Allow common redis and leveldb connections (#12385)

* Allow common redis and leveldb connections

Prevents multiple reopening of redis and leveldb connections to the same
place by sharing connections.

Further allows for more configurable redis connection type using the
redisURI and a leveldbURI scheme.

Signed-off-by: Andrew Thornton <art27@cantab.net>

* add unit-test

Signed-off-by: Andrew Thornton <art27@cantab.net>

* as per @lunny

Signed-off-by: Andrew Thornton <art27@cantab.net>

* add test

Signed-off-by: Andrew Thornton <art27@cantab.net>

* Update modules/cache/cache_redis.go

* Update modules/queue/queue_disk.go

* Update modules/cache/cache_redis.go

* Update modules/cache/cache_redis.go

* Update modules/queue/unique_queue_disk.go

* Update modules/queue/queue_disk.go

* Update modules/queue/unique_queue_disk.go

* Update modules/session/redis.go

Co-authored-by: techknowlogick <techknowlogick@gitea.io>
Co-authored-by: Lauris BH <lauris@nix.lv>

vendor/github.com/go-redis/redis/v7/internal/proto/writer.go

@@ -0,0 +1,165 @@
+package proto
+
+import (
+	"bufio"
+	"encoding"
+	"fmt"
+	"io"
+	"strconv"
+	"time"
+
+	"github.com/go-redis/redis/v7/internal/util"
+)
+
+type Writer struct {
+	wr *bufio.Writer
+
+	lenBuf []byte
+	numBuf []byte
+}
+
+func NewWriter(wr io.Writer) *Writer {
+	return &Writer{
+		wr: bufio.NewWriter(wr),
+
+		lenBuf: make([]byte, 64),
+		numBuf: make([]byte, 64),
+	}
+}
+
+func (w *Writer) WriteArgs(args []interface{}) error {
+	err := w.wr.WriteByte(ArrayReply)
+	if err != nil {
+		return err
+	}
+
+	err = w.writeLen(len(args))
+	if err != nil {
+		return err
+	}
+
+	for _, arg := range args {
+		err := w.writeArg(arg)
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func (w *Writer) writeLen(n int) error {
+	w.lenBuf = strconv.AppendUint(w.lenBuf[:0], uint64(n), 10)
+	w.lenBuf = append(w.lenBuf, '\r', '\n')
+	_, err := w.wr.Write(w.lenBuf)
+	return err
+}
+
+func (w *Writer) writeArg(v interface{}) error {
+	switch v := v.(type) {
+	case nil:
+		return w.string("")
+	case string:
+		return w.string(v)
+	case []byte:
+		return w.bytes(v)
+	case int:
+		return w.int(int64(v))
+	case int8:
+		return w.int(int64(v))
+	case int16:
+		return w.int(int64(v))
+	case int32:
+		return w.int(int64(v))
+	case int64:
+		return w.int(v)
+	case uint:
+		return w.uint(uint64(v))
+	case uint8:
+		return w.uint(uint64(v))
+	case uint16:
+		return w.uint(uint64(v))
+	case uint32:
+		return w.uint(uint64(v))
+	case uint64:
+		return w.uint(v)
+	case float32:
+		return w.float(float64(v))
+	case float64:
+		return w.float(v)
+	case bool:
+		if v {
+			return w.int(1)
+		}
+		return w.int(0)
+	case time.Time:
+		return w.string(v.Format(time.RFC3339Nano))
+	case encoding.BinaryMarshaler:
+		b, err := v.MarshalBinary()
+		if err != nil {
+			return err
+		}
+		return w.bytes(b)
+	default:
+		return fmt.Errorf(
+			"redis: can't marshal %T (implement encoding.BinaryMarshaler)", v)
+	}
+}
+
+func (w *Writer) bytes(b []byte) error {
+	err := w.wr.WriteByte(StringReply)
+	if err != nil {
+		return err
+	}
+
+	err = w.writeLen(len(b))
+	if err != nil {
+		return err
+	}
+
+	_, err = w.wr.Write(b)
+	if err != nil {
+		return err
+	}
+
+	return w.crlf()
+}
+
+func (w *Writer) string(s string) error {
+	return w.bytes(util.StringToBytes(s))
+}
+
+func (w *Writer) uint(n uint64) error {
+	w.numBuf = strconv.AppendUint(w.numBuf[:0], n, 10)
+	return w.bytes(w.numBuf)
+}
+
+func (w *Writer) int(n int64) error {
+	w.numBuf = strconv.AppendInt(w.numBuf[:0], n, 10)
+	return w.bytes(w.numBuf)
+}
+
+func (w *Writer) float(f float64) error {
+	w.numBuf = strconv.AppendFloat(w.numBuf[:0], f, 'f', -1, 64)
+	return w.bytes(w.numBuf)
+}
+
+func (w *Writer) crlf() error {
+	err := w.wr.WriteByte('\r')
+	if err != nil {
+		return err
+	}
+	return w.wr.WriteByte('\n')
+}
+
+func (w *Writer) Buffered() int {
+	return w.wr.Buffered()
+}
+
+func (w *Writer) Reset(wr io.Writer) {
+	w.wr.Reset(wr)
+}
+
+func (w *Writer) Flush() error {
+	return w.wr.Flush()
+}