added electrum - electrs module

src/system/modules/bitcoin/default.nix

@@ -11,6 +11,7 @@ let
 in
 { options.modules.system.bitcoin = { enable = mkEnableOption "system.bitcoin"; };
   config = mkIf cfg.enable {
+    imports = [ ./modules ];
     nixpkgs.overlays = [
       (final: prev: {
         bitcoind = prev.bitcoind.overrideAttrs (old: rec {

src/system/modules/bitcoin/modules/default.nix

@@ -0,0 +1,5 @@
+{
+  imports = [
+    ./electrum
+  ];
+}

src/system/modules/bitcoin/modules/electrum/config/default.nix

@@ -0,0 +1,22 @@
+{ home, ... }:
+
+let
+  daemonDir = /var/lib/bitcoin;
+
+in
+''
+  network = "bitcoin"
+
+  electrum_rpc_addr = "127.0.0.1:50001"
+
+  cookie-file = "${daemonDir}/.cookie"
+
+  db_dir = "${home}/db"
+
+  log_filters = "INFO"
+  timestamp = true
+
+  daemon-rpc-addr = "127.0.0.1:8332"
+  daemon-p2p-addr = "127.0.0.1:8333"
+  daemon-dir = "${daemonDir}"
+''

src/system/modules/bitcoin/modules/electrum/default.nix

@@ -0,0 +1,72 @@
+{ lib, pkgs, config, ... }:
+
+with lib;
+let
+  cfg = config.modules.system.bitcoin.electrum;
+  home = /var/lib/electrs;
+
+  btc = config.modules.system.bitcoin;
+
+  conf = pkgs.writeText "config.toml" (import ./config { inherit home; });
+
+in
+{ options.modules.system.bitcoin.electrum = { enable = mkEnableOption "bitcoin.electrum"; };
+  config = mkIf (cfg.enable && btc.enable) {
+    nixpkgs.overlays = [
+      (final: prev: {
+        electrs = prev.electrs.overrideAttrs (old: rec {
+          version = "0.10.4";
+          src = fetchFromGithub {
+            owner = old.owner;
+            repo = old.pname;
+            rev = "${version}";
+            hash = ''
+              sha256-0xw2532nmaxx9bjdpnnby03b83wc9zs8bv1wdfgv9q1phccqbkz1
+            '';
+          };
+        });
+      })
+    ];
+
+    environment.systemPackages = with pkgs; [
+      electrs
+    ];
+
+    users = {
+      users = {
+        "electrs" = {
+          inherit home;
+          description = "electrs system user";
+          isSystemUser = true;
+          group = "bitcoin";
+          createHome = true;
+        };
+      };
+    };
+
+
+    systemd.services.electrs = {
+      Unit = {
+        Description = "Electrs Bitcoin Indexer";
+        After = [ "network.target" "bitcoind.service" ];
+        Requires = [ "bitcoind.service" ];
+      };
+      Service = {
+        ExecStartPre = "${pkgs.coreutils}/sleep 10";
+        ExecStart = "${pkgs.electrs}/bin/electrs --conf=${conf}";
+
+        User = "electrs";
+        Group = "bitcoin";
+
+        Type = "simple";
+        KillMode = "process";
+        TimeoutSec = 60;
+        Restart = "always";
+        RestartSec = 60;
+      };
+      Install = {
+        WantedBy = [ "multi-user.target" ];
+      };
+    };
+  };
+}