WIP: create tests

Co-authored-by: h7x4 <h7x4@nani.wtf>

.gitignore

@@ -0,0 +1 @@
+result

COPYING

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2020, 2022-2023 Daniel Løvbrøtte Olsen and contributors
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

MIGRATIONS.MD

@@ -0,0 +1,10 @@
+# Migrations
+
+This is a best effort document descibing neccecary changes you might have to do when updating
+
+## 0.5.0 UNRELEASED
+
+The module has been renamed from `synapse` to `default`
+
+
+

README.MD

@@ -9,6 +9,10 @@ With matrix.YOURDOMAIN pointing at the server:
 
     workers.federationSenders = 1;
     workers.federationReceivers = 1;
+    workers.initialSyncers = 1;
+    workers.normalSyncers = 1;
+    workers.eventPersisters = 2;
+    workers.useUserDirectoryWorker = true;
 
     enableNginx = true;
 
@@ -31,4 +35,20 @@ With matrix.YOURDOMAIN pointing at the server:
 }
 ```
 
-is ~enough to get a functional matrix-server running one federation sender and one federation receiver
+is ~enough to get a functional matrix-server running with some workers
+
+## Sliding Sync (Element X)
+
+Just add the following to your config and point `slidingsync.YOURDOMAIN` at the server
+
+```
+services.matrix-synapse-next = {
+  enableSlidingSync = true;
+};
+
+services.matrix-synapse.sliding-sync.environmentFile = "/some/file/containing/SYNCV3_SECRET=<some secret>";
+
+```
+
+If using [well-known delagation](https://matrix-org.github.io/synapse/v1.37/delegate.html) make sure `YOURDOMAIN/.well-known/matrix/client` matches
+what's in `matrix.YOURDOMAIN/.well-known/matrix/client`

flake.lock

@@ -0,0 +1,42 @@
+{
+  "nodes": {
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1690789960,
+        "narHash": "sha256-3K+2HuyGTiJUSZNJxXXvc0qj4xFx1FHC/ItYtEa7/Xs=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "fb942492b7accdee4e6d17f5447091c65897dde4",
+        "type": "github"
+      },
+      "original": {
+        "id": "nixpkgs",
+        "ref": "nixos-unstable",
+        "type": "indirect"
+      }
+    },
+    "nixpkgs-lib": {
+      "locked": {
+        "lastModified": 1673743903,
+        "narHash": "sha256-sloY6KYyVOozJ1CkbgJPpZ99TKIjIvM+04V48C04sMQ=",
+        "owner": "nix-community",
+        "repo": "nixpkgs.lib",
+        "rev": "7555e2dfcbac1533f047021f1744ac8871150f9f",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-community",
+        "repo": "nixpkgs.lib",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "nixpkgs": "nixpkgs",
+        "nixpkgs-lib": "nixpkgs-lib"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

@@ -1,9 +1,28 @@
 {
   description = "NixOS modules for matrix related services";
 
-  outputs = { self }: {
+  inputs = {
+    nixpkgs-lib.url = "github:nix-community/nixpkgs.lib";
+    nixpkgs.url = "nixpkgs/nixos-unstable";
+  };
+
+  outputs = { self, nixpkgs, nixpkgs-lib }: {
     nixosModules = {
-      synapse = import ./synapse-module;
+      default = import ./module.nix;
+    };
+
+    lib = import ./lib.nix { lib = nixpkgs-lib.lib; };
+
+    packages = let
+      system = "x86_64-linux";
+      pkgs = nixpkgs.legacyPackages.${system};
+    in {
+        ${system}.tests = import ./tests {
+        inherit system;
+        inherit nixpkgs;
+        inherit pkgs;
+        nixosModule = self.outputs.nixosModules.synapse;
+      };
     };
   };
 }

lib.nix

@@ -0,0 +1,20 @@
+{ lib }:
+rec {
+  # checks if given listener configuration has type as a resource
+  isListenerType = type: l: lib.any (r: lib.any (n: n == type) r.names) l.resources;
+  # Get the first listener that includes the given resource from worker
+  firstListenerOfType = type: ls: lib.lists.findFirst (isListenerType type)
+    (lib.throw "No listener with resource: ${type} configured")
+    ls;
+  # Get an attrset of the host and port from a listener 
+  connectionInfo = l: {
+    host = lib.head l.bind_addresses;
+    port = l.port;
+  };
+
+  # Get an attrset of the host and port from a worker given a type
+  workerConnectionResource = r: w: let
+    l = firstListenerOfType r w.settings.worker_listeners;
+  in connectionInfo l;
+
+}

module.nix

@@ -0,0 +1,8 @@
+{ ... }:
+
+{
+  imports = [
+    ./synapse-module
+    ./sliding-sync
+  ];
+}

pkgs/matrix-sliding-sync/default.nix

@@ -0,0 +1,37 @@
+{ lib
+, buildGoModule
+, fetchFromGitHub
+}:
+
+buildGoModule rec {
+  pname = "matrix-sliding-sync";
+  version = "0.99.11";
+
+  src = fetchFromGitHub {
+    owner = "matrix-org";
+    repo = "sliding-sync";
+    rev = "refs/tags/v${version}";
+    hash = "sha256-Wd/nnJhKg+BDyOIz42zEScjzQRrpEq6YG9/9Tk24hgg=";
+  };
+
+  vendorHash = "sha256-0QSyYhOht1j1tWNxHQh+NUZA/W1xy7ANu+29H/gusOE=";
+
+  subPackages = [ "cmd/syncv3" ];
+
+  ldflags = [
+    "-s"
+    "-w"
+    "-X main.GitCommit=${src.rev}"
+  ];
+
+  # requires a running matrix-synapse
+  doCheck = false;
+
+  meta = with lib; {
+    description = "A sliding sync implementation of MSC3575 for matrix";
+    homepage = "https://github.com/matrix-org/sliding-sync";
+    license = with licenses; [ asl20 ];
+    maintainers = with maintainers; [ emilylange ];
+    mainProgram = "syncv3";
+  };
+}

sliding-sync/default.nix

@@ -0,0 +1,117 @@
+{ config, lib, pkgs, ... }:
+
+let
+  cfg = config.services.matrix-synapse.sliding-sync;
+in
+{
+  disabledModules = [ "services/matrix/matrix-sliding-sync.nix" ];
+
+  options.services.matrix-synapse.sliding-sync = {
+    enable = lib.mkEnableOption (lib.mdDoc "sliding sync");
+
+    package = lib.mkOption {
+      type = lib.types.package;
+      default = pkgs.callPackage ../pkgs/matrix-sliding-sync { };
+      description = "What package to use for the sliding-sync proxy.";
+    };
+
+    enableNginx = lib.mkEnableOption (lib.mdDoc "autogenerated nginx config");
+    publicBaseUrl = lib.mkOption {
+      type = lib.types.str;
+      description = "The domain where clients connect, only has an effect with enableNginx";
+      example = "slidingsync.matrix.org";
+    };
+
+    settings = lib.mkOption {
+      type = lib.types.submodule {
+        freeformType = with lib.types; attrsOf str;
+        options = {
+          SYNCV3_SERVER = lib.mkOption {
+            type = lib.types.str;
+            description = lib.mdDoc ''
+              The destination homeserver to talk to not including `/_matrix/` e.g `https://matrix.example.org`.
