1 files changed, 60 insertions, 0 deletions
diff --git a/tools/emacs-pkgs/defzone/defzone.el b/tools/emacs-pkgs/defzone/defzone.el
new file mode 100644
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+++ b/tools/emacs-pkgs/defzone/defzone.el
@@ -0,0 +1,60 @@
+;;; defzone.el --- Generate zone files from Elisp  -*- lexical-binding: t; -*-
+
+(require 'dash)
+(require 'dash-functional)
+(require 's)
+
+(defun record-to-record (zone record &optional subdomain)
+  "Evaluate a record definition and turn it into a zone file
+  record in ZONE, optionally prefixed with SUBDOMAIN."
+
+  (cl-labels ((plist->alist (plist)
+                            (when plist
+                              (cons
+                               (cons (car plist) (cadr plist))
+                               (plist->alist (cddr plist))))))
+    (let ((name (if subdomain (s-join "." (list subdomain zone)) zone)))
+      (pcase record
+        ;; SOA RDATA (RFC 1035; 3.3.13)
+        ((and `(SOA . (,ttl . ,keys))
+              (let (map (:mname mname) (:rname rname) (:serial serial)
+                        (:refresh refresh) (:retry retry) (:expire expire)
+                        (:minimum min))
+                (plist->alist keys)))
+         (if-let ((missing (-filter #'null (not (list mname rname serial
+                                                      refresh retry expire min)))))
+             (error "Missing fields in SOA record: %s" missing)
+             (format "%s %s IN SOA %s %s %s %s %s %s %s"
+                     name ttl mname rname serial refresh retry expire min)))
+
+        (`(NS . (,ttl . ,targets))
+         (->> targets
+              (-map (lambda (target) (format "%s %s IN NS %s" name ttl target)))
+              (s-join "\n")))
+
+        (`(MX . (,ttl . ,pairs))
+         (->> pairs
+              (-map (-lambda ((preference . exchange))
+                      (format "%s %s IN MX %s %s" name ttl preference exchange)))
+              (s-join "\n")))
+
+        (`(TXT ,ttl ,text) (format "%s %s IN TXT %s" name ttl (prin1-to-string text)))
+
+        (`(A . (,ttl . ,ips))
+         (->> ips
+              (-map (lambda (ip) (format "%s %s IN A %s" name ttl ip)))
+              (s-join "\n")))
+
+        (`(CNAME ,ttl ,target) (format "%s %s IN CNAME %s" name ttl target))
+
+        ((and `(,sub . ,records)
+              (guard (stringp sub)))
+         (s-join "\n" (-map (lambda (r) (record-to-record zone r sub)) records)))
+
+        (_ (error "Invalid record definition: %s" record))))))
+
+(defmacro defzone (fqdn &rest records)
+  "Generate zone file for the zone at FQDN from a simple DSL."
+  (declare (indent defun))
+
+  `(s-join "\n" (-map (lambda (r) (record-to-record ,fqdn r)) (quote ,records))))