feat: ✨ input validation using schema

.github/PULL_REQUEST_TEMPLATE.md

@@ -11,6 +11,7 @@
 ### More
 
 - [ ] Yes, I updated the tests accordingly
+- [ ] Yes, I updated the schema accordingly
 - [ ] Yes, I ran `make test` and all the tests passed
 
 <!--

.github/workflows/test.yml

@@ -22,6 +22,14 @@ jobs:
         run: |
           git config user.name "$GITHUB_ACTOR"
           git config user.email "[email protected]"
+
+      - name: Check if values schema is up-to-date
+        uses: losisin/helm-values-schema-json-action@v1
+        with:
+          input: traefik/values.yaml
+          output: traefik/values.schema.json
+          fail-on-diff: true
+
       - name: Lint
         run: make lint
 

.schema.yaml

@@ -0,0 +1,13 @@
+# Required
+input:
+  - traefik/values.yaml
+
+draft: 2020
+indent: 4
+output: traefik/values.schema.json
+
+schemaRoot:
+  id: https://traefik.io/traefik-helm-chart.schema.json
+  title: Traefik Proxy Helm Chart
+  description: The Cloud Native Application Proxy
+  additionalProperties: true

Makefile

@@ -20,6 +20,12 @@ docs:
 test-install:
 	docker run ${DOCKER_ARGS} --network=host --env GIT_SAFE_DIR="true" --entrypoint /bin/sh --rm -v $(CURDIR):/charts -v $(HOME)/.kube:/root/.kube -w /charts $(IMAGE_CHART_TESTING) /charts/hack/ct.sh install
 
+
+# Requires to install schema generation plugin beforehand
+# $ helm plugin install https://github.com/losisin/helm-values-schema-json.git
+schema:
+	helm schema
+
 changelog:
 	@echo "== Updating Changelogs..."
 	@docker run -it --rm -v $(CURDIR):/data $(IMAGE_HELM_CHANGELOG)

traefik/Guidelines.md

@@ -4,77 +4,19 @@ This document outlines the guidelines for developing, managing and extending the
 
 This Helm Chart is documented using field description from comments with [helm-docs](https://github.com/norwoodj/helm-docs).
 
-Optionality
-All non-critical features (Features not mandatory to starting Traefik) in the helm chart must be optional. All non-critical features should be disabled (commented out) in the values.yaml file. All optional non-critical features should be disabled (commented out) in the values.yaml file, and have a comment # (Optional) in the line above. This allows minimal configuration, and ease of extension.
+It comes with a JSON schema generated from values with [helm schema](https://github.com/losisin/helm-values-schema-json) plugin.
 
 ## Feature Example
 
 ```yaml
-image:
-  # -- Traefik image host registry
-  registry: docker.io
+logs:
+  general:
+    # -- Set [logs format](https://doc.traefik.io/traefik/observability/logs/#format)
+    format:  # @schema enum:["common", "json", null]; type:[string, null]; default: "common"
 ```
 
-This feature is expected and therefore is defined clearly in the values.yaml file.
-
-## Optional Feature Example
-
-```yaml
-# storage:
-#   controlNode:
-#     type: emptyDir
-```
-
-This feature is optional, non-critical, and therefore is commented out by default in the values.yaml file.
-
-To allow this, template blocks that use this need to recursively test for existence of values before using them:
-
-```yaml
-{{- if .Values.storage}}
-  {{- if .Values.storage.controlNode }}
-    //code
-    {{ .Values.storage.controlNode.type }}
-  {{- end }}
-{{- end }}
-```
-
-The non-critical feature defaults should be populated so that they can be enabled by simply uncommenting the section in the values.yaml file.
-
-## Optional Non-Critical Feature Example
-
-```yaml
-# storage:
-#   controlNode:
-#     type: emptyDir
-#     # (Optional)
-#     # volume: 1Gi
-```
-
-The volume option is clearly optional, and non-critical. It is commented out (apart from the storage section comment block), and is also preceded by a comment of # (Optional) in the preceding line. This facilitates configuration, when the storage section is uncommented, the optional features are still disabled by default.
-
-Similar to non-critical features, these options need to be tested for existence before use in the template.
-
-Note
-There can be optional values in critical features. These should just be added as an uncommented non-critical feature:
-
-```yaml
-image:
-  name: traefik
-  tag: 2.0.0
-  # (Optional)
-  # pullPolicy: IfNotPresent
-```
-
-Also, the first value under the primary value key does not require an optional comment:
-
-```yaml
-# ports:
-#   http: 80
-#   # (Optional)
-#   # https: 443
-```
-
-This is because if the main subkey is not defined, the entirety of the feature is optional.
+Documention is on the first comment, starting with `# --`
+Specific instructions for schema, when needed, are done with the inline comment starting with `# @schema`.
 
 ## Whitespace