Allow to share configuration between middlewares

[ThePlenkov]

Hi!

Currently writing multiple middleware ( cannot be wrapped into one as used in different moments ) I found out that it's not possible to share configuration between them.

Yes, we have resources - but then we need to detect which is active config and then read and parse yaml manually.

So one of solutions is to use a separate file or environment variables, but more elegant solution to my opinion might be give an option to read the whole configuration file from middleware util.

One of the use cases is to write extensions for existing middlewares ( like fiori-tools-proxy ) when we don't copy configuration but just reading it from the global config.

As a simple workaround - it might be easier to provide also custom customConfiguration as a parameter or util method.

Thank you!

[ThePlenkov]

I have solved my task currently by using yaml merge:

specVersion: "2.2"
#type: application|library|theme-library|module
type: library
metadata:
  name: test
customConfiguration: &global
  fiori-tools-proxy: &fiori-tools-proxy
    ui5:
      path:
        - /resources
        - /test-resources
      url: https://sapui5.hana.ondemand.com
      version: 1.78.0
  myTool:
    key: value
  myOtherTool:
    otherKey: otherValue
server:
  customMiddleware:    
    - name: fiori-tools-proxy
      afterMiddleware: compression
      configuration: 
        <<: *fiori-tools-proxy        
    - name: fiori-tools-home-page
      beforeMiddleware: serveIndex
      configuration: 
        <<: *global        
    - name: fiori-tools-proxy-cdn
      beforeMiddleware: fiori-tools-proxy
      configuration: 
        <<: *global

It works but then it requires ui5.yaml configuration which impacts middleware's usability

[RandomByte]

It works but then it requires ui5.yaml configuration which impacts middleware's usability

Could you elaborate a bit more on that? I guess some configuration needs to be in the ui5.yaml in any case, right? In your example, would that be the "customConfiguration"?

Which parts of your example would be unnecessary in that case?

[ThePlenkov]

I meant if the application already exists and ui5.yaml let's say already has this section:

server:
  customMiddleware:    
    - name: fiori-tools-proxy
      afterMiddleware: compression
      configuration: 
        ui5:
         path:
           - /resources
           - /test-resources
        url: https://sapui5.hana.ondemand.com
        version: 1.78.0

and if I want to develop another middleware which is reusing fiori-tools-proxy configuration - i need to copy this configuration in ui5.yaml file. If I want to develop easy-to-use middleware I would like to avoid this situation when consumer needs to modify also descriptor instead of just adding couple new lines.

Just about this =). But yaml merge also works quite good. I found this way already after creating a ticket