docker-compose need to get properties by service name , espesely ports - docker

Question

I try to get the ports from the services I defined in the compose_file.yml
as i need to to extract the ports docker generate me.
no option to inject them to docker .
version: '3.3'
services:
oracleTest:
image: ora_image
container_name: "test1"
ports:
- 15211:1521
mysqlTest:
image: mysql:8.0
container_name: "test2"
restart: always
ports:
- 33061:3306
what I found is that I can get the ports by container name , this is not what I need
I can get the services with :
docker-compose ps --services
also can cat the mapped port with docker command again not what I need
docker port mysql8.0 | cut -d':' -f 2
what I need is something like this pseudo code:
docker-compose -f compose_file.yml port oracleTest
or any think like this ... any idea?

Answer 1

If you want ports to be access explicitly anyway, then you might want to inject the port into docker-compose.yml file vie environment variables.
Say you have .env file (default for docker-compose to look up) as follow
oraclePort=15211
mysqlPort=33061
you can then edit your docker-compose.yml to accept variable as
version: '3.3'
services:
oracleTest:
image: ora_image
container_name: "test1"
ports:
-$oraclePort:1521 #<-- notice the variable
mysqlTest:
image: mysql:8.0
container_name: "test2"
restart: always
ports:
-$mysqlPort:3306 #<-- notice the variable
hope this is what you need.

Answer 2

Since docker-compose.yml is a regular YAML file, you can use yq as YAML shell parser.
kislyuk/yq: Command-line YAML and XML processor - jq wrapper for YAML/XML documents
Command-line YAML and XML processor - jq wrapper for YAML/XML documents https://kislyuk.github.io/yq/
install yq and jq
pip install yq
pip install jq
Parse ports from docker-compose.yml
cat docker-compose.yml | yq '.services|.[].ports'
[
"15211:1521"
]
[
"33061:3306"
]
Get ports of oracleTest
what i need is something like this pseudo code:
docker-compose -f compose_file.yml port oracleTest
To get ports of specific service, use:
cat docker-compose.yml | yq '.services.oracleTest.ports'
[
"15211:1521"
]