocation: '_global/search/SearchRequest.ts#L54-L530'
    }
  }
]

This cannot be sent as is to the java request converter, it needs a bit of tweaking: some fields have aliases in the specification, and the java clients uses those, so use the getCodeGenParamNames in usage.js to set the correct names; then prepare a json object with this structure:

[
  {
    "params": {},
    "query": {},
    "body": {},
    "api": "api-name"
  }
]

and fill it with the correct fields from the intermediate request (replacing params with the ones from getCodeGenParamNames). It should look like this:

[
  {
    params: { index: 'my-index-000001' },
    query: { size: '20' },
    body: {
     "query": {
       "term": {
         "user.id": {
         "value": "kimchy"
       }
       }
     }
    },
    api: 'search',
  }
]

Now this can be sent to the java request converter as the first argument of the jar, and the client call will be returned.

client.search(s -> s
    .index("my-index-000001")
    .query(q -> q
        .term(t -> t
            .field("user.id")
            .value(FieldValue.of("kimchy"))
        )
    )
    .size(20)
,Void.class);

The jar accepts two more arguments:

• a boolean, if true the converter will return a full class instead of just single requests, complete with imports and the client setup.
• a string which will be used as server url in case the previous arg is true

Of course the jar can also be run with java -jar, but it's not really recommended since the json requests will have to be all escaped, for example:

java -jar java-es-request-converter-1.0-SNAPSHOT.jar  "[{\"api\":\"indices.update_aliases\",\"params\":{},\"body\":{\"actions\":[{\"add\":{\"index\":\"test-bulk\",\"alias\":\"my-alias-bulk\"}}]}},{\"api\":\"indices.get_alias\",\"params\":{\"name\":\"my-alias-bulk,test2\"}}] true server-url"