Are environment variables not passed to the application?

[jrunestone]

(aspire 9.5.1, azd 1.19.0)

Hi,

When running azd infra gen I can see that my azd environment name is being populated in the DOTNET_ENVIRONMENT variable but none of my custom variables inside my azd .env file are being passed on to my application code (Environment.GetEnvironmentVariables). Is this intended?

[vhvb1989]

Hi @jrunestone , can you tell me more about your use-case? Why are you running azd infra gen ?

[jrunestone]

Hi,

I'm running azd infra gen to verify what would be published and to see how I can modify it to my needs using C# code only. I will be running azd provision later on. Is there a difference between these commands as to what's being generated or how they behave?

I'm trying to influence my infrastructure code generation by means of external variables without modifying the resulting bicep files after the fact, say from a CI/CD workflow. Also to use these variables directly in the Aspire AppHost where I can't resolve Parameters manually during publish mode (I think?).

For example I might have the following azd environments defined: myproject-develop, myproject-staging, myproject-production. In my Aspire app I want to automatically suffix my resource names with -dev, -stage, -prod, and also with a region name. I thought I could define variables to my environments (say ENV_SUFFIX=dev, REGION=swc) and they would then get passed on to my Aspire app when it's being built/run in publish mode and I could there use those variables to name and locate my resources accordingly. Yes this could also be done by just parsing the DOTNET_ENVIRONMENT variable.

Other situations might be controlling the scaling or tier of certain resources that are not tied directly to an environment and other configuration like that. Maybe I want to provision 10 pull request environments in the stage environment but with slightly different resource configurations.

Is the location/region I choose when provisioning sent down to the application code?

[vhvb1989]

IIRC, env vars are not used during build time for the AppHost, only during runtime. You might want to use configuration for that. However, azd does not translate env values into configuration for building the AppHost.

When you run azd infra gen, you are disconnecting the AppHost as the source of truth for your resources. The output bicep becomes the source of what it gets deployed. This means that if you do any change to the AppHost after azd infra gen, you need to re-run azd infra gen and override the bicep files. Azd has no validation to detect if the local bicep files became out of synch with the AppHost.

Let me bring @captainsafia and @davidfowl here. I think we have considered leveraging the azd's env values for building and controlling the AppHost in the past but we haven't landed into any concrete solution.
There is an aspire deploy <env-name> which you could probably try, but it might still need more values if you are using more than just one env var from azd's env