Heroku上的Golang Redis错误

Question

I am having a hard time on this one because I cannot reproduce it locally. Intention originally was to test if a Redis connection is accessible from a go method if so continue else inform.

In my code:

if os.Getenv("REDISTOGO_URL") != "" {
    host, password = parseRedistogoUrl()
} else {
    host = "tcp:localhost:6379"
    password = ""
}

db := 0

redis = godis.New(host, db, password)

// Try to set a "dummy" value:
err = redis.Set("INIT", time.Now().UTC())

With a Redis server available locally this executes without an error, but fails when on heroku.

What makes the problem more interesting is that if the last line (with err) is commented out then the next redis.Set in the program succeeds, which indicates that the server is accessible later on, but not "just after" the instanciation. Any ideas on how I should resolve this? Is godis.New(...) running asynchronously?

Update: This is the parsing function currently used from https://gist.github.com/TheDudeWithTheThing/6468746:

func ParseRedistogoUrl() (string, string) {
  redisUrl := os.Getenv("REDISTOGO_URL")
  redisInfo, _ := url.Parse(redisUrl)
  server := redisInfo.Host
  password := ""
  if redisInfo.User != nil {
    password, _ = redisInfo.User.Password()
  }
  return server, password
}

Rewriting the same method with redigo and https://github.com/soveran/redisurl:

// Gets redis instance from configuration parameters or environment's REDISTOGO_URL.
func redis_instance() (redis_con redis.Conn, err error) {
    if os.Getenv("REDISTOGO_URL") != "" {
        redis_con, err = redisurl.ConnectToURL(os.Getenv("REDISTOGO_URL"))
    } else {
        redis_con, err = redis.Dial("tcp", ":6379")
    }

    if err != nil {
        return
    }

    // Try to set a "dummy" value, panic if redis is not accessible.
    err = redis_con.Send("Set", "INIT", time.Now().UTC())

    return
}

and from program's main:

redis, err := redis_instance()

redis.Send("Set", "SOMETHING", "ELSE")

if err != nil {
    log.Critical("Cannot access Redis server")
    log.Critical(fmt.Sprintf("%s", err))
    os.Exit(2)
}

On logs I get the following output:

2014-09-16T18:15:10.084908+00:00 app[web.1]: 2014/09/16 18:15:10 CRITICAL003 Cannot access Redis server
2014-09-16T18:15:10.084974+00:00 app[web.1]: 2014/09/16 18:15:10 CRITICAL004 Connection error 10942

About redis access:

~ $ echo $REDISTOGO_URL
redis://redistogo:47███████████@hoki.redistogo.com:10███/
~ $ ping hoki.redistogo.com
bash: ping: command not found
~ $ nc hoki.redistogo.com 10███
flushdb
-NOAUTH Authentication required.
AUTH 47███████████
+OK
get XXX
$-1
set XXX 2
+OK
get XXX
$1
2