Error while reindexing with inference processor and ELSER v1 in version 8.10

[ardi]

I tried to set up an inference processor for 8.10 with ELSER v1, with following definitions:

Mapping for search index, where results of ELSER v1 have to be stored

{
  "mappings": {
    "properties": {
      "ml.tokens": { 
        "type": "rank_features" 
      },
      "text": { 
        "type": "text" 
      }
    }
  }
}'

Inference processor with ELSER v1

{
  "processors": [
    {
      "inference": {
        "model_id": ".elser_model_1",
        "target_field": "ml",
        "field_map": { 
          "text": "text_field"
        },
        "inference_config": {
          "text_expansion": { 
            "results_field": "tokens"
          }
        }
      }
    }
  ]
}'

Reindexing with previous defined pipeline:

{
  "source": {
    "index": "p.pdf" #is just the name of the index
  },
  "dest": {
    "index": "search-test",
    "pipeline": "elser-v1-test"
  }
}'

I get an error if I call the task status with task ID,

 "index" : "search-test",
        "id" : "76abc827-a530-4ba6-be09-08d2d475750d",
        "cause" : {
          "type" : "status_exception",
          "reason" : "Input field [body_content_field] does not exist in the source document",
          "caused_by" : {
            "type" : "status_exception",
            "reason" : "Input field [body_content_field] does not exist in the source document"

I have no clue why this happens, does someone of you have an idea?

Thank you in advance!

[mmcmahon (Mike)]

I had the same issue. In the inference processor change the field map to read body_content_field versus text_field.

{
  "processors": [
    {
      "inference": {
        "model_id": ".elser_model_1",
        "target_field": "ml",
        "field_map": { 
          "text": "body_content_field"
        },
        "inference_config": {
          "text_expansion": { 
            "results_field": "tokens"
          }
        }
      }
    }
  ]
}'