Add container attach support.

Signed-off-by: Lantao Liu <lantaol@google.com>

pkg/server/io/logger_test.go

@@ -0,0 +1,81 @@
+/*
+Copyright 2017 The Kubernetes Authors.
+
+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 agents
+
+import (
+	"bytes"
+	"io/ioutil"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	cioutil "github.com/kubernetes-incubator/cri-containerd/pkg/ioutil"
+)
+
+func TestRedirectLogs(t *testing.T) {
+	for desc, test := range map[string]struct {
+		input   string
+		stream  StreamType
+		content []string
+	}{
+		"stdout log": {
+			input:  "test stdout log 1\ntest stdout log 2",
+			stream: Stdout,
+			content: []string{
+				"test stdout log 1",
+				"test stdout log 2",
+			},
+		},
+		"stderr log": {
+			input:  "test stderr log 1\ntest stderr log 2",
+			stream: Stderr,
+			content: []string{
+				"test stderr log 1",
+				"test stderr log 2",
+			},
+		},
+		"long log": {
+			input:  strings.Repeat("a", bufSize+10) + "\n",
+			stream: Stdout,
+			content: []string{
+				strings.Repeat("a", bufSize),
+				strings.Repeat("a", 10),
+			},
+		},
+	} {
+		t.Logf("TestCase %q", desc)
+		rc := ioutil.NopCloser(strings.NewReader(test.input))
+		buf := bytes.NewBuffer(nil)
+		wc := cioutil.NewNopWriteCloser(buf)
+		redirectLogs("test-path", rc, wc, test.stream)
+		output := buf.String()
+		lines := strings.Split(output, "\n")
+		lines = lines[:len(lines)-1] // Discard empty string after last \n
+		assert.Len(t, lines, len(test.content))
+		for i := range lines {
+			fields := strings.SplitN(lines[i], string([]byte{delimiter}), 3)
+			require.Len(t, fields, 3)
+			_, err := time.Parse(timestampFormat, fields[0])
+			assert.NoError(t, err)
+			assert.EqualValues(t, test.stream, fields[1])
+			assert.Equal(t, test.content[i], fields[2])
+		}
+	}
+}