Add marckdowncli linting script, config file and makefile target to enable markdown linting

Signed-off-by: Sekiranda <sekirandahamza@gmail.com>

Makefile

@@ -218,3 +218,8 @@ verify-go-versions:
 .PHONY: sync-toolchain-directive
 sync-toolchain-directive:
 	./scripts/sync_go_toolchain_directive.sh
+
+.PHONY: markdown-diff-lint
+markdown-diff-lint:
+	./scripts/markdown_diff_lint.sh
+	

scripts/markdown_diff_lint.sh

@@ -0,0 +1,94 @@
+#!/usr/bin/env bash
+# This script runs markdownlint-cli2 on changed files.
+# Usage: ./markdown_lint.sh
+
+
+# We source ./scripts/test_lib.sh, it sets the log functions and color variables.
+source ./scripts/test_lib.sh
+
+# When we source ./scripts/test_lib.sh, it has the line set -u which treats unset variables as errors.
+# We need to unset the variable to avoid the error.
+set +u -eo pipefail
+
+if ! command markdownlint-cli2 dummy.md &>/dev/null; then
+  log_error "markdownlint-cli2 needs to be installed."
+  log_error "Please refer to https://github.com/DavidAnson/markdownlint-cli2?tab=readme-ov-file#install for installation instructions."
+  exit 1
+fi
+
+
+if [ -z "${PULL_BASE_SHA}" ]; then
+  echo "Empty base reference (\$PULL_BASE_SHA), assuming: main"
+  PULL_BASE_SHA=main
+fi
+
+if [ -z "${PULL_PULL_SHA}" ]; then
+  PULL_PULL_SHA="$(git rev-parse HEAD)"
+  echo "Empty pull reference (\$PULL_PULL_SHA), assuming: ${PULL_PULL_SHA}"
+fi
+
+MD_LINT_URL_PREFIX="https://github.com/DavidAnson/markdownlint/blob/main/doc/"
+
+mapfile -t changed_files < <(git diff "${PULL_BASE_SHA}" --name-only)
+declare -A files_with_failures start_ranges end_ranges
+
+for file in "${changed_files[@]}"; do
+  if ! [[ "$file" =~ .md$ ]]; then
+    continue
+  fi
+
+  # Find start and end ranges from changed files.
+  start_ranges=()
+  end_ranges=()
+  # From https://github.com/paleite/eslint-plugin-diff/blob/46c5bcf296e9928db19333288457bf2805aad3b9/src/git.ts#L8-L27
+  ranges=$(git diff "${PULL_BASE_SHA}" \
+           --diff-algorithm=histogram \
+           --diff-filter=ACM \
+           --find-renames=100% \
+           --no-ext-diff \
+           --relative \
+           --unified=0 -- "${file}" | \
+    gawk 'match($0, /^@@\s-[0-9,]+\s\+([0-9]+)(,([0-9]+))?/, m) { \
+               print m[1] ":" m[1] + ((m[3] == "") ? "0" : m[3]) }')
+  i=0
+  for range in ${ranges}; do
+    start_ranges["${i}"]=$(echo "${range}" | awk -F: '{print $1}')
+    end_ranges["${i}"]=$(echo "${range}" | awk -F: '{print $2}')
+    i=$((1 + i))
+  done
+  if [ -z "${ranges}" ]; then
+    start_ranges[0]=0
+    end_ranges[0]=0
+  fi
+
+  i=0
+  # Run markdownlint-cli2 with the changed file and print only the summary (stdout).
+  markdownlint-cli2 "${file}" --config "${ETCD_ROOT_DIR}/tools/.markdownlint.jsonc" 2>/dev/null || true
+  while IFS= read -r line; do
+    line_number=$(echo "${line}" | awk -F: '{print $2}' | awk '{print $1}')
+    while [ "${i}" -lt "${#end_ranges[@]}" ] && [ "${line_number}" -gt "${end_ranges["${i}"]}" ]; do
+      i=$((1 + i))
+    done
+    rule=$(echo "${line}" | gawk 'match($2, /([^\/]+)/, m) {print tolower(m[1])}')
+    lint_error="${line} (${MD_LINT_URL_PREFIX}${rule}.md)"
+
+    if [ "${i}" -lt "${#start_ranges[@]}" ] && [ "${line_number}" -ge "${start_ranges["${i}"]}" ] && [ "${line_number}" -le "${end_ranges["${i}"]}" ]; then
+      # Inside range with changes, raise an error.
+      log_error "${lint_error}"
+      files_with_failures["${file}"]=1
+    else
+      # Outside of range, raise a warning.
+      log_warning "${lint_error}"
+    fi
+  done < <(markdownlint-cli2 "${file}" --config "${ETCD_ROOT_DIR}/tools/.markdownlint.jsonc" 2>&1 >/dev/null || true)
+done
+
+echo "Finished linting"
+
+for file in "${!files_with_failures[@]}"; do
+  log_error "${file} has linting issues"
+done
+if [ "${#files_with_failures[@]}" -gt "0" ]; then
+  exit 1
+fi
+

