Lint markdown files for broken links.

.github/workflows/ci-docs.yml

@@ -0,0 +1,20 @@
+name: CI Documentation Checks
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+
+
+jobs:
+  lint-markdown:
+    name: Lint markdown
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      # This is the GitHub Actions-friendly port of the linter used in the Makefile.
+      - uses: gaurav-nelson/[email protected]
+        with:
+          use-quiet-mode: 'yes'  # errors only.
+          config-file: '.github/workflows/markdownlint-config.json'

.github/workflows/markdownlint-config.json

@@ -0,0 +1,8 @@
+{
+  "replacementPatterns": [
+    {
+      "pattern": "^/",
+      "replacement": "{{BASEURL}}/"
+    }
+  ]
+}

Makefile

@@ -39,6 +39,7 @@ __check_defined = \
 	infra-configure-network \
 	infra-format \
 	infra-lint \
+	infra-lint-markdown \
 	infra-lint-scripts \
 	infra-lint-terraform \
 	infra-lint-workflows \
@@ -136,7 +137,10 @@ infra-check-compliance-checkov: ## Run checkov compliance checks
 infra-check-compliance-tfsec: ## Run tfsec compliance checks
 	tfsec infra
 
-infra-lint: infra-lint-scripts infra-lint-terraform infra-lint-workflows ## Lint infra code
+infra-lint: infra-lint-markdown infra-lint-scripts infra-lint-terraform infra-lint-workflows ## Lint infra code
+
+infra-lint-markdown: ## Lint Markdown docs for broken links
+	BASEURL=`pwd`; markdown-link-check *.md **/*.md --config .github/workflows/markdownlint-config.json
 
 infra-lint-scripts: ## Lint shell scripts
 	shellcheck bin/**

docs/infra/set-up-infrastructure-tools.md

@@ -44,11 +44,17 @@ brew install gh
 
 ### Install linters
 
-[Shellcheck](https://github.com/koalaman/shellcheck) and [actionlint](https://github.com/rhysd/actionlint) are optional utilites for running infrastructure linters locally.
+We have several optional utilities for running infrastructure linters locally. These are run as part of the CI pipeline, therefore, it is often simpler to test them locally first.
+
+* [Shellcheck](https://github.com/koalaman/shellcheck)
+* [actionlint](https://github.com/rhysd/actionlint)
+* [markdown-link-check](https://github.com/tcort/markdown-link-check)
 
 ```bash
+
 brew install shellcheck
 brew install actionlint
+npm install -g markdown-link-check
 ```
 
 ## AWS Authentication