indexer: sort headers to have deterministic output

internal/indexer/index/local.go

@@ -7,6 +7,7 @@ import (
 	"net/url"
 	"os"
 	"path/filepath"
+	"sort"
 	"strconv"
 	"strings"
 	"time"
@@ -63,9 +64,16 @@ func formatResource(url string, body string, headers map[string]string) ([]byte,
 	// First URL
 	builder.WriteString(fmt.Sprintf("%s\n\n", url))
 
+	// Sort headers to have deterministic output
+	var headerNames []string
+	for headerName := range headers {
+		headerNames = append(headerNames, headerName)
+	}
+	sort.Strings(headerNames)
+
 	// Then headers
-	for key, value := range headers {
+	for _, name := range headerNames {
-		builder.WriteString(fmt.Sprintf("%s: %s\n", key, value))
+		builder.WriteString(fmt.Sprintf("%s: %s\n", name, headers[name]))
 	}
 	builder.WriteString("\n")
 

internal/indexer/index/local_test.go

@@ -134,7 +134,7 @@ func TestFormatResource(t *testing.T) {
 		t.FailNow()
 	}
 
-	if string(res) != "https://google.com\n\nServer: Traefik\nContent-Type: text/html\n\nHello, world" {
+	if string(res) != "https://google.com\n\nContent-Type: text/html\nServer: Traefik\n\nHello, world" {
 		t.Errorf("got %s want %s", string(res), "https://google.com\n\nServer: Traefik\nContent-Type: text/html\n\nHello, world")
 	}
 }