add debug buffer time based access

debug/buffer/buffer.go

@@ -3,12 +3,18 @@ package buffer
 
 import (
 	"sync"
+	"time"
 )
 
 type Buffer struct {
 	size int
 	sync.RWMutex
-	vals []interface{}
+	vals []*Entry
+}
+
+type Entry struct {
+	Value     interface{}
+	Timestamp time.Time
 }
 
 func (b *Buffer) Put(v interface{}) {
@@ -16,7 +22,10 @@ func (b *Buffer) Put(v interface{}) {
 	defer b.Unlock()
 
 	// append to values
-	b.vals = append(b.vals, v)
+	b.vals = append(b.vals, &Entry{
+		Value:     v,
+		Timestamp: time.Now(),
+	})
 
 	// trim if bigger than size required
 	if len(b.vals) > b.size {
@@ -25,7 +34,7 @@ func (b *Buffer) Put(v interface{}) {
 }
 
 // Get returns the last n entries
-func (b *Buffer) Get(n int) []interface{} {
+func (b *Buffer) Get(n int) []*Entry {
 	// reset any invalid values
 	if n > b.size || n < 0 {
 		n = b.size
@@ -46,6 +55,34 @@ func (b *Buffer) Get(n int) []interface{} {
 	return b.vals[delta:]
 }
 
+// Return the entries since a specific time
+func (b *Buffer) Since(t time.Time) []*Entry {
+	b.RLock()
+	defer b.RUnlock()
+
+	// return all the values
+	if t.IsZero() {
+		return b.vals
+	}
+
+	// if its in the future return nothing
+	if time.Since(t).Seconds() < 0.0 {
+		return nil
+	}
+
+	for i, v := range b.vals {
+		// find the starting point
+		d := v.Timestamp.Sub(t)
+
+		// return the values
+		if d.Seconds() > 0.0 {
+			return b.vals[i:]
+		}
+	}
+
+	return nil
+}
+
 func (b *Buffer) Size() int {
 	return b.size
 }

debug/buffer/buffer_test.go

@@ -2,6 +2,7 @@ package buffer
 
 import (
 	"testing"
+	"time"
 )
 
 func TestBuffer(t *testing.T) {
@@ -11,7 +12,7 @@ func TestBuffer(t *testing.T) {
 	b.Put("foo")
 	v := b.Get(1)
 
-	if val := v[0].(string); val != "foo" {
+	if val := v[0].Value.(string); val != "foo" {
 		t.Fatalf("expected foo got %v", val)
 	}
 
@@ -22,10 +23,11 @@ func TestBuffer(t *testing.T) {
 		b.Put(i)
 	}
 
+	d := time.Now()
 	v = b.Get(10)
 
 	for i := 0; i < 10; i++ {
-		val := v[i].(int)
+		val := v[i].Value.(int)
 
 		if val != i {
 			t.Fatalf("expected %d got %d", i, val)
@@ -42,11 +44,36 @@ func TestBuffer(t *testing.T) {
 	v = b.Get(10)
 
 	for i := 0; i < 10; i++ {
-		val := v[i].(int)
+		val := v[i].Value.(int)
 		expect := i * 2
 		if val != expect {
 			t.Fatalf("expected %d got %d", expect, val)
 		}
 	}
 
+	// sleep 100 ms
+	time.Sleep(time.Millisecond * 100)
+
+	// assume we'll get everything
+	v = b.Since(d)
+
+	if len(v) != 10 {
+		t.Fatalf("expected 10 entries but got %d", len(v))
+	}
+
+	// write 1 more entry
+	d = time.Now()
+	b.Put(100)
+
+	// sleep 100 ms
+	time.Sleep(time.Millisecond * 100)
+
+	v = b.Since(d)
+	if len(v) != 1 {
+		t.Fatalf("expected 1 entries but got %d", len(v))
+	}
+
+	if v[0].Value.(int) != 100 {
+		t.Fatalf("expected value 100 got %v", v[0])
+	}
 }