+            '';
+          };
+
+          SYNCV3_DB = lib.mkOption {
+            type = lib.types.str;
+            default = "postgresql:///matrix-sliding-sync?host=/run/postgresql";
+            description = lib.mdDoc ''
+              The postgres connection string.
+              Refer to <https://www.postgresql.org/docs/current/libpq-connect.html#LIBPQ-CONNSTRING>.
+            '';
+          };
+
+          SYNCV3_BINDADDR = lib.mkOption {
+            type = lib.types.str;
+            default = "127.0.0.1:8009";
+            example = "[::]:8008";
+            description = lib.mdDoc "The interface and port to listen on.";
+          };
+
+          SYNCV3_LOG_LEVEL = lib.mkOption {
+            type = lib.types.enum [ "trace" "debug" "info" "warn" "error" "fatal" ];
+            default = "info";
+            description = lib.mdDoc "The level of verbosity for messages logged.";
+          };
+        };
+      };
+      default = { };
+      description = ''
+        Freeform environment variables passed to the sliding sync proxy.
+        Refer to <https://github.com/matrix-org/sliding-sync#setup> for all supported values.
+      '';
+    };
+
+    createDatabase = lib.mkOption {
+      type = lib.types.bool;
+      default = true;
+      description = lib.mdDoc ''
+        Whether to enable and configure `services.postgres` to ensure that the database user `matrix-sliding-sync`
+        and the database `matrix-sliding-sync` exist.
+      '';
+    };
+
+    environmentFile = lib.mkOption {
+      type = lib.types.str;
+      description = lib.mdDoc ''
+        Environment file as defined in {manpage}`systemd.exec(5)`.
+
+        This must contain the {env}`SYNCV3_SECRET` variable which should
+        be generated with {command}`openssl rand -hex 32`.
+      '';
+    };
+  };
+
+  config = lib.mkIf cfg.enable {
+    services.postgresql = lib.optionalAttrs cfg.createDatabase {
+      enable = true;
+      ensureDatabases = [ "matrix-sliding-sync" ];
+      ensureUsers = [ rec {
+        name = "matrix-sliding-sync";
+        ensurePermissions."DATABASE \"${name}\"" = "ALL PRIVILEGES";
+      } ];
+    };
+
+    systemd.services.matrix-sliding-sync = {
+      after = lib.optional cfg.createDatabase "postgresql.service";
+      wantedBy = [ "multi-user.target" ];
+      environment = cfg.settings;
+      serviceConfig = {
+        DynamicUser = true;
+        EnvironmentFile = cfg.environmentFile;
+        ExecStart = lib.getExe cfg.package;
+        StateDirectory = "matrix-sliding-sync";
+        WorkingDirectory = "%S/matrix-sliding-sync";
+      };
+    };
+
+    services.nginx.virtualHosts.${cfg.publicBaseUrl} = lib.mkIf cfg.enableNginx {
+      enableACME = true;
+      forceSSL = true;
+      locations."/" = {
+        proxyPass = lib.replaceStrings [ "0.0.0.0" "::" ] [ "127.0.0.1" "::1" ] "http://${cfg.settings.SYNCV3_BINDADDR}";
+      };
+    };
+  };
+}

synapse-module/default.nix

@@ -1,35 +1,52 @@
-{ lib, pkgs, config, ... }:
+{ pkgs, lib, config, ... }:
-
 let 
+  matrix-lib = (import ../lib.nix { inherit lib; });
+
   cfg = config.services.matrix-synapse-next;
   wcfg = cfg.workers;
 
+  # Used to generate proper defaultTexts.
+  cfgText = "config.services.matrix-synapse-next";
+  wcfgText = "config.services.matrix-synapse-next.workers";
+
   format = pkgs.formats.yaml {};
   matrix-synapse-common-config = format.generate "matrix-synapse-common-config.yaml" cfg.settings;
   pluginsEnv = cfg.package.python.buildEnv.override {
     extraLibs = cfg.plugins;
   };
 
-  genAttrs' = items: f: g: builtins.listToAttrs (builtins.map (i: lib.attrsets.nameValuePair (f i) (g i)) items);
+  inherit (lib)
+    literalExpression
+    mkEnableOption
+    mkIf
+    mkMerge
+    mkOption
+    mkPackageOption
+    types;
 
-  isListenerType = type: listener: lib.lists.any (r: lib.lists.any (n: n == type) r.names) listener.resources;  
+  throw' = str: throw ''
+    matrix-synapse-next error:
+    ${str}
+  '';
 in
 {
-  imports = [ ./nginx.nix ];
+  imports = [
+    ./nginx.nix
+    (import ./workers.nix {
+      inherit matrix-lib throw' format matrix-synapse-common-config pluginsEnv;
+    })
+  ];
 
   options.services.matrix-synapse-next = {
-    enable = lib.mkEnableOption "matrix-synapse";
+    enable = mkEnableOption "matrix-synapse";
 
-    package = lib.mkOption {
+    package = mkPackageOption pkgs "matrix-synapse" {};
-      type = lib.types.package;
-      default = pkgs.matrix-synapse;
-    };
 
-    plugins = lib.mkOption {
+    plugins = mkOption {
-      type = lib.types.listOf lib.types.package;
+      type = types.listOf types.package;
       default = [ ];
-      example = lib.literalExample ''
+      example = literalExpression ''
-        with config.services.matrix-synapse-advanced.package.plugins; [
+        with ${cfgText}.package.plugins; [
           matrix-synapse-ldap3
           matrix-synapse-pam
         ];
@@ -39,8 +56,8 @@ in
       '';
     };
 
-    dataDir = lib.mkOption {
+    dataDir = mkOption {
-      type = lib.types.str;
+      type = types.path;
       default = "/var/lib/matrix-synapse";
       description = ''
         The directory where matrix-synapse stores its stateful data such as
@@ -48,239 +65,33 @@ in
       '';
     };
 
-    enableNginx = lib.mkEnableOption "Enable the synapse module managing nginx";
+    enableNginx = mkEnableOption "The synapse module managing nginx";
 
-    public_baseurl = lib.mkOption {
+    public_baseurl = mkOption {
-      type = lib.types.str;
+      type = types.str;
       default = "matrix.${cfg.settings.server_name}";
-      description = "The domain where clients and such will connect (May be different from server_name if using delegation)";
+      defaultText =
-    };
+        literalExpression ''matrix.''${${cfgText}.settings.server_name}'';
-
-    mainLogConfig = lib.mkOption {
-      type = lib.types.lines;
-      description = "A yaml python logging config file";
-      default = lib.readFile ./matrix-synapse-log_config.yaml;
-    };
-
-    workers = let
-      isReplication = l: lib.lists.any (r: lib.lists.any (n: n == "replication") r.names) l.resources;
-
-      dMRL = lib.lists.findFirst isReplication
-        (throw "No replication listener configured!")
