Add YAMLLint to CI

.github/workflows/ci.yml

@@ -18,6 +18,7 @@ jobs:
       with:
         filters: |
           md: [ '**.md' ]
+          yml: [ '**.yml, '**.yaml', '.yamllint' ]
           build: ['build/**', '.github/**/*.yml', '!.github/workflows/package-*', '**/*.targets', '**/*.props']
           shared: ['src/Shared/**', 'test/Shared/**']
           contrib-shared-tests: ['test/OpenTelemetry.Contrib.Shared.Tests/**']
@@ -68,6 +69,13 @@ jobs:
       || contains(needs.detect-changes.outputs.changes, 'build')
     uses: ./.github/workflows/markdownlint.yml
 
+  lint-yml:
+    needs: detect-changes
+    if: |
+      contains(needs.detect-changes.outputs.changes, 'yml')
+      || contains(needs.detect-changes.outputs.changes, 'build')
+    uses: ./.github/workflows/yamllint.yml
+
   lint-dotnet-format:
     needs: detect-changes
     if: |

.github/workflows/yamllint.yml

@@ -0,0 +1,18 @@
+name: Lint - YAML
+
+on:
+  workflow_call:
+
+jobs:
+  run-yamllint:
+    runs-on: ubuntu-latest
+
+    steps:
+    - name: check out code
+      uses: actions/checkout@v4
+
+    - name: install yamllint
+      run: pip install yamllint
+
+    - name: run yamllint
+      run: yamllint .

.yamllint

@@ -0,0 +1,22 @@
+# Copyright The OpenTelemetry Authors
+# SPDX-License-Identifier: Apache-2.0
+extends: default
+
+ignore-from-file: [.gitignore]
+
+rules:
+  document-start: disable
+  octal-values: enable
+  truthy:
+    allowed-values: ['true', 'false', 'on']  # 'on' for GH action trigger
+  line-length:
+    max: 200
+  indentation:
+    check-multi-line-strings: false
+    indent-sequences: consistent
+  brackets:
+    max-spaces-inside: 1
+    max-spaces-inside-empty: 0
+  braces:
+    max-spaces-inside: 1
+    max-spaces-inside-empty: 0

CONTRIBUTING.md

@@ -96,6 +96,13 @@ If you made changes to the Markdown documents (`*.md` files), install the latest
 markdownlint .
 ```
 
+If you made changes to any YAML files (`*.yaml` or `*.yml` files), install the latest
+[`yamllint`](https://github.com/adrienverge/yamllint) and run:
+
+```sh
+yamllint .
+```
+
 Check out a new branch, make modifications and push the branch to your fork:
 
 ```sh