From 10877e9a0783f9d8a1f7503f6e428884014c4b23 Mon Sep 17 00:00:00 2001
From: Dirk Moermans <dirk.moermans@telekom.de>
Date: Mon, 11 Oct 2021 11:54:21 +0200
Subject: [PATCH] add redis logger

---
 cmd_scripting.go      |  5 ++++-
 cmd_scripting_test.go | 11 +++++++++++
 lua.go                | 27 +++++++++++++++++++++++++--
 3 files changed, 40 insertions(+), 3 deletions(-)

diff --git a/cmd_scripting.go b/cmd_scripting.go
index 99b87215..ef10aaef 100644
--- a/cmd_scripting.go
+++ b/cmd_scripting.go
@@ -80,10 +80,13 @@ func (m *Miniredis) runLuaScript(c *server.Peer, script string, args []string) b
 	}
 	l.SetGlobal("ARGV", argvTable)
 
-	redisFuncs := mkLuaFuncs(m.srv, c)
+	redisFuncs, redisConstants := mkLua(m.srv, c)
 	// Register command handlers
 	l.Push(l.NewFunction(func(l *lua.LState) int {
 		mod := l.RegisterModule("redis", redisFuncs).(*lua.LTable)
+		for k, v := range redisConstants {
+			mod.RawSetString(k, v)
+		}
 		l.Push(mod)
 		return 1
 	}))
diff --git a/cmd_scripting_test.go b/cmd_scripting_test.go
index bc5ec25c..a7786662 100644
--- a/cmd_scripting_test.go
+++ b/cmd_scripting_test.go
@@ -226,6 +226,17 @@ func TestCJSON(t *testing.T) {
 	)
 }
 
+func TestLog(t *testing.T) {
+	s, err := Run()
+	ok(t, err)
+	defer s.Close()
+	c, err := proto.Dial(s.Addr())
+	ok(t, err)
+	defer c.Close()
+	mustNil(t, c,
+		"EVAL", "redis.log(redis.LOG_NOTICE, 'hello')", "0")
+}
+
 func TestSha1Hex(t *testing.T) {
 	s, err := Run()
 	ok(t, err)
diff --git a/lua.go b/lua.go
index 7a99252f..6bfb869e 100644
--- a/lua.go
+++ b/lua.go
@@ -11,7 +11,14 @@ import (
 	"github.com/alicebob/miniredis/v2/server"
 )
 
-func mkLuaFuncs(srv *server.Server, c *server.Peer) map[string]lua.LGFunction {
+var luaRedisConstants = map[string]lua.LValue{
+	"LOG_DEBUG":   lua.LNumber(0),
+	"LOG_VERBOSE": lua.LNumber(1),
+	"LOG_NOTICE":  lua.LNumber(2),
+	"LOG_WARNING": lua.LNumber(3),
+}
+
+func mkLua(srv *server.Server, c *server.Peer) (map[string]lua.LGFunction, map[string]lua.LValue) {
 	mkCall := func(failFast bool) func(l *lua.LState) int {
 		// one server.Ctx for a single Lua run
 		pCtx := &connCtx{}
@@ -107,6 +114,22 @@ func mkLuaFuncs(srv *server.Server, c *server.Peer) map[string]lua.LGFunction {
 			l.Push(res)
 			return 1
 		},
+		"log": func(l *lua.LState) int {
+			v := l.Get(1)
+			level, ok := v.(lua.LNumber)
+			if !ok {
+				l.Error(lua.LString("wrong type for the level"), 1)
+				return 0
+			}
+			v = l.Get(2)
+			msg, ok := v.(lua.LString)
+			if !ok {
+				l.Error(lua.LString("wrong number or type of arguments"), 1)
+				return 0
+			}
+			fmt.Printf("%v: %v", level, msg)
+			return 0
+		},
 		"status_reply": func(l *lua.LState) int {
 			v := l.Get(1)
 			msg, ok := v.(lua.LString)
@@ -133,7 +156,7 @@ func mkLuaFuncs(srv *server.Server, c *server.Peer) map[string]lua.LGFunction {
 			// ignored
 			return 1
 		},
-	}
+	}, luaRedisConstants
 }
 
 func luaToRedis(l *lua.LState, c *server.Peer, value lua.LValue) {