Add optional support for helm diff (#355)

There are some cases where the existing module has difficulty
determining if an upgrade would result in changes. This can particularly
be a problem when changes are made to a local chart.

This adds optional support for helm diff. If the plugin is present it
will be used. Otherwise, the default implementation will be used and a
warning will be issued. One caveat: helm diff does not currently support
using a repo url, so the default implementation will be used in this
case, as well.

Closes: #248

molecule/default/roles/helm/defaults/main.yml

@@ -16,3 +16,4 @@ chart_test_repo: "https://kubernetes.github.io/ingress-nginx"
 chart_test_git_repo: "http://github.com/helm/charts.git"
 chart_test_values:
   revisionHistoryLimit: 0
+  myValue: "changed"

molecule/default/roles/helm/files/appversionless-chart-v2/Chart.yaml

@@ -0,0 +1,5 @@
+apiVersion: v2
+name: appversionless-chart
+description: A chart used in molecule tests
+type: application
+version: 0.2.0

molecule/default/roles/helm/files/appversionless-chart-v2/templates/configmap.yaml

@@ -0,0 +1,7 @@
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: test-chart-configmap
+data:
+  myValue: {{ default "test" .Values.myValue }}
+  myOtherValue: {{ default "foo" .Values.myOtherValue }}

molecule/default/roles/helm/files/appversionless-chart/templates/configmap.yaml

@@ -0,0 +1,6 @@
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: test-chart-configmap
+data:
+  myValue: {{ default "test" .Values.myValue }}

molecule/default/roles/helm/files/test-chart-v2/Chart.yaml

@@ -0,0 +1,6 @@
+apiVersion: v2
+name: test-chart
+description: A chart used in molecule tests
+type: application
+version: 0.2.0
+appVersion: "default"

molecule/default/roles/helm/files/test-chart-v2/templates/configmap.yaml

@@ -0,0 +1,7 @@
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: test-chart-configmap
+data:
+  myValue: {{ default "test" .Values.myValue }}
+  myOtherValue: {{ default "foo" .Values.myOtherValue }}

molecule/default/roles/helm/files/test-chart/templates/configmap.yaml

@@ -0,0 +1,6 @@
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: test-chart-configmap
+data:
+  myValue: {{ default "test" .Values.myValue }}

molecule/default/roles/helm/tasks/run_test.yml

@@ -30,6 +30,9 @@
 - name: Test helm plugin
   include_tasks: tests_helm_plugin.yml
 
+- name: Test helm diff
+  include_tasks: tests_helm_diff.yml
+
 - name: Clean helm install
   file:
     path: "{{ item }}"

molecule/default/roles/helm/tasks/tests_chart/from_local_path.yml

@@ -26,8 +26,9 @@
 - name: Test appVersion idempotence
   vars:
     chart_test: "test-chart"
+    chart_test_upgrade: "test-chart-v2"
     chart_test_version: "0.1.0"
-    chart_test_version_upgrade: "0.1.0"
+    chart_test_version_upgrade: "0.2.0"
     chart_test_app_version: "v1"
     chart_test_upgrade_app_version: "v2"
   block:
@@ -36,6 +37,11 @@
         src: "{{ chart_test }}"
         dest: "/tmp/helm_test_appversion/test-chart/"
 
+    - name: Copy test chart v2
+      copy:
+        src: "{{ chart_test_upgrade }}"
+        dest: "/tmp/helm_test_appversion/test-chart/"
+
     # create package with appVersion v1
     - name: "Package chart into archive with appVersion {{ chart_test_app_version }}"
       command: "{{ helm_binary }} package --app-version {{ chart_test_app_version }} /tmp/helm_test_appversion/test-chart/{{ chart_test }}"
@@ -47,41 +53,47 @@
 
     # create package with appVersion v2
     - name: "Package chart into archive with appVersion {{ chart_test_upgrade_app_version }}"
-      command: "{{ helm_binary }} package --app-version {{ chart_test_upgrade_app_version }} /tmp/helm_test_appversion/test-chart/{{ chart_test }}"
+      command: "{{ helm_binary }} package --app-version {{ chart_test_upgrade_app_version }} /tmp/helm_test_appversion/test-chart/{{ chart_test_upgrade }}"
     - name: "Move appVersion {{ chart_test_upgrade_app_version }} chart archive"
       copy:
         remote_src: true
-        src: "test-chart-{{ chart_test_version }}.tgz"
-        dest: "/tmp/helm_test_appversion/test-chart/{{ chart_test }}-{{ chart_test_upgrade_app_version }}-{{ chart_test_version }}.tgz"
+        src: "test-chart-{{ chart_test_version_upgrade }}.tgz"
+        dest: "/tmp/helm_test_appversion/test-chart/{{ chart_test }}-{{ chart_test_upgrade_app_version }}-{{ chart_test_version_upgrade }}.tgz"
 
     - name: Install Chart from local path
       include_tasks: "../tests_chart.yml"
       vars:
         source: local_path
         chart_source: "/tmp/helm_test_appversion/test-chart/{{ chart_test }}-{{ chart_test_app_version }}-{{ chart_test_version }}.tgz"
-        chart_source_upgrade: "/tmp/helm_test_appversion/test-chart/{{ chart_test }}-{{ chart_test_upgrade_app_version }}-{{ chart_test_version }}.tgz"
+        chart_source_upgrade: "/tmp/helm_test_appversion/test-chart/{{ chart_test }}-{{ chart_test_upgrade_app_version }}-{{ chart_test_version_upgrade }}.tgz"
 
