1 files changed, 49 insertions, 0 deletions
diff --git a/hostnix/elmo/acme.nix b/hostnix/elmo/acme.nix
new file mode 100644
index 0000000..fccd5c8
--- /dev/null
+++ b/hostnix/elmo/acme.nix
@@ -0,0 +1,49 @@
+{ config, lib, pkgs, ... }:
+
+{
+  imports = [ ./dyndns.nix ];
+
+  # https://github.com/NixOS/nixpkgs/issues/210807#issuecomment-1383263210
+  options.services.nginx.virtualHosts = lib.mkOption {
+    type = lib.types.attrsOf (lib.types.submodule {
+      config.acmeRoot = lib.mkDefault null;
+    });
+  };
+
+  config = {
+    security.acme.acceptTerms = true;
+    security.acme.defaults.email = "hostmaster@mou.fo";
+
+    # https://go-acme.github.io/lego/dns/exec/
+    security.acme.defaults.dnsProvider = "exec";
+    security.acme.defaults.credentialFiles = {
+      "DDNS_FILE" = "/var/secrets/dyndns/";
+    };
+    security.acme.defaults.environmentFile = pkgs.writeText "lego.env" ''
+      # While it can be helpful to follow CNAMEs to find the challenge domain,
+      # this heuristic may not work with wildcard domains or DNAME.
+      LEGO_DISABLE_CNAME_SUPPORT=1
+      EXEC_PATH=${pkgs.writers.writeBash "lego-exec" ''
+        set -e
+
+        fqdn=${config.networking.fqdn}
+        challenge_fqdn=$2''${fqdn%%.*}.dynamic.''${fqdn#*.}
+
+        unset update_rr
+        if [[ $1 = present ]]; then
+          update_rr="update add $challenge_fqdn. 300 TXT $3"
+        fi
+
+        ${pkgs.dnsutils}/bin/nsupdate -v -k ''${DDNS_FILE}_$(< ''${DDNS_FILE}_basename).private <<.
+        update delete $challenge_fqdn. TXT
+        $update_rr
+        send
+        .
+
+        if [[ $1 = present ]]; then
+          sleep 5
+        fi
+      ''}
+    '';
+  };
+}