Run additional options for logstash in docker container

[vinci]

Hello,

I would like to run logstash as such:

logstash -e 'input { stdin {}} output { stdout {}}'

but within a docker container, using the logstash official image. Is there a way I can do this? I simply want to test the way it it processes some input text initially, but I don't want to install it directly on the host, because then I need to make sure that the java version is correct and so on, and so forth. So running it within a container would be much more practical.

The problem is that it doesn't work as such, because the default command in the container is a huge java executable, which probably doesn't allow for additional options in a 'normal way'.
Any ideas?

What I've tried thus far is changing the logstash.yml to:

input {
   stdin {}
}

output {
   stdout {}
}

But I get:

line 3: cannot unmarshal !!str `input {...` into map[string]interface {}

[Badger]

@vinci

What I've tried thus far is changing the logstash.yml

The input and output sections should be in the logstash.conf, not the logstash.yml.

[vinci]

Thanks for the tip!

So now what I've done is delete the contents of logstash.yml, so that it doesn't try to connect to any elasticsearch instance and put the input/output content into logstash.conf.
It doesn't complain anymore, but I also cannot input any strings while attaching to the container as follows:

docker run -it --name logstash -v logstashconfig:/usr/share/logstash/config docker.elastic.co/logstash/logstash:7.7.1

It simply ignores whatever I write. So I'm not sure what I'm doing wrong.
Maybe it would be easier to use curl? And if yes, what default settings am I supposed to use for logstash.conf?