Environment variables not passed through to logstash

[jgough]

It looks like environment variables aren't being passed through to logstash when it is run. For example with this config file:

input { generator { lines => ["msg"] count => 1 } }
filter { mutate { add_field=>{"myvar"=>"${MYVAR}" } } }
output { stdout { codec => rubydebug } }

When I run MYVAR=foo logstash -f ./test.conf

I get the correct output:

{
         "myvar" => "foo",
       "message" => "msg",
      "@version" => "1",
    "@timestamp" => 2020-07-23T16:25:36.113Z,
          "host" => "a8bef8d96fb6",
      "sequence" => 0
}

If I run MYVAR=foo logstash-filter-verifier test.json test.conf

Then logstash exits with an error:

Failed to execute action {:action=>LogStash::PipelineAction::Create/pipeline_id:main, :exception=>"LogStash::ConfigurationError", :message=>"Cannot evaluate `${MYVAR}`. Replacement variable `MYVAR` is not defined in a Logstash secret store or as an Environment entry and there is no default value given."

I'm actually trying to use variables to change the config values in a test environment so it would be good if this were supported.

[magnusbaeck]

The environment variables are scrubbed so they won't affect the test execution. To explicitly indicate that an environment variable should be passed on to the Logstash child invoke LFV with --keep-env MYVAR. I should document this in the readme file so people won't have to read the --help fine print.

[jgough]

Sorry, didn't spot that option in there! Thanks for all your work on this :-)