The update API allows to update(also allows to delete, or ignore the operation). a document based on a script provided.
- The operation gets the document from the index, runs the script (with optional script language and parameters), and index back the result.
- The _source field needs to be enabled for this feature to work.
For example, let’s index a simple doc:
curl -X PUT "localhost:9200/test/_doc/1" -H 'Content-Type: application/json' -d'
{
"counter" : 1,
"tags" : ["red"]
}
'
Now, we can execute a script that would increment the counter:
curl -X POST "localhost:9200/test/_doc/1/_update" -H 'Content-Type: application/json' -d'
{
"script" : {
"source": "ctx._source.counter += params.count",
"lang": "painless",
"params" : {
"count" : 4
}
}
}
'
We can add a tag to the list of tags (note, if the tag exists, it will still add it, since its a list):
curl -X POST "localhost:9200/test/_doc/1/_update" -H 'Content-Type: application/json' -d'
{
"script" : {
"source": "ctx._source.tags.add(params.tag)",
"lang": "painless",
"params" : {
"tag" : "blue"
}
}
}
'
ng>We can also add a new field to the document:
curl -X POST "localhost:9200/test/_doc/1/_update" -H 'Content-Type: application/json' -d'
{
"script" : "ctx._source.new_field = \u0027value_of_new_field\u0027"
}
'
We can also add a new field to the document:
curl -X POST "localhost:9200/test/_doc/1/_update" -H 'Content-Type: application/json' -d'
{
"script" : "ctx._source.new_field = \u0027value_of_new_field\u0027"
}
'
Or remove a field from the document:
curl -X POST "localhost:9200/test/_doc/1/_update" -H 'Content-Type: application/json' -d'
{
"script" : "ctx._source.remove(\u0027new_field\u0027)"
}
'
Reference
https://www.elastic.co/guide/en/elasticsearch/reference/current/docs-update.html
ctx is a special variable that allows you to access the source of the object that you want to update. The ctx._source is a writable version of the source.
NOTE: You can modify this document in the script and the modified source will be persisted as the new version of the document.
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