-        cfg.settings.listeners;
-
-      dMRH = lib.findFirst (x: true) (throw "Replication listener had no addresses")
-        dMRL.bind_addresses;
-      dMRP = dMRL.port;
-    in {
-      mainReplicationHost = lib.mkOption {
-        type = lib.types.str;
-        default = if builtins.elem dMRH [ "0.0.0.0" "::" ] then "127.0.0.1" else dMRH;
-        description = "Host of the main synapse instance's replication listener";
-      };
-
-      mainReplicationPort = lib.mkOption {
-        type = lib.types.port;
-        default = dMRP;
-        description = "Port for the main synapse instance's replication listener";
-      };
-
-      defaultListenerAddress = lib.mkOption {
-        type = lib.types.str;
-        default = "127.0.0.1";
-        description = "The default listener address for the worker";
-      };
-
-      workerStartingPort = lib.mkOption {
-        type = lib.types.port;
-        description = "What port should the automatically configured workers start enumerating from";
-        default = 8083;
-      };
-
-      enableMetrics = lib.mkOption {
-        type = lib.types.bool;
-        default = cfg.settings.enable_metrics;
-      };
-
-      metricsStartingPort = lib.mkOption {
-        type = lib.types.port;
-        default = 18083;
-      };
-
-      federationSenders = lib.mkOption {
-        type = lib.types.ints.unsigned;
-        description = "How many automatically configured federation senders to set up";
-        default = 0;
-      };
-
-      federationReceivers = lib.mkOption {
-        type = lib.types.ints.unsigned;
-        description = "How many automatically configured federation recievers to set up";
-        default = 0;
-      };
-
-      initialSyncers = lib.mkOption {
-        type = lib.types.ints.unsigned;
-        description = "How many automatically configured intial syncers to set up";
-        default = 0;
-      };
-
-      normalSyncers = lib.mkOption {
-        type = lib.types.ints.unsigned;
-        description = "How many automatically configured sync workers to set up";
-        default = 0;
-      };
-
-      eventPersisters = lib.mkOption {
-        type = lib.types.ints.unsigned;
-        description = "How many automatically configured event-persisters to set up";
-        default = 0;
-      };
-
-      useUserDirectoryWorker = lib.mkEnableOption "user directory worker";
-
-      instances = lib.mkOption {
-        type = lib.types.attrsOf (lib.types.submodule ({config, ...}: {
-
-          options.isAuto = lib.mkOption {
-            type = lib.types.bool;
-            internal = true;
-            default = false;
-          };
-
-          options.index = lib.mkOption {
-            internal = true;
-            type = lib.types.ints.positive;
-          };
-
-          # The custom string type here is mainly for the name to use for the metrics of custom worker types
-          options.type = lib.mkOption {
-            type = lib.types.either (lib.types.str) (lib.types.enum [ "fed-sender" "fed-receiver" ]);
-          };
-
-          options.settings = let
-            instanceCfg = config;
-            inherit (instanceCfg) type isAuto;
-          in lib.mkOption {
-            type = lib.types.submodule ({config, ...}: {
-              freeformType = format.type;
-            
-              options.worker_app = let
-                mapTypeApp = t: {
-                  "fed-sender"    = "synapse.app.generic_worker";
-                  "fed-receiver"  = "synapse.app.generic_worker";
-                  "initial-sync"  = "synapse.app.generic_worker";
-                  "normal-sync"   = "synapse.app.generic_worker";
-                  "event-persist" = "synapse.app.generic_worker";
-                  "user-dir"      = "synapse.app.generic_worker";
-                }.${t};
-                defaultApp = if (!isAuto)
-                  then "synapse.app.generic_worker"
-                  else mapTypeApp type;
-              in lib.mkOption {
-                type = lib.types.enum [
-                  "synapse.app.generic_worker"
-                  "synapse.app.appservice"
-                  "synapse.app.media_repository"
-                  "synapse.app.user_dir"
-                ];
-                description = "The type of worker application";
-                default = defaultApp;
-              };
-              options.worker_replication_host = lib.mkOption {
-                type = lib.types.str;
-                default = cfg.workers.mainReplicationHost;
-                description = "The replication listeners ip on the main synapse process";
-              };
-              options.worker_replication_http_port = lib.mkOption {
-                type = lib.types.port;
-                default = cfg.workers.mainReplicationPort;
-                description = "The replication listeners port on the main synapse process";
-              };
-              options.worker_listeners = lib.mkOption {
-                type = lib.types.listOf (lib.types.submodule {
-                  options.type = lib.mkOption {
-                    type = lib.types.enum [ "http" "metrics" ];
-                    description = "The type of the listener";
-                    default = "http";
-                  };
-                  options.port = lib.mkOption {
-                    type = lib.types.port;
-                    description = "the TCP port to bind to";
-                  };
-                  options.bind_addresses = lib.mkOption {
-                    type = lib.types.listOf lib.types.str;
-                    description = "A list of local addresses to listen on";
-                    default = [ cfg.workers.defaultListenerAddress ];
-                  };
-                  options.tls = lib.mkOption {
-                    type = lib.types.bool;
-                    description = "set to true to enable TLS for this listener. Will use the TLS key/cert specified in tls_private_key_path / tls_certificate_path.";
-                    default = false;
-                  };
-                  options.x_forwarded = lib.mkOption {
-                    type = lib.types.bool;
       description = ''
-                      Only valid for an 'http' listener. Set to true to use the X-Forwarded-For header as the client IP.
+        The domain where clients and such will connect.
-                      Useful when Synapse is behind a reverse-proxy.
+        This may be different from server_name if using delegation.
