From 3ec9637a059d310f68c1014f946adacd97c89394 Mon Sep 17 00:00:00 2001
From: Pascal Bach <pascal.bach@nextrem.ch>
Date: Sun, 22 Nov 2020 17:35:39 +0100
Subject: [PATCH] nixos/geth: initial service

---
 nixos/modules/module-list.nix                 |   1 +
 .../services/blockchain/ethereum/geth.nix     | 178 ++++++++++++++++++
 nixos/tests/geth.nix                          |  41 ++++
 3 files changed, 220 insertions(+)
 create mode 100644 nixos/modules/services/blockchain/ethereum/geth.nix
 create mode 100644 nixos/tests/geth.nix

diff --git a/nixos/modules/module-list.nix b/nixos/modules/module-list.nix
index f831e302b161..44b30d0e6c24 100644
--- a/nixos/modules/module-list.nix
+++ b/nixos/modules/module-list.nix
@@ -256,6 +256,7 @@
   ./services/backup/tsm.nix
   ./services/backup/zfs-replication.nix
   ./services/backup/znapzend.nix
+  ./services/blockchain/ethereum/geth.nix
   ./services/cluster/hadoop/default.nix
   ./services/cluster/k3s/default.nix
   ./services/cluster/kubernetes/addons/dns.nix
diff --git a/nixos/modules/services/blockchain/ethereum/geth.nix b/nixos/modules/services/blockchain/ethereum/geth.nix
new file mode 100644
index 000000000000..be3f40f6bd86
--- /dev/null
+++ b/nixos/modules/services/blockchain/ethereum/geth.nix
@@ -0,0 +1,178 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+  eachGeth = config.services.geth;
+
+  gethOpts = { config, lib, name, ...}: {
+
+    options = {
+
+      enable = lib.mkEnableOption "Go Ethereum Node";
+
+      port = mkOption {
+        type = types.port;
+        default = 30303;
+        description = "Port number Go Ethereum will be listening on, both TCP and UDP.";
+      };
+
+      http = {
+        enable = lib.mkEnableOption "Go Ethereum HTTP API";
+        address = mkOption {
+          type = types.str;
+          default = "127.0.0.1";
+          description = "Listen address of Go Ethereum HTTP API.";
+        };
+
+        port = mkOption {
+          type = types.port;
+          default = 8545;
+          description = "Port number of Go Ethereum HTTP API.";
+        };
+
+        apis = mkOption {
+          type = types.nullOr (types.listOf types.str);
+          default = null;
+          description = "APIs to enable over WebSocket";
+          example = ["net" "eth"];
+        };
+      };
+
+      websocket = {
+        enable = lib.mkEnableOption "Go Ethereum WebSocket API";
+        address = mkOption {
+          type = types.str;
+          default = "127.0.0.1";
+          description = "Listen address of Go Ethereum WebSocket API.";
+        };
+
+        port = mkOption {
+          type = types.port;
+          default = 8546;
+          description = "Port number of Go Ethereum WebSocket API.";
+        };
+
+        apis = mkOption {
+          type = types.nullOr (types.listOf types.str);
+          default = null;
+          description = "APIs to enable over WebSocket";
+          example = ["net" "eth"];
+        };
+      };
+
+      metrics = {
+        enable = lib.mkEnableOption "Go Ethereum prometheus metrics";
+        address = mkOption {
+          type = types.str;
+          default = "127.0.0.1";
+          description = "Listen address of Go Ethereum metrics service.";
+        };
+
+        port = mkOption {
+          type = types.port;
+          default = 6060;
+          description = "Port number of Go Ethereum metrics service.";
+        };
+      };
+
+      network = mkOption {
+        type = types.nullOr (types.enum [ "goerli" "rinkeby" "yolov2" "ropsten" ]);
+        default = null;
+        description = "The network to connect to. Mainnet (null) is the default ethereum network.";
+      };
+
+      syncmode = mkOption {
+        type = types.enum [ "fast" "full" "light" ];
+        default = "fast";
+        description = "Blockchain sync mode.";
+      };
+
+      gcmode = mkOption {
+        type = types.enum [ "full" "archive" ];
+        default = "full";
