Bulk index / create documents with elasticsearch for python

Question

I am generating a large number of elasticsearch documents with random content using python and index them with elasticsearch-py.

Simplified working example (document with just one field):

from elasticsearch import Elasticsearch
from random import getrandbits

es_client = Elasticsearch('https://elastic.host:9200')

for i in range(1,10000000):
    document = {'my_field': getrandbits(64)}
    es_client.index(index='my_index', document=document)

Since this makes one request per document, I tried to speed it up by sending chunks of 1000 documents each using the _bulk API. However, my attempts so far have been unsuccessful.

My understanding from the docs is that you can pass an iterable to bulk(), so I tried:

from elasticsearch import Elasticsearch
from random import getrandbits

es_client = Elasticsearch('https://elastic.host:9200')

document_list = []
for i in range(1,10000000):
    document = {'my_field': getrandbits(64)}
    document_list.append(document)
    if i % 1000 == 0:
        es_client.bulk(operations=document_list, index='my_index')
        document_list = []

but this results in a

elasticsearch.BadRequestError: BadRequestError(400, 'illegal_argument_exception', 'Malformed action/metadata line [1], expected START_OBJECT or END_OBJECT but found [VALUE_STRING]')

Answer 1

Ok, seems I have mixed up two different functions: helpers.bulk() and Elasticsearch.bulk(). Either can be used to achieve what I intended to do, but they have a slightly different signature.

The helpers.bulk() function takes an Elasticsearch() object and an iterable containing the documents as parameters. The operation can be specified as _op_type and can be one of index, create, delete, or update. Since _op_type defaults to index, we can just omit it and simply pass the list of documents in this case:

from elasticsearch import Elasticsearch, helpers
from random import getrandbits

es_client = Elasticsearch('https://elastic.host:9200')

document_list = []
for i in range(1,10000000):
    document = {'my_field': getrandbits(64)}
    document_list.append(document)
    if i % 1000 == 0:
        helpers.bulk(es_client, document_list, index='my_index')
        document_list = []

This works fine.

The Elasticsearch.bulk() function can be used alternatively, but the actions/operations are mandatory as part of the iterable here and the syntax is slightly different. This means that instead of just a dict with the document contents, we need to have a dict specifying both the action (in this case "index": {}), as well as the body for each document. See also _bulk documentation:

from elasticsearch import Elasticsearch
from random import getrandbits

es_client = Elasticsearch('https://elastic.host:9200')

actions_list = []
for i in range(1,10000000):
    document = {'my_field': getrandbits(64)}
    actions_list.append({"index": {}, "doc": document})
    if i % 1000 == 0:
        es_client.bulk(operations=actions_list, index='my_index')
        actions_list = []

This works fine as well.

I assume that both of the above generate the same _bulk REST API statement internally, so they should be equivalent in the end.