From 49111a4dce6e1cbb9c3c6efe6d60dc4fec00f5b9 Mon Sep 17 00:00:00 2001
From: Alex Roitman <aroitman@housecanary.com>
Date: Wed, 24 Apr 2019 17:00:52 -0700
Subject: [PATCH 1/2] Add timeouts for lua scripts

---
 internal/deadline/deadline.go |  6 ++++++
 internal/server/scripts.go    | 11 +++++++++++
 2 files changed, 17 insertions(+)

diff --git a/internal/deadline/deadline.go b/internal/deadline/deadline.go
index 6be76543..697492a3 100644
--- a/internal/deadline/deadline.go
+++ b/internal/deadline/deadline.go
@@ -13,6 +13,7 @@ func New(deadline time.Time) *Deadline {
 	return &Deadline{unixNano: deadline.UnixNano()}
 }
 
+// Empty deadline does nothing, just a place holder for future updates
 func Empty() *Deadline {
 	return &Deadline{}
 }
@@ -38,3 +39,8 @@ func (deadline *Deadline) Check() {
 func (deadline *Deadline) Hit() bool {
 	return deadline.hit
 }
+
+// GetDeadlineTime returns the time object for the deadline, and an "empty" boolean
+func (deadline *Deadline) GetDeadlineTime() (time.Time, bool) {
+	return time.Unix(0, deadline.unixNano), deadline.unixNano == 0
+}
diff --git a/internal/server/scripts.go b/internal/server/scripts.go
index 42735db5..9f87a1ac 100644
--- a/internal/server/scripts.go
+++ b/internal/server/scripts.go
@@ -2,6 +2,7 @@ package server
 
 import (
 	"bytes"
+	"context"
 	"crypto/sha1"
 	"encoding/hex"
 	"encoding/json"
@@ -391,6 +392,13 @@ func (c *Server) cmdEvalUnified(scriptIsSha bool, msg *Message) (res resp.Value,
 	if err != nil {
 		return
 	}
+	deadline, empty := msg.Deadline.GetDeadlineTime()
+	if !empty {
+		ctx, cancel := context.WithDeadline(context.Background(), deadline)
+		defer cancel()
+		luaState.SetContext(ctx)
+		defer luaState.RemoveContext()
+	}
 	defer c.luapool.Put(luaState)
 
 	keysTbl := luaState.CreateTable(int(numkeys), 0)
@@ -454,6 +462,9 @@ func (c *Server) cmdEvalUnified(scriptIsSha bool, msg *Message) (res resp.Value,
 			"EVAL_CMD": lua.LNil,
 		})
 	if err := luaState.PCall(0, 1, nil); err != nil {
+		if strings.Contains(err.Error(), "context deadline exceeded") {
+			msg.Deadline.Check()
+		}
 		log.Debugf("%v", err.Error())
 		return NOMessage, makeSafeErr(err)
 	}

From 2020f537dc5fd362dca89e830ff4704175344532 Mon Sep 17 00:00:00 2001
From: Alex Roitman <aroitman@housecanary.com>
Date: Wed, 24 Apr 2019 17:17:49 -0700
Subject: [PATCH 2/2] Add tests for script timeouts.

---
 tests/timeout_test.go | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)

diff --git a/tests/timeout_test.go b/tests/timeout_test.go
index 7178c0b1..011ad281 100644
--- a/tests/timeout_test.go
+++ b/tests/timeout_test.go
@@ -13,6 +13,7 @@ func subTestTimeout(t *testing.T, mc *mockServer) {
 	runStep(t, mc, "session set/unset", timeout_session_set_unset_test)
 	runStep(t, mc, "session spatial", timeout_session_spatial_test)
 	runStep(t, mc, "session search", timeout_session_search_test)
+	runStep(t, mc, "session scripts", timeout_session_scripts_test)
 	runStep(t, mc, "command spatial", timeout_command_spatial_test)
 	runStep(t, mc, "command search", timeout_command_search_test)
 }
@@ -112,3 +113,35 @@ func timeout_command_search_test(mc *mockServer) (err error) {
 		{"SEARCH", "mykey", "TIMEOUT", "0.000001", "MATCH", "val:*", "COUNT"}, {"ERR timeout"},
 	})
 }
+
+func timeout_session_scripts_test(mc *mockServer) (err error) {
+	script := `
+		local clock = os.clock
+		local function sleep(n)
+			local t0 = clock()
+			while clock() - t0 <= n do end
+		end
+		sleep(0.5)
+	`
+	sha := "e3ce9449853a622327f30c727a6e086ccd91d9d4"
+
+	return mc.DoBatch([][]interface{}{
+		{"SCRIPT LOAD", script}, {sha},
+
+		{"EVALSHA", sha, 0}, {nil},
+		{"EVALROSHA", sha, 0}, {nil},
+		{"EVALNASHA", sha, 0}, {nil},
+
+		{"TIMEOUT", "0.1"}, {"OK"},
+
+		{"EVALSHA", sha, 0}, {"ERR timeout"},
+		{"EVALROSHA", sha, 0}, {"ERR timeout"},
+		{"EVALNASHA", sha, 0}, {"ERR timeout"},
+
+		{"TIMEOUT", "0.9"}, {"OK"},
+
+		{"EVALSHA", sha, 0}, {nil},
+		{"EVALROSHA", sha, 0}, {nil},
+		{"EVALNASHA", sha, 0}, {nil},
+	})
+}