Calling lua script from redigo throwing error wrong number of args

Question

I am trying to use redigo to execute a lua script on redis. My code looks like below:-

package main

import (
    "github.com/PuerkitoBio/redisc"
    "github.com/garyburd/redigo/redis"
    "log"
    "time"
)

const script = `if redis.call("EXISTS", KEYS[1]) == 1 then
    local keyvalues = redis.call("HGETALL", KEYS[1])
    local a = {}
    for i=2, table.getn(ARGV) do
      a[i-1] = ARGV[i]
    end
    local res = redis.call("HMSET", KEYS[1], unpack(a))
    redis.call("EXPIRE", KEYS[1], ARGV[1])  
    return keyvalues
else
    return 2 -- "Key doesn't exists"
end`

func main() {
    cluster := redisc.Cluster{
        StartupNodes: []string{":30001", ":30002", ":30003", ":30004", ":30005", ":30006"},
        DialOptions:  []redis.DialOption{redis.DialConnectTimeout(5 * time.Second)},
        CreatePool:   createPool,
    }
    defer cluster.Close()

    // initialize its mapping
    if err := cluster.Refresh(); err != nil {
        log.Fatalf("Refresh failed: %v", err)
    }

    // grab a connection from the pool
    conn := cluster.Get()
    defer cluster.Close()
    retryConn, errRe := redisc.RetryConn(conn, 3, 1*time.Millisecond)
    if errRe != nil {
        log.Println("Failed to get retry connection " + errRe.Error())
        return
    }
    rScript := redis.NewScript(1, script)
    argv := make([]string, 5)
    argv[0] = "30000"
    argv[1] = "SSF_lastAccessedDate"
    argv[2] = "1481627386"
    argv[3] = "SSF_expiryDate"
    argv[4] = "2481657386"
    reply, errS := rScript.Do(retryConn, "JJNb324a680c35d11e6a1123c15c2d271f21481871788G", argv)
    if errS != nil {
        log.Println("Error in executing script " + errS.Error())
    } else {
        log.Printf("Result %+v", reply)
    }
}

func createPool(addr string, opts ...redis.DialOption) (*redis.Pool, error) {
    return &redis.Pool{
        MaxIdle:     100,
        MaxActive:   4000,
        IdleTimeout: time.Minute,
        Dial: func() (redis.Conn, error) {
            return redis.Dial("tcp", addr, opts...)
        },
        TestOnBorrow: func(c redis.Conn, t time.Time) error {
            if time.Since(t) < time.Minute {
                return nil
            }
            _, err := c.Do("PING")
            return err
        },
    }, nil
}

But on executing the code it is throwing the error:-

2016/12/16 12:52:32 Error in executing script ERR Error running script (call to f_5a127779e5c1c2daa0b636d9b02f6b570a9f7f13): @user_script:7: @user_script: 7: Wrong number of args calling Redis command From Lua script 

Can someone let me know what is going wrong & how to make this work?

Environment:-

• Go - 1.7.4

EDIT

As suggested in the answers I modified the call as:-

rScript.Do(retryConn, "JJNb324a680c35d11e6a1123c15c2d271f21481871788G", argv[0], argv[1], argv[2], argv[3], argv[4])

But it is giving the output as:-

2016/12/16 21:39:51 Result [[116 121 112 101] [50] [100 97 116 97] [72 101 108 108 111] [120] [50] [83 83 70 95 99 114 101 97 116 105 111 110 68 97 116 101] [49 52 56 49 56 55 49 55 56 56] [83 83 70 95 108 97 115 116 77 111 100 105 102 105 101 100 68 97 116 101] [49 52 56 49 56 55 49 55 56 56] [83 83 70 95 101 120 112 105 114 121 68 97 116 101] [50 52 56 49 54 53 55 51 56 54] [83 83 70 95 108 97 115 116 65 99 99 101 115 115 101 100 68 97 116 101] [49 52 56 49 54 50 55 51 56 54]]

