unifi, nixos/unifi: support LTS (5.6.36) and release (5.7.20)

Ubiquiti has both a LTS and current version of their Unifi controller software.

The latter adds new features, but may drop support for some devices.

This adds the capability to use either for the unifi module but defaults
to the LTS version, which was the previous behavior.

nixos/modules/services/networking/unifi.nix

@@ -4,22 +4,22 @@ let
   cfg = config.services.unifi;
   stateDir = "/var/lib/unifi";
   cmd = ''
-    @${pkgs.jre}/bin/java java \
+    @${cfg.jrePackage}/bin/java java \
         ${optionalString (cfg.initialJavaHeapSize != null) "-Xms${(toString cfg.initialJavaHeapSize)}m"} \
         ${optionalString (cfg.maximumJavaHeapSize != null) "-Xmx${(toString cfg.maximumJavaHeapSize)}m"} \
         -jar ${stateDir}/lib/ace.jar
   '';
   mountPoints = [
     {
-      what = "${pkgs.unifi}/dl";
+      what = "${cfg.unifiPackage}/dl";
       where = "${stateDir}/dl";
     }
     {
-      what = "${pkgs.unifi}/lib";
+      what = "${cfg.unifiPackage}/lib";
       where = "${stateDir}/lib";
     }
     {
-      what = "${pkgs.mongodb}/bin";
+      what = "${cfg.mongodbPackage}/bin";
       where = "${stateDir}/bin";
     }
     {
@@ -41,6 +41,33 @@ in
       '';
     };
 
+    services.unifi.jrePackage = mkOption {
+      type = types.package;
+      default = pkgs.jre8;
+      defaultText = "pkgs.jre8";
+      description = ''
+        The JRE package to use. Check the release notes to ensure it is supported.
+      '';
+    };
+
+    services.unifi.unifiPackage = mkOption {
+      type = types.package;
+      default = pkgs.unifiLTS;
+      defaultText = "pkgs.unifiLTS";
+      description = ''
+        The unifi package to use.
+      '';
+    };
+
+    services.unifi.mongodbPackage = mkOption {
+      type = types.package;
+      default = pkgs.mongodb;
+      defaultText = "pkgs.mongodb";
+      description = ''
+        The mongodb package to use.
+      '';
+    };
+
     services.unifi.dataDir = mkOption {
       type = types.str;
       default = "${stateDir}/data";
@@ -137,7 +164,7 @@ in
         rm -rf "${stateDir}/webapps"
         mkdir -p "${stateDir}/webapps"
         chown unifi "${stateDir}/webapps"
-        ln -s "${pkgs.unifi}/webapps/ROOT" "${stateDir}/webapps/ROOT"
+        ln -s "${cfg.unifiPackage}/webapps/ROOT" "${stateDir}/webapps/ROOT"
       '';
 
       postStop = ''

pkgs/servers/unifi/default.nix

@@ -2,21 +2,37 @@
 , dpkg
 , fetchurl
 , unzip
+, useLTS ? false
 }:
 
-stdenv.mkDerivation rec {
-  name = "unifi-controller-${version}";
-  version = "5.6.36";
 
-  src = fetchurl {
+let
+  versions = {
+    stable = {
+      version = "5.7.20";
+      sha256 = "1ylj4i5mcv6z9n32275ccdf1rqk74zilqsih3r6xzhm30pxrd8dd";
+    };
+    lts = {
+      version = "5.6.36";
+      sha256 = "075q7vm56fdsjwh72y2cb1pirl2pxdkvqnhvd3bf1c2n64mvp6bi";
+    };
+  };
+  selectedVersion =
+    let attr = if useLTS then "lts" else "stable";
+    in versions."${attr}";
+in
+
+stdenv.mkDerivation {
+  name = "unifi-controller-${selectedVersion.version}";
+  src = with selectedVersion; fetchurl {
     url = "https://dl.ubnt.com/unifi/${version}/unifi_sysvinit_all.deb";
-    sha256 = "075q7vm56fdsjwh72y2cb1pirl2pxdkvqnhvd3bf1c2n64mvp6bi";
+    inherit sha256;
   };
 
   buildInputs = [ dpkg ];
 
   unpackPhase = ''
-    dpkg-deb -x ${src} ./
+    dpkg-deb -x $src ./
   '';
 
   doConfigure = false;

pkgs/top-level/all-packages.nix

@@ -12909,6 +12909,7 @@ with pkgs;
   axis2 = callPackage ../servers/http/tomcat/axis2 { };
 
   unifi = callPackage ../servers/unifi { };
+  unifiLTS = callPackage ../servers/unifi { useLTS=true; };
 
   virtuoso6 = callPackage ../servers/sql/virtuoso/6.x.nix { };