refactor: move request-compression out of codegen, avoid some buffering (#118)

pkg/gzip/pipe.go

@@ -0,0 +1,47 @@
+package gzip
+
+import (
+	"compress/gzip"
+	"io"
+)
+
+var _ io.ReadCloser = (*gzipPipe)(nil)
+
+type gzipPipe struct {
+	underlying io.ReadCloser
+	pipeOut    io.ReadCloser
+}
+
+// NewGzipPipe returns an io.ReadCloser that wraps an input data stream,
+// applying gzip compression to the underlying data on Read and closing the
+// underlying data on Close.
+func NewGzipPipe(in io.ReadCloser) *gzipPipe {
+	pr, pw := io.Pipe()
+	gw := gzip.NewWriter(pw)
+
+	go func() {
+		_, err := io.Copy(gw, in)
+		gw.Close()
+		if err != nil {
+			pw.CloseWithError(err)
+		} else {
+			pw.Close()
+		}
+	}()
+
+	return &gzipPipe{underlying: in, pipeOut: pr}
+}
+
+func (gzp gzipPipe) Read(p []byte) (int, error) {
+	return gzp.pipeOut.Read(p)
+}
+
+func (gzp gzipPipe) Close() error {
+	if err := gzp.pipeOut.Close(); err != nil {
+		return err
+	}
+	if err := gzp.underlying.Close(); err != nil {
+		return err
+	}
+	return nil
+}

pkg/gzip/pipe_test.go

@@ -0,0 +1,66 @@
+package gzip_test
+
+import (
+	"bytes"
+	"compress/gzip"
+	"errors"
+	"io"
+	"io/ioutil"
+	"strings"
+	"testing"
+
+	pgzip "github.com/influxdata/influx-cli/v2/pkg/gzip"
+	"github.com/stretchr/testify/require"
+)
+
+func TestGzipPipe(t *testing.T) {
+	t.Parallel()
+
+	t.Run("success", func(t *testing.T) {
+		t.Parallel()
+
+		data := strings.Repeat("Data data I'm some data\n", 1024)
+		reader := strings.NewReader(data)
+		pipe := pgzip.NewGzipPipe(ioutil.NopCloser(reader))
+		defer pipe.Close()
+		gunzip, err := gzip.NewReader(pipe)
+		require.NoError(t, err)
+		defer gunzip.Close()
+
+		out := bytes.Buffer{}
+		_, err = io.Copy(&out, gunzip)
+		require.NoError(t, err)
+
+		require.Equal(t, data, out.String())
+	})
+
+	t.Run("error", func(t *testing.T) {
+		t.Parallel()
+
+		reader := &failingReader{n: 3, err: errors.New("I BROKE")}
+		pipe := pgzip.NewGzipPipe(ioutil.NopCloser(reader))
+		defer pipe.Close()
+		gunzip, err := gzip.NewReader(pipe)
+		require.NoError(t, err)
+		defer gunzip.Close()
+
+		out := bytes.Buffer{}
+		_, err = io.Copy(&out, gunzip)
+		require.Error(t, err)
+		require.Equal(t, reader.err, err)
+	})
+}
+
+type failingReader struct {
+	n int
+	err error
+}
+
+func (frc *failingReader) Read(p []byte) (int, error) {
+	if frc.n <= 0 {
+		return 0, frc.err
+	}
+	frc.n--
+	p[0] = 'a'
+	return 1, nil
+}