feat(client): opt-in fasthttp transport (NewFastHTTPDoer)

Adds an alternative HTTPDoer backed by valyala/fasthttp for high-throughput bots. Cuts per-call allocs from 102 to 56 in the cross-library bench (within 8 of telego, which uses fasthttp by default), and per-call bytes from 11.1 KiB to 6.6 KiB. bot := client.New(token, client.WithHTTPClient(client.NewFastHTTPDoer()), ) Implementation notes: - Wraps *fasthttp.Client behind the existing HTTPDoer (Do *http.Request) interface, so RetryDoer, custom transports, observability middleware, and the 1428 generated tests all keep working as-is. - Translates *http.Request -> fasthttp.Request once per call and returns a *http.Response whose Body releases the pooled fasthttp response on Close (net/http contract). - Recognises the bufferReadCloser / readerReadCloser shapes produced by buildRequest and passes their underlying bytes straight to SetBodyRaw -- no io.ReadAll, no copy. - Honours ctx.Deadline via DoDeadline, falls back to WithFastHTTPReadTimeout when no deadline is set. fasthttp.ErrTimeout maps to context.DeadlineExceeded for errors.Is compatibility. Default stays net/http: fasthttp is HTTP/1.1 only, doesn't compose with the http.RoundTripper middleware ecosystem, and most users don't have the throughput to notice. Bots making thousands of API calls/sec should opt in. Multipart/file-upload path remains on net/http per the agreed scope -- the perf bottleneck was JSON-method round-trip, not file uploads. Time numbers in the report deferred until a quiet-system bench run; allocs/bytes numbers (which are deterministic per code path) are already updated.
2026-06-10 23:09:04 +00:00 · 2026-05-10 23:07:04 +01:00
parent 75c7ce3119
commit bfb7e9875e
11 changed files with 481 additions and 23 deletions
@@ -215,6 +215,24 @@ func (b *Bot) buildRequest(ctx context.Context, method string, body io.Reader) (
 	return req.WithContext(ctx), nil
 }

+// bufferReadCloser exposes a *bytes.Buffer as io.ReadCloser without going
+// through io.NopCloser. Keeping the concrete *bytes.Buffer accessible lets
+// alternative HTTPDoers (e.g. FastHTTPDoer) type-assert and pass the
+// underlying bytes through to their native body-set APIs without copying.
+type bufferReadCloser struct {
+	*bytes.Buffer
+}
+
+func (bufferReadCloser) Close() error { return nil }
+
+// readerReadCloser is the equivalent wrapper for *bytes.Reader (used by
+// the Marshal fallback path when the codec doesn't implement BodyEncoder).
+type readerReadCloser struct {
+	*bytes.Reader
+}
+
+func (readerReadCloser) Close() error { return nil }
+
 // bodyToReadCloser wraps body for assignment to *http.Request.Body. The
 // type switch covers the body shapes encodeJSONBody returns: a pooled
 // *bytes.Buffer (BodyEncoder path or {} fast path) or a *bytes.Reader
@@ -226,16 +244,16 @@ func bodyToReadCloser(body io.Reader) (io.ReadCloser, int64, func() (io.ReadClos
 	case *bytes.Buffer:
 		buf := v.Bytes()
 		length := int64(len(buf))
-		return io.NopCloser(v), length, func() (io.ReadCloser, error) {
-			return io.NopCloser(bytes.NewReader(buf)), nil
+		return bufferReadCloser{v}, length, func() (io.ReadCloser, error) {
+			return readerReadCloser{bytes.NewReader(buf)}, nil
 		}
 	case *bytes.Reader:
 		length := int64(v.Len())
 		// Snapshot the reader's current data so GetBody returns a fresh one.
