new try

flake.nix

@@ -27,7 +27,6 @@
               '';
               nativeBuildInputs = [ cargo clang cmake ];
             };
-          # default = "${productName}";
         };
   
         devShells.default = mkShell {
@@ -47,7 +46,7 @@
         nixosModules = {
           # add moduleA from flakeA as an output
           # moduleA = flakeA.nixosModules.moduleA;
-          default = import ./module.nix;
+          default = import ./module.nix  { inherit nixpkgs };
         };
       });
 }

module.nix

@@ -36,20 +36,20 @@ let
     };
     group = mkOption {
       type = types.str;
-      default = cfg.user;
+      default = config.services.blockstream-electrs.user;
       description = mdDoc "The group as which to run electrs.";
     };
     tor.enforce = nbLib.tor.enforce;
   };
 
-  cfg = config.services.blockstream-electrs;
+  # config.services.blockstream-electrs = config.services.blockstream-electrs;
   nbLib = config.nix-bitcoin.lib;
   secretsDir = config.nix-bitcoin.secretsDir;
   bitcoind = config.services.bitcoind;
 in {
   inherit options;
 
-  config = mkIf cfg.enable {
+  config = mkIf config.services.blockstream-electrs.enable {
     assertions = [
       { assertion = bitcoind.prune == 0;
         message = "electrs does not support bitcoind pruning.";
@@ -62,7 +62,7 @@ in {
     };
 
     systemd.tmpfiles.rules = [
-      "d '${cfg.dataDir}' 0770 ${cfg.user} ${cfg.group} - -"
+      "d '${config.services.blockstream-electrs.dataDir}' 0770 ${config.services.blockstream-electrs.user} ${config.services.blockstream-electrs.group} - -"
     ];
 
     systemd.services.blockstream-electrs = {
@@ -75,32 +75,32 @@ in {
         '';
       serviceConfig = nbLib.defaultHardening // {
         # electrs only uses the working directory for reading electrs.toml
-        WorkingDirectory = cfg.dataDir;
+        WorkingDirectory = config.services.blockstream-electrs.dataDir;
         ExecStart = ''
           ${self.packages.${system}.blockstream-electrs}/bin/electrs \
           --log-filters=INFO \
           --network=${bitcoind.makeNetworkName "bitcoin" "regtest"} \
-          --db-dir='${cfg.dataDir}' \
+          --db-dir='${config.services.blockstream-electrs.dataDir}' \
           --daemon-dir='${bitcoind.dataDir}' \
-          --electrum-rpc-addr=${cfg.address}:${toString cfg.port} \
-          --monitoring-addr=${cfg.address}:${toString cfg.monitoringPort} \
+          --electrum-rpc-addr=${config.services.blockstream-electrs.address}:${toString config.services.blockstream-electrs.port} \
+          --monitoring-addr=${config.services.blockstream-electrs.address}:${toString config.services.blockstream-electrs.monitoringPort} \
           --daemon-rpc-addr=${nbLib.addressWithPort bitcoind.rpc.address bitcoind.rpc.port} \
           --daemon-p2p-addr=${nbLib.addressWithPort bitcoind.address bitcoind.whitelistedPort} \
-          ${cfg.extraArgs}
+          ${config.services.blockstream-electrs.extraArgs}
         '';
-        User = cfg.user;
-        Group = cfg.group;
+        User = config.services.blockstream-electrs.user;
+        Group = config.services.blockstream-electrs.group;
         Restart = "on-failure";
         RestartSec = "10s";
-        ReadWritePaths = [ cfg.dataDir ];
-      } // nbLib.allowedIPAddresses cfg.tor.enforce;
+        ReadWritePaths = [ config.services.blockstream-electrs.dataDir ];
+      } // nbLib.allowedIPAddresses config.services.blockstream-electrs.tor.enforce;
     };
 
-    users.users.${cfg.user} = {
+    users.users.${config.services.blockstream-electrs.user} = {
       isSystemUser = true;
-      group = cfg.group;
+      group = config.services.blockstream-electrs.group;
       extraGroups = [ "bitcoinrpc-public" ];
     };
-    users.groups.${cfg.group} = {};
+    users.groups.${config.services.blockstream-electrs.group} = {};
   };
 }