resources: Add `key` to reources.GetRemote options map

If set, `key` will be used as the only cache key element for the resource.

The default behaviour is to calculate the key based on the URL and all the options.

This means that you can now do:

```
{{ $cacheKey := print $url (now.Format "2006-01-02") }}
{{ $resource := resource.GetRemote $url (dict "key" $cacheKey) }}
```

Fixes #9755

2 files changed, 37 insertions, 0 deletions

diff --git a/common/maps/maps.go b/common/maps/maps.go
index 5552da55d..2d8a122ca 100644
--- a/common/maps/maps.go
+++ b/common/maps/maps.go
@@ -109,6 +109,20 @@ func ToSliceStringMap(in any) ([]map[string]any, error) {
 	}
 }
 
+// LookupEqualFold finds key in m with case insensitive equality checks.
+func LookupEqualFold[T any | string](m map[string]T, key string) (T, bool) {
+	if v, found := m[key]; found {
+		return v, true
+	}
+	for k, v := range m {
+		if strings.EqualFold(k, key) {
+			return v, true
+		}
+	}
+	var s T
+	return s, false
+}
+
 type keyRename struct {
 	pattern glob.Glob
 	newKey  string
diff --git a/common/maps/maps_test.go b/common/maps/maps_test.go
index 53120dce7..0b84d2dd7 100644
--- a/common/maps/maps_test.go
+++ b/common/maps/maps_test.go
@@ -171,3 +171,26 @@ func TestRenameKeys(t *testing.T) {
 		t.Errorf("Expected\n%#v, got\n%#v\n", expected, m)
 	}
 }
+
+func TestLookupEqualFold(t *testing.T) {
+	c := qt.New(t)
+
+	m1 := map[string]any{
+		"a": "av",
+		"B": "bv",
+	}
+
+	v, found := LookupEqualFold(m1, "b")
+	c.Assert(found, qt.IsTrue)
+	c.Assert(v, qt.Equals, "bv")
+
+	m2 := map[string]string{
+		"a": "av",
+		"B": "bv",
+	}
+
+	v, found = LookupEqualFold(m2, "b")
+	c.Assert(found, qt.IsTrue)
+	c.Assert(v, qt.Equals, "bv")
+
+}