Docker-compose of elk stack with logstash 2.4 not working

[pkaramol (Pantelis Karamolegkos)]

I am trying to run a simple pipeline with elk using however logstash 2.4 as follows

  logstash:
    build:
      context: logstash/
    volumes:
      - ./logstash/pipeline-production:/etc/logstash/conf.d:rw
      - ./logstash/files:/usr/share/logstash/files:rw
    ports:
      - "5000:5000"
    # environment:
    #   LS_JAVA_OPTS: "-Xmx4096m -Xms4096m"
    networks:
      - elk
    depends_on:
      - elasticsearch

My production-pipeline folder has simple input / output files.

However I see no reasonable output in my docker logs:

elasticsearch_1  | WARNING: no logs are available with the 'none' log driver
kibana_1         | WARNING: no logs are available with the 'none' log driver
logstash_1       | {:timestamp=>"2018-11-02T15:22:36.374000+0000", :message=>"Pipeline main started"}
logstash_1       | {:timestamp=>"2018-11-02T15:22:36.480000+0000", :message=>"Pipeline main has been shutdown"}
dockerelk_kibana_1 exited with code 137
logstash_1       | {:timestamp=>"2018-11-02T15:22:39.382000+0000", :message=>"stopping pipeline", :id=>"main"}

What could be the issue?