forked from asonawalla/gazette
/
memory_writer.go
57 lines (45 loc) · 1.24 KB
/
memory_writer.go
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package topic
import (
"bufio"
"bytes"
"io"
"github.com/LiveRamp/gazette/pkg/journal"
)
// MemoryWriter is an implementation of journal.Writer which uses a provided Framing and
// message initializer to decode and capture messages as they are written. The intended
// use is within unit tests which publish and subsequently verify expected messages.
type MemoryWriter struct {
framing Framing
new func() Message
Messages []Envelope
}
func NewMemoryWriter(framing Framing, new func() Message) *MemoryWriter {
return &MemoryWriter{framing: framing, new: new}
}
func (w *MemoryWriter) Write(j journal.Name, b []byte) (*journal.AsyncAppend, error) {
return w.ReadFrom(j, bytes.NewReader(b))
}
func (w *MemoryWriter) ReadFrom(j journal.Name, r io.Reader) (*journal.AsyncAppend, error) {
var br = bufio.NewReader(r)
var result = &journal.AsyncAppend{
Ready: make(chan struct{}),
}
close(result.Ready)
for {
var frame, err = w.framing.Unpack(br)
if err != nil {
if err == io.EOF {
err = nil
}
return result, err
}
var msg = w.new()
if err = w.framing.Unmarshal(frame, msg); err != nil {
return result, err
}
w.Messages = append(w.Messages, Envelope{
Mark: journal.Mark{Journal: j},
Message: msg,
})
}
}