Add redis support for distributed caching

vendor/github.com/redis/go-redis/v9/internal/log.go

@@ -0,0 +1,26 @@
+package internal
+
+import (
+	"context"
+	"fmt"
+	"log"
+	"os"
+)
+
+type Logging interface {
+	Printf(ctx context.Context, format string, v ...interface{})
+}
+
+type logger struct {
+	log *log.Logger
+}
+
+func (l *logger) Printf(ctx context.Context, format string, v ...interface{}) {
+	_ = l.log.Output(2, fmt.Sprintf(format, v...))
+}
+
+// Logger calls Output to print to the stderr.
+// Arguments are handled in the manner of fmt.Print.
+var Logger Logging = &logger{
+	log: log.New(os.Stderr, "redis: ", log.LstdFlags|log.Lshortfile),
+}