@Marvin How do I pass an environment variable into a deployment in the prefect.yaml

To pass an environment variable into a deployment in the

prefect.yaml

file, you can use Prefect's templating system which allows you to reference variables using the

{{ prefect.variables.my_variable }}

syntax. This enables the templating of deployment steps by referencing them in the

prefect.yaml

file. For instance, if you want to specify a branch for a git repository in a deployment pull step, you can do so like this:

yaml
pull:
  - prefect.deployments.steps.git_clone:
      repository: <https://github.com/PrefectHQ/hello-projects.git>
      branch: "{{ prefect.variables.deployment_branch }}"

In this example, the

deployment_branch

variable will be evaluated at runtime for the deployed flow. This allows you to make changes to variables used in a pull action without updating a deployment directly. Variables can also be used to dynamically set infrastructure-specific fields, such as Docker image tags, etc. Here's an example of referencing a Docker image variable in a

job_variables

field:

yaml
job_variables:
  image: "{{ build-image.image }}"

So long as your build steps produce fields that correspond to the variables being referenced, they will be dynamically populated with the relevant values when you deploy a new version of your deployment. If you want to set environment variables that will be passed to the job running your flow, you might use something like the following in your `prefect.yaml`:

yaml
env:
  MY_ENV_VARIABLE: "some-value"

Please ensure that this structure aligns with the most up-to-date documentation of Prefect 2.x, as formats may evolve over time. You can learn more about how to use variables in deployments in the Prefect Docs.