Added: add a count for an opensearch query - without the need to get … (

#130)

## What
Added a count only func which does not return any body - only the
affected documents

pkg/openSearch/openSearchClient/client.go

@@ -7,8 +7,10 @@ package openSearchClient
 import (
 	"bytes"
 	"context"
+	"encoding/json"
 	"fmt"
 	"io"
+	"net/http"
 	"strings"
 	"time"
 
@@ -73,6 +75,36 @@ func (c *Client) Search(indexName string, requestBody []byte) (responseBody []by
 	return result, nil
 }
 
+func (c *Client) Count(indexName string, requestBody []byte) (count int64, err error) {
+	log.Debug().Msgf("count requestBody: %s", string(requestBody))
+	request := CountReq{
+		Indices: []string{indexName},
+		Body:    bytes.NewReader(requestBody),
+	}
+	countRequest, err := request.GetRequest()
+	if err != nil {
+		return 0, err
+	}
+	response, err := c.openSearchProjectClient.Client.Perform(countRequest)
+	if err != nil {
+		return 0, err
+	}
+	defer response.Body.Close()
+
+	if response.StatusCode != http.StatusOK {
+		responseBody, _ := io.ReadAll(response.Body)
+		log.Warn().Msgf("count response - statusCode:'%d' body:'%s'", response.StatusCode, responseBody)
+	}
+
+	var countResp CountResp
+	if err := json.NewDecoder(response.Body).Decode(&countResp); err != nil {
+		log.Error().Msgf("error decoding count response: %v", err)
+		return 0, err
+	}
+
+	return countResp.Count, nil
+}
+
 func (c *Client) SearchStream(indexName string, requestBody []byte, scrollTimeout time.Duration, ctx context.Context) (io.Reader, error) {
 	reader, writer := io.Pipe()
 	startSignal := make(chan error, 1)
@@ -98,7 +130,9 @@ func (c *Client) SearchStream(indexName string, requestBody []byte, scrollTimeou
 		if searchResponse.Errors || searchResponse.Inspect().Response.IsError() {
 			writer.Close()
 			startSignal <- fmt.Errorf("search failed")
-			log.Error().Msgf("search response: %s: %s", searchResponse.Inspect().Response.Status(), searchResponse.Inspect().Response.String())
+			log.Error().Msgf("search response: %s: %s",
+				searchResponse.Inspect().Response.Status(),
+				searchResponse.Inspect().Response.String())
 			return
 		}
 
@@ -141,7 +175,9 @@ func (c *Client) SearchStream(indexName string, requestBody []byte, scrollTimeou
 
 			if scrollResult.Inspect().Response.IsError() {
 				writer.CloseWithError(fmt.Errorf("scroll-result error"))
-				log.Error().Msgf("search response: %s: %s", scrollResult.Inspect().Response.Status(), scrollResult.Inspect().Response.String())
+				log.Error().Msgf("search response: %s: %s",
+					scrollResult.Inspect().Response.Status(),
+					scrollResult.Inspect().Response.String())
 				return
 			}
 

pkg/openSearch/openSearchClient/count.go

@@ -0,0 +1,55 @@
+package openSearchClient
+
+import (
+	"fmt"
+	"io"
+	"net/http"
+	"strings"
+
+	"github.com/opensearch-project/opensearch-go/v4"
+	"github.com/opensearch-project/opensearch-go/v4/opensearchapi"
+)
+
+type CountReq struct {
+	Indices []string
+	Body    io.Reader
+	Header  http.Header
+	Params  map[string]string
+}
+
+// GetRequest returns the *http.Request that gets executed by the client
+func (r CountReq) GetRequest() (*http.Request, error) {
+	if r.Params == nil {
+		r.Params = make(map[string]string)
+	}
+	var path string
+	if len(r.Indices) > 0 {
+		path = fmt.Sprintf("/%s/_search", strings.Join(r.Indices, ","))
+	} else {
+		path = "/_search"
+	}
+
+	return opensearch.BuildRequest(
+		"GET",
+		path,
+		r.Body,
+		r.Params,
+		r.Header,
+	)
+}
+
+type CountResp struct {
+	Count  int64      `json:"count"`
+	Shards ShardStats `json:"_shards"`
+}
+
+type ShardStats struct {
+	Total      int `json:"total"`
+	Successful int `json:"successful"`
+	Skipped    int `json:"skipped"`
+	Failed     int `json:"failed"`
+}
+
+func (r CountResp) Inspect() opensearchapi.Inspect {
+	return opensearchapi.Inspect{}
+}