# Could not load : can't convert nil into String?

**URL:** <https://discuss.elastic.co/t/could-not-load-cant-convert-nil-into-string/1814>\
**Category:** Logstash\
**Created:** [June 3, 2015, 10:04am UTC](https://discuss.elastic.co/t/could-not-load-cant-convert-nil-into-string/1814 "2015-06-03T10:04:48Z")\
**Posts on this page:** 12\
**Page:** 1

<div class="post-metadata">

**Author:** ![Siddharth\_Trikha](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/siddharth_trikha/32/133867_2.png) [@Siddharth\_Trikha](https://discuss.elastic.co/u/Siddharth_Trikha)\
**Post date:** [June 3, 2015, 10:04am UTC](https://discuss.elastic.co/t/could-not-load-cant-convert-nil-into-string/1814/1 "2015-06-03T10:04:48Z")

</div>

I want to read logs only after a particular date. So my approach is to drop all the events previous to that date. I try to achieve it like this:

So I am dropping all logs before June 1, 2015:

Logstash config file:

```
input {
         file{
                path => [
                         "/var/log/rsyslog/**/*.log"
                ]
        }
}

filter {

        grok {

        match => ["path", "/var/log/rsyslog/(?<server>[^/]+)/%{YEAR:year}-%{MONTHNUM:month}-%{MONTHDAY:month_day}/(?<logtype>.*).log"]

        }

        if [year] < "2015" and [month] < "6" and [month_day] < "1" {

                drop { }

        }

```

My logstash.err file keeps printing this:

```
Could not load : can't convert nil into String

```

Any idea why ??

---

<div class="post-metadata">

**Author:** ![magnusbaeck](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/magnusbaeck/32/44943_2.png) [@magnusbaeck](https://discuss.elastic.co/u/magnusbaeck)\
**Post date:** [June 3, 2015, 10:36am UTC](https://discuss.elastic.co/t/could-not-load-cant-convert-nil-into-string/1814/2 "2015-06-03T10:36:55Z")

</div>

Have you double-checked that the `year`, `month`, and `monthday` fields are defined?

You should convert the fields to integers with %{YEAR:year:int} etc so that you can say

```
if [year] < 2015 and [month] < 6 and [month_day] < 1 {

```

instead. As it stands you'll drop all messages from October, November, and December since `"10" < "6"` is true (but `10 < 6` is false).

---

<div class="post-metadata">

**Author:** ![Siddharth\_Trikha](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/siddharth_trikha/32/133867_2.png) [@Siddharth\_Trikha](https://discuss.elastic.co/u/Siddharth_Trikha)\
**Post date:** [June 3, 2015, 11:06am UTC](https://discuss.elastic.co/t/could-not-load-cant-convert-nil-into-string/1814/3 "2015-06-03T11:06:05Z")

</div>

Actually I am getting this error:

```
{:timestamp=>"2015-06-03T16:29:26.478000+0530", :message=>"Failed parsing date from field", :field=>"timestamp", :value=>"%{timestamp} 2015", :exception=>java.lang.IllegalArgumentException: Invalid format: "%{timestamp} 2015", :level=>:warn}

```

and my timestamp field as taken from log does not has a year so I add year field to timestamp:

```
        mutate {
                replace => ["timestamp", "%{timestamp} %{year}"]
        }

date {
                "locale" => "en"
                match => ["timestamp", "MMM d HH:mm:ss YYYY", "MMM dd HH:mm:ss YYYY", "ISO8601"]
                target => "@timestamp"
        }
```

---

<div class="post-metadata">

**Author:** ![magnusbaeck](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/magnusbaeck/32/44943_2.png) [@magnusbaeck](https://discuss.elastic.co/u/magnusbaeck)\
**Post date:** [June 3, 2015, 11:08am UTC](https://discuss.elastic.co/t/could-not-load-cant-convert-nil-into-string/1814/4 "2015-06-03T11:08:17Z")

</div>

The `timestamp` field hasn't been set.

---

<div class="post-metadata">

**Author:** ![Siddharth\_Trikha](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/siddharth_trikha/32/133867_2.png) [@Siddharth\_Trikha](https://discuss.elastic.co/u/Siddharth_Trikha)\
**Post date:** [June 3, 2015, 11:11am UTC](https://discuss.elastic.co/t/could-not-load-cant-convert-nil-into-string/1814/5 "2015-06-03T11:11:21Z")

</div>

The `timestamp` filed as read is replaced with year added in that.  
Where is i going wrong ?

---

<div class="post-metadata">

**Author:** ![magnusbaeck](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/magnusbaeck/32/44943_2.png) [@magnusbaeck](https://discuss.elastic.co/u/magnusbaeck)\
**Post date:** [June 3, 2015, 11:16am UTC](https://discuss.elastic.co/t/could-not-load-cant-convert-nil-into-string/1814/6 "2015-06-03T11:16:49Z")

</div>

The evidence suggests that the `timestamp` isn't set when you attempt to append the contents of the `year` field. That's why the value ends up as "%{timestamp} 2015", because non-existent fields referenced with the `%{varname}` notation are left untouched. When is `timestamp` set the first time?

