Reranking search results using models hosted on Amazon Bedrock
A reranking pipeline can rerank search results, providing a relevance score for each document in the search results with respect to the search query. The relevance score is calculated by a cross-encoder model.
This tutorial illustrates using the Amazon Bedrock Rerank API to rerank search results using a model hosted on Amazon Bedrock.
Replace the placeholders beginning with the prefix your_ with your own values.
Prerequisite: Test the model on Amazon Bedrock
Before using your model, test it on Amazon Bedrock. For supported reranker models, see Supported Regions and models for reranking in Amazon Bedrock. For model IDs, see Supported foundation models in Amazon Bedrock. To perform a reranking test, use the following code:
import json
import boto3
bedrock_region = "your_bedrock_model_region_like_us-west-2"
bedrock_agent_runtime_client = boto3.client("bedrock-agent-runtime", region_name=bedrock_region)
model_id = "amazon.rerank-v1:0"
response = bedrock_agent_runtime_client.rerank(
queries=[
{
"textQuery": {
"text": "What is the capital city of America?",
},
"type": "TEXT"
}
],
rerankingConfiguration={
"bedrockRerankingConfiguration": {
"modelConfiguration": {
"modelArn": f"arn:aws:bedrock:{bedrock_region}::foundation-model/{model_id}"
},
},
"type": "BEDROCK_RERANKING_MODEL"
},
sources=[
{
"inlineDocumentSource": {
"textDocument": {
"text": "Carson City is the capital city of the American state of Nevada.",
},
"type": "TEXT"
},
"type": "INLINE"
},
{
"inlineDocumentSource": {
"textDocument": {
"text": "The Commonwealth of the Northern Mariana Islands is a group of islands in the Pacific Ocean. Its capital is Saipan.",
},
"type": "TEXT"
},
"type": "INLINE"
},
{
"inlineDocumentSource": {
"textDocument": {
"text": "Washington, D.C. (also known as simply Washington or D.C., and officially as the District of Columbia) is the capital of the United States. It is a federal district.",
},
"type": "TEXT"
},
"type": "INLINE"
},
{
"inlineDocumentSource": {
"textDocument": {
"text": "Capital punishment (the death penalty) has existed in the United States since beforethe United States was a country. As of 2017, capital punishment is legal in 30 of the 50 states."
},
"type": "TEXT"
},
"type": "INLINE"
},
]
)
results = response["results"]
print(json.dumps(results, indent=2))
The reranked results are ordered by the highest score:
[
{
"index": 2,
"relevanceScore": 0.7711548805236816
},
{
"index": 0,
"relevanceScore": 0.0025114635936915874
},
{
"index": 1,
"relevanceScore": 2.4876489987946115e-05
},
{
"index": 3,
"relevanceScore": 6.339210358419223e-06
}
]
To sort the results by index, use the following code:
print(json.dumps(sorted(results, key=lambda x: x['index']),indent=2))
The following are the results sorted by index:
[
{
"index": 0,
"relevanceScore": 0.0025114635936915874
},
{
"index": 1,
"relevanceScore": 2.4876489987946115e-05
},
{
"index": 2,
"relevanceScore": 0.7711548805236816
},
{
"index": 3,
"relevanceScore": 6.339210358419223e-06
}
]
Step 1: Create a connector and register the model
To create a connector and register the model, use the following steps.
Step 1.1: Create a connector for the model
First, create a connector for the model.
