Merge branch 'vegz' into 'master'

[gzep] Add simple sync.Pool task.

See merge request slon/shad-go-private!72

.deadlines.yml

@@ -1,3 +1,12 @@
+- group:    Analysis
+  start:    05-05-2022 18:00
+  deadline: 15-05-2022 23:59
+  tasks:
+    - task: testifycheck
+      score: 200
+    - task: gzep
+      score: 100
+
 - group:    Bonus
   start:    14-04-2022 17:59
   deadline: 22-05-2022 23:59

gzep/README.md

@@ -0,0 +1,21 @@
+## gzep [runtime]
+
+В этой задаче нужно победить бенчмарк, "улучшив" функцию сериализации в `gzip`.
+
+Пример запуска бенчмарка для бейзлайна и авторского решения:
+```
+goos: linux
+goarch: amd64
+pkg: gitlab.com/slon/shad-go/gzep
+cpu: Intel(R) Core(TM) i7-8650U CPU @ 1.90GHz
+BenchmarkEncodeSimple
+BenchmarkEncodeSimple-8   	    8307	    124841 ns/op	  813872 B/op	      17 allocs/op
+BenchmarkEncode
+BenchmarkEncode-8         	 2094512	       620.0 ns/op	       0 B/op	       0 allocs/op
+PASS
+ok  	gitlab.com/slon/shad-go/gzep	3.756s
+```
+
+### С чего начать?
+
+Запустите бенчмарк локально. Найдите в коде `compress/gzip` откуда берутся эти 800 килобайт на операцию?

gzep/encode.go

@@ -0,0 +1,17 @@
+//go:build !solution
+
+package gzep
+
+import (
+	"compress/gzip"
+	"io"
+)
+
+func Encode(data []byte, w io.Writer) error {
+	ww := gzip.NewWriter(w)
+	defer func() { _ = ww.Close() }()
+	if _, err := ww.Write(data); err != nil {
+		return err
+	}
+	return ww.Flush()
+}

gzep/encode_test.go

@@ -0,0 +1,64 @@
+package gzep
+
+import (
+	"bytes"
+	"compress/gzip"
+	"io"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	"gitlab.com/slon/shad-go/tools/testtool"
+)
+
+func BenchmarkEncode(b *testing.B) {
+	data := []byte(
+		"New function should generally only return pointer types, " +
+			"since a pointer can be put into the return interface " +
+			"value without an allocation. " +
+			testtool.RandomName(),
+	)
+
+	b.ResetTimer()
+	b.ReportAllocs()
+	for n := 0; n < b.N; n++ {
+		require.NoError(b, Encode(data, io.Discard))
+	}
+}
+
+func TestRoundTrip(t *testing.T) {
+	testCases := []struct {
+		name string
+		in   string
+	}{
+		{name: "empty", in: ""},
+		{name: "simple", in: "A long time ago in a galaxy far, far away..."},
+		{name: "random", in: testtool.RandomName()},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			buf := new(bytes.Buffer)
+			require.NoError(t, Encode([]byte(tc.in), buf))
+
+			out, err := decode(buf.Bytes())
+			require.NoError(t, err, tc.in)
+			require.Equal(t, tc.in, string(out))
+		})
+
+	}
+}
+
+func decode(data []byte) ([]byte, error) {
+	r, err := gzip.NewReader(bytes.NewReader(data))
+	if err != nil {
+		return nil, err
+	}
+
+	buf := &bytes.Buffer{}
+	if _, err := io.Copy(buf, r); err != nil {
+		return nil, err
+	}
+
+	return buf.Bytes(), nil
+}