Sending Logs to Logstash in ELK using Ruby on Rails Docker Image - ruby-on-rails

Question

I've been following these tutorials, repos, docs, and everything:
https://medium.com/#AnjLab/how-to-set-up-elk-for-rails-log-management-using-docker-and-docker-compose-a6edc290669f
https://github.com/OrthoDex/Docker-ELK-Rails
http://ericlondon.com/2017/01/26/integrate-rails-logs-with-elasticsearch-logstash-kibana-in-docker-compose.html
https://manas.tech/blog/2015/12/15/logging-for-rails-apps-in-docker.html
https://logz.io/blog/docker-logging/
https://www.youtube.com/watch?v=KR2FZiqu57I
https://dzone.com/articles/docker-logging-with-the-elk-stack-part-i
Docker container cannot send log to docker ELK stack
Well, you got the point. I have several more which I've omitted due to brevity
Unfortunately, either they're outdated, don't show the whole picture, or my config is bad (I think it's the latter one).
I honestly don't know if I'm missing anything.
I'm currently using a docker-compose version 3. I'm currently using this image (sebp/elk). I'm able to boot everything, and access Kibana, but I am not able to send the logs to Logstash so it gets processed and sent to ElasticSearch.
I've tried these approaches to no avail:
Inside application.rb
1) Use Lograge and send it to port 5044 (which apparently is the one which Logstash is listening to)
config.lograge.enabled = true
config.lograge.logger = LogStashLogger.new(type: :udp, host: 'localhost', port: 5044)
2) Setting it to STDOUT, and let Docker process it as gelf and send it to Logstash:
logger = ActiveSupport::Logger.new(STDOUT)
logger.formatter = config.log_formatter
config.logger = ActiveSupport::TaggedLogging.new(logger)
And mapping it back to the compose file:
rails_app:
logging:
driver: gelf
options:
gelf-address: "tcp://localhost:5044"
3) I've tried
Other Errors I've encountered:
Whenever I try to use the config.lograge.logger = LogStashLogger.new(type: :udp, host: 'localhost', port: 5044) I get:
- Errno::EADDRNOTAVAIL - Cannot assign requested address - connect(2) for "localhost port 5044.
Funny thing this error may disappear from time to time.
Other problem is that whenever I try to create a dummy log entry I receive a Elasticsearch Unreachable: [http://localhost:9200...] This is inside the container... I don't know if it can't connect because the URL is exposed outside from it... or there's another error. I can curl to localhost:9200 and receive a positive response.
I was checking the sebp/ELK image, and I see that it's using Filebeat. Could that be the reason why I am not able to send the logs?
I'd appreciate any kind of help!
Just in case, here's my docker-compose.yml file:
version: '3'
services:
db:
image: mariadb:10.3.5
restart: always
environment:
MYSQL_ROOT_PASSWORD: "rootPassword"
MYSQL_USER: "ruby"
MYSQL_PASSWORD: "userPassword"
MYSQL_DATABASE: "dev"
ports:
- "3306:3306"
volumes:
- db-data:/var/lib/mysql/data
- ./db/rails_cprint.sql:/docker-entrypoint-initdb.d/rails_cprint.sql
elk:
image: sebp/elk:623
ports:
- 5601:5601
- 9200:9200
- 5044:5044
- 2020:2020
volumes:
- elasticsearch:/var/lib/elasticsearch
app:
build: .
depends_on:
- db
- elk
environment:
RAILS_ENV: development
LOGSTASH_HOST: localhost
SECRET_MYSQL_HOST: 'db'
SECRET_MYSQL_DATABASE: 'dev'
SECRET_MYSQL_USERNAME: 'ruby'
SECRET_MYSQL_PASSWORD: 'userPassword'
command: bash -c "rm -f tmp/pids/server.pid && bundle exec rails s -p 3001 -b '0.0.0.0'"
stdin_open: true
tty: true
logging:
driver: gelf
options:
gelf-address: "tcp://localhost:5044"
links:
- db
volumes:
- "./:/var/www/cprint"
ports:
- "3001:3001"
expose:
- "3001"
volumes:
db-data:
driver: local
elasticsearch:
driver: local

Answer 1

Don't use "localhost" in your configs. In the docker network, the service name is the host name. Use "elk" instead, for example:
config.lograge.logger = LogStashLogger.new(type: :udp, host: 'elk', port: 5044)