feat: find PGP keys from within the linter

- Find PGP keys using the same methods as other scripts;
- Lower threshold to 30 days by default;
- Add environment variable to set threshold;
- Add colors to distinguish expired from expires soon; and
- Add days until key expiration when it is below threshold.

.github/workflows/cron.yaml

@@ -24,4 +24,4 @@ jobs:
         with:
           fetch-depth: 0
       - name: Discover keys that are expired or close to expiration date
-        run: scripts/pgp-lint.sh $(find -type f -name "*.asc")
+        run: scripts/pgp-lint.sh

scripts/pgp-lint.sh

@@ -6,41 +6,96 @@
 
 set -eu
 
+command -v git >/dev/null || { echo "Missing program: git" >&2; exit 1; }
+repo_toplevel="$(git rev-parse --show-toplevel)"
+test -d "${repo_toplevel}" || exit 1
+unset repo_toplevel
 now="$(date +%s)"
 fail="0"
-if test -z "${1-}"; then
-  echo "No file provided" >&2
-  exit 1
+find_tool="$(./scripts/best-program.sh fd fdfind find)"
+
+if test -n "${1-}"; then
+  files=""
+  for f in "${@}"; do
+    test -f "${f}" || continue
+    test -r "${f}" || continue
+    extension="${f##*.}"
+    case "${extension}" in
+      asc|gpg) files="${files} ${f}";;
+      *) continue;;
+    esac
+  done
+else
+  case "${find_tool}" in
+    fd|fdfind)
+      files="$(${find_tool} . -H -t f -e asc -e gpg | sort -d)"
+      ;;
+    find)
+      files="$(find . -type f \( -name '*.asc' -o -name '*.gpg' \) | sort -d)"
+      ;;
+    *) echo "Unsupported find tool" >&2; exit 1;;
+  esac
 fi
-for key in "${@}"; do
+
+if test -z "${files}"; then
+  exit 0
+fi
+
+for key in ${files}; do
   data="$(gpg --no-keyring --no-auto-check-trustdb --no-autostart \
     --with-colons --show-keys "${key}")"
-  nr="$(echo "${data}" | awk '/^(p|s)ub:/' | wc -l | cut -d " " -f1)"
+  nr="$(echo "${data}" | grep -Ec '^(p|s)ub:')"
+  ## Threshold in days.
+  threshold="${PGP_LINT_THRESHOLD:-30}"
+  tty_stderr=0
+  if test -t 2; then
+    tty_stderr=1
+  fi
   echo "${data}" | awk -v fail="0" -v key="${key}" -v nr="${nr}" \
-    -v now="${now}" -F ':' '/^(p|s)ub:/ {
-    nlines++;
+    -v threshold="${threshold}" -v now="${now}" -v color="${tty_stderr}" \
+    -F ':' '
+    BEGIN {
+      MAGENTA = ""
+      YELLOW = ""
+      RED = ""
+      RESET = ""
+      if (color == 1) {
+        MAGENTA = "\033[1;35m"
+        YELLOW = "\033[1;33m"
+        RED = "\033[1;31m"
+        RESET = "\033[0m"
+      }
+    }
 
-    if ($7=="") {
-      if (nlines==nr) { if (fail==1) { exit 1; }; }
+    /^(p|s)ub:/{
+
+      nlines++
+
+      if ($7 == "") {
+        if (nlines == nr ) { if (fail == 1) { exit 1 } }
         next
       }
 
-    if ($7<now) {
-      print key ": expired:", $5 >"/dev/stderr";
-      fail=1
-      if (nlines==nr) { if (fail==1) { exit 1; }; }
+      if ($7 < now) {
+        message = MAGENTA key RESET ":" RED " expired " RESET ": " $5
+        print message >"/dev/stderr"
+        fail = 1
+        if (nlines == nr ) { if (fail == 1) { exit 1 } }
         next
       }
 
-    # 60 days
-    else if (($7-now)<(60*60*24*60)) {
-      print key ": expires soon:", $5 >"/dev/stderr";
-      fail=1
-      if (nlines==nr) { if (fail==1) { exit 1; }; }
+      else if (($7 - now) < (60 * 60 * 24 * threshold )) {
+        remaining_days = int(($7 - now) / (60 * 60 * 24))
+        message_prefix = MAGENTA key RESET ":" YELLOW " expires in "
+        message_suffix = remaining_days " days" RESET ": " $5
+        message = message_prefix message_suffix
+        print message >"/dev/stderr"
+        fail = 1
+        if (nlines == nr ) { if (fail == 1) { exit 1 } }
         next
       }
 
-    if (fail==1) {
+      if (fail == 1) {
         exit 1
       }
     }' || fail="1"