Logstash -t option returning false config ok message

Elastic Stack Logstash
1

I've run into an unexpected behaviour of the -t test option and if statements. If I use the following invalid config,

input { stdin {} }
filter {
if somefield == "somevalue" { drop {}}
}
output { stdout {} }

and run /opt/logstash/bin/logstash -t testfile.conf I get a configuration ok message. However if I run it as the config file for logstash it errors (as expected) with the following error.

fetched an invalid config {:config=>"input { stdin {} }\nfilter {\nif somefield == "somevalue" { drop {}}\n}\noutput { stdout {} }\n\n", :reason=>"Expected one of #, ( at line 3, column 14 (byte 42) after filter {\nif somefield ", :level=>:error}

I'm pretty sure this is a bug but the github page said to post here first.

2

Which version of Logstash? With 2.3.4 I get the expected error message:

$ cat test.conf 
input { stdin {} }
filter {
if somefield == "somevalue" { drop {}}
}
output { stdout {} }
$ /opt/logstash/bin/logstash --configtest -f test.conf            
The given configuration is invalid. Reason: Expected one of #, ( at line 3, column 14 (byte 42) after filter {
if somefield  {:level=>:fatal}
$ /opt/logstash/bin/logstash --version
logstash 2.3.4
3

I'm running 2.3.2. Whats weird is if I run the command with both --configtest and -f it fails as well with the correct error message. If I run just logstash -t with no filename specified I also get a config Ok message. So it looks like logstash always requires the -f option even for testing.

4

What I think is happening is that Logstash, absent the -f option, uses the default for the -e option,

    -e CONFIG_STRING              Use the given string as the configuration
                                  data. Same syntax as the config file. If no
                                  input is specified, then the following is
                                  used as the default input:
                                  "input { stdin { type => stdin } }"
                                  and if no output is specified, then the
                                  following is used as the default output:
                                  "output { stdout { codec => rubydebug } }"
                                  If you wish to use both defaults, please use
                                  the empty string for the '-e' flag.
                                   (default: "")

and when you also supply -t it will test that configuration (which of course is okay).