       '';
-                    default = true;
-                  };
-                  options.resources = let
-                    typeToResources = t: {
-                      "fed-receiver"  = [ "federation" ];
-                      "fed-sender"    = [ ];
-                      "initial-sync"  = [ "client" ];
-                      "normal-sync"   = [ "client" ];
-                      "event-persist" = [ "replication" ];
-                      "user-dir"      = [ "client" ];
-                    }.${t};
-                  in lib.mkOption {
-                    type = lib.types.listOf (lib.types.submodule {
-                      options.names = lib.mkOption {
-                        type = lib.types.listOf (lib.types.enum [ "client" "consent" "federation" "keys" "media" "metrics" "openid" "replication" "static" "webclient" ]);
-                        description = "A list of resources to host on this port";
-                        default = lib.optionals isAuto (typeToResources type);
-                      };
-                      options.compress = lib.mkOption {
-                        type = lib.types.bool;
-                        description = "enable HTTP compression for this resource";
-                        default = false;
-                      };
-                    });
-                    default = [{ }];
-                  };
-                });
-                description = "Listener configuration for the worker, similar to the main synapse listener";
-                default = [ ];
-              };
-            });
-            default = { };
-          };
-        }));
-        default = { };
-        description = "Worker configuration";
-        example = {
-          "federation_sender1" = {
-            settings = {
-              worker_name = "federation_sender1";
-              worker_app = "synapse.app.generic_worker";
-
-              worker_replication_host = "127.0.0.1";
-              worker_replication_http_port = 9093;
-              worker_listeners = [ ];
-            };
-        };
-      };
-    };
     };
 
-    settings = lib.mkOption {
+    mainLogConfig = mkOption {
-      type = lib.types.submodule {
+      type = with types; coercedTo path lib.readFile lines;
+      default = ./matrix-synapse-log_config.yaml;
+      description = "A yaml python logging config file";
+    };
+
+    enableSlidingSync = mkEnableOption (lib.mdDoc "automatic Sliding Sync setup at `slidingsync.<domain>`");
+
+    settings = mkOption {
+      type = types.submodule {
         freeformType = format.type;
-
+        options = {
-        options.server_name = lib.mkOption {
+          server_name = mkOption {
-          type = lib.types.str;
+            type = types.str;
             description = ''
               The server_name name will appear at the end of usernames and room addresses
               created on this server. For example if the server_name was example.com,
@@ -300,55 +111,80 @@ in
             example = "matrix.org";
           };
 
-        options.use_presence = lib.mkOption {
+          use_presence = mkOption {
-          type = lib.types.bool;
+            type = types.bool;
-          description = "disable presence tracking, if you're having perfomance issues this can have a big impact";
+            description = "Disable presence tracking, if you're having perfomance issues this can have a big impact";
             default = true;
           };
-        options.listeners = lib.mkOption {
+
-          type = lib.types.listOf (lib.types.submodule {
+          listeners = mkOption {
-            options.port = lib.mkOption {
+            type = types.listOf (types.submodule {
-              type = lib.types.port;
+              options = {
-              description = "the TCP port to bind to";
+                port = mkOption {
+                  type = types.port;
+                  description = "The TCP port to bind to";
                   example = 8448;
                 };
-            options.bind_addresses = lib.mkOption {
+
-              type = lib.types.listOf lib.types.str;
+                bind_addresses = mkOption {
+                  type = types.listOf types.str;
                   description = "A list of local addresses to listen on";
                 };
-            options.type = lib.mkOption {
+
-              type = lib.types.enum [ "http" "manhole" "metrics" "replication" ];
+                type = mkOption {
+                  type = types.enum [ "http" "manhole" "metrics" "replication" ];
                   description = "The type of the listener";
                   default = "http";
                 };
-            options.tls = lib.mkOption {
+
-              type = lib.types.bool;
+                tls = mkOption {
-              description = "set to true to enable TLS for this listener. Will use the TLS key/cert specified in tls_private_key_path / tls_certificate_path.";
+                  type = types.bool;
+                  description = ''
+                    Set to true to enable TLS for this listener.
+
+                    Will use the TLS key/cert specified in tls_private_key_path / tls_certificate_path.
+                  '';
                   default = false;
                 };
-            options.x_forwarded = lib.mkOption {
+
-              type = lib.types.bool;
+                x_forwarded = mkOption {
+                  type = types.bool;
                   description = ''
-                Only valid for an 'http' listener. Set to true to use the X-Forwarded-For header as the client IP.
+                    Set to true to use the X-Forwarded-For header as the client IP.
+
+                    Only valid for an 'http' listener.
                     Useful when Synapse is behind a reverse-proxy.
                   '';
                   default = true;
                 };
-            options.resources = lib.mkOption {
+
-              type = lib.types.listOf (lib.types.submodule {
+                resources = mkOption {
-                options.names = lib.mkOption {
+                  type = types.listOf (types.submodule {
-                  type = lib.types.listOf (lib.types.enum [ "client" "consent" "federation" "keys" "media" "metrics" "openid" "replication" "static" "webclient" ]);
+                    options = {
+                      names = mkOption {
+                        type = with types; listOf (enum [
+                          "client"
+                          "consent"
+                          "federation"
+                          "keys"
+                          "media"
+                          "metrics"
+                          "openid"
+                          "replication"
+                          "static"
+                          "webclient"
+                        ]);
                         description = "A list of resources to host on this port";
                       };
-                options.compress = lib.mkOption {
+
-                  type = lib.types.bool;
+                      compress = mkEnableOption "HTTP compression for this resource";
-                  description = "enable HTTP compression for this resource";
-                  default = false;
                     };
                   });
                 };
+              };
             });
             description = "List of ports that Synapse should listen on, their purpose and their configuration";
+            # TODO: add defaultText
             default = [
               {
                 port = 8008;
@@ -358,14 +194,14 @@ in
                   { names = [ "federation" ]; compress = false; }
                 ];
               }
-            (lib.mkIf (wcfg.instances != { }) {
+              (mkIf (wcfg.instances != { }) {
                 port = 9093;
                 bind_addresses = [ "127.0.0.1" ];
                 resources = [
                   {  names = [ "replication" ]; }
                 ];
               })
-            (lib.mkIf cfg.settings.enable_metrics {
+              (mkIf cfg.settings.enable_metrics {
                 port = 9000;
                 bind_addresses = [ "127.0.0.1" ];
                 resources = [
@@ -375,8 +211,8 @@ in
             ];
           };
 
-        options.federation_ip_range_blacklist = lib.mkOption {
+          federation_ip_range_blacklist = mkOption {
-          type = lib.types.listOf lib.types.str;
+            type = types.listOf types.str;
             description = ''
               Prevent federation requests from being sent to the following
               blacklist IP address CIDR ranges. If this option is not specified, or
@@ -394,62 +230,55 @@ in
               "fc00::/7"
             ];
           };
-        options.log_config = lib.mkOption {
+
-          type = lib.types.path;
+          log_config = mkOption {
+            type = types.path;
             description = ''
               A yaml python logging config file as described by
               https://docs.python.org/3.7/library/logging.config.html#configuration-dictionary-schema
             '';
             default = pkgs.writeText "log_config.yaml" cfg.mainLogConfig;
+            defaultText = "A config file generated from ${cfgText}.mainLogConfig";
           };
 
-        options.media_store_path = lib.mkOption {
+          media_store_path = mkOption {
-          type = lib.types.path;
+            type = types.path;
             description = "Directory where uploaded images and attachments are stored";
             default = "${cfg.dataDir}/media_store";
+            defaultText = literalExpression ''''${${cfgText}.dataDir}/media_store'';
           };
-        options.max_upload_size = lib.mkOption {
+
-          type = lib.types.str;
+          max_upload_size = mkOption {
+            type = types.str;
             description = "The largest allowed upload size in bytes";
             default = "50M";
+            example = "800K";
           };
 
-        options.enable_registration = lib.mkOption {
+          enable_registration = mkEnableOption "registration for new users";
-          type = lib.types.bool;
+          enable_metrics = mkEnableOption "collection and rendering of performance metrics";
-          description = "Enable registration for new users";
+          report_stats = mkEnableOption "reporting usage stats";
-          default = false;
-        };
 
-        options.enable_metrics = lib.mkOption {
+          app_service_config_files = mkOption {
-          type = lib.types.bool;
+            type = types.listOf types.path;
-          description = "Enable collection and rendering of performance metrics";
-          default = false;
-        };
-        options.report_stats = lib.mkOption {
-          type = lib.types.bool;
-          description = "TODO: Enable and Disable reporting usage stats";
-          default = false;
-        };
-
-        options.app_service_config_files = lib.mkOption {
-          type = lib.types.listOf lib.types.path;
             description = "A list of application service config files to use";
             default = [];
           };
 
-        options.signing_key_path = lib.mkOption {
+          signing_key_path = mkOption {
-          type = lib.types.path;
+            type = types.path;
             description = "Path to the signing key to sign messages with";
             default = "${cfg.dataDir}/homeserver.signing.key";
+            defaultText = literalExpression ''''${${cfgText}.dataDir}/homeserver.signing.key'';
           };
 
-        options.trusted_key_servers = lib.mkOption {
+          trusted_key_servers = mkOption {
-          type = lib.types.listOf (lib.types.submodule {
+            type = types.listOf (types.submodule {
               freeformType = format.type;
 
-            options.server_name = lib.mkOption {
+              options.server_name = mkOption {
-              type = lib.types.str;
+                type = types.str;
-              description = "the name of the server. required";
+                description = "The name of the server. This is required.";
               };
             });
             description = "The trusted servers to download signing keys from";
@@ -461,36 +290,42 @@ in
             ];
           };
 
-        options.federation_sender_instances = lib.mkOption {
+          federation_sender_instances = mkOption {
-          type = lib.types.listOf lib.types.str;
+            type = types.listOf types.str;
             description = ''
-            This configuration must be shared between all federation sender workers, and if
+              This configuration must be shared between all federation sender workers.
