Is it possible that getting a value from a fetch context provider returns something other than a string?

Below you can see that it will replace full objects if its a varString. I worry based on placing this before the switch val.(type) we are missing that as a possibility with a fetch context provider.

I see, however no strong opinion here since I'm not super familiar with the combinations that could occur. Do you think that removing continue and being able to get to the switch block after the Fetch() action would be sth that we want?

Now that I took a closer look at this file. This is definitely in the wrong place. At its current location it would try to find a constant string in a fetch context provider, we do not want that.

Looking at it, this needs to be removed from here and moved into the:

func (v *Vars) Lookup(name string) (interface{}, bool) {
	return v.tree.Lookup(name)
}

Leaving this function untouched.

@blakerouse I tried to move (see f023688) the code inside func (v *Vars) Lookup(name string) (interface{}, bool) method of the same file but it does not seem to work (using same configuration so far) and I'm not sure that I can follow the flow here. I see that the method is called at

I think I see the issue. You need to do the following:

Add the following function to Vars:

// lookupNode performs a lookup on the AST, but keeps the result as a `Node`.
//
// This is different from `Lookup` which returns the actual type, not the AST type.
func (v *Vars) lookupNode(name string) (Node, bool) {
	// check if the value can be retrieved from a FetchContextProvider
	for providerName, provider := range v.fetchContextProviders {
		if varPrefixMatched(name, providerName) {
			fetchProvider := provider.(composable.FetchContextProvider)
			fval, found := fetchProvider.Fetch(name)
			if found {
				return &StrVal{value: fval}, true
			} else {
				return &StrVal{value: ""}, false
			}
		}
	}
	// lookup in the AST tree
	return Lookup(v.tree, name)
}

Then change node, ok := Lookup(v.tree, val.Value()) to node, ok := v.lookupNode(val.Value()).

See if that works.

👍🏼 This fixes the issue, thank you!

Being that a context provider is only considered a fetch context provider if it implements the FetchContextProvider interface and if it stops implementing the interface it will just stop working without any warning.

It would be good to add a compile check to ensure that it implements that interface in this file.

var _ FetchContextProvider = (*contextProviderK8sSecrets)(nil)