We run into a strange error when we added a new environment variable to our Docker Compose file:
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$ docker-compose up |
ERROR: Invalid interpolation format for “environment” option in service “api”: “MY_KEY=Abc$5”
Our docker-compose.yaml file looks like this:
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version: "3.2" services: db: image: mcr.microsoft.com/mssql/server:latest volumes: - ./container_db:/var/opt/mssql/data environment: ACCEPT_EULA: Y SA_PASSWORD: P@ssword123 ports: - 6000:1433 api: image: mcr.microsoft.com/dotnet/sdk:6.0 volumes: - ./MinApi:/workspace working_dir: /workspace command: sh -c 'while true; do sleep 30; done' environment: - MY_KEY=Abc$5 ports: - 7001:7000 depends_on: - db |
The problem is the $ in the value of the environment variable MY_KEY. Docker allows a lot of flexibility in its configuration files. One way to do that is to use variables. Unfortunately, in our case the $ is just a $ and not an indicator for a variable. It is basically the same problem we had a few years ago with DbUp.
We can escape the $ sign by using two $$ to prevent the variable substitution:
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environment: - MY_KEY=Abc$$5 |
With this change we can run docker-compose without any errors. Inside the container, our variable has the right number of $:
Nice Blog… great
I just faced a similar issue with a docker environment variable not within the .env file but with the docker-compose.tml there was also a definiiton of an env variable inside of the file and the issue of the single “$” was within that file not in the .env i repeat. for example
JWT_PUBLIC_KEY: “$${JWT_PUBLIC_KEY:—-}”
Just so if someone else haves an issuw with this you are aware to also look on this file.