-            changed all federation sender workers must be stopped at the same time and then
+
-            started, to ensure that all instances are running with the same config (otherwise
+              When changed, all federation sender workers must be stopped at the same time and
-            events may be dropped)
+              restarted, to ensure that all instances are running with the same config.
+              Otherwise, events may be dropped.
             '';
             default = [ ];
           };
 
-        options.redis = lib.mkOption {
+          redis = mkOption {
-          type = lib.types.submodule {
+            type = types.submodule {
               freeformType = format.type;
 
-            options.enabled = lib.mkOption {
+              options.enabled = mkOption {
-              type = lib.types.bool;
+                type = types.bool;
-              description = "Enables using redis, required for worker support";
+                description = ''
-              default = (lib.lists.count (x: true)
+                  Whether to enable redis within synapse.
-                (lib.attrsets.attrValues cfg.workers.instances)) > 0;
+
+                  This is required for worker support.
+                '';
+                default = wcfg.instances != { };
+                defaultText = literalExpression "${wcfgText}.instances != { }";
               };
             };
             default = { };
-          description = "configuration of redis for synapse and workers"; 
+            description = "Redis configuration for synapse and workers";
+          };
         };
       };
     };
 
-    extraConfigFiles = lib.mkOption {
+    extraConfigFiles = mkOption {
-      type = lib.types.listOf lib.types.path;
+      type = types.listOf types.path;
       default = [];
       description = ''
         Extra config files to include.
@@ -500,11 +335,9 @@ in
         NixOPS is in use.
       '';
     };
-
   };
 
-  config = lib.mkIf cfg.enable (lib.mkMerge [
+  config = mkIf cfg.enable {
-    ({
     users.users.matrix-synapse = {
       group = "matrix-synapse";
       home = cfg.dataDir;
@@ -512,174 +345,70 @@ in
       shell = "${pkgs.bash}/bin/bash";
       uid = config.ids.uids.matrix-synapse;
     };
+
     users.groups.matrix-synapse = {
       gid = config.ids.gids.matrix-synapse;
     };
-      systemd.targets.matrix-synapse = {
+
-        description = "Synapse parent target";
+    systemd = {
+      targets.matrix-synapse = {
+        description = "Matrix synapse parent target";
         after = [ "network.target" ];
         wantedBy = [ "multi-user.target" ];
       };
-    })
 
-    ({
+      slices.system-matrix-synapse = {
-      systemd.services.matrix-synapse = {
+        description = "Matrix synapse slice";
+        requires= [ "system.slice" ];
+        after= [ "system.slice" ];
+      };
+
+      services.matrix-synapse = {
         description = "Synapse Matrix homeserver";
         partOf = [ "matrix-synapse.target" ];
         wantedBy = [ "matrix-synapse.target" ];
-        preStart = ''
+
-        ${cfg.package}/bin/synapse_homeserver \
+        preStart = let
-          ${ lib.concatMapStringsSep "\n  " (x: "--config-path ${x} \\") ([ matrix-synapse-common-config ] ++ cfg.extraConfigFiles) }
+          flags = lib.cli.toGNUCommandLineShell {} {
-          --keys-directory ${cfg.dataDir} \
+            config-path = [ matrix-synapse-common-config ] ++ cfg.extraConfigFiles;
-          --generate-keys
+            keys-directory = cfg.dataDir;
-      '';
+            generate-keys = true;
-        environment.PYTHONPATH = lib.makeSearchPathOutput "lib" cfg.package.python.sitePackages [ pluginsEnv ];
+          };
+        in "${cfg.package}/bin/synapse_homeserver ${flags}";
+
+        environment.PYTHONPATH =
+          lib.makeSearchPathOutput "lib" cfg.package.python.sitePackages [ pluginsEnv ];
+
         serviceConfig = {
           Type = "notify";
           User = "matrix-synapse";
           Group = "matrix-synapse";
+          Slice = "system-matrix-synapse.slice";
           WorkingDirectory = cfg.dataDir;
-          ExecStart = ''
+          ExecStart = let
-            ${cfg.package}/bin/synapse_homeserver \
+            flags = lib.cli.toGNUCommandLineShell {} {
-              ${ lib.concatMapStringsSep "\n  " (x: "--config-path ${x} \\") ([ matrix-synapse-common-config ] ++ cfg.extraConfigFiles) }
+              config-path = [ matrix-synapse-common-config ] ++ cfg.extraConfigFiles;
-              --keys-directory ${cfg.dataDir}
+              keys-directory = cfg.dataDir;
-          '';
+            };
+          in "${cfg.package}/bin/synapse_homeserver ${flags}";
           ExecReload = "${pkgs.utillinux}/bin/kill -HUP $MAINPID";
           Restart = "on-failure";
         };
       };
-    })
-
-    (lib.mkMerge [
-      ({
-        services.matrix-synapse-next.settings.federation_sender_instances = lib.genList (i: "auto-fed-sender${toString (i + 1)}") cfg.workers.federationSenders;
-        services.matrix-synapse-next.workers.instances = genAttrs' (lib.lists.range 1 cfg.workers.federationSenders)
-          (i: "auto-fed-sender${toString i}")
-          (i: {
-            isAuto = true; type = "fed-sender"; index = i;
-            settings.worker_listeners = lib.mkIf wcfg.enableMetrics [
-              { port = cfg.workers.metricsStartingPort + i - 1;
-                resources = [ { names = [ "metrics" ]; } ];
-              }
-            ];
-          });
-      })
-
-      ({
-        services.matrix-synapse-next.workers.instances = genAttrs' (lib.lists.range 1 cfg.workers.federationReceivers)
-          (i: "auto-fed-receiver${toString i}")
-          (i: {
-            isAuto = true; type = "fed-receiver"; index = i;
-            settings.worker_listeners = [{ port = cfg.workers.workerStartingPort + i - 1; }]
-             ++ lib.optional wcfg.enableMetrics { port = cfg.workers.metricsStartingPort + cfg.workers.federationSenders + i;
-               resources = [ { names = [ "metrics" ]; } ];
     };
-          });
-      })
 
-      
+    services.matrix-synapse-next.settings.extra_well_known_client_content."org.matrix.msc3575.proxy" = mkIf cfg.enableSlidingSync {
-      ({
+      url = "https://${config.services.matrix-synapse.sliding-sync.publicBaseUrl}";
-        services.matrix-synapse-next.workers.instances = genAttrs' (lib.lists.range 1 cfg.workers.initialSyncers)
-          (i: "auto-initial-sync${toString i}")
