Support Native Environment Variable Discovery for Thunder

[ayeshajay]

In Thunder, we provide the capability to supply values via environment variables. To utilize these variables, the deployment.yaml file must be updated with the following placeholder:

{{ "{{.VAR_NAME}}" }}

Currently, when using the product with environment variables, users must manually mark the references in deployment.yaml. When managing multiple variables, this manual mapping is not a scalable solution.

Proposed Improvement

As an enhancement, rather than requiring manual markers in the deployment.yaml for every environment variable reference, the product should inherently support resolving environment variables based on a defined priority order. This would significantly improve workflows for:

• Helm & Docker: Users can inject environment variables directly without needing to constantly override the deployment.yaml file via a ConfigMap.
• VM Deployments: Environment variables can be injected into the product seamlessly, eliminating the need to edit the deployment.yaml file manually.

[darshanasbg]

Sounds good.. So, are you suggesting something like this?

For a given key in the deployment.yaml:

1. If the value defined directly in the file, use that.
2. If the value defined in the {{.VAR_NAME}} format, lookup for that VAR_NAME environment variable to derive the value.
3. If this key not present in the deployment.yaml, derive a environment variable name in some convention (like Thunder.Key) and derive the value if that environment variable is present.
4. Fallback to the default.json if value cannot be found with any of above.

[ayeshajay]

Yes. To build on that, we could offer even greater flexibility by allowing users to configure the lookup precedence (the order of priority). This ensures the product fits various deployment strategies without locking users into a single workflow.

Example Scenarios:

case 1

• priority 1 - deployment.yaml
• priority 2 - env variable
• priority 3 - default.json

case 2

• priority 1 - env variable
• priority 2 - deployment.yaml
• priority 3 - default.json