Add fingerprint processor

Signed-off-by: gaobinlong <[email protected]>

_ingest-pipelines/processors/fingerprint.md

@@ -0,0 +1,156 @@
+---
+layout: default
+title: Fingerprint
+parent: Ingest processors
+nav_order: 55
+---
+
+# Fingerprint processor
+
+The `fingerprint` processor is used to generate hash value for the specified fields or all fields in a document, the hash value can be used to deduplicate documents within a index and collapse search results.
+
+To generate hash value for the specified fields, field name, the length of field value and field value are concatenated and separated by `|`, e.g: `|field1|3:value1|field2|10:value2|`, for object fields, the field name is flattened, e.g: `|root_field.sub_field1|1:value1|root_field.sub_field2|100:value2|`.
+
+The following is the `fingerprint` processor syntax:
+
+```json
+{
+  "community_id": {
+    "fields": ["foo", "bar"],
+    "target_field": "fingerprint",
+    "hash_method": "[email protected]"
+  }
+}
+```
+{% include copy-curl.html %}
+
+## Configuration parameters
+
+The following table lists the required and optional parameters for the `fingerprint` processor.
+
+Parameter | Required/Optional | Description |
+|-----------|-----------|-----------|
+`fields`  | Optional  | The field list used to generate hash value.  |
+`exclude_fields`  | Optional  | All fields other than the fields in this excluding list are used to generate hash value. The `exclude_fields` and `fields` options are mutually exclusive. If `fields` and `exclude_fields` are both empty or null, it means `include all fields`, all fields will be used to generate hash value.|
+`hash_method`  | Optional  | One of [email protected], [email protected], [email protected] or [email protected]. Defaults to [email protected]. This processor is introduced in 2.16.0, we append the OpenSearch version to the hash method name to ensure that this processor always generates same hash value based on a specific hash method, if the processing logic of this processor changes in future version, then this parameter will support new hash method with new version. |
+`target_field`  | Optional  | The name of the field in which to store the hash value. Default target field is `fingerprint`. |
+`ignore_missing`  | Optional  | Specifies whether the processor should exit quietly if one of the required fields is missing. Default is `false`. |
+`description`  | Optional  | A brief description of the processor.  |
+`if` | Optional | A condition for running the processor. |
+`ignore_failure` | Optional | If set to `true`, then failures are ignored. Default is `false`. |
+`on_failure` | Optional | A list of processors to run if the processor fails. |
+`tag` | Optional | An identifier tag for the processor. Useful for debugging in order to distinguish between processors of the same type. |
+
+## Using the processor
+
+Follow these steps to use the processor in a pipeline.
+
+**Step 1: Create a pipeline**
+
+The following query creates a pipeline named `fingerprint_pipeline` that uses the `fingerprint` processor to generate a hash value for some specified fields in the document: 
+
+```json
+PUT /_ingest/pipeline/fingerprint_pipeline
+{
+  "description": "generate hash value for some specified fields the document",
+  "processors": [
+    {
+      "fingerprint": {
+        "fields": ["foo", "bar"]
+     }
+    }
+  ]
+}
+```
+{% include copy-curl.html %}
+
+**Step 2 (Optional): Test the pipeline**
+
+It is recommended that you test your pipeline before ingesting documents.
+{: .tip}
+
+To test the pipeline, run the following query:
+
+```json
+POST _ingest/pipeline/fingerprint_pipeline/_simulate
+{
+  "docs": [
+    {
+      "_index": "testindex1",
+      "_id": "1",
+      "_source": {
+        "foo": "foo",
+        "bar": "bar"
+      }
+    }
+  ]
+}
+```
+{% include copy-curl.html %}
+
+#### Response
+
+The following example response confirms that the pipeline is working as expected:
+
+```json
+{
+  "docs": [
+    {
+      "doc": {
+        "_index": "testindex1",
+        "_id": "1",
+        "_source": {
+          "foo": "foo",
+          "bar": "bar",
+          "fingerprint": "[email protected]:fYeen7hTJ2zs9lpmUnk6nvH54sM="
+        },
+        "_ingest": {
+          "timestamp": "2024-03-11T02:17:22.329823Z"
+        }
+      }
+    }
+  ]
+}
+```
+
+**Step 3: Ingest a document**
+
+The following query ingests a document into an index named `testindex1`:
+
+```json
+PUT testindex1/_doc/1?pipeline=fingerprint_pipeline
+{
+  "foo": "foo",
+  "bar": "bar"
+}
+```
+{% include copy-curl.html %}
+
+#### Response
+
+The request indexes the document into the `testindex1` index:
+
+```json
+{
+  "_index": "testindex1",
+  "_id": "1",
+  "_version": 1,
+  "result": "created",
+  "_shards": {
+    "total": 2,
+    "successful": 1,
+    "failed": 0
+  },
+  "_seq_no": 0,
+  "_primary_term": 1
+}
+```
+
+**Step 4 (Optional): Retrieve the document**
+
+To retrieve the document, run the following query:
+
+```json
+GET testindex1/_doc/1
+```
+{% include copy-curl.html %}

_ingest-pipelines/processors/index-processors.md

@@ -40,6 +40,7 @@ Processor type | Description
 `dot_expander` | Expands a field with dots into an object field. 
 `drop` |Drops a document without indexing it or raising any errors.
 `fail` | Raises an exception and stops the execution of a pipeline. 
+`fingerprint` | Generate hash value for specified fields or all fields in a document. 
 `foreach` | Allows for another processor to be applied to each element of an array or an object field in a document.
 `geoip` | Adds information about the geographical location of an IP address.
 `geojson-feature` | Indexes GeoJSON data into a geospatial field.