Init

example/lua-scripting/README.md

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+# Redis Lua scripting example
+
+This is an example for [Redis Lua scripting](https://redis.uptrace.dev/guide/lua-scripting.html)
+article. To run it:
+
+```shell
+go run .
+```

example/lua-scripting/go.mod

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+module github.com/redis/go-redis/example/lua-scripting
+
+go 1.18
+
+replace github.com/redis/go-redis/v9 => ../..
+
+require github.com/redis/go-redis/v9 v9.5.3
+
+require (
+	github.com/cespare/xxhash/v2 v2.2.0 // indirect
+	github.com/dgryski/go-rendezvous v0.0.0-20200823014737-9f7001d12a5f // indirect
+)

example/lua-scripting/go.sum

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+github.com/bsm/ginkgo/v2 v2.12.0 h1:Ny8MWAHyOepLGlLKYmXG4IEkioBysk6GpaRTLC8zwWs=
+github.com/bsm/gomega v1.27.10 h1:yeMWxP2pV2fG3FgAODIY8EiRE3dy0aeFYt4l7wh6yKA=
+github.com/cespare/xxhash/v2 v2.2.0 h1:DC2CZ1Ep5Y4k3ZQ899DldepgrayRUGE6BBZ/cd9Cj44=
+github.com/cespare/xxhash/v2 v2.2.0/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
+github.com/dgryski/go-rendezvous v0.0.0-20200823014737-9f7001d12a5f h1:lO4WD4F/rVNCu3HqELle0jiPLLBs70cWOduZpkS1E78=
+github.com/dgryski/go-rendezvous v0.0.0-20200823014737-9f7001d12a5f/go.mod h1:cuUVRXasLTGF7a8hSLbxyZXjz+1KgoB3wDUb6vlszIc=

example/lua-scripting/main.go

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+package main
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/redis/go-redis/v9"
+)
+
+func main() {
+	ctx := context.Background()
+
+	rdb := redis.NewClient(&redis.Options{
+		Addr: ":6379",
+	})
+	_ = rdb.FlushDB(ctx).Err()
+
+	fmt.Printf("# INCR BY\n")
+	for _, change := range []int{+1, +5, 0} {
+		num, err := incrBy.Run(ctx, rdb, []string{"my_counter"}, change).Int()
+		if err != nil {
+			panic(err)
+		}
+		fmt.Printf("incr by %d: %d\n", change, num)
+	}
+
+	fmt.Printf("\n# SUM\n")
+	sum, err := sum.Run(ctx, rdb, []string{"my_sum"}, 1, 2, 3).Int()
+	if err != nil {
+		panic(err)
+	}
+	fmt.Printf("sum is: %d\n", sum)
+}
+
+var incrBy = redis.NewScript(`
+local key = KEYS[1]
+local change = ARGV[1]
+
+local value = redis.call("GET", key)
+if not value then
+  value = 0
+end
+
+value = value + change
+redis.call("SET", key, value)
+
+return value
+`)
+
+var sum = redis.NewScript(`
+local key = KEYS[1]
+
+local sum = redis.call("GET", key)
+if not sum then
+  sum = 0
+end
+
+local num_arg = #ARGV
+for i = 1, num_arg do
+  sum = sum + ARGV[i]
+end
+
+redis.call("SET", key, sum)
+
+return sum
+`)