Add nightly link checker.

.github/workflows/link-check.json

@@ -0,0 +1,70 @@
+{
+  "ignorePatterns": [
+    {
+      "pattern": "^http(s)?://localhost"
+    },
+    {
+      "pattern": "^http(s)?://127.0.0.1"
+    },
+    {
+      "comment": "This is a private repos",
+      "pattern": "^http(s)?://gitlab.com/ConsenSys/"
+    },
+    {
+      "comment": "This is a private repos",
+      "pattern": "^http(s)?://github.com/ConsenSys/orchestrate"
+    },
+    {
+      "comment": "This is a private repo",
+      "pattern": "^http(s)?://github.com/INFURA/docs(?:/(issues|pulls))?"
+    },
+    {
+      "comment": "Consensys.net now has DDoS attack protection",
+      "pattern": "^http(s)?://consensys.net"
+    },
+    {
+      "comment": "Exclude addresses with extra data variable placeholders (not yet replaced when checking for links)",
+      "pattern": "{{[a-zA-Z_\\-\\.\\[\\]\\']+}}"
+    },
+    {
+       "comment": "Exclude Infura endpoints that require an API key",
+       "pattern": "^https?:\\/\\/[a-zA-Z0-9.-]*\\.infura\\.io\\/v3\\/.*$"
+    },
+    {
+      "pattern": "^http(s)?://.+.zendesk.com"
+    },
+    {
+      "pattern": "^http(s)?://.+.etherscan.io"
+    },
+    {
+      "pattern": "^http(s)?://help.figma.com"
+    },
+    {
+      "pattern": "^http(s)?://(docs\\.)?metamask\\.io"
+    },
+    {
+      "comment": "Skip urls in the redoc macro with entity",
+      "pattern": "http(s)?://.+\\&\\#39\\;"
+    },
+    {
+      "comment": "Skip urls in the redoc macro with char",
+      "pattern": "http(s)?://.+'"
+    }
+  ],
+  "httpHeaders": [
+    {
+      "urls": [
+        "https://github.com/",
+        "https://guides.github.com/",
+        "https://help.github.com/",
+        "https://docs.github.com/"
+      ],
+      "headers": {
+        "Accept-Encoding": "zstd, br, gzip, deflate"
+      }
+    }
+  ],
+  "timeout": "30s",
+  "aliveStatusCodes": [200, 206, 403],
+  "retryOn429": true
+}

.github/workflows/nightly.yml

@@ -0,0 +1,45 @@
+---
+  name: Nightly check
+
+  on:
+    schedule:
+      - cron: "0 0 * * *"
+    workflow_dispatch: {}
+
+  concurrency:
+    group: nightly-${{ github.ref }}
+    cancel-in-progress: true
+
+  jobs:
+    linkCheck:
+      name: Run link check
+      runs-on: ubuntu-latest
+      permissions:
+        contents: read
+      steps:
+        - uses: actions/checkout@v4
+        - name: LinkCheck
+          id: linkcheck
+          uses: gaurav-nelson/github-action-markdown-link-check@v1
+          with:
+            use-quiet-mode: 'yes'
+            use-verbose-mode: 'yes'
+            folder-path: './docs'
+            check-modified-files-only: 'no'
+            base-branch: main
+            config-file: './.github/workflows/link-check.json'
+
+    slackNotification:
+      needs: linkCheck
+      if: ${{ failure() }}
+      runs-on: ubuntu-latest
+      steps:
+        - name: Slack Notification
+          uses: rtCamp/action-slack-notify@v2
+          env:
+            SLACK_CHANNEL: doc-ci-alerts
+            SLACK_COLOR: danger
+            SLACK_USERNAME: ci
+            SLACK_TITLE: Web3Signer docs nightly build - Failure
+            SLACK_WEBHOOK: ${{ secrets.SLACK_WEBHOOK }}
+            MSG_MINIMAL: true