+        description = "Blockchain garbage collection mode.";
+      };
+
+      maxpeers = mkOption {
+        type = types.int;
+        default = 50;
+        description = "Maximum peers to connect to.";
+      };
+
+      extraArgs = mkOption {
+        type = types.listOf types.str;
+        description = "Additional arguments passed to Go Ethereum.";
+        default = [];
+      };
+
+      package = mkOption {
+        default = pkgs.go-ethereum.geth;
+        type = types.package;
+        description = "Package to use as Go Ethereum node.";
+      };
+    };
+  };
+in
+
+{
+
+  ###### interface
+
+  options = {
+    services.geth = mkOption {
+      type = types.attrsOf (types.submodule gethOpts);
+      default = {};
+      description = "Specification of one or more geth instances.";
+    };
+  };
+
+  ###### implementation
+
+  config = mkIf (eachGeth != {}) {
+
+    environment.systemPackages = flatten (mapAttrsToList (gethName: cfg: [
+      cfg.package
+    ]) eachGeth);
+
+    systemd.services = mapAttrs' (gethName: cfg: (
+      nameValuePair "geth-${gethName}" (mkIf cfg.enable {
+      description = "Go Ethereum node (${gethName})";
+      wantedBy = [ "multi-user.target" ];
+      after = [ "network.target" ];
+
+      serviceConfig = {
+        DynamicUser = true;
+        Restart = "always";
+        StateDirectory = "goethereum/${gethName}/${if (cfg.network == null) then "mainnet" else cfg.network}";
+
+        # Hardening measures
+        PrivateTmp = "true";
+        ProtectSystem = "full";
+        NoNewPrivileges = "true";
+        PrivateDevices = "true";
+        MemoryDenyWriteExecute = "true";
+      };
+
+      script = ''
+        ${cfg.package}/bin/geth \
+          --nousb \
+          --ipcdisable \
+          ${optionalString (cfg.network != null) ''--${cfg.network}''} \
+          --syncmode ${cfg.syncmode} \
+          --gcmode ${cfg.gcmode} \
+          --port ${toString cfg.port} \
+          --maxpeers ${toString cfg.maxpeers} \
+          ${if cfg.http.enable then ''--http --http.addr ${cfg.http.address} --http.port ${toString cfg.http.port}'' else ""} \
+          ${optionalString (cfg.http.apis != null) ''--http.api ${lib.concatStringsSep "," cfg.http.apis}''} \
+          ${if cfg.websocket.enable then ''--ws --ws.addr ${cfg.websocket.address} --ws.port ${toString cfg.websocket.port}'' else ""} \
+          ${optionalString (cfg.websocket.apis != null) ''--ws.api ${lib.concatStringsSep "," cfg.websocket.apis}''} \
+          ${optionalString cfg.metrics.enable ''--metrics --metrics.addr ${cfg.metrics.address} --metrics.port ${toString cfg.metrics.port}''} \
+          ${lib.escapeShellArgs cfg.extraArgs} \
+          --datadir /var/lib/goethereum/${gethName}/${if (cfg.network == null) then "mainnet" else cfg.network}
+      '';
+    }))) eachGeth;
+
+  };
+
+}
diff --git a/nixos/tests/geth.nix b/nixos/tests/geth.nix
new file mode 100644
index 000000000000..10cbd6d9038c
--- /dev/null
+++ b/nixos/tests/geth.nix
@@ -0,0 +1,41 @@
+import ./make-test-python.nix ({ pkgs, ... }: {
+  name = "geth";
+  meta = with pkgs.lib; {
+    maintainers = with maintainers; [bachp ];
+  };
+
+  machine = { ... }: {
+    services.geth."mainnet" = {
+      enable = true;
+      http = {
+        enable = true;
+      };
+    };
+    services.geth."testnet" = {
+      enable = true;
+      port = 30304;
+      network = "goerli";
+      http = {
+        enable = true;
+        port = 18545;
+      };
+    };
+  };
+
+  testScript = ''
+    start_all()
+
+    machine.wait_for_unit("geth-mainnet.service")
+    machine.wait_for_unit("geth-testnet.service")
+    machine.wait_for_open_port(8545)
+    machine.wait_for_open_port(18545)
+
+    machine.succeed(
+        'geth attach --exec "eth.chainId()" http://localhost:8545 | grep \'"0x0"\' '
+    )
+
+    machine.succeed(
+        'geth attach --exec "eth.chainId()" http://localhost:18545 | grep \'"0x5"\' '
+    )
+  '';
+})