Improve syncPolicy options for applications

modules/applications/default.nix

@@ -65,6 +65,11 @@
     lib.mkIf (lib.length filtered > 0) {
       "argocd.argoproj.io/compare-options" = lib.mkDefault (lib.concatStringsSep "," filtered);
     };
+
+  convertSyncOptionsList = opts: let
+    filtered = lib.filter (val: val != null) (lib.mapAttrsToList (_: val: val) opts);
+  in
+    filtered;
 in {
   imports = [
     ./helm.nix
@@ -130,25 +135,112 @@ in {
       };
     };
     syncPolicy = {
-      automated = {
+      autoSync = {
+        enabled = mkOption {
+          type = types.bool;
+          default = nixidyDefaults.syncPolicy.autoSync.enabled;
+          defaultText = literalExpression "config.nixidy.defaults.syncPolicy.autoSync.enabled";
+          description = ''
+            Specifies if application should automatically sync.
+          '';
+        };
         prune = mkOption {
           type = types.bool;
-          default = nixidyDefaults.syncPolicy.automated.prune;
-          defaultText = literalExpression "config.nixidy.defaults.syncPolicy.automated.prune";
+          default = nixidyDefaults.syncPolicy.autoSync.prune;
+          defaultText = literalExpression "config.nixidy.defaults.syncPolicy.autoSync.prune";
           description = ''
             Specifies if resources should be pruned during auto-syncing.
           '';
         };
         selfHeal = mkOption {
           type = types.bool;
-          default = nixidyDefaults.syncPolicy.automated.selfHeal;
-          defaultText = literalExpression "config.nixidy.defaults.syncPolicy.automated.selfHeal";
+          default = nixidyDefaults.syncPolicy.autoSync.selfHeal;
+          defaultText = literalExpression "config.nixidy.defaults.syncPolicy.autoSync.selfHeal";
           description = ''
             Specifies if partial app sync should be executed when resources are changed only in
             target Kubernetes cluster and no git change detected.
           '';
         };
       };
+      syncOptions = {
+        applyOutOfSyncOnly = mkOption {
+          type = types.bool;
+          default = false;
+          apply = val:
+            if val
+            then "ApplyOutOfSyncOnly=true"
+            else null;
+          description = ''
+            Currently when syncing using auto sync Argo CD applies every object in the application.
+            For applications containing thousands of objects this takes quite a long time and puts undue pressure on the api server.
+            Turning on selective sync option which will sync only out-of-sync resources.
+          '';
+        };
+        pruneLast = mkOption {
+          type = types.bool;
+          default = false;
+          apply = val:
+            if val
+            then "PruneLast=true"
+            else null;
+          description = ''
+            This feature is to allow the ability for resource pruning to happen as a final, implicit wave of a sync operation,
+            after the other resources have been deployed and become healthy, and after all other waves completed successfully.
+          '';
+        };
+        replace = mkOption {
+          type = types.bool;
+          default = false;
+          apply = val:
+            if val
+            then "Replace=true"
+            else null;
+          description = ''
+            By default, Argo CD executes `kubectl apply` operation to apply the configuration stored in Git.
+            In some cases `kubectl apply` is not suitable. For example, resource spec might be too big and won't fit into
+            `kubectl.kubernetes.io/last-applied-configuration` annotation that is added by kubectl apply.
+
+            If the `replace = true;`` sync option is set the Argo CD will use `kubectl replace` or `kubectl create` command
+            to apply changes.
+          '';
+        };
+        serverSideApply = mkOption {
+          type = types.bool;
+          default = false;
+          apply = val:
+            if val
+            then "ServerSideApply=true"
+            else null;
+          description = ''
+            By default, Argo CD executes `kubectl apply` operation to apply the configuration stored in Git.
+            This is a client side operation that relies on `kubectl.kubernetes.io/last-applied-configuration` annotation to
+            store the previous resource state.
+
+            If `serverSideApply = true;` sync option is set, Argo CD will use `kubectl apply --server-side` command to apply changes.
+
+            More info [here](https://argo-cd.readthedocs.io/en/stable/user-guide/sync-options/#server-side-apply).
+          '';
+        };
+        failOnSharedResource = mkOption {
+          type = types.bool;
+          default = false;
+          apply = val:
+            if val
+            then "FailOnSharedResource=true"
+            else null;
+          description = ''
+            By default, Argo CD will apply all manifests found in the git path configured in the Application regardless if the
+            resources defined in the yamls are already applied by another Application. If the `failOnSharedResource` sync option
+            is set, Argo CD will fail the sync whenever it finds a resource in the current Application that is already applied in
+            the cluster by another Application.
+          '';
+        };
+      };
+      finalSyncOpts = mkOption {
+        type = types.listOf types.str;
+        default = [];
+        internal = true;
+      };
     };
     output = {
       path = mkOption {
@@ -274,5 +366,7 @@ in {
         config.types);
 
     annotations = convertCmpOptionsAnnotation config.compareOptions;
+
+    syncPolicy.finalSyncOpts = convertSyncOptionsList config.syncPolicy.syncOptions;
   };
 }

modules/nixidy.nix

@@ -111,7 +111,15 @@ in {
       };
 
       syncPolicy = {
-        automated = {
+        autoSync = {
+          enabled = mkOption {
+            type = types.bool;
+            default = false;
+            description = ''
+              Specifies if the application should automatically sync.
+              This is the default value for all applications if not explicitly set.
+            '';
+          };
           prune = mkOption {
             type = types.bool;
             default = false;
@@ -187,9 +195,15 @@ in {
                 inherit (app) namespace;
                 server = "https://kubernetes.default.svc";
               };
-              syncPolicy.automated = {
-                inherit (app.syncPolicy.automated) prune selfHeal;
-              };
+              syncPolicy =
+                (lib.optionalAttrs (app.syncPolicy.autoSync.enabled) {
+                  automated = {
+                    inherit (app.syncPolicy.autoSync) prune selfHeal;
+                  };
+                })
+                // (lib.optionalAttrs (lib.length app.syncPolicy.finalSyncOpts > 0) {
+                  syncOptions = app.syncPolicy.finalSyncOpts;
+                });
             };
           }
         )