 - name: Test appVersion handling when null
   vars:
     chart_test: "appversionless-chart"
+    chart_test_upgrade: "appversionless-chart-v2"
     chart_test_version: "0.1.0"
-    chart_test_version_upgrade: "0.1.0"
+    chart_test_version_upgrade: "0.2.0"
   block:
     - name: Copy test chart
       copy:
         src: "{{ chart_test }}"
         dest: "/tmp/helm_test_appversion/test-null/"
 
+    - name: Copy test chart v2
+      copy:
+        src: "{{ chart_test_upgrade }}"
+        dest: "/tmp/helm_test_appversion/test-null/"
+
     # create package with appVersion v1
     - name: "Package chart into archive with appVersion v1"
-      command: "{{ helm_binary }} package --app-version v1 /tmp/helm_test_appversion/test-null/{{ chart_test }}"
+      command: "{{ helm_binary }} package --app-version v1 /tmp/helm_test_appversion/test-null/{{ chart_test_upgrade }}"
 
     - name: Install Chart from local path
       include_tasks: "../tests_chart.yml"
       vars:
         source: local_path
         chart_source: "/tmp/helm_test_appversion/test-null/{{ chart_test }}/"
-        chart_source_upgrade: "{{ chart_test }}-{{ chart_test_version }}.tgz"
+        chart_source_upgrade: "{{ chart_test }}-{{ chart_test_version_upgrade }}.tgz"
 
 - name: Remove clone repos
   file:

molecule/default/roles/helm/tasks/tests_helm_diff.yml

@@ -0,0 +1,153 @@
+---
+- name: Test helm diff functionality
+  vars:
+    test_chart_ref: "/tmp/test-chart"
+
+  block:
+    - name: Install helm diff
+      helm_plugin:
+        namespace: "{{ helm_namespace }}"
+        state: present
+        plugin_path: https://github.com/databus23/helm-diff
+
+    - name: Copy test chart
+      copy:
+        src: "test-chart/"
+        dest: "{{ test_chart_ref }}"
+
+    - name: Install local chart
+      helm:
+        binary_path: "{{ helm_binary }}"
+        name: test-chart
+        namespace: "{{ helm_namespace }}"
+        chart_ref: "{{ test_chart_ref }}"
+        create_namespace: yes
+      register: install
+
+    - assert:
+        that:
+          - install is changed
+
+    - name: Modify local chart
+      blockinfile:
+        create: yes
+        path: "{{ test_chart_ref }}/templates/anothermap.yaml"
+        block: !unsafe |
+          apiVersion: v1
+          kind: ConfigMap
+          metadata:
+            name: test-chart-another-configmap
+          data:
+            foo: {{ .Values.foo | default "bar" }}
+
+    - name: Upgrade local chart with modifications
+      helm:
+        binary_path: "{{ helm_binary }}"
+        name: test-chart
+        namespace: "{{ helm_namespace }}"
+        chart_ref: "{{ test_chart_ref }}"
+      register: install
+
+    - assert:
+        that:
+          - install is changed
+
+    - name: Upgrade modified local chart idempotency check
+      helm:
+        binary_path: "{{ helm_binary }}"
+        name: test-chart
+        namespace: "{{ helm_namespace }}"
+        chart_ref: "{{ test_chart_ref }}"
+      register: install
+
+    - assert:
+        that:
+          - install is not changed
+
+    - name: Modify values
+      blockinfile:
+        create: yes
+        path: "{{ test_chart_ref }}/values.yml"
+        block: |
+          ---
+          foo: baz
+
+    - name: Upgrade with values file
+      helm:
+        binary_path: "{{ helm_binary }}"
+        name: test-chart
+        namespace: "{{ helm_namespace }}"
+        chart_ref: "{{ test_chart_ref }}"
+        values_files:
+          - "{{ test_chart_ref }}/values.yml"
+      register: install
+
+    - assert:
+        that:
+          - install is changed
+
+    - name: Upgrade with values file idempotency check
+      helm:
+        binary_path: "{{ helm_binary }}"
+        name: test-chart
+        namespace: "{{ helm_namespace }}"
+        chart_ref: "{{ test_chart_ref }}"
+        values_files:
+          - "{{ test_chart_ref }}/values.yml"
+      register: install
+
+    - assert:
+        that:
+          - install is not changed
+
+    - name: Upgrade with values
+      helm:
+        binary_path: "{{ helm_binary }}"
+        name: test-chart
+        namespace: "{{ helm_namespace }}"
+        chart_ref: "{{ test_chart_ref }}"
+        values:
+          foo: gaz
+      register: install
+
+    - assert:
+        that:
+          - install is changed
+
+    - name: Upgrade with values idempotency check
+      helm:
+        binary_path: "{{ helm_binary }}"
+        name: test-chart
+        namespace: "{{ helm_namespace }}"
+        chart_ref: "{{ test_chart_ref }}"
+        values:
+          foo: gaz
+      register: install
+
+    - assert:
+        that:
+          - install is not changed
+
+  always:
+    - name: Remove chart directory
+      file:
+        path: "{{ test_chart_ref }}"
+        state: absent
+      ignore_errors: yes
+
+    - name: Uninstall helm diff
+      helm_plugin:
+        namespace: "{{ helm_namespace }}"
+        state: absent
+        plugin_name: diff
+      ignore_errors: yes
+
+    - name: Remove helm namespace
+      k8s:
+        api_version: v1
+        kind: Namespace
+        name: "{{ helm_namespace }}"
+        state: absent
+        wait: yes
+        wait_timeout: 180
+      ignore_errors: yes