Add experimental s2 support

README.md

@@ -6,3 +6,9 @@ algorithms that are not available in google.golang.org/grpc.
 * https://github.com/golang/snappy
 * https://github.com/klauspost/compress/tree/master/zstd
 * https://github.com/pierrec/lz4
+
+The following algorithms also have experimental implementations, which have
+not been tested as much as those above. These may be changed significantly, or
+even removed from this library at a future point.
+
+* https://github.com/klauspost/compress/tree/master/s2

experimental/s2/s2.go

@@ -0,0 +1,86 @@
+// Copyright 2022 Mostyn Bramley-Moore.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package s2 is an experimental wrapper for using
+// github.com/klauspost/compress/s2 stream compression with gRPC.
+package s2
+
+import (
+	"io"
+	"io/ioutil"
+	"sync"
+
+	"github.com/klauspost/compress/s2"
+	"google.golang.org/grpc/encoding"
+)
+
+const Name = "s2"
+
+type compressor struct {
+	poolCompressor   sync.Pool
+	poolDecompressor sync.Pool
+}
+
+type writer struct {
+	*s2.Writer
+	pool *sync.Pool
+}
+
+type reader struct {
+	*s2.Reader
+	pool *sync.Pool
+}
+
+func init() {
+	c := &compressor{}
+	c.poolCompressor.New = func() interface{} {
+		w := s2.NewWriter(ioutil.Discard, s2.WriterConcurrency(1))
+		return &writer{Writer: w, pool: &c.poolCompressor}
+	}
+	encoding.RegisterCompressor(c)
+}
+
+func (c *compressor) Compress(w io.Writer) (io.WriteCloser, error) {
+	s := c.poolCompressor.Get().(*writer)
+	s.Writer.Reset(w)
+	return s, nil
+}
+
+func (c *compressor) Decompress(r io.Reader) (io.Reader, error) {
+	s, inPool := c.poolDecompressor.Get().(*reader)
+	if !inPool {
+		newR := s2.NewReader(r)
+		return &reader{Reader: newR, pool: &c.poolDecompressor}, nil
+	}
+	s.Reset(r)
+	return s, nil
+}
+
+func (c *compressor) Name() string {
+	return Name
+}
+
+func (s *writer) Close() error {
+	err := s.Writer.Close()
+	s.pool.Put(s)
+	return err
+}
+
+func (s *reader) Read(p []byte) (n int, err error) {
+	n, err = s.Reader.Read(p)
+	if err == io.EOF {
+		s.pool.Put(s)
+	}
+	return n, err
+}

experimental/s2/s2_test.go

@@ -0,0 +1,96 @@
+// Copyright 2022 Mostyn Bramley-Moore.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package s2
+
+import (
+	"bytes"
+	"context"
+	"io/ioutil"
+	"net"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/encoding"
+	"google.golang.org/grpc/test/bufconn"
+
+	"github.com/mostynb/go-grpc-compression/internal/testserver"
+)
+
+const (
+	bufSize = 1024
+	message = "Message Request s2"
+)
+
+func TestRegisteredCompression(t *testing.T) {
+	comp := encoding.GetCompressor(Name)
+	require.NotNil(t, comp)
+	assert.Equal(t, Name, comp.Name())
+
+	buf := bytes.NewBuffer(make([]byte, 0, bufSize))
+	wc, err := comp.Compress(buf)
+	require.NoError(t, err)
+
+	_, err = wc.Write([]byte(message))
+	require.NoError(t, err)
+	assert.NoError(t, wc.Close())
+
+	r, err := comp.Decompress(buf)
+	require.NoError(t, err)
+	expected, err := ioutil.ReadAll(r)
+	require.NoError(t, err)
+
+	assert.Equal(t, message, string(expected))
+}
+
+func TestRoundTrip(t *testing.T) {
+	lis := bufconn.Listen(bufSize)
+	t.Cleanup(func() {
+		assert.NoError(t, lis.Close())
+	})
+
+	done := make(chan struct{}, 1)
+
+	s := grpc.NewServer()
+	defer func() {
+		s.GracefulStop()
+		<-done
+	}()
+	testserver.RegisterTestServerServer(s, &testserver.EchoTestServer{})
+	go func() {
+		if err := s.Serve(lis); err != nil && err != grpc.ErrServerStopped {
+			t.Errorf("Server exited with error: %v", err)
+		}
+		done <- struct{}{}
+	}()
+
+	ctx := context.Background()
+	conn, err := grpc.DialContext(ctx, "bufnet",
+		grpc.WithContextDialer(func(context.Context, string) (net.Conn, error) {
+			return lis.Dial()
+		}),
+		grpc.WithDefaultCallOptions(grpc.UseCompressor(Name)),
+		grpc.WithInsecure())
+	require.NoError(t, err)
+	t.Cleanup(func() {
+		assert.NoError(t, conn.Close())
+	})
+
+	client := testserver.NewTestServerClient(conn)
+	resp, err := client.SendMessage(ctx, &testserver.MessageRequest{Request: message})
+	require.NoError(t, err)
+	assert.Equal(t, message, resp.Response)
+}