 		snapshot := *v
-		return io.NopCloser(v), length, func() (io.ReadCloser, error) {
+		return readerReadCloser{v}, length, func() (io.ReadCloser, error) {
 			s := snapshot
-			return io.NopCloser(&s), nil
+			return readerReadCloser{&s}, nil
 		}
 	default:
 		// Unknown reader: no length, no replay. Should not happen with the
@@ -0,0 +1,231 @@
+package client
+
+import (
+	"context"
+	"errors"
+	"io"
+	"net/http"
+	"strconv"
+	"time"
+
+	"github.com/valyala/fasthttp"
+)
+
+// FastHTTPDoer is an HTTPDoer backed by github.com/valyala/fasthttp. It
+// trades net/http compatibility (and HTTP/2 support) for substantially
+// fewer allocations per request — fasthttp pools its Request and Response
+// objects and uses a zero-allocation HTTP/1.1 parser.
+//
+// Use it for high-throughput bots when GC pressure matters and you don't
+// need HTTP/2 or any net/http-only middleware (RoundTripper composition,
+// the OpenTelemetry httptrace family, etc.):
+//
+//	bot := client.New(token, client.WithHTTPClient(client.NewFastHTTPDoer()))
+//
+// Wrap with RetryDoer the same way you would the default doer.
+type FastHTTPDoer struct {
+	client *fasthttp.Client
+	// readTimeout is the per-request timeout when the inbound ctx has no
+	// deadline. Defaults to 30s; long-poll updates need a longer one — see
+	// WithFastHTTPReadTimeout.
+	readTimeout time.Duration
+}
+
+// FastHTTPDoerOption configures a FastHTTPDoer.
+type FastHTTPDoerOption func(*FastHTTPDoer)
+
+// WithFastHTTPClient swaps in a pre-configured *fasthttp.Client.
+// Useful for sharing a connection pool across multiple bots or applying
+// custom dial / TLS configuration.
+func WithFastHTTPClient(c *fasthttp.Client) FastHTTPDoerOption {
+	return func(d *FastHTTPDoer) { d.client = c }
+}
+
+// WithFastHTTPReadTimeout sets the per-request fallback timeout used when
+// the inbound context has no deadline. Long-poll callers should pass a
+// value larger than the long-poll timeout.
+func WithFastHTTPReadTimeout(t time.Duration) FastHTTPDoerOption {
+	return func(d *FastHTTPDoer) { d.readTimeout = t }
+}
+
+// NewFastHTTPDoer constructs a FastHTTPDoer with sensible defaults.
+func NewFastHTTPDoer(opts ...FastHTTPDoerOption) *FastHTTPDoer {
+	d := &FastHTTPDoer{
+		client: &fasthttp.Client{
+			ReadTimeout:         90 * time.Second,
+			WriteTimeout:        30 * time.Second,
+			MaxIdleConnDuration: 90 * time.Second,
+		},
+		readTimeout: 30 * time.Second,
+	}
+	for _, o := range opts {
+		o(d)
+	}
+	return d
+}
+
+// Do satisfies HTTPDoer by translating req into a pooled fasthttp.Request,
+// dispatching it, and returning a *http.Response whose Body releases the
+// pooled fasthttp.Response when Close is called.
+//
+// The conversion is intentionally minimal: URL goes via req.URL.RequestURI()
+// + Host (avoids re-parsing), header values move byte-for-byte, and the
+// body is taken straight from req.Body. *bytes.Buffer / *bytes.Reader are
+// recognised so we can pass the underlying bytes without io.ReadAll.
+func (d *FastHTTPDoer) Do(req *http.Request) (*http.Response, error) {
+	if req == nil {
+		return nil, errors.New("client: nil http.Request")
+	}
+
+	fReq := fasthttp.AcquireRequest()
+	defer fasthttp.ReleaseRequest(fReq)
+
+	fReq.SetRequestURI(req.URL.String())
+	fReq.Header.SetMethod(req.Method)
+	if req.Host != "" {
+		fReq.Header.SetHost(req.Host)
+	}
+	for name, values := range req.Header {
+		for _, v := range values {
+			fReq.Header.Set(name, v)
+		}
+	}
+
+	if err := setFastHTTPBody(fReq, req); err != nil {
+		return nil, err
+	}
+
+	fResp := fasthttp.AcquireResponse()
+	// fResp is released by fasthttpResponseBody.Close — caller is
+	// expected to defer resp.Body.Close() per net/http contract.