-          (i: {
-            isAuto = true; type = "initial-sync"; index = i;
-            settings.worker_listeners = [{ port = cfg.workers.workerStartingPort + cfg.workers.federationReceivers + i - 1; }]
-             ++ lib.optional wcfg.enableMetrics { port = cfg.workers.metricsStartingPort + cfg.workers.federationSenders + cfg.workers.federationReceivers + i;
-               resources = [ { names = [ "metrics" ]; } ];
     };
-          });
+    services.matrix-synapse.sliding-sync = mkIf cfg.enableSlidingSync {
-      })
+      enable = true;
+      enableNginx = lib.mkDefault cfg.enableNginx;
+      publicBaseUrl = lib.mkDefault "slidingsync.${cfg.settings.server_name}";
 
-      ({
+      settings = {
-        services.matrix-synapse-next.workers.instances = genAttrs' (lib.lists.range 1 cfg.workers.normalSyncers)
+        SYNCV3_SERVER = lib.mkDefault "https://${cfg.public_baseurl}";
-          (i: "auto-normal-sync${toString i}")
+        SYNCV3_PROM = lib.mkIf cfg.settings.enable_metrics (lib.mkDefault "127.0.0.1:9001");
-          (i: {
-            isAuto = true; type = "normal-sync"; index = i;
-            settings.worker_listeners = [{ port = cfg.workers.workerStartingPort + cfg.workers.federationReceivers + cfg.workers.initialSyncers + i - 1; }]
-             ++ lib.optional wcfg.enableMetrics { port = cfg.workers.metricsStartingPort + cfg.workers.federationSenders + cfg.workers.federationReceivers + cfg.workers.initialSyncers + i;
-               resources = [ { names = [ "metrics" ]; } ];
       };
-          });
-      })
-
-      ({
-        services.matrix-synapse-next.settings.instance_map = genAttrs' (lib.lists.range 1 cfg.workers.eventPersisters)
-          (i: "auto-event-persist${toString i}")
-          (i: let
-            isReplication = l: lib.lists.any (r: lib.lists.any (n: n == "replication") r.names) l.resources;
-            wRL = lib.lists.findFirst isReplication
-              (throw "No replication listener configured!")
-              cfg.workers.instances."auto-event-persist${toString i}".settings.worker_listeners;
-            wRH = lib.findFirst (x: true) (throw "Replication listener had no addresses")
-              wRL.bind_addresses;
-            wRP = wRL.port;
-          in {
-            host = wRH;
-            port = wRP;
-          }
-        );
-        services.matrix-synapse-next.settings.stream_writers.events = lib.mkIf (cfg.workers.eventPersisters > 0) (lib.genList (i: "auto-event-persist${toString (i + 1)}") cfg.workers.eventPersisters); 
-        services.matrix-synapse-next.workers.instances = genAttrs' (lib.lists.range 1 cfg.workers.eventPersisters)
-          (i: "auto-event-persist${toString i}")
-          (i: {
-            isAuto = true; type = "event-persist"; index = i;
-            settings.worker_listeners = [{ port = cfg.workers.workerStartingPort + cfg.workers.federationReceivers + cfg.workers.initialSyncers + cfg.workers.normalSyncers + i - 1;}]
-              ++ lib.optional wcfg.enableMetrics { port = cfg.workers.metricsStartingPort + cfg.workers.federationSenders + cfg.workers.federationReceivers + cfg.workers.initialSyncers + cfg.workers.normalSyncers + i;
-                resources = [ { names = [ "metrics" ]; } ];
-          };
-        });
-      })
-
-      (lib.mkIf cfg.workers.useUserDirectoryWorker {
-        services.matrix-synapse-next.workers.instances."auto-user-dir" = {
-          isAuto = true; type = "user-dir"; index = 1;
-          settings.worker_listeners = [{ port = cfg.workers.workerStartingPort + cfg.workers.federationReceivers + cfg.workers.initialSyncers + cfg.workers.normalSyncers + cfg.workers.eventPersisters + 1 - 1;}]
-            ++ lib.optional wcfg.enableMetrics { port = cfg.workers.metricsStartingPort + cfg.workers.federationSenders + cfg.workers.federationReceivers + cfg.workers.initialSyncers + cfg.workers.normalSyncers + cfg.workers.eventPersisters + 1;
-              resources = [ { names = [ "metrics"]; } ];
-            };
-        };
-        services.matrix-synapse-next.settings.update_user_directory_from_worker = "auto-user-dir";
-      })
-    ])
-
-    ({
-      systemd.services = let
-        workerList = lib.mapAttrsToList (name: value: lib.nameValuePair name value ) cfg.workers.instances;
-        workerName = worker: worker.name;
-        workerSettings = worker: (worker.value.settings // {worker_name = (workerName worker);});
-        workerConfig = worker: format.generate "matrix-synapse-worker-${workerName worker}-config.yaml" (workerSettings worker);
-      in builtins.listToAttrs (map (worker:
-        {
-          name = "matrix-synapse-worker-${workerName worker}";
-          value = {
-            description = "Synapse Matrix Worker";
-            partOf = [ "matrix-synapse.target" ];
-            wantedBy = [ "matrix-synapse.target" ];
-            after = [ "matrix-synapse.service" ];
-            requires = [ "matrix-synapse.service" ];
-            environment.PYTHONPATH = lib.makeSearchPathOutput "lib" cfg.package.python.sitePackages [
-              pluginsEnv
-            ];
-            serviceConfig = {
-              Type = "notify";
-              User = "matrix-synapse";
-              Group = "matrix-synapse";
-              WorkingDirectory = cfg.dataDir;
-              ExecStartPre = pkgs.writers.writeBash "wait-for-synapse" ''
-                # From https://md.darmstadt.ccc.de/synapse-at-work
-                while ! systemctl is-active -q matrix-synapse.service; do
-                    sleep 1
-                done
-              '';
-              ExecStart = ''
-                ${cfg.package}/bin/synapse_worker \
-                  ${ lib.concatMapStringsSep "\n  " (x: "--config-path ${x} \\") ([ matrix-synapse-common-config (workerConfig worker) ] ++ cfg.extraConfigFiles) }
-                  --keys-directory ${cfg.dataDir}
-              '';
     };
   };
 }
-      ) workerList);
-    })    
-  ]);
-}

synapse-module/nginx.nix

@@ -1,4 +1,4 @@
-{ lib, pkgs, config, ...}:
+{ pkgs, lib, config, ... }:
 let
   cfg = config.services.matrix-synapse-next;
 
@@ -140,7 +140,7 @@ in
     services.nginx.upstreams.synapse_master.servers = let
       isMainListener = l: isListenerType "client" l && isListenerType "federation" l;
       firstMainListener = lib.findFirst isMainListener
-      (throw "No cartch-all listener configured") cfg.settings.listeners;
+        (throw "No catch-all listener configured") cfg.settings.listeners;
