etl/webserver: support ETL pipeline handling in Go-based framework

Signed-off-by: Tony Chen <a122774007@gmail.com>

Author: Nahemah1022

api/apc/headers.go

@@ -118,7 +118,8 @@ const (
 	HdrPromoteNamesNum  = aisPrefix + "Promote-Names-Num"
 
 	// ETL
-	HdrETLPodInfo = aisPrefix + "ETL-Pod-Info" // serialized etl.Info
+	HdrETLPodInfo      = aisPrefix + "ETL-Pod-Info" // serialized etl.Info
+	HdrDirectPutLength = aisPrefix + "Direct-Put-Length"
 
 	// shared streams
 	HdrActiveEC = aisPrefix + "Ec"

ext/etl/webserver/cmn.go

@@ -10,14 +10,18 @@ import (
 	"io"
 	"net/http"
 	"strconv"
+	"strings"
 
+	"github.com/NVIDIA/aistore/api/apc"
 	"github.com/NVIDIA/aistore/cmn/cos"
 )
 
 const GetContentType = "binary/octet-stream"
 
 func setResponseHeaders(header http.Header, size int64) {
-	header.Set(cos.HdrContentLength, strconv.FormatInt(size, 10))
+	if size > 0 {
+		header.Set(cos.HdrContentLength, strconv.FormatInt(size, 10))
+	}
 	header.Set(cos.HdrContentType, GetContentType)
 }
 
@@ -40,3 +44,24 @@ func wrapHTTPError(resp *http.Response, err error) (*http.Response, error) {
 
 	return resp, nil
 }
+
+func parsePipelineURL(pipelineURLHdr string) (string, string) {
+	pipelineURLHdr = strings.TrimSpace(pipelineURLHdr)
+	if pipelineURLHdr == "" {
+		return "", ""
+	}
+	pipelineURLs := strings.Split(pipelineURLHdr, apc.ETLPipelineSeparator)
+	for _, pipelineURL := range pipelineURLs {
+		pipelineURL = strings.TrimSpace(pipelineURL)
+		if pipelineURL == "" {
+			return "", ""
+		}
+	}
+	commaIndex := strings.Index(pipelineURLHdr, apc.ETLPipelineSeparator)
+	if commaIndex == -1 {
+		// No comma found, only one URL (already validated)
+		return pipelineURLHdr, ""
+	}
+	// Extract first URL and remaining pipeline
+	return pipelineURLHdr[:commaIndex], pipelineURLHdr[commaIndex+1:]
+}