If you are using self-managed OpenSearch, supply your AWS credentials:
POST /_plugins/_ml/connectors/_create
{
"name": "Amazon Bedrock Rerank API",
"description": "Test connector for Amazon Bedrock Rerank API",
"version": 1,
"protocol": "aws_sigv4",
"credential": {
"access_key": "your_access_key",
"secret_key": "your_secret_key",
"session_token": "your_session_token"
},
"parameters": {
"service_name": "bedrock",
"endpoint": "bedrock-agent-runtime",
"region": "your_bedrock_model_region_like_us-west-2",
"api_name": "rerank",
"model_id": "amazon.rerank-v1:0"
},
"actions": [
{
"action_type": "PREDICT",
"method": "POST",
"url": "https://${parameters.endpoint}.${parameters.region}.amazonaws.com/${parameters.api_name}",
"headers": {
"x-amz-content-sha256": "required",
"content-type": "application/json"
},
"pre_process_function": "connector.pre_process.bedrock.rerank",
"request_body": """
{
"queries": ${parameters.queries},
"rerankingConfiguration": {
"bedrockRerankingConfiguration": {
"modelConfiguration": {
"modelArn": "arn:aws:bedrock:${parameters.region}::foundation-model/${parameters.model_id}"
}
},
"type": "BEDROCK_RERANKING_MODEL"
},
"sources": ${parameters.sources}
}
""",
"post_process_function": "connector.post_process.bedrock.rerank"
}
]
}
If you are using Amazon OpenSearch Service, you can provide an AWS Identity and Access Management (IAM) role Amazon Resource Name (ARN) that allows access to Amazon Bedrock. For more information, see the AWS documentation. Use the following request to create a connector:
POST /_plugins/_ml/connectors/_create
{
"name": "Amazon Bedrock Rerank API",
"description": "Test connector for Amazon Bedrock Rerank API",
"version": 1,
"protocol": "aws_sigv4",
"credential": {
"roleArn": "your_role_arn_which_allows_access_to_bedrock_agent_runtime_rerank_api"
},
"parameters": {
"service_name": "bedrock",
"endpoint": "bedrock-agent-runtime",
"region": "your_bedrock_model_region_like_us-west-2",
"api_name": "rerank",
"model_id": "amazon.rerank-v1:0"
},
"actions": [
{
"action_type": "PREDICT",
"method": "POST",
"url": "https://${parameters.endpoint}.${parameters.region}.amazonaws.com/${parameters.api_name}",
"headers": {
"x-amz-content-sha256": "required",
"content-type": "application/json"
},
"pre_process_function": "connector.pre_process.bedrock.rerank",
"request_body": """
{
"queries": ${parameters.queries},
"rerankingConfiguration": {
"bedrockRerankingConfiguration": {
"modelConfiguration": {
"modelArn": "arn:aws:bedrock:${parameters.region}::foundation-model/${parameters.model_id}"
}
},
"type": "BEDROCK_RERANKING_MODEL"
},
"sources": ${parameters.sources}
}
""",
"post_process_function": "connector.post_process.bedrock.rerank"
}
]
}
Step 1.2: Register and deploy the model
Use the connector ID from the response to register and deploy the model:
POST /_plugins/_ml/models/_register?deploy=true
{
"name": "Amazon Bedrock Rerank API",
"function_name": "remote",
"description": "test Amazon Bedrock Rerank API",
"connector_id": "your_connector_id"
}
Note the model ID in the response; you’ll use it in the following steps.
Step 1.3: Test the model
Test the model by using the Predict API:
POST _plugins/_ml/_predict/text_similarity/your_model_id
{
"query_text": "What is the capital city of America?",
"text_docs": [
"Carson City is the capital city of the American state of Nevada.",
"The Commonwealth of the Northern Mariana Islands is a group of islands in the Pacific Ocean. Its capital is Saipan.",
"Washington, D.C. (also known as simply Washington or D.C., and officially as the District of Columbia) is the capital of the United States. It is a federal district.",
"Capital punishment (the death penalty) has existed in the United States since beforethe United States was a country. As of 2017, capital punishment is legal in 30 of the 50 states."
]
}
Alternatively, you can test the model using the following query. This query bypasses the pre_process_function and calls the Rerank API directly:
POST _plugins/_ml/models/your_model_id/_predict
{
"parameters": {
"queries": [
{
"textQuery": {
"text": "What is the capital city of America?"
},
"type": "TEXT"
}
],
"sources": [
{
"inlineDocumentSource": {
"textDocument": {
"text": "Carson City is the capital city of the American state of Nevada."
},
"type": "TEXT"
},
"type": "INLINE"
},
{
"inlineDocumentSource": {
"textDocument": {
"text": "The Commonwealth of the Northern Mariana Islands is a group of islands in the Pacific Ocean. Its capital is Saipan."
},
"type": "TEXT"
},
"type": "INLINE"
},
{
"inlineDocumentSource": {
"textDocument": {
"text": "Washington, D.C. (also known as simply Washington or D.C., and officially as the District of Columbia) is the capital of the United States. It is a federal district."
},
"type": "TEXT"
},
"type": "INLINE"
},
{
"inlineDocumentSource": {
"textDocument": {
"text": "Capital punishment (the death penalty) has existed in the United States since beforethe United States was a country. As of 2017, capital punishment is legal in 30 of the 50 states."
},
"type": "TEXT"
},
"type": "INLINE"
}
]
}
}
The connector pre_process_function transforms the input into the format required by the Predict API parameters.
By default, the Amazon Bedrock Rerank API output is formatted as follows:
[
{
"index": 2,
"relevanceScore": 0.7711548724998493
},
{
"index": 0,
"relevanceScore": 0.0025114635138098534
},
{
"index": 1,
"relevanceScore": 2.4876490010363496e-05
},
{
"index": 3,
"relevanceScore": 6.339210403977635e-06
}
]
The connector post_process_function transforms the model’s output into a format that the Reranker processor can interpret and orders the results by index.
