modules: use consistent service variables

Benefits of adding top-level variables for used services:
- Makes it obvious which other services are referenced by a service
- Less code

We already do this in many other places.

modules/btcpayserver.nix

@@ -100,6 +100,8 @@ let
   cfg = config.services;
   nbLib = config.nix-bitcoin.lib;
   nbPkgs = config.nix-bitcoin.pkgs;
+
+  bitcoind = config.services.bitcoind;
 in {
   inherit options;
 
@@ -139,10 +141,10 @@ in {
 
     systemd.services.nbxplorer = let
       configFile = builtins.toFile "config" ''
-        network=${config.services.bitcoind.network}
+        network=${bitcoind.network}
         btcrpcuser=${cfg.bitcoind.rpc.users.btcpayserver.name}
-        btcrpcurl=http://${config.services.bitcoind.rpc.address}:${toString cfg.bitcoind.rpc.port}
+        btcrpcurl=http://${bitcoind.rpc.address}:${toString cfg.bitcoind.rpc.port}
-        btcnodeendpoint=${config.services.bitcoind.address}:${toString config.services.bitcoind.port}
+        btcnodeendpoint=${bitcoind.address}:${toString bitcoind.port}
         bind=${cfg.nbxplorer.address}
         port=${toString cfg.nbxplorer.port}
         ${optionalString cfg.btcpayserver.lbtc ''
@@ -180,9 +182,9 @@ in {
 
     systemd.services.btcpayserver = let
       nbExplorerUrl = "http://${cfg.nbxplorer.address}:${toString cfg.nbxplorer.port}/";
-      nbExplorerCookie = "${cfg.nbxplorer.dataDir}/${config.services.bitcoind.makeNetworkName "Main" "RegTest"}/.cookie";
+      nbExplorerCookie = "${cfg.nbxplorer.dataDir}/${bitcoind.makeNetworkName "Main" "RegTest"}/.cookie";
       configFile = builtins.toFile "config" (''
-        network=${config.services.bitcoind.network}
+        network=${bitcoind.network}
         bind=${cfg.btcpayserver.address}
         port=${toString cfg.btcpayserver.port}
         socksendpoint=${config.nix-bitcoin.torClientAddressWithPort}

modules/charge-lnd.nix

@@ -69,6 +69,7 @@ let
 
   cfg = config.services.charge-lnd;
   nbLib = config.nix-bitcoin.lib;
+
   lnd = config.services.lnd;
   electrs = if (config.services ? electrs) && config.services.electrs.enable
             then config.services.electrs
@@ -77,7 +78,6 @@ let
   user = "charge-lnd";
   group = user;
   dataDir = "/var/lib/charge-lnd";
-
   configFile = builtins.toFile "charge-lnd.config" cfg.policies;
   checkedConfig = pkgs.runCommandNoCC "charge-lnd-checked.config" { } ''
     ${config.nix-bitcoin.pkgs.charge-lnd}/bin/charge-lnd --check --config ${configFile}

modules/clightning.nix

@@ -76,6 +76,7 @@ let
   cfg = config.services.clightning;
   nbLib = config.nix-bitcoin.lib;
   nbPkgs = config.nix-bitcoin.pkgs;
+
   network = config.services.bitcoind.makeNetworkName "bitcoin" "regtest";
   configFile = pkgs.writeText "config" ''
     network=${network}

modules/liquid.nix

@@ -140,9 +140,12 @@ let
   nbLib = config.nix-bitcoin.lib;
   nbPkgs = config.nix-bitcoin.pkgs;
   secretsDir = config.nix-bitcoin.secretsDir;
+
+  bitcoind = config.services.bitcoind;
+
   pidFile = "${cfg.dataDir}/liquidd.pid";
   configFile = pkgs.writeText "elements.conf" ''
-    chain=${config.services.bitcoind.makeNetworkName "liquidv1" ''
+    chain=${bitcoind.makeNetworkName "liquidv1" ''
       regtest
       [regtest]'' # Add [regtest] config section
     }
@@ -166,9 +169,9 @@ let
     rpcconnect=${cfg.rpc.address}
     ${lib.concatMapStrings (rpcallowip: "rpcallowip=${rpcallowip}\n") cfg.rpcallowip}
     rpcuser=${cfg.rpcuser}
-    mainchainrpchost=${config.services.bitcoind.rpc.address}
+    mainchainrpchost=${bitcoind.rpc.address}
-    mainchainrpcport=${toString config.services.bitcoind.rpc.port}
+    mainchainrpcport=${toString bitcoind.rpc.port}
-    mainchainrpcuser=${config.services.bitcoind.rpc.users.public.name}
+    mainchainrpcuser=${bitcoind.rpc.users.public.name}
 
     # Extra config options (from liquidd nixos service)
     ${cfg.extraConfig}

modules/lnd.nix

@@ -128,6 +128,7 @@ let
   runAsUser = config.nix-bitcoin.runAsUserCmd;
 
   bitcoind = config.services.bitcoind;
+
   bitcoindRpcAddress = bitcoind.rpc.address;
   networkDir = "${cfg.dataDir}/chain/bitcoin/${bitcoind.network}";
   configFile = pkgs.writeText "lnd.conf" ''

modules/spark-wallet.nix

@@ -44,6 +44,8 @@ let
   cfg = config.services.spark-wallet;
   nbLib = config.nix-bitcoin.lib;
 
+  clightning = config.services.clightning;
+
   # Use wasabi rate provider because the default (bitstamp) doesn't accept
   # connections through Tor
   torRateProvider = "--rate-provider wasabi --proxy socks5h://${config.nix-bitcoin.torClientAddressWithPort}";
@@ -52,7 +54,7 @@ let
       publicURL="--public-url http://$(${cfg.getPublicAddressCmd})"
     ''}
     exec ${config.nix-bitcoin.pkgs.spark-wallet}/bin/spark-wallet \
-      --ln-path '${config.services.clightning.networkDir}'  \
+      --ln-path '${clightning.networkDir}'  \
       --host ${cfg.address} --port ${toString cfg.port} \
       --config '${config.nix-bitcoin.secretsDir}/spark-wallet-login' \
       ${optionalString cfg.enforceTor torRateProvider} \
@@ -81,7 +83,7 @@ in {
     users.users.${cfg.user} = {
       isSystemUser = true;
       group = cfg.group;
-      extraGroups = [ config.services.clightning.group ];
+      extraGroups = [ clightning.group ];
     };
     users.groups.${cfg.group} = {};