add an example of serialized structures used in config map

examples/k8s-config-map-files/README.md

@@ -0,0 +1,3 @@
+This example was created to show how to include YAML structures into k8s ConfigMap as YAML serialized files. We use functions to group configuration that is later serialized via `yaml.encode`.
+
+[slack thread](https://kubernetes.slack.com/archives/CH8KCCKA5/p1562863952459400)

examples/k8s-config-map-files/config.yml

@@ -0,0 +1,14 @@
+#@ load("@ytt:yaml", "yaml")
+#@ load("@ytt:json", "json")
+#@ load("config1.lib.yml", "config1")
+#@ load("config2.lib.yml", "config2")
+
+---
+kind: ConfigMap
+apiVersion: v1
+metadata:
+  name: configs
+data:
+  config1.yml: #@ yaml.encode(config1())
+  config2.yml: #@ yaml.encode(config2())
+  config3.json: #@ json.encode(config2())

examples/k8s-config-map-files/config1.lib.yml

@@ -0,0 +1,7 @@
+#@ def config1():
+---
+config1a: config1a
+config1b: config1b
+---
+config1c: config1c
+#@ end

examples/k8s-config-map-files/config2.lib.yml

@@ -0,0 +1,9 @@
+#@ def config2():
+rules2a: 123
+rules2b: #@ config2sub()
+#@ end
+
+---
+#@ def config2sub():
+[a, b, c]
+#@ end

examples/k8s-config-map-files/expected.txt

@@ -0,0 +1,17 @@
+kind: ConfigMap
+apiVersion: v1
+metadata:
+  name: configs
+data:
+  config1.yml: |
+    config1a: config1a
+    config1b: config1b
+    ---
+    config1c: config1c
+  config2.yml: |
+    rules2a: 123
+    rules2b:
+    - a
+    - b
+    - c
+  config3.json: '{"rules2a":123,"rules2b":["a","b","c"]}'

hack/test-e2e.sh

@@ -34,6 +34,7 @@ done
 diff <(./ytt -f examples/k8s-adjust-rbac-version)     examples/k8s-adjust-rbac-version/expected.txt
 diff <(./ytt -f examples/k8s-docker-secret)           examples/k8s-docker-secret/expected.txt
 diff <(./ytt -f examples/k8s-relative-rolling-update) examples/k8s-relative-rolling-update/expected.txt
+diff <(./ytt -f examples/k8s-config-map-files)        examples/k8s-config-map-files/expected.txt
 diff <(./ytt -f examples/concourse-overlay)           examples/concourse-overlay/expected.txt
 
 echo E2E SUCCESS