CODEWITHSUNDEEP
pythonjsonelasticsearchelasticsearch-exception
snowfire257
snowfire257

Reputation: 55

ElasticSearch throwing mapper parsing exception when indexing JSON array of integers and strings

I am attempting to use python to pull a JSON array from a file and input it into ElasticSearch. The array looks as follows:

{"name": [["string1", 1, "string2"],["string3", 2, "string4"], ... (variable length) ... ["string n-1", 3, "string n"]]}

ElasticSearch throws a TransportError(400, mapper_parsing_exception, failed to parse) when attempting to index the array. I discovered that ElasticSearch sometimes throws the same error whenever I try to feed it a string with both strings and integers. So, for example, the following will sometimes crash and sometimes succeed:

import json
from elasticsearch import Elasticsearch

es = Elasticsearch()

test = json.loads('{"test": ["a", 1, "b"]}')
print test
es.index(index, body=test)

This code is everything I could safely comment out without breaking the program. I put the JSON in the program instead of having it read from a file. The actual strings I'm inputting are quite long (or else I would just post them) and will always crash the program. Changing the JSON to "test": ["a"] will cause it to work. The current setup crashes if it last crashed, or works if it last worked. What is going on? Will some sort of mapping setup fix this? I haven't figured out how to set a map with variable array length. I'd prefer to take advantage of the schema-less input but I'll take whatever works.

Upvotes: 2

Views: 14127

Answers (1)

BrookeB
BrookeB

Reputation: 1769

It is possible you are running into type conflicts with your mapping. Since you have expressed a desire to stay "schema-less", I am assuming you have not explicitly provided a mapping for your index. That works fine, just recognize that the first document you index will determine the schema for your index. Each document you index afterwards that has the same fields (by name), those fields must conform to the same type as the first document.

Elasticsearch has no issues with arrays of values. In fact, under the hood it treats all values as arrays (with one or more entries). What is slightly concerning is the example array you chose, which mixes string and numeric types. Since each value in your array gets mapped to the field named "test", and that field may only have one type, if the first value of the first document ES processes is numeric, it will likely assign that field as a long type. Then, future documents that contain a string that does not parse nicely into a number, will cause an exception in Elasticsearch.

Have a look at the documentation on Dynamic Mapping.

It can be nice to go schema-less, but in your scenario you may have more success by explicitly declaring a mapping on your index for at least some of the fields in your documents. If you plan to index arrays full of mixed datatypes, you are better off declaring that field as string type.

Upvotes: 5

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