         address = lib.findFirst (_: true) (throw "No address in main listener") firstMainListener.bind_addresses;
         port = firstMainListener.port;
         socketAddress = "${address}:${builtins.toString port}";
@@ -198,7 +198,7 @@ in
     };
 
     services.nginx.virtualHosts."${cfg.public_baseurl}" = {
-    enableACME = true;
+      enableACME = lib.mkDefault true;
       forceSSL = true;
       locations."/_matrix" = {
         proxyPass = "http://$synapse_backend";
@@ -230,6 +230,9 @@ in
       locations."/_synapse/client" = {
         proxyPass = "http://$synapse_backend";
       };
+      locations."/.well-known/matrix" = {
+        proxyPass = "http://$synapse_backend";
+      };
     };
   };
 }

synapse-module/workers.nix

@@ -0,0 +1,318 @@
+{ matrix-synapse-common-config,
+  matrix-lib,
+  pluginsEnv,
+  throw',
+  format
+}:
+{ pkgs, lib, config, ... }: let
+
+  cfg = config.services.matrix-synapse-next;
+  wcfg = config.services.matrix-synapse-next.workers;
+
+  # Used to generate proper defaultTexts.
+  cfgText = "config.services.matrix-synapse-next";
+  wcfgText = "config.services.matrix-synapse-next.workers";
+
+  inherit (lib) types mkOption mkEnableOption mkIf mkMerge literalExpression;
+
+  mkWorkerCountOption = workerType: mkOption {
+    type = types.ints.unsigned;
+    description = "How many automatically configured ${workerType} workers to set up";
+    default = 0;
+    example = 1;
+  };
+
+  genAttrs' = items: f: g: builtins.listToAttrs (map (i: lib.nameValuePair (f i) (g i)) items);
+
+  mainReplicationListener = matrix-lib.firstListenerOfType "replication" cfg.settings.listeners;
+in {
+  # See https://github.com/matrix-org/synapse/blob/develop/docs/workers.md for more info
+  options.services.matrix-synapse-next.workers = let
+    workerInstanceType = types.submodule ({ config, ... }: {
+      options = {
+        isAuto = mkOption {
+          type = types.bool;
+          internal = true;
+          default = false;
+          description = ''
+            This is an internal flag that signals that this worker is part of the
+            workers generated by either of the following:
+
+            - federationSenders
+            - federationReceivers
+            - initialSyncers
+            - normalSyncers
+            - eventPersisters
+            - useUserDirectoryWorker
+          '';
+        };
+
+        index = mkOption {
+          internal = true;
+          type = types.ints.positive;
+          description = ''
+            This is an internal variable that indexes the worker of this type.
+          '';
+        };
+
+        # The custom string type here is mainly for the name to use
+        # for the metrics of custom worker types
+        type = mkOption {
+          type = types.str;
+          # TODO: add description and possibly default value?
+        };
+
+        settings = mkOption {
+          type = workerSettingsType config;
+          default = { };
+        };
+      };
+    });
+
+    workerSettingsType = instanceCfg: types.submodule {
+      freeformType = format.type;
+      
+      options = {
+        worker_app = mkOption {
+          type = types.enum [
+            "synapse.app.generic_worker"
+            "synapse.app.appservice"
+            "synapse.app.media_repository"
+            "synapse.app.user_dir"
+          ];
+          description = "The type of worker application";
+          default = "synapse.app.generic_worker";
+        };
+
+        worker_listeners = mkOption {
+          type = types.listOf (workerListenerType instanceCfg);
+          description = "Listener configuration for the worker, similar to the main synapse listener";
+          default = [ ];
+        };
+      };
+    };
+
+    workerListenerType = instanceCfg: types.submodule {
+      options = {
+        type = mkOption {
+          type = types.enum [ "http" "metrics" ];
+          description = "The type of the listener";
+          default = "http";
+        };
+
+        path = mkOption {
+          type = types.path;
+          default = instanceCfg.name;
+          description = ''
+            A path and filename for a Unix socket.
+          '';
+        };
+
+        # port = mkOption {
+        #   type = types.port;
+        #   description = "The TCP port to bind to";
+        # };
+
+        # bind_addresses = mkOption {
+        #   type = with types; listOf str;
+        #   description = "A list of local addresses to listen on";
+        #   default = [ wcfg.defaultListenerAddress ];
+        #   defaultText = literalExpression "[ ${wcfgText}.defaultListenerAddress ]";
+        # };
+
+        tls = mkOption {
+          type = types.bool;
+          description = ''
+            Whether to enable TLS for this listener.
+            Will use the TLS key/cert specified in tls_private_key_path / tls_certificate_path.
+          '';
+          default = false;
+          example = true;
+        };
+
+        x_forwarded = mkOption {
+          type = types.bool;
+          description = ''
+            Whether to use the X-Forwarded-For HTTP header as the client IP.
+
+            This option is only valid for an 'http' listener.
+            It is useful when Synapse is running behind a reverse-proxy.
+          '';
+          default = true;
+          example = false;
+        };
+
+        resources = let
+          typeToResources = t: {
+            "fed-receiver"  = [ "federation" ];
+            "fed-sender"    = [ ];
+            "initial-sync"  = [ "client" ];
+            "normal-sync"   = [ "client" ];
+            "event-persist" = [ "replication" ];
+            "user-dir"      = [ "client" ];
+          }.${t};
+        in mkOption {
+          type = types.listOf (types.submodule {
+            options = {
+              names = mkOption {
+                type = with types; listOf (enum [
+                  "client"
+                  "consent"
+                  "federation"
+                  "keys"
+                  "media"
+                  "metrics"
+                  "openid"
+                  "replication"
+                  "static"
+                  "webclient"
+                ]);
+                description = "A list of resources to host on this port";
+                default = lib.optionals instanceCfg.isAuto (typeToResources instanceCfg.type);
+                defaultText = ''
+                  If the worker is generated from other config, the resource type will
+                  be determined automatically.
