feat: set X-Influxdb-Version and X-Influxdb-Build headers (#22535)

Closes #20224
Also a forward port of #22038 since I saw the same test failing on 2.x

http/handler.go

@@ -6,6 +6,7 @@ import (
 	"net/http"
 
 	"github.com/go-chi/chi"
+	"github.com/influxdata/influxdb/v2"
 	"github.com/influxdata/influxdb/v2/kit/platform/errors"
 	"github.com/influxdata/influxdb/v2/kit/prom"
 	kithttp "github.com/influxdata/influxdb/v2/kit/transport/http"
@@ -90,6 +91,19 @@ func WithMetrics(reg *prom.Registry, exposed bool) HandlerOptFn {
 	}
 }
 
+type AddHeader struct {
+	WriteHeader func(header http.Header)
+}
+
+// Middleware is a middleware that mutates the header of all responses
+func (h *AddHeader) Middleware(next http.Handler) http.Handler {
+	fn := func(w http.ResponseWriter, r *http.Request) {
+		h.WriteHeader(w.Header())
+		next.ServeHTTP(w, r)
+	}
+	return http.HandlerFunc(fn)
+}
+
 // NewRootHandler creates a new handler with the given name and registers any root-level
 // (non-API) routes enabled by the caller.
 func NewRootHandler(name string, opts ...HandlerOptFn) *Handler {
@@ -112,6 +126,13 @@ func NewRootHandler(name string, opts ...HandlerOptFn) *Handler {
 	h.initMetrics()
 
 	r := chi.NewRouter()
+	buildHeader := &AddHeader{
+		WriteHeader: func(header http.Header) {
+			header.Add("X-Influxdb-Build", "OSS")
+			header.Add("X-Influxdb-Version", influxdb.GetBuildInfo().Version)
+		},
+	}
+	r.Use(buildHeader.Middleware)
 	// only gather metrics for system handlers
 	r.Group(func(r chi.Router) {
 		r.Use(

tsdb/index/tsi1/index_test.go

@@ -528,10 +528,14 @@ func (idx Index) Open() error {
 // Close closes and removes the index directory.
 func (idx *Index) Close() error {
 	defer os.RemoveAll(idx.Path())
+	// Series file is opened first and must be closed last
+	if err := idx.Index.Close(); err != nil {
+		return err
+	}
 	if err := idx.SeriesFile.Close(); err != nil {
 		return err
 	}
-	return idx.Index.Close()
+	return nil
 }
 
 // Reopen closes and opens the index.