Elasticsearch: Client refactor (#114745)

* split up client.go

* split up search_request.go

* remove double spaces

pkg/tsdb/elasticsearch/client/request_encoder.go

@@ -0,0 +1,53 @@
+package es
+
+import (
+	"bytes"
+	"encoding/json"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/grafana/grafana-plugin-sdk-go/backend/log"
+)
+
+// requestEncoder handles encoding of search requests to Elasticsearch format
+type requestEncoder struct {
+	logger log.Logger
+}
+
+// newRequestEncoder creates a new request encoder
+func newRequestEncoder(logger log.Logger) *requestEncoder {
+	return &requestEncoder{
+		logger: logger,
+	}
+}
+
+// encodeBatchRequests encodes multiple requests into NDJSON format
+func (e *requestEncoder) encodeBatchRequests(requests []*multiRequest) ([]byte, error) {
+	start := time.Now()
+
+	payload := bytes.Buffer{}
+	for _, r := range requests {
+		reqHeader, err := json.Marshal(r.header)
+		if err != nil {
+			return nil, err
+		}
+		payload.WriteString(string(reqHeader) + "\n")
+
+		reqBody, err := json.Marshal(r.body)
+		if err != nil {
+			return nil, err
+		}
+
+		body := string(reqBody)
+		body = strings.ReplaceAll(body, "$__interval_ms", strconv.FormatInt(r.interval.Milliseconds(), 10))
+		body = strings.ReplaceAll(body, "$__interval", r.interval.String())
+
+		payload.WriteString(body + "\n")
+	}
+
+	elapsed := time.Since(start)
+	e.logger.Debug("Completed encoding of batch requests to json", "duration", elapsed)
+
+	return payload.Bytes(), nil
+}