Split reader interface from logger interface

Implement new reader interface on jsonfile.
Moves jsonlog decoding from daemon to jsonfile logger.

Signed-off-by: Brian Goff <cpuguy83@gmail.com>

ioutils/multireader_test.go

@@ -0,0 +1,149 @@
+package ioutils
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"os"
+	"strings"
+	"testing"
+)
+
+func TestMultiReadSeekerReadAll(t *testing.T) {
+	str := "hello world"
+	s1 := strings.NewReader(str + " 1")
+	s2 := strings.NewReader(str + " 2")
+	s3 := strings.NewReader(str + " 3")
+	mr := MultiReadSeeker(s1, s2, s3)
+
+	expectedSize := int64(s1.Len() + s2.Len() + s3.Len())
+
+	b, err := ioutil.ReadAll(mr)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	expected := "hello world 1hello world 2hello world 3"
+	if string(b) != expected {
+		t.Fatalf("ReadAll failed, got: %q, expected %q", string(b), expected)
+	}
+
+	size, err := mr.Seek(0, os.SEEK_END)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if size != expectedSize {
+		t.Fatalf("reader size does not match, got %d, expected %d", size, expectedSize)
+	}
+
+	// Reset the position and read again
+	pos, err := mr.Seek(0, os.SEEK_SET)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if pos != 0 {
+		t.Fatalf("expected position to be set to 0, got %d", pos)
+	}
+
+	b, err = ioutil.ReadAll(mr)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if string(b) != expected {
+		t.Fatalf("ReadAll failed, got: %q, expected %q", string(b), expected)
+	}
+}
+
+func TestMultiReadSeekerReadEach(t *testing.T) {
+	str := "hello world"
+	s1 := strings.NewReader(str + " 1")
+	s2 := strings.NewReader(str + " 2")
+	s3 := strings.NewReader(str + " 3")
+	mr := MultiReadSeeker(s1, s2, s3)
+
+	var totalBytes int64
+	for i, s := range []*strings.Reader{s1, s2, s3} {
+		sLen := int64(s.Len())
+		buf := make([]byte, s.Len())
+		expected := []byte(fmt.Sprintf("%s %d", str, i+1))
+
+		if _, err := mr.Read(buf); err != nil && err != io.EOF {
+			t.Fatal(err)
+		}
+
+		if !bytes.Equal(buf, expected) {
+			t.Fatalf("expected %q to be %q", string(buf), string(expected))
+		}
+
+		pos, err := mr.Seek(0, os.SEEK_CUR)
+		if err != nil {
+			t.Fatalf("iteration: %d, error: %v", i+1, err)
+		}
+
+		// check that the total bytes read is the current position of the seeker
+		totalBytes += sLen
+		if pos != totalBytes {
+			t.Fatalf("expected current position to be: %d, got: %d, iteration: %d", totalBytes, pos, i+1)
+		}
+
+		// This tests not only that SEEK_SET and SEEK_CUR give the same values, but that the next iteration is in the expected position as well
+		newPos, err := mr.Seek(pos, os.SEEK_SET)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if newPos != pos {
+			t.Fatalf("expected to get same position when calling SEEK_SET with value from SEEK_CUR, cur: %d, set: %d", pos, newPos)
+		}
+	}
+}
+
+func TestMultiReadSeekerReadSpanningChunks(t *testing.T) {
+	str := "hello world"
+	s1 := strings.NewReader(str + " 1")
+	s2 := strings.NewReader(str + " 2")
+	s3 := strings.NewReader(str + " 3")
+	mr := MultiReadSeeker(s1, s2, s3)
+
+	buf := make([]byte, s1.Len()+3)
+	_, err := mr.Read(buf)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// expected is the contents of s1 + 3 bytes from s2, ie, the `hel` at the end of this string
+	expected := "hello world 1hel"
+	if string(buf) != expected {
+		t.Fatalf("expected %s to be %s", string(buf), expected)
+	}
+}
+
+func TestMultiReadSeekerNegativeSeek(t *testing.T) {
+	str := "hello world"
+	s1 := strings.NewReader(str + " 1")
+	s2 := strings.NewReader(str + " 2")
+	s3 := strings.NewReader(str + " 3")
+	mr := MultiReadSeeker(s1, s2, s3)
+
+	s1Len := s1.Len()
+	s2Len := s2.Len()
+	s3Len := s3.Len()
+
+	s, err := mr.Seek(int64(-1*s3.Len()), os.SEEK_END)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if s != int64(s1Len+s2Len) {
+		t.Fatalf("expected %d to be %d", s, s1.Len()+s2.Len())
+	}
+
+	buf := make([]byte, s3Len)
+	if _, err := mr.Read(buf); err != nil && err != io.EOF {
+		t.Fatal(err)
+	}
+	expected := fmt.Sprintf("%s %d", str, 3)
+	if string(buf) != fmt.Sprintf("%s %d", str, 3) {
+		t.Fatalf("expected %q to be %q", string(buf), expected)
+	}
+}