feat ctx: Let sub-resource-sets inherit vars from parent

Users of kontemplate may expect variables defined on the parent resource to be
inherited by children.

This implements that functionality. Values defined twice are overwritten by the
child's definition.

Fixes #20

4 files changed, 81 insertions, 0 deletions

diff --git a/context/context.go b/context/context.go
index 108bda28a90d..520070d88f67 100644
--- a/context/context.go
+++ b/context/context.go
@@ -9,6 +9,7 @@ import (
 
 	"github.com/ghodss/yaml"
 	"github.com/polydawn/meep"
+	"github.com/tazjin/kontemplate/util"
 )
 
 type ResourceSet struct {
@@ -82,6 +83,7 @@ func flattenResourceSetCollections(rs *[]ResourceSet) *[]ResourceSet {
 			for _, subResourceSet := range r.Include {
 				subResourceSet.Parent = r.Name
 				subResourceSet.Name = path.Join(r.Name, subResourceSet.Name)
+				subResourceSet.Values = *util.Merge(&r.Values, &subResourceSet.Values)
 				flattened = append(flattened, subResourceSet)
 			}
 		}
diff --git a/context/context_test.go b/context/context_test.go
index b34222ed4650..66b857ffe822 100644
--- a/context/context_test.go
+++ b/context/context_test.go
@@ -81,3 +81,62 @@ func TestLoadContextWithResourceSetCollections(t *testing.T) {
 	}
 
 }
+
+func TestSubresourceVariableInheritance(t *testing.T) {
+	ctx, err := LoadContextFromFile("testdata/parent-variables.yaml")
+
+	if err != nil {
+		t.Error(err)
+		t.Fail()
+	}
+
+	expected := Context{
+		Name: "k8s.prod.mydomain.com",
+		ResourceSets: []ResourceSet{
+			{
+				Name: "parent/child",
+				Values: map[string]interface{}{
+					"foo": "bar",
+					"bar": "baz",
+				},
+				Include: nil,
+				Parent: "parent",
+			},
+		},
+		BaseDir: "testdata",
+	}
+
+	if !reflect.DeepEqual(*ctx, expected) {
+		t.Error("Loaded and expected context did not match")
+		t.Fail()
+	}
+}
+
+func TestSubresourceVariableInheritanceOverride(t *testing.T) {
+	ctx, err := LoadContextFromFile("testdata/parent-variable-override.yaml")
+
+	if err != nil {
+		t.Error(err)
+		t.Fail()
+	}
+
+	expected := Context{
+		Name: "k8s.prod.mydomain.com",
+		ResourceSets: []ResourceSet{
+			{
+				Name: "parent/child",
+				Values: map[string]interface{}{
+					"foo": "newvalue",
+				},
+				Include: nil,
+				Parent: "parent",
+			},
+		},
+		BaseDir: "testdata",
+	}
+
+	if !reflect.DeepEqual(*ctx, expected) {
+		t.Error("Loaded and expected context did not match")
+		t.Fail()
+	}
+}
diff --git a/context/testdata/parent-variable-override.yaml b/context/testdata/parent-variable-override.yaml
new file mode 100644
index 000000000000..42676c3028fe
--- /dev/null
+++ b/context/testdata/parent-variable-override.yaml
@@ -0,0 +1,10 @@
+---
+context: k8s.prod.mydomain.com
+include:
+  - name: parent
+    values:
+      foo: bar
+    include:
+      - name: child
+        values:
+          foo: newvalue
diff --git a/context/testdata/parent-variables.yaml b/context/testdata/parent-variables.yaml
new file mode 100644
index 000000000000..8459fd30405b
--- /dev/null
+++ b/context/testdata/parent-variables.yaml
@@ -0,0 +1,10 @@
+---
+context: k8s.prod.mydomain.com
+include:
+  - name: parent
+    values:
+      foo: bar
+    include:
+      - name: child
+        values:
+          bar: baz