+                '';
+              };
+
+              compress = mkEnableOption "HTTP compression for this resource";
+            };
+          });
+          default = [{ }];
+        };
+      };
+    };
+  in {
+    enableMetrics = mkOption {
+      type = types.bool;
+      default = cfg.settings.enable_metrics;
+      defaultText = literalExpression "${cfgText}.settings.enable_metrics";
+      # TODO: add description
+    };
+
+    federationSenders = mkWorkerCountOption "federation-sender";
+    federationReceivers = mkWorkerCountOption "federation-reciever";
+    initialSyncers = mkWorkerCountOption "initial-syncer";
+    normalSyncers = mkWorkerCountOption "sync";
+    eventPersisters = mkWorkerCountOption "event-persister";
+
+    useUserDirectoryWorker = mkEnableOption "user directory worker";
+
+    instances = mkOption {
+      type = types.attrsOf workerInstanceType;
+      default = { };
+      description = "Worker configuration";
+      example = {
+        "federation-sender-1" = {
+          settings = {
+            worker_name = "federation-sender-1";
+            worker_app = "synapse.app.generic_worker";
+
+            path = "/run/matrix-synapse/federation-sender-1.sock";
+            # worker_replication_host = "127.0.0.1";
+            # worker_replication_http_port = 9093;
+            worker_listeners = [ ];
+          };
+        };
+      };
+    };
+  };
+
+  config = let 
+    genList1 = f: builtins.genList (i: f (i + 1));
+  in {
+    services.matrix-synapse-next.settings = {
+      federation_sender_instances =
+        genList1 (i: "auto-fed-sender-${toString i}") wcfg.federationSenders;
+
+      instance_map = lib.mkIf (cfg.workers.instances != { }) ({
+        main.path = "/run/matrix-synapse/main-replication-worker.sock";
+      } // builtins.mapAttrs (n: v: {
+        inherit (builtins.head v.settings.worker_listeners) path;
+      }) wcfg.instances);
+
+      stream_writers.events =
+        mkIf (wcfg.eventPersisters > 0)
+          (genList1 (i: "auto-event-persist-${toString i}") wcfg.eventPersisters); 
+
+      update_user_directory_from_worker =
+        mkIf wcfg.useUserDirectoryWorker "auto-user-dir-1";
+    };
+
+    services.matrix-synapse-next.workers.instances =
+      let
+        workerInstances = {
+          "fed-sender" = wcfg.federationSenders;
+          "fed-receiver" = wcfg.federationReceivers;
+          "initial-sync" = wcfg.initialSyncers;
+          "normal-sync" = wcfg.normalSyncers;
+          "event-persist" = wcfg.eventPersisters;
+          "user-dir" = if wcfg.useUserDirectoryWorker then 1 else 0;
+        };
+      in
+        lib.pipe workerInstances [
+          (lib.mapAttrsToList (type: count: { inherit type count; }))
+          (map ({ type, count }: genList1 (i: rec {
+            name = "auto-${type}-${toString i}";
+            value = {
+              inherit type;
+              isAuto = true;
+              index = i;
+              settings.worker_listeners =
+                [
+                  { path = "/run/matrix-synapse/${name}.sock"; }
+                ] ++ lib.optionals wcfg.enableMetrics [{
+                  path = "/run/matrix-synapse/${name}-metrics.sock";
+                  resources = [{ names = [ "metrics" ]; }];
+                  type = "metrics";
+                }];
+            };
+          }) count))
+          lib.flatten
+          builtins.listToAttrs
+        ];
+
+    systemd.services = let
+      workerList = lib.mapAttrsToList lib.nameValuePair wcfg.instances;
+      workerConfig = worker: format.generate "matrix-synapse-worker-${worker.name}-config.yaml"
+        (worker.value.settings // { worker_name = worker.name; });
+    in builtins.listToAttrs (lib.flip map workerList (worker: {
+      name = "matrix-synapse-worker-${worker.name}";
+      value = {
+        documentation = [ "https://github.com/matrix-org/synapse/blob/develop/docs/workers.md" ];
+        description = "Synapse Matrix Worker";
+        partOf = [ "matrix-synapse.target" ];
+        wantedBy = [ "matrix-synapse.target" ];
+        after = [ "matrix-synapse.service" ];
+        requires = [ "matrix-synapse.service" ];
+        restartTriggers = [ matrix-synapse-common-config (workerConfig worker) ] ++ cfg.extraConfigFiles;
+        environment = {
+          PYTHONPATH = lib.makeSearchPathOutput "lib" cfg.package.python.sitePackages [
+            pluginsEnv
+          ];
+        };
+        serviceConfig = {
+          Restart = "always";
+          Type = "notify";
+          User = "matrix-synapse";
+          Group = "matrix-synapse";
+          Slice = "system-matrix-synapse.slice";
+          WorkingDirectory = cfg.dataDir;
+          RuntimeDirectory = [ "matrix-synapse" ];
+          ExecStartPre = pkgs.writers.writeBash "wait-for-synapse" ''
+            # From https://md.darmstadt.ccc.de/synapse-at-work
+            while ! systemctl is-active -q matrix-synapse.service; do
+                sleep 1
+            done
+          '';
+          ExecStart = let
+            flags = lib.cli.toGNUCommandLineShell {} {
+              config-path = [ matrix-synapse-common-config (workerConfig worker) ] ++ cfg.extraConfigFiles;
+              keys-directory = cfg.dataDir;
+            };
+          in "${cfg.package}/bin/synapse_worker ${flags}";
+        };
+      };
+    }));
+  };
+}

tests/auto-workers-config.nix

@@ -0,0 +1,18 @@
+{ pkgs, lib, ... }:
+{
+  services.matrix-synapse-next = {
+    enable = true;
+    settings.server_name = "matrix.example.com";
+
+    workers = {
+      enableMetrics = true;
+
+      federationSenders = 2;
+      federationReceivers = 2;
+      initialSyncers = 2;
+      normalSyncers = 2;
+      eventPersisters = 2;
+      useUserDirectoryWorker = true;
+    };
+  };
+}

tests/base-config.nix

@@ -0,0 +1,7 @@
+{ pkgs, lib, ... }:
+{
+  services.matrix-synapse-next = {
+    enable = true;
+    settings.server_name = "matrix.example.com";
+  };
+}

tests/default.nix

@@ -0,0 +1,16 @@
+{ nixpkgs, pkgs, system ? pkgs.system, nixosModule, ... }: let
+  buildSystemWithConfig = configPath: (nixpkgs.lib.nixosSystem {
+    inherit system;
+    modules = [
+      nixosModule
+      configPath
+      {
+        boot.isContainer = true;
+      }
+    ];
+  }).config.system.build.toplevel;
+in {
+  a = pkgs.writeText "hello-world" ''a'';
+  base-config = buildSystemWithConfig ./base-config.nix;
+  auto-workers-config = buildSystemWithConfig ./auto-workers-config.nix;
+}