---

<div class="post-metadata">

**Author:** ![Siddharth\_Trikha](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/siddharth_trikha/32/133867_2.png) [@Siddharth\_Trikha](https://discuss.elastic.co/u/Siddharth_Trikha)\
**Post date:** [June 3, 2015, 11:39am UTC](https://discuss.elastic.co/t/could-not-load-cant-convert-nil-into-string/1814/7 "2015-06-03T11:39:52Z")

</div>

timestamp is set using grok:

```
grok{
                match => ["message", "%{SYSLOGTIMESTAMP:timestamp} %{SYSLOGHOST} %{SYSLOGPROG}: %{GREEDYDATA:rsyslog-message}"]
        }

```

and when I check my logstash.stdout I can see the output:

```
{
          "message" => "Jun 3 12:02:28 server1 snmpd[6234]: some message",
         "@version" => "1",
       "@timestamp" => "2015-06-03T06:32:28.000Z",
             "path" => "/var/log/rsyslog/server1/2015-06-03/snmpd.log",
           "server" => "server1",
             "year" => 2015,
            "month" => 6,
        "month_day" => 3,
          "logtype" => "snmpd",
        "timestamp" => "Jun 3 12:02:28 2015",
          "program" => "snmpd",
         "snmpd-id" => "6234",
    "snmpd.message" => "some message"
}
```

---

<div class="post-metadata">

**Author:** ![magnusbaeck](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/magnusbaeck/32/44943_2.png) [@magnusbaeck](https://discuss.elastic.co/u/magnusbaeck)\
**Post date:** [June 3, 2015, 11:49am UTC](https://discuss.elastic.co/t/could-not-load-cant-convert-nil-into-string/1814/8 "2015-06-03T11:49:23Z")

</div>

And this grok filter comes prior to the mutate filter? Please show your full configuration.

---

<div class="post-metadata">

**Author:** ![Siddharth\_Trikha](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/siddharth_trikha/32/133867_2.png) [@Siddharth\_Trikha](https://discuss.elastic.co/u/Siddharth_Trikha)\
**Post date:** [June 3, 2015, 11:54am UTC](https://discuss.elastic.co/t/could-not-load-cant-convert-nil-into-string/1814/9 "2015-06-03T11:54:11Z")

</div>

```
filter {

        grok {

        match => ["path", "/var/log/rsyslog/(?<server>[^/]+)/%{YEAR:year:int}-%{MONTHNUM:month:int}-%{MONTHDAY:month_day:int}/(?<logtype>.*).log"]

        }

        if [year] < 2015{
                drop {}
        }else if [year] == 2015{

                if [month] < 6 {
                        drop {}
                }

        }

        if [logtype] == "snmpd" {

        grok{
                match => ["message", "%{SYSLOGTIMESTAMP:timestamp} %{SYSLOGHOST} %{SYSLOGPROG}: %{GREEDYDATA:rsyslog-message}"]
        }

        }

 mutate {
                replace => ["timestamp", "%{timestamp} %{year}"]
        }

        date {
                "locale" => "en"
                match => ["timestamp", "MMM d HH:mm:ss YYYY", "MMM dd HH:mm:ss YYYY", "ISO8601"]
                target => "@timestamp"
        }
```

---

<div class="post-metadata">

**Author:** ![magnusbaeck](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/magnusbaeck/32/44943_2.png) [@magnusbaeck](https://discuss.elastic.co/u/magnusbaeck)\
**Post date:** [June 3, 2015, 12:52pm UTC](https://discuss.elastic.co/t/could-not-load-cant-convert-nil-into-string/1814/10 "2015-06-03T12:52:39Z")

</div>

The grok filter that populates `timestamp` only executes if `logtype` is "snmpd" but the date filter isn't wrapped by the same kind of conditional.

---

<div class="post-metadata">

**Author:** ![Siddharth\_Trikha](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/siddharth_trikha/32/133867_2.png) [@Siddharth\_Trikha](https://discuss.elastic.co/u/Siddharth_Trikha)\
**Post date:** [June 4, 2015, 9:15am UTC](https://discuss.elastic.co/t/could-not-load-cant-convert-nil-into-string/1814/11 "2015-06-04T09:15:20Z")

</div>

Do you have any idea about this: [Logstash close file handles?](https://discuss.elastic.co/t/logstash-close-file-handles/1706?u=siddharth_trikha)

---

<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [July 6, 2017, 5:38am UTC](https://discuss.elastic.co/t/could-not-load-cant-convert-nil-into-string/1814/12 "2017-07-06T05:38:36Z")

</div>