I have a docker-compose file that allows me to pass the environment variables as a file (.env file). As I have multiple ENV variables, Is there any option in Dockerfile like env_file in docker-compose for passing multiple environment variables during docker build?
This is the docker-compose.yml
services:
web:
image: "node"
links:
- "db"
env_file: "env.app"
AFAIK, there is no such way to inject environment variables using a file during the build step using Dockerfile. However, in most cases, people do end up using an entrypoint script & injecting variables during the docker run or docker-compose up.
In case it's a necessity you might need to write a shell wrapper which will change the values in the Dockerfile dynamically by taking a key-value pair text file as an input or make it something as below but the ENV file name need to be included in Dockerfile.
COPY my-env-vars /
RUN export $(cat my-env-vars | xargs)
It's an open issue - https://github.com/moby/moby/issues/28617
PS - You need to be extra careful while using this approach because the secrets are baked into the image itself.
Related
If I want to provide custom value for ASPNETCORE_ENVIRONMENT to docker-compose up cli command how would I do that?
Is it possible to provide this through cli or I need to use docker-compose.yml file (this solution I would like to skip).
Unlike docker-compose run, docker-compose up does not provide this - unfortunately. Alternatively, you can make use of env_file for this:
services:
webapi:
image: aspnetcore-image
env_file:
- .env
By creating a file named .env (it can be named as desired) and placing it in the appropriate directory (here it is placed in the same directory as docker-compose.yml), docker-compose up will then export the respective env vars to the docker container.
I'm trying to get the Env-Variables in Docker-Compose to work. My Files:
env/test.env:
XUSER=you
XHOME=/home/${XUSER}
docker-compose.yml:
version: '3'
services:
abc:
build: .
image: xyz:latest
container_name: xyz
env_file:
- env/test.env
user: "${XUSER}"
docker-compose up --build
docker-compose config
WARNING: The XUSER variable is not set. Defaulting to a blank string.
services:
kernel:
build:
context: xyz
container_name: xyz
environment:
XHOME: /home/you
XUSER: you
image: xyz:latest
user: ''
As you can see user: '' is an empty string, but the env_file works. I found some old Bug reports about this issue, I'm not sure I doing something wrong or not.
Although the other answers are both correct they do not highlight the underlying misunderstanding here enough:
With the env_file option you can specify a file with variables to be injected into the environment in the container.
Using variable substitution in the docker-compose.yml you can access variables in the environment of the docker-compose command, i.e. on the host.
You can set these using the usual mechanisms of your OS/shell, e.g. in bash:
export XUSER=you
docker-compose up
Additionally with docker-compose you can use a .env file in the current directory.
So in your concrete example you should just move env/test.env to .env to add the variables to the environment of docker-compose for variable substitution.
If you also want to add them to the environment in the container you can do it like this:
version: '3'
services:
abc:
build: .
image: xyz:latest
container_name: xyz
# add variables from the docker-compose environment to the container:
environment:
- XUSER=$XUSER
# or even shorter:
- XHOME
# use variable from the docker-compose environment in the config:
user: "${XUSER}"
It says WARNING: The XUSER variable is not set. Defaulting to a blank string. because ${XUSER} doesn't exist at the time this is executed:
user: "${XUSER}"
${XUSER} is not in your environment (you can verify this by running: env | grep XUSER, which should output nothing), and docker-compose didn't find any .env file at the same level or no .env file was passed at the time you ran docker-compose up --build or docker-compose config
Flexible solution:
Rename env/test.env for .env and place it a the root of the folder container your docker-compose file so that docker automatically parses it.
Or use:
docker-compose --env-file path/to/env/test.env up --build
docker-compose --env-file path/to/env/test.env config
Permanent solution:
Export them manually in your environment by running:
export XUSER=you && export XHOME=/home/${XUSER}
Or you use your env/test.env file as a source (note that you'll need to prefix with 'export'):
env/test.env:
export XUSER=you
export XHOME=/home/${XUSER}
And then your run . /path/to/env/test.env or source /path/to/env/test.env
What you need to do is create .env file at the same directory as your docker-compose.yml file, the content of .env is :
XUSER=user1
then run docker-compose config
reference : https://docs.docker.com/compose/environment-variables/
Since +1.28 .env file is placed in project root, not where docker-compose is executed. If you do that the variables will be automatically pulled through to be available to the container.
