45 lines
1.2 KiB
Markdown
45 lines
1.2 KiB
Markdown
|
+++
|
||
|
|
title = "Shared environment variables for make, bash and docker"
|
||
|
|
date = 2020-01-07
|
||
|
|
+++
|
||
|
|
|
||
|
|
It is possible to define a set of variables and share them in Make, Bash and the Docker containers that are orchestrated by `docker-compose`.
|
||
|
|
|
||
|
|
Docker-compose can use an `.env` file to substitute variables in a `docker-compose.yml` file in the same directory. In this docker-compose.yml they can be exported to the containers.
|
||
|
|
|
||
|
|
Incuding this `.env` file in your `Makefile` makes hem available there as well, but they are not automatically exported to the Bash shells that are spawned by `make` to execute the targets. This can be changed by adding the `.EXPORTALLVARIABLES:` target to your `Makefile`.
|
||
|
|
|
||
|
|
```
|
||
|
|
# .env
|
||
|
|
VAR1=this
|
||
|
|
VAR2=that
|
||
|
|
VAR3=those
|
||
|
|
```
|
||
|
|
|
||
|
|
```make
|
||
|
|
# Makefile
|
||
|
|
include .env
|
||
|
|
|
||
|
|
.EXPORT_ALL_VARIABLES:
|
||
|
|
|
||
|
|
task:
|
||
|
|
@echo "VAR1 is ${VAR1}"
|
||
|
|
@some_command # some_command can use $VAR1, $VAR2 and $VAR3
|
||
|
|
@docker-compose up
|
||
|
|
```
|
||
|
|
|
||
|
|
```
|
||
|
|
# docker-compose.yml
|
||
|
|
...
|
||
|
|
app:
|
||
|
|
image: "registry/the_app:${VAR2}"
|
||
|
|
environment:
|
||
|
|
- VAR3=${VAR3}
|
||
|
|
```
|
||
|
|
|
||
|
|
## Sources
|
||
|
|
|
||
|
|
- [vsupalov.com](https://vsupalov.com/docker-arg-env-variable-guide/#the-dot-env-file-env)
|
||
|
|
- [www.gnu.org](https://www.gnu.org/software/make/manual/html_node/Special-Targets.html#Special-Targets)
|
||
|
|
|