The response contains four similarity outputs. For each similarity output, the data array contains a relevance score for each document against the query. The similarity outputs are provided in the order of the input documents; the first similarity result pertains to the first document:
{
"inference_results": [
{
"output": [
{
"name": "similarity",
"data_type": "FLOAT32",
"shape": [
1
],
"data": [
0.0025114636
]
},
{
"name": "similarity",
"data_type": "FLOAT32",
"shape": [
1
],
"data": [
2.487649e-05
]
},
{
"name": "similarity",
"data_type": "FLOAT32",
"shape": [
1
],
"data": [
0.7711549
]
},
{
"name": "similarity",
"data_type": "FLOAT32",
"shape": [
1
],
"data": [
6.3392104e-06
]
}
],
"status_code": 200
}
]
}
Step 2: Create a reranking pipeline
To create a reranking pipeline, use the following steps.
Step 2.1: Ingest test data
Use the following request to ingest data into your index:
POST _bulk
{ "index": { "_index": "my-test-data" } }
{ "passage_text" : "Carson City is the capital city of the American state of Nevada." }
{ "index": { "_index": "my-test-data" } }
{ "passage_text" : "The Commonwealth of the Northern Mariana Islands is a group of islands in the Pacific Ocean. Its capital is Saipan." }
{ "index": { "_index": "my-test-data" } }
{ "passage_text" : "Washington, D.C. (also known as simply Washington or D.C., and officially as the District of Columbia) is the capital of the United States. It is a federal district." }
{ "index": { "_index": "my-test-data" } }
{ "passage_text" : "Capital punishment (the death penalty) has existed in the United States since beforethe United States was a country. As of 2017, capital punishment is legal in 30 of the 50 states." }
Step 2.2: Create a reranking pipeline
Create a reranking pipeline using the Amazon Bedrock reranking model:
PUT /_search/pipeline/rerank_pipeline_bedrock
{
"description": "Pipeline for reranking with Bedrock rerank model",
"response_processors": [
{
"rerank": {
"ml_opensearch": {
"model_id": "your_model_id_created_in_step1"
},
"context": {
"document_fields": ["passage_text"]
}
}
}
]
}
If you provide multiple field names in document_fields, the values of all fields are first concatenated, after which reranking is performed.
Step 2.3: Test reranking
First, test the query without using the reranking pipeline:
POST my-test-data/_search
{
"query": {
"match": {
"passage_text": "What is the capital city of America?"
}
},
"highlight": {
"pre_tags": ["<strong>"],
"post_tags": ["</strong>"],
"fields": {"passage_text": {}}
},
"_source": false,
"fields": ["passage_text"]
}
The first document in the response is Carson City is the capital city of the American state of Nevada, which is incorrect:
{
"took": 2,
"timed_out": false,
"_shards": {
"total": 1,
"successful": 1,
"skipped": 0,
"failed": 0
},
"hits": {
"total": {
"value": 4,
"relation": "eq"
},
"max_score": 2.5045562,
"hits": [
{
"_index": "my-test-data",
"_id": "1",
"_score": 2.5045562,
"fields": {
"passage_text": [
"Carson City is the capital city of the American state of Nevada."
]
},
"highlight": {
"passage_text": [
"Carson <strong>City</strong> <strong>is</strong> <strong>the</strong> <strong>capital</strong> <strong>city</strong> <strong>of</strong> <strong>the</strong> American state <strong>of</strong> Nevada."
]
}
},
{
"_index": "my-test-data",
"_id": "2",
"_score": 0.5807494,
"fields": {
"passage_text": [
"The Commonwealth of the Northern Mariana Islands is a group of islands in the Pacific Ocean. Its capital is Saipan."
]
},
"highlight": {
"passage_text": [
"<strong>The</strong> Commonwealth <strong>of</strong> <strong>the</strong> Northern Mariana Islands <strong>is</strong> a group <strong>of</strong> islands in <strong>the</strong> Pacific Ocean.",
"Its <strong>capital</strong> <strong>is</strong> Saipan."
]
}
},
{
"_index": "my-test-data",
"_id": "3",
"_score": 0.5261191,
"fields": {
"passage_text": [
"Washington, D.C. (also known as simply Washington or D.C., and officially as the District of Columbia) is the capital of the United States. It is a federal district."
]
},
"highlight": {
"passage_text": [
"(also known as simply Washington or D.C., and officially as <strong>the</strong> District <strong>of</strong> Columbia) <strong>is</strong> <strong>the</strong> <strong>capital</strong>",
"<strong>of</strong> <strong>the</strong> United States.",
"It <strong>is</strong> a federal district."