This works great in dev, especially with a a bind-mount volume to make .env available to compose in project root without also going into image build by including .env in .dockerignore
But in production I was not comfortable including it in my project root especially since I was pulling those project files down from github. The Compose file expects them to be in the production environment to replace for substitution SECRET_VAR=${SECRET_VAR}
So one hack solution was to stick the .env file high in my production directory tree, far away from my project (ideally these would come from an environment store on the hosting service, or another encrypted store), but inject those variables into the container at runtime by using the --env_file flag in Compose up.
The env_file flag works Like this:
docker-compose -f docker-compose.prod.yml --env-file ../.env up -d
Its in the docs
I also started encountering this after upgrading to Docker Desktop 4.12.0. This error started happening for quoted strings inside of .env (when using env_file to load variables in docker-compose.yml). In that case, be sure to use single quotes instead of double quotes, i.e.
MY_VAR='foo$bar'
# ... instead of...
MY_VAR="foo$bar"
Try this, I hope it will work.
You need to escape the variable if you want it to be expanded inside the container, using a double-dollar sign ($${envVariable}).
If however, you want it to be interpreted on your host, the $envVariable needs to be defined in your environment or in the .env file. The env_file option defines environment variables that will be available inside the container only.
I am trying to use the same docker-compose.yml and .env files for both docker-compose and swarm. The variables from the .env file should get parsed, via sed, into a config file by running a run.sh script at boot. This setup works fine when using the docker-compose up command, but they're not getting passed when I use the docker stack deploy command.
How can I pass the variables into the container so that the run.sh script will parse them at boot?
Loading the .env file is a feature of docker-compose that is not part of the docker CLI. You can manually load the contents of this file in your shell before performing the deploy:
set -a; . ./.env; set +a
docker stack deploy -c docker-compose.yml stack_name
Other options include using docker-compose to pre process the compose file:
docker-compose config >docker-compose.processed.yml
Or you could use envsubst to replace the variables to make a compose file with the variables already expanded:
set -a; . ./.env; set +a
envsubst <docker-compose.yml >docker-compose.processed.yml
To pass shell environment variables through to containers use env_file syntax:
web:
env_file:
- web-variables.env
As docs state:
You can pass multiple environment variables from an external file through to a service’s containers with the ‘env_file’ option
However, using .env as external filename may cause unexpected results and is semantically problematic.
Placing .env in the folder where the docker-compose command serves different purpose:
As Docs, Docs2, Docs3 state:
The environment variables you define here are used for variable
substitution in your Compose file
You can set default values for environment variables using a .env
file, which Compose automatically looks for
So if compose file contains:
db:
image: "postgres:${POSTGRES_VERSION}"
You .env would contain:
POSTGRES_VERSION=4.0
This feature indeed works only in compose:
The .env file feature only works when you use the docker-compose up
command and does not work with docker stack deploy
Actually I found the best/easiest way is to just add this argument to the docker-compose.yml file:
env_file:
- .env
I have writte a docker-compose.yml file to create a multi-container app with nodejs and mongodb (so 2 containers), and I want to make some options configurable, as the choice of server address and port.
To do that, I have written what follows in docker-compose.yml to set them as env variables:
..
web:
environment:
- PORT=3000
- ADDRESS=xxx.xxx.xxx.xxx
..
Within the source code of my application, I use process.env.PORT and process.env.ADDRESS to refer to these variables.
But how can I do if I want to change those values, and for example set PORT=3001?
I have to use docker-compose build and docker-compose up again and build all the application, included mongodb container?
I have to use docker-compose build and docker-compose up again and build all the application, included mongodb container?
Not build, just up. They are runtime options, not build options. Changing them in the docker-compose.yml file and then doing a docker-compose up again should recreate the containers with the new environment variables.