tools/.markdownlint.jsonc

@@ -0,0 +1,310 @@
+// Example markdownlint configuration with all properties set to their default value
+{
+
+    // Default state for all rules
+    "default": true,
+  
+    // Path to configuration file to extend
+    "extends": null,
+  
+    // MD001/heading-increment : Heading levels should only increment by one level at a time : https://github.com/DavidAnson/markdownlint/blob/v0.37.4/doc/md001.md
+    "MD001": true,
+  
+    // MD003/heading-style : Heading style : https://github.com/DavidAnson/markdownlint/blob/v0.37.4/doc/md003.md
+    "MD003": {
+      // Heading style
+      "style": "consistent"
+    },
+  
+    // MD004/ul-style : Unordered list style : https://github.com/DavidAnson/markdownlint/blob/v0.37.4/doc/md004.md
+    "MD004": {
+      // List style
+      "style": "consistent"
+    },
+  
+    // MD005/list-indent : Inconsistent indentation for list items at the same level : https://github.com/DavidAnson/markdownlint/blob/v0.37.4/doc/md005.md
+    "MD005": true,
+  
+    // MD007/ul-indent : Unordered list indentation : https://github.com/DavidAnson/markdownlint/blob/v0.37.4/doc/md007.md
+    "MD007": {
+      // Spaces for indent
+      "indent": 2,
+      // Whether to indent the first level of the list
+      "start_indented": false,
+      // Spaces for first level indent (when start_indented is set)
+      "start_indent": 2
+    },
+  
+    // MD009/no-trailing-spaces : Trailing spaces : https://github.com/DavidAnson/markdownlint/blob/v0.37.4/doc/md009.md
+    "MD009": {
+      // Spaces for line break
+      "br_spaces": 2,
+      // Allow spaces for empty lines in list items
+      "list_item_empty_lines": false,
+      // Include unnecessary breaks
+      "strict": false
+    },
+  
+    // MD010/no-hard-tabs : Hard tabs : https://github.com/DavidAnson/markdownlint/blob/v0.37.4/doc/md010.md
+    "MD010": {
+      // Include code blocks
+      "code_blocks": true,
+      // Fenced code languages to ignore
+      "ignore_code_languages": [],
+      // Number of spaces for each hard tab
+      "spaces_per_tab": 1
+    },
+  
+    // MD011/no-reversed-links : Reversed link syntax : https://github.com/DavidAnson/markdownlint/blob/v0.37.4/doc/md011.md
+    "MD011": true,
+  
+    // MD012/no-multiple-blanks : Multiple consecutive blank lines : https://github.com/DavidAnson/markdownlint/blob/v0.37.4/doc/md012.md
+    "MD012": {
+      // Consecutive blank lines
+      "maximum": 1
+    },
+  
+    // MD013/line-length : Line length : https://github.com/DavidAnson/markdownlint/blob/v0.37.4/doc/md013.md
+    "MD013": {
+      // Number of characters
+      "line_length": 80,
+      // Number of characters for headings
+      "heading_line_length": 80,
+      // Number of characters for code blocks
+      "code_block_line_length": 80,
+      // Include code blocks
+      "code_blocks": true,
+      // Include tables
+      "tables": true,
+      // Include headings
+      "headings": true,
+      // Strict length checking
+      "strict": false,
+      // Stern length checking
+      "stern": false
+    },
+  
+    // MD014/commands-show-output : Dollar signs used before commands without showing output : https://github.com/DavidAnson/markdownlint/blob/v0.37.4/doc/md014.md
+    "MD014": true,
+  
+    // MD018/no-missing-space-atx : No space after hash on atx style heading : https://github.com/DavidAnson/markdownlint/blob/v0.37.4/doc/md018.md
+    "MD018": true,
+  
+    // MD019/no-multiple-space-atx : Multiple spaces after hash on atx style heading : https://github.com/DavidAnson/markdownlint/blob/v0.37.4/doc/md019.md
+    "MD019": true,
+  
+    // MD020/no-missing-space-closed-atx : No space inside hashes on closed atx style heading : https://github.com/DavidAnson/markdownlint/blob/v0.37.4/doc/md020.md
+    "MD020": true,
+  
+    // MD021/no-multiple-space-closed-atx : Multiple spaces inside hashes on closed atx style heading : https://github.com/DavidAnson/markdownlint/blob/v0.37.4/doc/md021.md
+    "MD021": true,
+  
+    // MD022/blanks-around-headings : Headings should be surrounded by blank lines : https://github.com/DavidAnson/markdownlint/blob/v0.37.4/doc/md022.md