But from redis-cli I am getting the output as:-

1) "type"
 2) "2"
 3) "data"
 4) "Hello"
 5) "x"
 6) "2"
 7) "SSF_creationDate"
 8) "1481871788"
 9) "SSF_lastModifiedDate"
10) "1481871788"
11) "SSF_expiryDate"
12) "2481657386"
13) "SSF_lastAccessedDate"
14) "1481627386"

Answer 1

You're not using Do method correctly, you must to give it every variable separately if you want to use them in the script:

rScript := redis.NewScript(1, script)
argv := make([]string, 6)
argv[0] = "JJNb324a680c35d11e6a1123c15c2d271f21481871788G" // the key
argv[1] = "30000"
argv[2] = "SSF_lastAccessedDate"
argv[3] = "1481627386"
argv[4] = "SSF_expiryDate"
argv[5] = "2481657386"
reply, err := rScript.Do(con, argv...)
if err != nil {
    log.Println("Error in executing script " + err.Error())
} else {
    log.Printf("Result %v\n", reply)
    // error if not return a map
    if data, err := redis.StringMap(reply, nil); err != nil {
        // error if not return an int
        if val, err := redis.Int64(reply, nil); err != nil {
            log.Printf("Error %v\n", err)
        } else {
            log.Printf("Result %v\n", val)
        }
    } else {
        log.Printf("Result %v\n", data)
    }
}

Answer 2

According to the error message, the error is on this line:

local res = redis.call("HMSET", KEYS[1], unpack(a))

The issue is that the application is passing two arguments to the script, the key and argv converted to a string. The call unpack(a) yields a single value.

The fix is to pass each argument separately to the script:

reply, errS := rScript.Do(retryConn,
   "JJNb324a680c35d11e6a1123c15c2d271f21481871788G",
   "30000",
   "SSF_lastAccessedDate", "1481627386",
   "SSF_expiryDate", "2481657386")

I recommend initializing a package level variable with the script so the hash of the script text is computed once instead of on every use of the script:

var rScript = redis.NewScript(1, `if redis.call("EXISTS", KEYS[1]) == 1 then
    local keyvalues = redis.call("HGETALL", KEYS[1])
    local a = {}
    for i=2, table.getn(ARGV) do
      a[i-1] = ARGV[i]
    end
    local res = redis.call("HMSET", KEYS[1], unpack(a))
    redis.call("EXPIRE", KEYS[1], ARGV[1])  
    return keyvalues
else
    return 2 -- "Key doesn't exists"
end`)

and use this script in main() :

func main() {
  ...
  reply, errS := rScript.Do(retryConn,
   "JJNb324a680c35d11e6a1123c15c2d271f21481871788G",
   "30000",
   "SSF_lastAccessedDate", "1481627386",
   "SSF_expiryDate", "2481657386")

  ...
}

Also, use table.remove to simplify the script:

var rScript = redis.NewScript(1, `if redis.call("EXISTS", KEYS[1]) == 1 then
    local keyvalues = redis.call("HGETALL", KEYS[1])
    local expires = table.remove(ARGV, 1)
    local res = redis.call("HMSET", KEYS[1], unpack(ARGV))
    redis.call("EXPIRE", KEYS[1], expires)  
    return keyvalues
else
    return 2 -- "Key doesn't exists"
end`)

Use redis.Strings to convert the slice of []byte returned from the server to a slice of strings:

  reply, errS := redis.Strings(rScript.Do(retryConn,
   "JJNb324a680c35d11e6a1123c15c2d271f21481871788G",
   "30000",
   "SSF_lastAccessedDate", "1481627386",
   "SSF_expiryDate", "2481657386"))

Printing this reply will give the result you are expecting.

Answer 3

You should begin use

args[1],args[2],args[3],args[4],args[5]

instead of

args[0],args[1],args[2],args[3],args[4]