Merge pull request #33331 from cransom/netdata-module

netdata service: fix permissions for apps.plugin

nixos/modules/services/monitoring/netdata.nix

@@ -5,18 +5,25 @@ with lib;
 let
   cfg = config.services.netdata;
 
-  configFile = pkgs.writeText "netdata.conf" cfg.configText;
+  wrappedPlugins = pkgs.runCommand "wrapped-plugins" {} ''
+    mkdir -p $out/libexec/netdata/plugins.d
+    ln -s /run/wrappers/bin/apps.plugin $out/libexec/netdata/plugins.d/apps.plugin
+  '';
+
+  localConfig = {
+    global = {
+      "plugins directory" = "${wrappedPlugins}/libexec/netdata/plugins.d ${pkgs.netdata}/libexec/netdata/plugins.d";
+    };
+  };
+  mkConfig = generators.toINI {} (recursiveUpdate localConfig cfg.config);
+  configFile = pkgs.writeText "netdata.conf" (if cfg.configText != null then cfg.configText else mkConfig);
 
   defaultUser = "netdata";
 
 in {
   options = {
     services.netdata = {
-      enable = mkOption {
-        default = false;
-        type = types.bool;
-        description = "Whether to enable netdata monitoring.";
-      };
+      enable = mkEnableOption "netdata";
 
       user = mkOption {
         type = types.str;
@@ -31,9 +38,9 @@ in {
       };
 
       configText = mkOption {
-        type = types.lines;
-        default = "";
-        description = "netdata.conf configuration.";
+        type = types.nullOr types.lines;
+        description = "Verbatim netdata.conf, cannot be combined with config.";
+        default = null;
         example = ''
           [global]
           debug log = syslog
@@ -42,11 +49,29 @@ in {
         '';
       };
 
+      config = mkOption {
+        type = types.attrsOf types.attrs;
+        default = {};
+        description = "netdata.conf configuration as nix attributes. cannot be combined with configText.";
+        example = literalExample ''
+          global = {
+            "debug log" = "syslog";
+            "access log" = "syslog";
+            "error log" = "syslog";
+          };
+        '';
+        };
       };
     };
 
   config = mkIf cfg.enable {
+    assertions =
+      [ { assertion = cfg.config != {} -> cfg.configText == null ;
+          message = "Cannot specify both config and configText";
+        }
+      ];
     systemd.services.netdata = {
+      path = with pkgs; [ gawk curl ];
       description = "Real time performance monitoring";
       after = [ "network.target" ];
       wantedBy = [ "multi-user.target" ];
@@ -66,6 +91,15 @@ in {
       };
     };
 
+    security.wrappers."apps.plugin" = {
+      source = "${pkgs.netdata}/libexec/netdata/plugins.d/apps.plugin";
+      capabilities = "cap_dac_read_search,cap_sys_ptrace+ep";
+      owner = cfg.user;
+      group = cfg.group;
+      permissions = "u+rx,g+rx,o-rwx";
+    };
+
+
     users.extraUsers = optional (cfg.user == defaultUser) {
       name = defaultUser;
     };

nixos/release.nix

@@ -304,6 +304,7 @@ in rec {
   tests.nat.firewall = callTest tests/nat.nix { withFirewall = true; };
   tests.nat.firewall-conntrack = callTest tests/nat.nix { withFirewall = true; withConntrackHelpers = true; };
   tests.nat.standalone = callTest tests/nat.nix { withFirewall = false; };
+  tests.netdata = callTest tests/netdata.nix { };
   tests.networking.networkd = callSubTests tests/networking.nix { networkd = true; };
   tests.networking.scripted = callSubTests tests/networking.nix { networkd = false; };
   # TODO: put in networking.nix after the test becomes more complete

nixos/tests/netdata.nix

@@ -0,0 +1,31 @@
+# This test runs netdata and checks for data via apps.plugin
+
+import ./make-test.nix ({ pkgs, ...} : {
+  name = "netdata";
+  meta = with pkgs.stdenv.lib.maintainers; {
+    maintainers = [ cransom ];
+  };
+
+  nodes = {
+    netdata =
+      { config, pkgs, ... }:
+        {
+          environment.systemPackages = with pkgs; [ curl jq ];
+          services.netdata.enable = true;
+        };
+    };
+
+  testScript = ''
+    startAll;
+
+    $netdata->waitForUnit("netdata.service");
+    # check if netdata can read disk ops for root owned processes. 
+    # if > 0, successful. verifies both netdata working and 
+    # apps.plugin has elevated capabilities.
+    my $cmd = <<'CMD';
+    curl -s http://localhost:19999/api/v1/data\?chart=users.pwrites | \
+       jq -e '[.data[range(10)][.labels | indices("root")[0]]] | add | . > 0'
+    CMD
+    $netdata->waitUntilSucceeds($cmd);
+  '';
+})