+    "MD022": {
+      // Blank lines above heading
+      "lines_above": 1,
+      // Blank lines below heading
+      "lines_below": 1
+    },
+  
+    // MD023/heading-start-left : Headings must start at the beginning of the line : https://github.com/DavidAnson/markdownlint/blob/v0.37.4/doc/md023.md
+    "MD023": true,
+  
+    // MD024/no-duplicate-heading : Multiple headings with the same content : https://github.com/DavidAnson/markdownlint/blob/v0.37.4/doc/md024.md
+    "MD024": {
+      // Only check sibling headings
+      "siblings_only": false
+    },
+  
+    // MD025/single-title/single-h1 : Multiple top-level headings in the same document : https://github.com/DavidAnson/markdownlint/blob/v0.37.4/doc/md025.md
+    "MD025": {
+      // Heading level
+      "level": 1,
+      // RegExp for matching title in front matter
+      "front_matter_title": "^\\s*title\\s*[:=]"
+    },
+  
+    // MD026/no-trailing-punctuation : Trailing punctuation in heading : https://github.com/DavidAnson/markdownlint/blob/v0.37.4/doc/md026.md
+    "MD026": {
+      // Punctuation characters
+      "punctuation": ".,;:!。，；：！"
+    },
+  
+    // MD027/no-multiple-space-blockquote : Multiple spaces after blockquote symbol : https://github.com/DavidAnson/markdownlint/blob/v0.37.4/doc/md027.md
+    "MD027": true,
+  
+    // MD028/no-blanks-blockquote : Blank line inside blockquote : https://github.com/DavidAnson/markdownlint/blob/v0.37.4/doc/md028.md
+    "MD028": true,
+  
+    // MD029/ol-prefix : Ordered list item prefix : https://github.com/DavidAnson/markdownlint/blob/v0.37.4/doc/md029.md
+    "MD029": {
+      // List style
+      "style": "one_or_ordered"
+    },
+  
+    // MD030/list-marker-space : Spaces after list markers : https://github.com/DavidAnson/markdownlint/blob/v0.37.4/doc/md030.md
+    "MD030": {
+      // Spaces for single-line unordered list items
+      "ul_single": 1,
+      // Spaces for single-line ordered list items
+      "ol_single": 1,
+      // Spaces for multi-line unordered list items
+      "ul_multi": 1,
+      // Spaces for multi-line ordered list items
+      "ol_multi": 1
+    },
+  
+    // MD031/blanks-around-fences : Fenced code blocks should be surrounded by blank lines : https://github.com/DavidAnson/markdownlint/blob/v0.37.4/doc/md031.md
+    "MD031": {
+      // Include list items
+      "list_items": true
+    },
+  
+    // MD032/blanks-around-lists : Lists should be surrounded by blank lines : https://github.com/DavidAnson/markdownlint/blob/v0.37.4/doc/md032.md
+    "MD032": true,
+  
+    // MD033/no-inline-html : Inline HTML : https://github.com/DavidAnson/markdownlint/blob/v0.37.4/doc/md033.md
+    "MD033": {
+      // Allowed elements
+      "allowed_elements": []
+    },
+  
+    // MD034/no-bare-urls : Bare URL used : https://github.com/DavidAnson/markdownlint/blob/v0.37.4/doc/md034.md
+    "MD034": true,
+  
+    // MD035/hr-style : Horizontal rule style : https://github.com/DavidAnson/markdownlint/blob/v0.37.4/doc/md035.md
+    "MD035": {
+      // Horizontal rule style
+      "style": "consistent"
+    },
+  
+    // MD036/no-emphasis-as-heading : Emphasis used instead of a heading : https://github.com/DavidAnson/markdownlint/blob/v0.37.4/doc/md036.md
+    "MD036": {
+      // Punctuation characters
+      "punctuation": ".,;:!?。，；：！？"
+    },
+  
+    // MD037/no-space-in-emphasis : Spaces inside emphasis markers : https://github.com/DavidAnson/markdownlint/blob/v0.37.4/doc/md037.md
+    "MD037": true,
+  
+    // MD038/no-space-in-code : Spaces inside code span elements : https://github.com/DavidAnson/markdownlint/blob/v0.37.4/doc/md038.md
+    "MD038": true,
+  
+    // MD039/no-space-in-links : Spaces inside link text : https://github.com/DavidAnson/markdownlint/blob/v0.37.4/doc/md039.md
+    "MD039": true,
+  
+    // MD040/fenced-code-language : Fenced code blocks should have a language specified : https://github.com/DavidAnson/markdownlint/blob/v0.37.4/doc/md040.md
+    "MD040": {
+      // List of languages
+      "allowed_languages": [],
+      // Require language only
