Add redis stress (#3363)

* Add redis stress tool

* Parametrize more things

* Rename folder back

* Log error

* Fix lint

tools/redis-stress/stress.go

@@ -0,0 +1,61 @@
+package main
+
+import (
+	"flag"
+	"fmt"
+	"log"
+	"time"
+
+	"github.com/fleetdm/fleet/v4/server/datastore/redis"
+)
+
+var (
+	addrFlag       = flag.String("addr", "", "Redis address, including port")
+	indexStartFlag = flag.Int("index-start", 1, "Index to start from when inserting keys")
+	debugFlag      = flag.Bool("debug", false, "Print debug logs")
+	waitFlag       = flag.Duration("wait", 10*time.Minute, "Amount of time to do SETs")
+)
+
+func main() {
+	flag.Parse()
+
+	pool, err := redis.NewPool(redis.PoolConfig{Server: *addrFlag, UseTLS: false})
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer pool.Close()
+
+	log.Println("pool created successfully")
+
+	conn := pool.Get()
+	defer conn.Close()
+
+	ticker := time.NewTicker(1 * time.Second)
+	quit := make(chan struct{})
+	go func() {
+		i := 0
+		if indexStartFlag != nil {
+			i = *indexStartFlag
+		}
+		for {
+			select {
+			case <-ticker.C:
+				_, err := conn.Do("SET", fmt.Sprintf("error:%d", i), 1, "EX", (10 * time.Minute).Seconds())
+				if debugFlag != nil && *debugFlag {
+					log.Println("SET", i)
+					if err != nil {
+						log.Println("err", err)
+					}
+				}
+			case <-quit:
+				ticker.Stop()
+				return
+			}
+			i++
+		}
+	}()
+
+	time.Sleep(*waitFlag)
+	close(quit)
+	log.Println("done")
+}