]
}
},
{
"_index": "my-test-data",
"_id": "4",
"_score": 0.5083029,
"fields": {
"passage_text": [
"Capital punishment (the death penalty) has existed in the United States since beforethe United States was a country. As of 2017, capital punishment is legal in 30 of the 50 states."
]
},
"highlight": {
"passage_text": [
"<strong>Capital</strong> punishment (<strong>the</strong> death penalty) has existed in <strong>the</strong> United States since beforethe United States",
"As <strong>of</strong> 2017, <strong>capital</strong> punishment <strong>is</strong> legal in 30 <strong>of</strong> <strong>the</strong> 50 states."
]
}
}
]
}
}
Next, test the query using the reranking pipeline:
POST my-test-data/_search?search_pipeline=rerank_pipeline_bedrock
{
"query": {
"match": {
"passage_text": "What is the capital city of America?"
}
},
"ext": {
"rerank": {
"query_context": {
"query_text": "What is the capital city of America?"
}
}
},
"highlight": {
"pre_tags": ["<strong>"],
"post_tags": ["</strong>"],
"fields": {"passage_text": {}}
},
"_source": false,
"fields": ["passage_text"]
}
The first document in the response is "Washington, D.C. (also known as simply Washington or D.C., and officially as the District of Columbia) is the capital of the United States. It is a federal district.", which is correct:
{
"took": 2,
"timed_out": false,
"_shards": {
"total": 1,
"successful": 1,
"skipped": 0,
"failed": 0
},
"hits": {
"total": {
"value": 4,
"relation": "eq"
},
"max_score": 0.7711549,
"hits": [
{
"_index": "my-test-data",
"_id": "3",
"_score": 0.7711549,
"fields": {
"passage_text": [
"Washington, D.C. (also known as simply Washington or D.C., and officially as the District of Columbia) is the capital of the United States. It is a federal district."
]
},
"highlight": {
"passage_text": [
"(also known as simply Washington or D.C., and officially as <strong>the</strong> District <strong>of</strong> Columbia) <strong>is</strong> <strong>the</strong> <strong>capital</strong>",
"<strong>of</strong> <strong>the</strong> United States.",
"It <strong>is</strong> a federal district."
]
}
},
{
"_index": "my-test-data",
"_id": "1",
"_score": 0.0025114636,
"fields": {
"passage_text": [
"Carson City is the capital city of the American state of Nevada."
]
},
"highlight": {
"passage_text": [
"Carson <strong>City</strong> <strong>is</strong> <strong>the</strong> <strong>capital</strong> <strong>city</strong> <strong>of</strong> <strong>the</strong> American state <strong>of</strong> Nevada."
]
}
},
{
"_index": "my-test-data",
"_id": "2",
"_score": 02.487649e-05,
"fields": {
"passage_text": [
"The Commonwealth of the Northern Mariana Islands is a group of islands in the Pacific Ocean. Its capital is Saipan."
]
},
"highlight": {
"passage_text": [
"<strong>The</strong> Commonwealth <strong>of</strong> <strong>the</strong> Northern Mariana Islands <strong>is</strong> a group <strong>of</strong> islands in <strong>the</strong> Pacific Ocean.",
"Its <strong>capital</strong> <strong>is</strong> Saipan."
]
}
},
{
"_index": "my-test-data",
"_id": "4",
"_score": 6.3392104e-06,
"fields": {
"passage_text": [
"Capital punishment (the death penalty) has existed in the United States since beforethe United States was a country. As of 2017, capital punishment is legal in 30 of the 50 states."
]
},
"highlight": {
"passage_text": [
"<strong>Capital</strong> punishment (<strong>the</strong> death penalty) has existed in <strong>the</strong> United States since beforethe United States",
"As <strong>of</strong> 2017, <strong>capital</strong> punishment <strong>is</strong> legal in 30 <strong>of</strong> <strong>the</strong> 50 states."
]
}
}
]
},
"profile": {
"shards": []
}
}
You can reuse the same query by specifying the query_text_path instead of query_text:
POST my-test-data/_search?search_pipeline=rerank_pipeline_bedrock
{
"query": {
"match": {
"passage_text": "What is the capital city of America?"
}
},
"ext": {
"rerank": {
"query_context": {
"query_text_path": "query.match.passage_text.query"
}
}
},
"highlight": {
"pre_tags": ["<strong>"],
"post_tags": ["</strong>"],
"fields": {"passage_text": {}}
},
"_source": false,
"fields": ["passage_text"]
}