+      "language_only": false
+    },
+  
+    // MD041/first-line-heading/first-line-h1 : First line in a file should be a top-level heading : https://github.com/DavidAnson/markdownlint/blob/v0.37.4/doc/md041.md
+    "MD041": {
+      // Heading level
+      "level": 1,
+      // RegExp for matching title in front matter
+      "front_matter_title": "^\\s*title\\s*[:=]"
+    },
+  
+    // MD042/no-empty-links : No empty links : https://github.com/DavidAnson/markdownlint/blob/v0.37.4/doc/md042.md
+    "MD042": true,
+  
+    // MD043/required-headings : Required heading structure : https://github.com/DavidAnson/markdownlint/blob/v0.37.4/doc/md043.md
+    "MD043": {
+      // List of headings
+      "headings": [],
+      // Match case of headings
+      "match_case": false
+    },
+  
+    // MD044/proper-names : Proper names should have the correct capitalization : https://github.com/DavidAnson/markdownlint/blob/v0.37.4/doc/md044.md
+    "MD044": {
+      // List of proper names
+      "names": [],
+      // Include code blocks
+      "code_blocks": true,
+      // Include HTML elements
+      "html_elements": true
+    },
+  
+    // MD045/no-alt-text : Images should have alternate text (alt text) : https://github.com/DavidAnson/markdownlint/blob/v0.37.4/doc/md045.md
+    "MD045": true,
+  
+    // MD046/code-block-style : Code block style : https://github.com/DavidAnson/markdownlint/blob/v0.37.4/doc/md046.md
+    "MD046": {
+      // Block style
+      "style": "consistent"
+    },
+  
+    // MD047/single-trailing-newline : Files should end with a single newline character : https://github.com/DavidAnson/markdownlint/blob/v0.37.4/doc/md047.md
+    "MD047": true,
+  
+    // MD048/code-fence-style : Code fence style : https://github.com/DavidAnson/markdownlint/blob/v0.37.4/doc/md048.md
+    "MD048": {
+      // Code fence style
+      "style": "consistent"
+    },
+  
+    // MD049/emphasis-style : Emphasis style : https://github.com/DavidAnson/markdownlint/blob/v0.37.4/doc/md049.md
+    "MD049": {
+      // Emphasis style
+      "style": "consistent"
+    },
+  
+    // MD050/strong-style : Strong style : https://github.com/DavidAnson/markdownlint/blob/v0.37.4/doc/md050.md
+    "MD050": {
+      // Strong style
+      "style": "consistent"
+    },
+  
+    // MD051/link-fragments : Link fragments should be valid : https://github.com/DavidAnson/markdownlint/blob/v0.37.4/doc/md051.md
+    "MD051": {
+      // Ignore case of fragments
+      "ignore_case": false
+    },
+  
+    // MD052/reference-links-images : Reference links and images should use a label that is defined : https://github.com/DavidAnson/markdownlint/blob/v0.37.4/doc/md052.md
+    "MD052": {
+      // Include shortcut syntax
+      "shortcut_syntax": false
+    },
+  
+    // MD053/link-image-reference-definitions : Link and image reference definitions should be needed : https://github.com/DavidAnson/markdownlint/blob/v0.37.4/doc/md053.md
+    "MD053": {
+      // Ignored definitions
+      "ignored_definitions": [
+        "//"
+      ]
+    },
+  
+    // MD054/link-image-style : Link and image style : https://github.com/DavidAnson/markdownlint/blob/v0.37.4/doc/md054.md
+    "MD054": {
+      // Allow autolinks
+      "autolink": true,
+      // Allow inline links and images
+      "inline": true,
+      // Allow full reference links and images
+      "full": true,
+      // Allow collapsed reference links and images
+      "collapsed": true,
+      // Allow shortcut reference links and images
+      "shortcut": true,
+      // Allow URLs as inline links
+      "url_inline": true
+    },
+  
+    // MD055/table-pipe-style : Table pipe style : https://github.com/DavidAnson/markdownlint/blob/v0.37.4/doc/md055.md
+    "MD055": {
+      // Table pipe style
+      "style": "consistent"
+    },
+  
+    // MD056/table-column-count : Table column count : https://github.com/DavidAnson/markdownlint/blob/v0.37.4/doc/md056.md
+    "MD056": true,
+  
+    // MD058/blanks-around-tables : Tables should be surrounded by blank lines : https://github.com/DavidAnson/markdownlint/blob/v0.37.4/doc/md058.md
+    "MD058": true
+  }