Add ring log + 429

ring.go

@@ -0,0 +1,101 @@
+package main
+
+import (
+	"fmt"
+	"sync"
+	"time"
+)
+
+// RingBuf implements an indefinitely writable circular buffer with a fixed size. Old data is overridden if write circle loops. Somewhat threadsafe.
+type RingBuf struct {
+	sync.RWMutex
+	data     []byte
+	writePos int
+	written  int
+	loop     bool
+}
+
+// NewRingBuf initializes a new RingBuf with a fixed size > 0
+func NewRingBuf(size int) *RingBuf {
+	if size <= 0 {
+		return nil
+	}
+	rb := &RingBuf{
+		data:     make([]byte, size),
+		writePos: 0,
+		written:  0,
+		loop:     false,
+	}
+	return rb
+}
+
+func (rb *RingBuf) WriteLine(in string) (int, error) {
+	return rb.Write([]byte(fmt.Sprintf("[%s]: %s\n", time.Now().Format("2006-01-02 15:04:05"), in)))
+}
+
+// Write writes all data from input buf to RingBuf, overriding looped data
+func (rb *RingBuf) Write(buf []byte) (int, error) {
+	rb.Lock()
+	defer rb.Unlock()
+
+	inLen := len(buf)
+	bufLen := len(rb.data)
+
+	if !rb.loop && rb.written < bufLen {
+		rb.written = rb.written + inLen
+		rb.loop = rb.written >= bufLen
+	}
+
+	// throw away bytes which would get looped over if input bigger than data
+	if inLen > bufLen {
+		buf = buf[inLen-bufLen:]
+	}
+
+	// Copy to data field
+	bytesToEnd := bufLen - rb.writePos
+	copy(rb.data[rb.writePos:], buf)
+	if len(buf) > bytesToEnd {
+		copy(rb.data, buf[bytesToEnd:])
+	}
+	// Move writePos
+	rb.writePos = ((rb.writePos + len(buf)) % bufLen)
+	return inLen, nil
+}
+
+// Size returns the maximum size of the RingBuf
+func (rb *RingBuf) Size() int {
+	return len(rb.data)
+}
+
+// Bytes returns content of RingBuf. DON'T WRITE TO SLICE!
+func (rb *RingBuf) Bytes() []byte {
+	rb.RLock()
+	defer rb.RUnlock()
+
+	bufLen := len(rb.data)
+	if rb.loop {
+		out := make([]byte, bufLen)
+		if rb.writePos == 0 {
+			copy(out, rb.data)
+		} else {
+			copy(out, rb.data[rb.writePos:])
+			copy(out[bufLen-rb.writePos:], rb.data[:rb.writePos])
+		}
+		return out
+	}
+	out := make([]byte, rb.writePos+1)
+	copy(out, rb.data[:rb.writePos])
+	return out
+}
+
+// Restart restarts RingBuf from 0
+func (rb *RingBuf) Restart() {
+	rb.writePos = 0
+	rb.written = 0
+	rb.loop = false
+}
+
+// String returns content of RingBuf as string
+func (rb *RingBuf) String() string {
+	return string(rb.Bytes())
+}