From 4d6c88ce97583e1a2bca3a2fbdeb8cee0c0e3f6b Mon Sep 17 00:00:00 2001
From: Max <max@privatevoid.net>
Date: Mon, 6 Mar 2023 16:42:14 +0100
Subject: [PATCH] modules/consul-service-registry: allow binding multiple
 services to one systemd unit

---
 cluster/services/dns/authoritative.nix      |  2 +-
 cluster/services/irc/irc-host.nix           |  2 +-
 cluster/services/patroni/worker.nix         |  2 +-
 cluster/services/websites/host.nix          |  2 +-
 modules/consul-service-registry/default.nix | 30 +++++++++++----------
 5 files changed, 20 insertions(+), 18 deletions(-)

diff --git a/cluster/services/dns/authoritative.nix b/cluster/services/dns/authoritative.nix
index d821a26..70fccc3 100644
--- a/cluster/services/dns/authoritative.nix
+++ b/cluster/services/dns/authoritative.nix
@@ -65,7 +65,7 @@ in {
 
   consul.services.pdns = {
     mode = "external";
-    definition.service = {
+    definition = {
       name = "authoritative-dns-backend";
       address = config.links.localAuthoritativeDNS.ipv4;
       port = config.links.localAuthoritativeDNS.port;
diff --git a/cluster/services/irc/irc-host.nix b/cluster/services/irc/irc-host.nix
index 6c8b411..97edd45 100644
--- a/cluster/services/irc/irc-host.nix
+++ b/cluster/services/irc/irc-host.nix
@@ -108,7 +108,7 @@ in {
   };
 
   consul.services.ngircd = {
-    definition.service = {
+    definition = {
       name = "irc";
       address = linkSecure.ipv4;
       port = linkSecure.port;
diff --git a/cluster/services/patroni/worker.nix b/cluster/services/patroni/worker.nix
index 72b5a9e..f2ec44f 100644
--- a/cluster/services/patroni/worker.nix
+++ b/cluster/services/patroni/worker.nix
@@ -75,7 +75,7 @@ in
 
   consul.services.patroni = {
     mode = "external";
-    definition.service = rec {
+    definition = rec {
       name = "patroni";
       address = getMeshIp vars.hostName;
       port = cluster.config.links.patroni-pg-internal.port;
diff --git a/cluster/services/websites/host.nix b/cluster/services/websites/host.nix
index e925065..c26d1c1 100644
--- a/cluster/services/websites/host.nix
+++ b/cluster/services/websites/host.nix
@@ -23,7 +23,7 @@ in {
 
   consul.services.nginx = {
     mode = "external";
-    definition.service = {
+    definition = {
       name = "static-lb";
       address = lib.toLower "${config.networking.hostName}.${config.networking.domain}";
       port = 443;
diff --git a/modules/consul-service-registry/default.nix b/modules/consul-service-registry/default.nix
index 5165ec2..2088d66 100644
--- a/modules/consul-service-registry/default.nix
+++ b/modules/consul-service-registry/default.nix
@@ -26,32 +26,34 @@ let
     };
   });
 
-  attachToService = name: conf: let
-    serviceJson = pkgs.writeText "consul-service-${name}.json" (builtins.toJSON conf.definition);
+  attachToService = unit: servicesRaw: let
+    services = map (getAttr "definition") servicesRaw;
+    servicesJson = pkgs.writeText "consul-services-${unit}.json" (builtins.toJSON { inherit services; });
+    mode = if any (x: x.mode == "external") servicesRaw then "external" else "direct";
   in {
     name = {
-      direct = conf.unit;
-      external = "register-consul-svc-${conf.unit}";
-    }.${conf.mode};
+      direct = unit;
+      external = "register-consul-svc-${unit}";
+    }.${mode};
     value = {
       direct = {
         serviceConfig = {
-          ExecStartPost = "${consul} services register ${serviceJson}";
-          ExecStopPost = "${consul} services deregister ${serviceJson}";
+          ExecStartPost = "${consul} services register ${servicesJson}";
+          ExecStopPost = "${consul} services deregister ${servicesJson}";
         };
       };
       external = {
-        after = [ "${conf.unit}.service" ];
-        wantedBy = [ "${conf.unit}.service" ];
-        unitConfig.BindsTo = "${conf.unit}.service";
+        after = [ "${unit}.service" ];
+        wantedBy = [ "${unit}.service" ];
+        unitConfig.BindsTo = "${unit}.service";
         serviceConfig = {
           Type = "oneshot";
           RemainAfterExit = true;
-          ExecStart = "${consul} services register ${serviceJson}";
-          ExecStop = "${consul} services deregister ${serviceJson}";
+          ExecStart = "${consul} services register ${servicesJson}";
+          ExecStop = "${consul} services deregister ${servicesJson}";
         };
       };
-    }.${conf.mode};
+    }.${mode};
   };
 in
 
@@ -64,7 +66,7 @@ in
   };
 
   config = lib.mkIf (cfg.services != {}) {
-    systemd.services = mapAttrs' attachToService cfg.services;
+    systemd.services = mapAttrs' attachToService (groupBy (getAttr "unit") (attrValues cfg.services));
     warnings = optional (!config.services.consul.enable) "Consul service registrations found, but Consul agent is not enabled on this machine.";
   };
 }