Using GitHub secrets in .NET application code?

Question

I am using GitHub actions to deploy a .NET core application to a Lambda function in AWS and am trying to retrieve secrets so that I can use them in the application.

I have two environments set up; staging and production. Each has a secret called MISC_KEY.

The following snippet of code is from the GitHub Actions workflow which sets the secret as an environment variable in the staging environment first...

deploy_staging:
    name: 'Deploy to Staging'
    environment: staging
    runs-on: ubuntu-latest

    steps:
    - name: 'Checkout repository'
      uses: actions/checkout@v3

    - name: 'Set Environment Secrets'
      run: echo "GitHubSecret=${{ secrets.MISC_KEY }}" >> $GITHUB_ENV

In my .NET application, I am trying to access this variable using Environment.GetEnvironmentVariable and then just pass this into the endpoint of the API...

// Get GitHub secret
string gitHubSecret = Environment.GetEnvironmentVariable("GitHubSecret");


app.UseHttpsRedirection();
app.UseAuthorization();
app.MapControllers();

app.MapGet("/", () => $"The GitHub secret for this environment is {gitHubSecret}");

app.Run();

I am getting nothing returning, and am wondering if I am missing anything out in this process? Can GitHub secrets actually be used within the application code itself, or can they only be used as part of the GitHub Actions workflow?

Answer 1

As the application is deployed on AWS, further configuration is required to pass the variables to the deployment stage which has been missed out.