mempool: add frontend settings

dev/dev-scenarios.nix

@@ -111,7 +111,10 @@ with lib;
     ];
     services.mempool = {
       enable = true;
-      frontend.address = "0.0.0.0";
+      frontend = {
+        address = "0.0.0.0";
+        settings.LIQUID_ENABLED = true;
+      };
     };
     nix-bitcoin.nodeinfo.enable = true;
   };

modules/mempool.nix

@@ -50,9 +50,23 @@ let
           default = 60845; # A random private port
           description = "HTTP server port.";
         };
+        settings = mkOption {
+          type = with types; attrsOf anything;
+          default = {};
+          example = {
+            TESTNET_ENABLED = true;
+            MEMPOOL_WEBSITE_URL = "mempool.mynode.org";
+          };
+          description = ''
+            Mempool frontend settings.
+            See here for available options:
+            https://github.com/mempool/mempool/blob/master/frontend/src/app/services/state.service.ts
+            (`interface Env` and `defaultEnv`)
+          '';
+        };
         staticContentRoot = mkOption {
           type = types.path;
-          default = nbPkgs.mempool-frontend;
+          default = nbPkgs.mempool-frontend.withConfig cfg.frontend.settings;
           defaultText = "config.nix-bitcoin.pkgs.mempool-frontend";
           description = "
             Path of the static frontend content root.
@@ -106,7 +120,7 @@ let
         };
         description = ''
           Mempool backend settings.
-          See here for possible options:
+          See here for available options:
           https://github.com/mempool/mempool/blob/master/backend/src/config.ts
         '';
       };

pkgs/mempool/default.nix

@@ -79,7 +79,14 @@ rec {
     };
   };
 
-  mempool-frontend = mkDerivationMempool {
+  mempool-frontend = mkFrontend {};
+
+  # Argument `config` (type: attrset) defines the mempool frontend config.
+  # If `{}`, the default config is used.
+  # See here for available options:
+  # https://github.com/mempool/mempool/blob/master/frontend/src/app/services/state.service.ts
+  # (`interface Env` and `defaultEnv`)
+  mkFrontend = config: mkDerivationMempool {
     pname = "mempool-frontend";
 
     buildPhase = ''
@@ -92,6 +99,10 @@ rec {
       # internet. Disable this script and instead add the assets manually after building.
       : > sync-assets.js
 
+      ${lib.optionalString (config != {}) ''
+        ln -s ${builtins.toFile "mempool-frontend-config" (builtins.toJSON config)} mempool-frontend-config.json
+      ''}
+
       npm run build
 
       # Add assets that would otherwise be downloaded by sync-assets.js
@@ -107,6 +118,7 @@ rec {
     '';
 
     passthru = {
+      withConfig = mkFrontend;
       assets = frontendAssets;
       nodeModules = nodeModules.frontend;
     };