How to define build-args in docker-compose?

Question

I have the following docker-compose file

version: '3'
services:
    node1:
            build: node1
            image: node1
            container_name: node1

    node2:
            build: node2
            image: node2
            container_name: node2

I can build both images and start them with a single command

docker-compose up -d --build

But I would like to use build-args on the builds. The original build script of the image outside of the scope of compose looks something like this

#!/bin/sh
docker build \
--build-arg ADMIN_USERNNAME_1=weblogic \
--build-arg ADMIN_PASSWORD_1=weblogic1 \
--build-arg ADMIN_NAME_1=admin \
--build-arg ...
--build-arg ... \
-t test/foo .

Both images would use build-args of the same name but different value. Also, as there are dozens of build args, it would be convenient to store them in a compose service specific build-properties file. Is this possible with docker-compose?

Warning for later people: for passwords, you might consider using a secret manager (Vault, k8s secrets, aws sms, docker swarm secrets) instead of a build arg to avoid security breaches. A build-time arg will bake the cred in the image, which means anyone with pull access can read it. Avoid using credentials at build-time. — James Fulford
– James Fulford, Commented Dec 25, 2020 at 20:02
Very important note about security, thanks a lot. Here is a solution: pythonspeed.com/articles/build-secrets-docker-compose — sekrett
– sekrett, Commented May 19, 2021 at 9:35
@Bira I fail to see what this question has to do with AWS. The question doesn't mention it, and docker-compose is indeed an independent product. — Raphael
– Raphael, Commented Apr 24, 2023 at 7:05

Raphael · Accepted Answer · 2023-04-29 17:45:19Z

218

You can specify the arguments directly in your docker-compose file:

node1:
    build:
        context: node1
        args:
            ADMIN_USERNNAME: weblogic1
            ADMIN_PASSWORD: weblogic1
            ADMIN_NAME: admin1
    image: node1
    container_name: node1

See a full example: MWE

The official docs (legacy v3 here) have all detail.

edited Apr 29, 2023 at 17:45

answered Feb 13, 2019 at 14:21

Raphael

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5 Comments

harvzor Over a year ago

For some reason args in the docker-compose file did not work for me when trying to use a shell var. Instead I had to use --build-arg VARNAME=$VARNAME when running the command.

Raphael Over a year ago

@harvzor Not sure what you mean by that. Do you expect docker-compose to have excess to a Bash variable outside of its own runtime? Yeah, that won't work, and it shouldn't. You can use environment variables, though: docs.docker.com/compose/environment-variables

prayagupadhyay Over a year ago

For multiline --build-arg, see stackoverflow.com/a/67135826/432903

Nils Feb 22 at 0:37

How can I do it without editing the compose file? I need to make the container use a proxy, but I don't want to change the config for anyone else on the team

Raphael Feb 25 at 9:07

@Nils check out docs.docker.com/compose/how-tos/multiple-compose-files/merge

lvthillo · Accepted Answer · 2018-06-07 09:20:51Z

63

You can define your args with your build command of docker-compose.

Example Dockerfile:

FROM nginx:1.13

RUN apt-get -y update && apt-get install -y \
    apache2-utils && \
    rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*

ARG username
ARG password

RUN htpasswd -bc /etc/nginx/.htpasswd $username $password

docker-compose file:

version: '3'
services:
  node1:
     build: ./dir

The ./dir contains the Dockerfile and I build with this command:

docker-compose build --build-arg username="my-user" --build-arg password="my-pass"

I see already:

Step 5/5 : RUN htpasswd -bc /etc/nginx/.htpasswd $username $password
 ---> Running in 80735195e35d
Adding password for user my-user
 ---> c52c92556825

I bring my stack up:

docker-compose up -d

Now I can check inside the nginx container and my username and (encrypted) password are there:

docker@default:~/test$ docker exec -it test_node1_1 bash
root@208e4d75e2bd:/# cat /etc/nginx/.htpasswd
my-user:$apr1$qg4I/5RO$KMaOPvjbnKdZH37z2WYfe1

Using this method your able to pass build args to your docker-compose stack.

edited Jun 7, 2018 at 9:20

answered Jun 7, 2018 at 6:34

lvthillo

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4 Comments

Alejandro Galera Over a year ago

Environment variables can be used as you said, but they have to be defined in .env, not inside the compose file

CvRChameleon Over a year ago

This answer is very useful, it actually shows how docker-compose can be used with --build-arg on command-line, you can define your ARG in Dockerfile, docker-compose.yml - the :args array defined and then finally override it on the command-line.

James Fulford Over a year ago

Seems correct, but for others, be wary of baking credentials into images like this. Username/password should be done at runtime, so your prod credentials don't show up in your repository

Gostega Over a year ago

This is the answer I was looking for, showing that --build-arg can be used with docker-compose

michalhosna · Accepted Answer · 2022-01-23 10:13:03Z

48

In your Dockerfile:

ARG CERTBOT_TAG=latest
FROM certbot/certbot:${CERTBOT_TAG}

In your docker-compose.yml file:

version: '3.4'
services:
  certbot:
    build:
      context: .
      args:
        CERTBOT_TAG: v0.40.1

And you can build or up your service:

docker-compose build certbot

edited Jan 23, 2022 at 10:13

michalhosna

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answered Nov 17, 2019 at 20:06

heralight

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2 Comments

alete Over a year ago

I got an error using this format,

ERROR: The Compose file './docker-compose.yml' is invalid because: services.certbot.build.args contains {"CERTBOT_TAG": "v0.40.1"}, which is an invalid type, it should be a string

My solution was to remove the - to turn it into a string instead of an object.

Martynas Jusevičius Over a year ago

@heralight please fix the YAML syntax!

PHZ.fi-Pharazon · Accepted Answer · 2021-05-09 08:43:45Z

7

As Salek mentioned above, adding context: . helps.

For example:

version: '3.5'
services:
  app:
    build:
      context: .
      args:
        NODE_VERSION: 14.15.4

`

answered May 9, 2021 at 8:43

PHZ.fi-Pharazon

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Comments

Bira · Accepted Answer · 2021-02-13 14:48:41Z

4

Docker File

ARG ACCOUNT_ID

FROM $ACCOUNT_ID.dkr.ecr.ap-southeast-1.amazonaws.com/my-composer:latest as composer
LABEL stage=intermediate

Buildspec or CLI execute the following command.

docker-compose build --build-arg ACCOUNT_ID="23423432423" --no-cache

If you want to print the ACCOUNT_ID in CLI

ARG ACCOUNT_ID

FROM amazonlinux:latest
RUN yum -y install aws-cli 
RUN echo $ACCOUNT_ID

FROM $ACCOUNT_ID.dkr.ecr.ap-southeast-1.amazonaws.com/my-composer:latest as composer
LABEL stage=intermediate

Note: ARG should be on top of all FROM statement, then it will work as global ARG.

answered Feb 13, 2021 at 14:48

Bira

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