1 files changed, 90 insertions, 18 deletions
diff --git a/error_buffer.go b/error_buffer.go
index fcf566c8..8be9c5a8 100644
--- a/error_buffer.go
+++ b/error_buffer.go
@@ -1,39 +1,111 @@
 package roadrunner
 
 import (
-	"bytes"
 	"sync"
+	"time"
+)
+
+const (
+	// EventStderrOutput - is triggered when worker sends data into stderr. The context is error message ([]byte).
+	EventStderrOutput = 1900
+
+	// WaitDuration - for how long error buffer should attempt to aggregate error messages before merging output
+	// together since lastError update (required to keep error update together).
+	WaitDuration = 100 * time.Millisecond
 )
 
 // thread safe errBuffer
 type errBuffer struct {
 	mu     sync.Mutex
-	buffer *bytes.Buffer
+	buf    []byte
+	last   int
+	wait   *time.Timer
+	update chan interface{}
+	stop   chan interface{}
+	lsn    func(event int, ctx interface{})
+}
+
+func newErrBuffer() *errBuffer {
+	eb := &errBuffer{
+		buf:    make([]byte, 0),
+		update: make(chan interface{}),
+		wait:   time.NewTimer(WaitDuration),
+		stop:   make(chan interface{}),
+	}
+
+	go func() {
+		for {
+			select {
+			case <-eb.update:
+				eb.wait.Reset(WaitDuration)
+			case <-eb.wait.C:
+				eb.mu.Lock()
+				if len(eb.buf) > eb.last {
+					if eb.lsn != nil {
+						eb.lsn(EventStderrOutput, eb.buf[eb.last:])
+					}
+					eb.last = len(eb.buf)
+				}
+				eb.mu.Unlock()
+			case <-eb.stop:
+				eb.wait.Stop()
+
+				eb.mu.Lock()
+				if len(eb.buf) > eb.last {
+					if eb.lsn != nil {
+						eb.lsn(EventStderrOutput, eb.buf[eb.last:])
+					}
+					eb.last = len(eb.buf)
+				}
+				eb.mu.Unlock()
+				return
+			}
+		}
+	}()
+
+	return eb
+}
+
+// Listen attaches error stream even listener.
+func (eb *errBuffer) Listen(l func(event int, ctx interface{})) {
+	eb.mu.Lock()
+	defer eb.mu.Unlock()
+
+	eb.lsn = l
 }
 
-// Len returns the number of bytes of the unread portion of the errBuffer;
-// b.Len() == len(b.Bytes()).
-func (b *errBuffer) Len() int {
-	b.mu.Lock()
-	defer b.mu.Unlock()
+// Len returns the number of buf of the unread portion of the errBuffer;
+// buf.Len() == len(buf.Bytes()).
+func (eb *errBuffer) Len() int {
+	eb.mu.Lock()
+	defer eb.mu.Unlock()
 
-	return b.buffer.Len()
+	// currently active message
+	return len(eb.buf)
 }
 
 // Write appends the contents of p to the errBuffer, growing the errBuffer as
-// needed. The return value n is the length of p; err is always nil. If the
-// errBuffer becomes too large, Write will panic with ErrTooLarge.
-func (b *errBuffer) Write(p []byte) (n int, err error) {
-	b.mu.Lock()
-	defer b.mu.Unlock()
+// needed. The return value n is the length of p; err is always nil.
+func (eb *errBuffer) Write(p []byte) (int, error) {
+	eb.mu.Lock()
+	defer eb.mu.Unlock()
 
-	return b.buffer.Write(p)
+	eb.buf = append(eb.buf, p...)
+	eb.update <- nil
+
+	return len(p), nil
 }
 
 // Strings fetches all errBuffer data into string.
-func (b *errBuffer) String() string {
-	b.mu.Lock()
-	defer b.mu.Unlock()
+func (eb *errBuffer) String() string {
+	eb.mu.Lock()
+	defer eb.mu.Unlock()
+
+	return string(eb.buf)
+}
 
-	return b.buffer.String()
+// Close aggregation timer.
+func (eb *errBuffer) Close() error {
+	close(eb.stop)
+	return nil
 }