Alternatively, you can specify environment variables outside the docker-compose.yml file to make for easier changes:
One of these methods is to use a .env file in the same folder that you execute docker-compose form (see https://docs.docker.com/compose/env-file/ for information on it).
Another option is to interpolate environment variables from your shell. You could specify them such as - PORT=${APP_PORT} and then export APP_PORT=3000 on your shell before running docker-compose. See https://docs.docker.com/compose/environment-variables/ for more information.
I have a docker-compose.yml file and in the terminal I am typing docker-compose up [something] but I would also like to pass an argument to docker-compose.yml. Is this possible? I've read about interpolation variables and tried to specify a variable in the .yml file using ${testval} and then docker-compose up [something] var="test" but I receive the following error:
WARNING: The testval variable is not set. Defaulting to a blank string.
ERROR: No such service: testval=test
Based on dnephin answer, I created this sample repo that you can pass an variable to docker-compose up.
The usage is simple:
MAC / LINUX
TEST= docker-compose up to create and start both app and db container. The api should then be running on your docker daemon on port 3030.
TEST=DO docker-compose up to create and start both app and db container. The api should execute the npm run test inside the package.json file.
WINDOWS (Powershell)
$env:TEST="";docker-compose up to create and start both app and db container. The api should then be running on your docker daemon on port 3030.
$env:TEST="do";docker-compose up to create and start both app and db container. The api should execute the npm run test inside the package.json file.
You need to ensure 2 things:
The docker-compose.yml has the environment variable declared. For example,
services:
app:
image: python3.7
environment:
- "SECRET_KEY=${SECRET_KEY}"
have the variable available in the environment when docker-compose up is called:
SECRET_KEY="not a secret" docker-compose up
Note that this is not equivalent to pass them during build, as it is not advisable to store secrets in docker images.
You need to pass the variables as environment variables:
testvar=test docker-compose up ...
or
export testvar=test
docker-compose up
From the docs:
https://docs.docker.com/compose/reference/up/
https://docs.docker.com/compose/reference/build/
You can't pass arguments to docker-compose up, but you can pass arguments to docker-compose build:
docker-compose build --build-arg KEY1=VALUE1 --build-arg KEY2=VALUE2
I'm not sure what you want to do here, but if what you need is to pass an environmental variable to a specific container docker-compose.yml allows you to do that:
web:
...
environment:
- RAILS_ENV=production
- VIRTUAL_HOST=www.example.com
- VIRTUAL_PORT=3011
This variables will be specific for the container you specified them to, and wil not be shared between containers.
Also "docker-compose up" doesn't take any argument.
When dealing with build argumenets please declare them in compose yml file as follows
services:
app: (name of service
build:
context: docker/app/ (where is your docker build root)
dockerfile: Dockerfile (that is optional)
args:
- COMPOSER_AUTH_TOKEN (name of variable, value will be taken from host environment)
Well before running docker-compose up, export variable as other guys suggested. It will work. I tried. Use docker compose version 3 and above. Have fun
Compose supports declaring default environment variables in an environment file named .env placed in the project directory.
Step 1:
Create a file named .env in the project directory
Step 2:
Declare variables in the form VAR=VAL
NOTE: There is no special handling of quotation mark i.e. TESTVAL='test' means TESTVAL is 'test'(with quotation mark) and not just test. So you'd declare it as TESTVAL=test.
Step 3:
Use the variables in the Compose file as:
environment:
myval=${TESTVAL}
Documentation: Declare default environment variables in file
BONUS: If you are building image on the fly in you docker-compose.yaml, then you can even pass the build args using environment variables. Eg:
version: "3.8"
services:
myapp:
build:
context: ./myDir
dockerfile: ./myDir/myDockerfile
args:
- MYARG=${TESTVAL}
I was trying to find solution for batch file, based on Rafael Delboni answer you can add command inside batch file for calling powershell:
powershell $env:TEST="";docker-compose up ...
but instead of that because it's expensive to call powershell inside batch file you can initialize TEST variable inside batch file and then call your docker-compose command.
Something like this:
set TEST = ...
docker compose up ...