Is there a tool to dynamically set services, external_links, etc. for container orchestration, depending on an environment variable?
Tool should have convenient syntax (Python/js/bash - any clearly readable), and support conditions (if).
Now I have 3 files like docker-compose.local.yml, and edit them all.
cp docker-compose.local.yml docker-compose.yml;
docker-compose up;
I wan't one config file
ENV=local;
docker-compose up; # or "node start-compose.js"
I know that docker-compose supports environment variables like
volumes:
- ${ENV}-filename:/.../filename
But I need more.
You can use .env files to store all your compose configuration.
Just as you do cp docker-compose.local.yml docker-compose.yml; You do cp local.env .env; docker-compose up will automatically pick up the .env file.
Taken from the docs Environment Variables in Compose
Related
If I want to provide custom value for ASPNETCORE_ENVIRONMENT to docker-compose up cli command how would I do that?
Is it possible to provide this through cli or I need to use docker-compose.yml file (this solution I would like to skip).
Unlike docker-compose run, docker-compose up does not provide this - unfortunately. Alternatively, you can make use of env_file for this:
services:
webapi:
image: aspnetcore-image
env_file:
- .env
By creating a file named .env (it can be named as desired) and placing it in the appropriate directory (here it is placed in the same directory as docker-compose.yml), docker-compose up will then export the respective env vars to the docker container.
I'm trying to get the Env-Variables in Docker-Compose to work. My Files:
env/test.env:
XUSER=you
XHOME=/home/${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=${APP_PORT} and then export APP_PORT=3000 on your shell before running docker-compose. See https://docs.docker.com/compose/environment-variables/ for more information.
I'm trying to get a docker-compose file working with multiple .env files, and I'm not having any luck. I'm trying to setup three .env files:
global settings that are the same across all container instances
environment-specific settings (stuff just for test or dev)
local settings - overridable things that a developer might need to change in case they have conflicts with, say, a port number
My docker-compose.yml file looks like this:
version: '2'
services:
db:
env_file:
- ./.env
- ./.env.${ENV}
- ./.env.local
image: postgres
ports:
- ${POSTGRES_PORT}:5432
.env looks like this:
POSTGRES_USER=myapp
and the .env.development looks like this:
POSTGRES_PASSWORD=supersecretpassword
POSTGRES_HOST=localhost
POSTGRES_PORT=25432
POSTGRES_DB=myapp_development
.env.local doesn't exist in this case.
After running ENV=development docker-compose up, I receive the following output:
$ ENV=development docker-compose up
WARNING: The POSTGRES_PASSWORD variable is not set. Defaulting to a blank string.
WARNING: The POSTGRES_DB variable is not set. Defaulting to a blank string.
WARNING: The POSTGRES_PORT variable is not set. Defaulting to a blank string.
ERROR: The Compose file './docker-compose.yml' is invalid because:
services.db.ports is invalid: Invalid port ":5432", should be [[remote_ip:]remote_port[-remote_port]:]port[/protocol]
From that error message, it looks like none of my environment variables are being used. I just upgraded to the newest available docker-compose as well - same errors:
$ docker-compose --version
docker-compose version 1.8.0-rc1, build 9bf6bc6
Any ideas here? Would be nice to have a single docker-compose.yml that would work across multiple environments.
In order to apply different/multiple env_files depending on the running environment, such as development/staging/production, I think a better way for docker-compose is to use multiple docker-compose yml files.
For example:
1. Start with a base file that defines the canonical configuration for the services.
docker-compose.yml
web:
image: example/my_web_app:latest
env_file:
- .env
2. Add the override file for development, as its name implies, can contain configuration overrides for existing services or entirely new services.
docker-compose.override.yml
web:
build: .
volumes:
- '.:/code'
ports:
- 8883:80
env_file:
- .env.dev
When you run docker-compose up it reads the overrides automatically.
3. Create another override file for the production environment.
docker-compose.prod.yml
web:
ports:
- 80:80
env_file:
- .env.prod
To deploy with this production Compose file you can run
docker-compose -f docker-compose.yml -f docker-compose.prod.yml up
Note
My Docker version:
$ docker -v
Docker version 18.06.1-ce, build e68fc7a
$ docker-compose -v
docker-compose version 1.22.0, build f46880fe
Reference: https://docs.docker.com/compose/extends/
Keep in mind that there are 2 different environments where you are defining variables. The host machine where you are executing the docker-compose command, and the container itself (running the db service in your case).
Your docker-compose.yml file has access to your host's environment variables. Hence ENV is reachable from the docker-compose command, but not these in your .env files.
On the contrary, the value for ENV is not reachable inside the container, but all variables defined in your .env files will.
I don't know if you really need your db container to access the variables defined on your .env.development. But at least seem that your host machine needs to have the content of that file, so when the docker-compose command is called, the POSTGRES_PORT variable is defined.
To fix your specific problem you would need to define the environment variables on your host machine too, not only for the container. You could do something like this:
#Set for host
ENV=development
#Also sets the variables on the host
source ./.env.$ENV
#POSTGRES_PORT defined in .env.development is used here
docker-compose up
#since env_file also contains .env.development, the variables will be reachable from the container.
Hope that helps.
There is a misconception regarding the .env file and the env_file option in the docker-compose.yml, as it is very ambiguous. Shin points it out very nicely in the github issue docker-compose doesn't use env_file. I will just quote his summary:
Variable substitution in your docker-compose.yml file will be pulled (in decreasing order of priority) from your shell's environment and your .env file.
Variables available in your container are a combination of values found in your env_file files and values described in the environment section of the service.
Those are two entirely separate sets of features.
while reading this page: https://docs.docker.com/compose/environment-variables/
and from my understanding, you should do the following:
for the global variables(that should not change) make an env file like so:
VAR1=VALUE1
VAR2=VALUE2
and for the others(that might change) you should add their name under environment in docker-compose.yml like this:
environment:
- VAR1
- VAR2
this will take the VAR1 and VAR2 values from the shell you are running docker-compose.
I hope this helps.