How do I refrence a secret in my Docker file?

[alexbjorlig]

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My objective is to set up Doppler in Github codespaces. To do this, I need to reference a Github codespace secret in the Docker file. How would I do this?

The relevant part of my Docker file:

# Install gnupg for doppler
RUN sudo apt install -y curl gnupg

# Install Doppler
RUN (curl -Ls --tlsv1.2 --proto "=https" --retry 3 https://cli.doppler.com/install.sh || wget -t 3 -qO- https://cli.doppler.com/install.sh) | sudo sh

RUN doppler configure set token ${{secrets.DOPPLER_TOKEN}}

I also need to install some private npm packages, so would very much like to know how this is done 😅

[spenserblack]

Secrets in codespaces are environment variables. If I'm understanding what you're trying to do correctly, I think that, instead of setting up Doppler in the Dockerfile, you would want to use a lifecycle hook like postCreateCommand.

For example,

// .devcontainer/devcontainer.json
{
  "build": { "dockerfile": "Dockerfile" },
  "postCreateCommand": "setup-doppler.sh",
  // ... other settings
}

#!/bin/sh
# setup-doppler.sh
doppler configure set token "$DOPPLER_TOKEN"

[alexbjorlig]

Hmm ok - fair enough. But what about npm install. Is that not supposed to be part of the docker file?

[spenserblack]

That depends. If you're globally installing necessary packages (e.g. a common CLI tool like tsc), you might want that to be part of the dockerfile. But if you're installing the project's dependencies, I believe it will need to be one of the lifecyle script ("postCreateCommand": "npm install" for example). As far as I know, the repository is cloned after the devcontainer is built from the image/dockerfile, so using a lifecycle script is necessary for dependency installation.

Here's a list of lifecycle scripts.

[alexbjorlig]

Ahh ok - I moved it to the postCreateCommand then.

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