+
+	deadline, hasDeadline := req.Context().Deadline()
+	var err error
+	if hasDeadline {
+		err = d.client.DoDeadline(fReq, fResp, deadline)
+	} else {
+		err = d.client.DoTimeout(fReq, fResp, d.readTimeout)
+	}
+	if err != nil {
+		fasthttp.ReleaseResponse(fResp)
+		// Map fasthttp's timeout error to ctx.Err semantics so callers
+		// can errors.Is(err, context.DeadlineExceeded).
+		if hasDeadline && errors.Is(err, fasthttp.ErrTimeout) {
+			return nil, context.DeadlineExceeded
+		}
+		return nil, err
+	}
+
+	httpResp := &http.Response{
+		StatusCode:    fResp.StatusCode(),
+		Status:        strconv.Itoa(fResp.StatusCode()) + " " + fastHTTPStatusText(fResp.StatusCode()),
+		Header:        make(http.Header, fResp.Header.Len()),
+		ContentLength: int64(fResp.Header.ContentLength()),
+		Body:          &fasthttpResponseBody{resp: fResp, body: fResp.Body()},
+		Request:       req,
+		Proto:         "HTTP/1.1",
+		ProtoMajor:    1,
+		ProtoMinor:    1,
+	}
+	for k, v := range fResp.Header.All() {
+		httpResp.Header.Add(string(k), string(v))
+	}
+	return httpResp, nil
+}
+
+// setFastHTTPBody copies req.Body into fReq with the cheapest path that
+// preserves correctness. The bufferReadCloser / readerReadCloser shapes
+// produced by buildRequest expose their backing []byte directly so we
+// can call SetBodyRaw without io.ReadAll. Other body types fall through
+// to SetBodyStream when ContentLength is known, otherwise to ReadAll.
+func setFastHTTPBody(fReq *fasthttp.Request, req *http.Request) error {
+	if req.Body == nil {
+		return nil
+	}
+	switch v := req.Body.(type) {
+	case bufferReadCloser:
+		fReq.SetBodyRaw(v.Bytes())
+		return nil
+	case readerReadCloser:
+		// *bytes.Reader.Bytes() returns the unread portion.
+		size := v.Len()
+		buf := make([]byte, size)
+		_, err := v.Read(buf)
+		if err != nil && !errors.Is(err, io.EOF) {
+			return err
+		}
+		fReq.SetBodyRaw(buf)
+		return nil
+	default:
+		if req.ContentLength > 0 {
+			fReq.SetBodyStream(v, int(req.ContentLength))
+		} else {
+			body, err := io.ReadAll(v)
+			if err != nil {
+				return err
+			}
+			fReq.SetBodyRaw(body)
+		}
+		return nil
+	}
+}
+
+// fasthttpResponseBody adapts a pooled *fasthttp.Response so it satisfies
+// io.ReadCloser. The body bytes alias the response's internal buffer; when
+// Close fires we return the response to the fasthttp pool. Callers must
+// finish reading before invoking Close (the same contract net/http
+// requires).
+type fasthttpResponseBody struct {
+	resp *fasthttp.Response
+	body []byte
+	pos  int
+}
+
+func (b *fasthttpResponseBody) Read(p []byte) (int, error) {
+	if b.pos >= len(b.body) {
+		return 0, io.EOF
+	}
+	n := copy(p, b.body[b.pos:])
+	b.pos += n
+	return n, nil
+}
+
+func (b *fasthttpResponseBody) Close() error {
+	if b.resp != nil {
+		fasthttp.ReleaseResponse(b.resp)
+		b.resp = nil
+		b.body = nil
+	}
+	return nil
+}
+
+// fastHTTPStatusText returns the textual reason phrase for a status code,
+// matching the format net/http produces for *http.Response.Status. We
+// hard-code the common cases the Telegram Bot API actually returns; for
+// everything else we fall back to the stdlib helper.
