Basic Delete Example

This sample deletes a document from an Elasticsearch server via the Elasticsearch Delete API and displays the results of the delete request.

For more information on the Elasticsearch Delete API, see the Elasticsearch Python Delete API and Elasticsearch REST Delete API documentation.

Prerequisites

• The samples configuration step has been completed (see Samples Configuration).
• The Elasticsearch API DXL service is running, using the sample configuration (see Running).
• Run through the steps in the Basic Index Example to store a document to Elasticsearch. This example will delete the stored document.

Running

To run this sample execute the sample/basic/basic_delete_example.py script as follows:

python sample/basic/basic_delete_example.py

If the document was previously stored via running the Basic Index Example, the output should appear similar to the following:

Response to the delete request:
{
    "_id": "12345",
    "_index": "opendxl-elasticsearch-service-examples",
    "_shards": {
        "failed": 0,
        "successful": 2,
        "total": 2
    },
    "_type": "basic-example-doc",
    "_version": 2,
    "found": true,
    "result": "deleted"
}

If the document to be deleted does not exist at the time the sample is run, the output should appear similar to the following:

Error invoking service with topic '/opendxl-elasticsearch/service/elasticsearch-api/delete': TransportError(404, u'{"found":false,"_index":"opendxl-elasticsearch-service-examples","_type":"basic-example-doc","_id":"12345","_version":3,"result":"not_found","_shards":{"total":2,"successful":2,"failed":0}}') (0)
Error payload:
{
    "class": "NotFoundError",
    "data": {
        "error": "{\"found\":false,\"_index\":\"opendxl-elasticsearch-service-examples\",\"_type\":\"basic-example-doc\",\"_id\":\"123
45\",\"_version\":3,\"result\":\"not_found\",\"_shards\":{\"total\":2,\"successful\":2,\"failed\":0}}",
        "info": {
            "_id": "12345",
            "_index": "opendxl-elasticsearch-service-examples",
            "_shards": {
                "failed": 0,
                "successful": 2,
                "total": 2
            },
            "_type": "basic-example-doc",
            "_version": 3,
            "found": false,
            "result": "not_found"
        },
        "status_code": 404
    },
    "module": "elasticsearch.exceptions"
}

Details

In order to enable the use of the delete API, the API name is listed in the apiNames setting under the [General] section in the sample "dxlelasticsearchservice.config" file that the service uses:

[General]
apiNames=...,delete

For more information on the configuration, see the Service Configuration File section.

The majority of the sample code is shown below:

# Create the client
with DxlClient(config) as client:

    # Connect to the fabric
    client.connect()

    logger.info("Connected to DXL fabric.")

    # Create the delete request
    request_topic = "/opendxl-elasticsearch/service/elasticsearch-api/delete"
    req = Request(request_topic)

    # Set the payload for the delete request
    MessageUtils.dict_to_json_payload(req, {
        "index": DOCUMENT_INDEX,
        "doc_type": DOCUMENT_TYPE,
        "id": DOCUMENT_ID})

    # Send the delete request
    res = client.sync_request(req, timeout=30)

    if res.message_type != Message.MESSAGE_TYPE_ERROR:
        # Display results for the delete request
        res_dict = MessageUtils.json_payload_to_dict(res)
        print("Response to the delete request:\n{}".format(
            MessageUtils.dict_to_json(res_dict, pretty_print=True)))
    else:
        print("Error invoking service with topic '{}': {} ({})".format(
            request_topic, res.error_message, res.error_code))
        if res.payload:
            # Display the payload in the error response
            res_dict = MessageUtils.json_payload_to_dict(res)
            print("Error payload:\n{}".format(
                MessageUtils.dict_to_json(res_dict, pretty_print=True)))

After connecting to the DXL fabric, a request message is created with a topic that targets the "delete" method of the Elasticsearch API DXL service.

The next step is to set the payload of the request message. The contents of the payload include the index, type (doc_type), and id of the document to delete.

From the Elasticsearch Python Delete API documentation:

"Delete a typed JSON document from a specific index based on its id."

The next step is to perform a synchronous request via the DXL fabric. If the response message is not an error, its contents are displayed.