feat: add pre-commit configuration (#9)

- add pre-commit-config
- add yamllint config
- add ci/validate-* custom scripts
  - verify no secrets added
  - verify clusters with kustomize and kubeconform
  - verify apps with kustomize and kubeconform

Reviewed-on: #9

.pre-commit-config.yaml

@@ -0,0 +1,53 @@
+repos:
+  # General file checks
+  - repo: https://github.com/pre-commit/pre-commit-hooks
+    rev: v4.5.0
+    hooks:
+      - id: check-executables-have-shebangs
+      - id: check-json
+      - id: check-added-large-files
+        args: ['--maxkb=500']
+      - id: check-merge-conflict
+      - id: check-shebang-scripts-are-executable
+      - id: check-symlinks
+      - id: check-toml
+      - id: check-yaml
+        args: [--allow-multiple-documents]
+      - id: detect-aws-credentials
+        args: [--allow-missing-credentials]
+      - id: detect-private-key
+      - id: end-of-file-fixer
+      - id: forbid-new-submodules
+      - id: no-commit-to-branch
+      - id: pretty-format-json
+      - id: trailing-whitespace
+
+  # YAML linting
+  - repo: https://github.com/adrienverge/yamllint.git
+    rev: v1.37.1
+    hooks:
+      - id: yamllint
+        args:
+          [
+            "-d {extends: relaxed, rules: {line-length: disable}, ignore: chart}",
+            "-s",
+          ]
+
+  # Kubernetes manifest validation
+  - repo: local
+    hooks:
+      - id: kubeconform_validate_apps
+        name: kubeconform validate apps
+        entry: ci/validate-apps.sh
+        language: system
+        pass_filenames: false
+      - id: kubeconform_validate_clusters
+        name: kubeconform validate clusters
+        entry: ci/validate-clusters.sh
+        language: system
+        pass_filenames: false
+      - id: no_plain_secrets
+        name: prevent plain kubernetes secrets
+        entry: ci/validate-no-secrets.sh
+        language: system
+        pass_filenames: false

.yamllint.yaml

@@ -0,0 +1,29 @@
+# .yamllint.yaml
+extends: default
+
+rules:
+  # Allow long lines for base64 encoded values and URLs
+  line-length:
+    max: 200
+    allow-non-breakable-words: true
+    allow-non-breakable-inline-mappings: true
+
+  # Kubernetes manifests use 2-space indentation
+  indentation:
+    spaces: 2
+    indent-sequences: consistent
+
+  # Allow multiple documents (---) in a single file
+  document-start: enable
+
+  # Be lenient with comments
+  comments:
+    require-starting-space: true
+    min-spaces-from-content: 1
+
+  # Allow empty values (common in Kustomize patches)
+  empty-values: enable
+
+  truthy:
+    # Allow 'on' and 'yes' values (common in Kubernetes)
+    allowed-values: ['true', 'false', 'yes', 'no', 'on', 'off']

ci/validate-apps.sh

@@ -0,0 +1,23 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+KUBE_VERSION="1.33.7"
+
+schema_args=(
+  -schema-location "https://raw.githubusercontent.com/yannh/kubernetes-json-schema/master/{{.NormalizedKubernetesVersion}}-standalone{{.StrictSuffix}}/{{.ResourceKind}}{{.KindSuffix}}.json"
+  -schema-location "https://raw.githubusercontent.com/datreeio/CRDs-catalog/main/{{.Group}}/{{.ResourceKind}}_{{.ResourceAPIVersion}}.json"
+)
+
+while IFS= read -r -d "" k; do
+  dir="$(dirname "$k")"
+  echo "==> kubeconform: $dir" >&2
+
+  kustomize build --enable-helm "$dir" \
+    | kubeconform \
+        -kubernetes-version "$KUBE_VERSION" \
+        -summary \
+        -output pretty \
+        -verbose \
+        -skip CustomResourceDefinition \
+        "${schema_args[@]}"
+done < <(find apps/overlays -name kustomization.yaml -print0)

ci/validate-clusters.sh

@@ -0,0 +1,23 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+KUBE_VERSION="1.33.7"
+
+schema_args=(
+  -schema-location "https://raw.githubusercontent.com/yannh/kubernetes-json-schema/master/{{.NormalizedKubernetesVersion}}-standalone{{.StrictSuffix}}/{{.ResourceKind}}{{.KindSuffix}}.json"
+  -schema-location "https://raw.githubusercontent.com/datreeio/CRDs-catalog/main/{{.Group}}/{{.ResourceKind}}_{{.ResourceAPIVersion}}.json"
+)
+
+while IFS= read -r -d "" k; do
+  dir="$(dirname "$k")"
+  echo "==> kubeconform: $dir" >&2
+
+  kustomize build --enable-helm "$dir" \
+    | kubeconform \
+        -kubernetes-version "$KUBE_VERSION" \
+        -summary \
+        -output pretty \
+        -verbose \
+        -skip CustomResourceDefinition \
+        "${schema_args[@]}"
+done < <(find clusters -name kustomization.yaml -print0)

ci/validate-no-secrets.sh

@@ -0,0 +1,22 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+# Check staged files for plain Kubernetes Secrets
+ERRORS=0
+
+while IFS= read -r -d '' file; do
+  # Skip if file doesn't exist (e.g., deleted files)
+  [[ -f "$file" ]] || continue
+
+  # Check if the file contains a plain Kubernetes Secret
+  if grep -q "^kind: Secret" "$file"; then
+    # Allow secure secret types
+    if ! grep -q -E "^kind: (SealedSecret|ExternalSecret|VaultStaticSecret|VaultDynamicSecret)" "$file"; then
+      echo "BLOCKED: $file contains a plain Kubernetes Secret" >&2
+      echo "  Use VaultStaticSecret or VaultDynamicSecret instead" >&2
+      ((ERRORS++))
+    fi
+  fi
+done < <(git diff --cached --name-only --diff-filter=ACM -z | grep -zE '\.(yaml|yml)$')
+
+exit $ERRORS