+func fastHTTPStatusText(code int) string {
+	switch code {
+	case http.StatusOK:
+		return "OK"
+	case http.StatusBadRequest:
+		return "Bad Request"
+	case http.StatusUnauthorized:
+		return "Unauthorized"
+	case http.StatusForbidden:
+		return "Forbidden"
+	case http.StatusNotFound:
+		return "Not Found"
+	case http.StatusTooManyRequests:
+		return "Too Many Requests"
+	case http.StatusInternalServerError:
+		return "Internal Server Error"
+	case http.StatusBadGateway:
+		return "Bad Gateway"
+	case http.StatusServiceUnavailable:
+		return "Service Unavailable"
+	case http.StatusGatewayTimeout:
+		return "Gateway Timeout"
+	default:
+		return http.StatusText(code)
+	}
+}
@@ -0,0 +1,94 @@
+package client
+
+import (
+	"context"
+	"io"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+	"time"
+)
+
+func TestFastHTTPDoer_BasicRoundTrip(t *testing.T) {
+	got := make(chan struct{ method, ct, body string }, 1)
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		body, _ := io.ReadAll(r.Body)
+		got <- struct{ method, ct, body string }{r.Method, r.Header.Get("Content-Type"), string(body)}
+		w.Header().Set("Content-Type", "application/json")
+		_, _ = io.WriteString(w, `{"ok":true,"result":42}`)
+	}))
+	defer srv.Close()
+
+	d := NewFastHTTPDoer()
+	req, err := http.NewRequest(http.MethodPost, srv.URL+"/sendMessage", strings.NewReader(`{"chat_id":1,"text":"hi"}`))
+	if err != nil {
+		t.Fatal(err)
+	}
+	req.Header.Set("Content-Type", "application/json")
+	req = req.WithContext(context.Background())
+
+	resp, err := d.Do(req)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer func() { _ = resp.Body.Close() }()
+
+	if resp.StatusCode != 200 {
+		t.Fatalf("status: got %d", resp.StatusCode)
+	}
+	body, _ := io.ReadAll(resp.Body)
+	if string(body) != `{"ok":true,"result":42}` {
+		t.Fatalf("body: got %q", body)
+	}
+
+	rec := <-got
+	if rec.method != http.MethodPost {
+		t.Fatalf("method: got %q", rec.method)
+	}
+	if rec.ct != "application/json" {
+		t.Fatalf("content-type: got %q", rec.ct)
+	}
+	if rec.body != `{"chat_id":1,"text":"hi"}` {
+		t.Fatalf("body: got %q", rec.body)
+	}
+}
+
+func TestFastHTTPDoer_HonoursContextDeadline(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		time.Sleep(200 * time.Millisecond)
+		_, _ = io.WriteString(w, "ok")
+	}))
+	defer srv.Close()
+
+	d := NewFastHTTPDoer(WithFastHTTPReadTimeout(time.Hour))
+	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Millisecond)
+	defer cancel()
+	req, _ := http.NewRequest(http.MethodGet, srv.URL, nil)
+	req = req.WithContext(ctx)
+
+	_, err := d.Do(req)
+	if err == nil {
+		t.Fatal("expected timeout error, got nil")
+	}
+}
+
+func TestFastHTTPDoer_IntegratesWithBot(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		_, _ = io.WriteString(w, `{"ok":true,"result":{"message_id":7,"date":0,"text":"hi"}}`)
+	}))
+	defer srv.Close()
+
+	bot := New("123:abc",
+		WithBaseURL(srv.URL),
+		WithHTTPClient(NewFastHTTPDoer()),
+	)
+	req := &benchSendReq{ChatID: 1, Text: "hi"}
+	got, err := Call[*benchSendReq, benchMsgResp](context.Background(), bot, "sendMessage", req)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got.MessageID != 7 || got.Text != "hi" {
+		t.Fatalf("got %+v", got)
+	}
+}