prometheus-node-exporter: use 1.6.1 pinned

pkgs/prometheus-node-exporter/default.nix

@@ -0,0 +1,43 @@
+{ lib, stdenv, buildGoModule, fetchFromGitHub, nixosTests
+}:
+
+buildGoModule rec {
+  pname = "node_exporter";
+  version = "1.6.1";
+  rev = "v${version}";
+
+  src = fetchFromGitHub {
+    inherit rev;
+    owner = "prometheus";
+    repo = "node_exporter";
+    sha256 = "sha256-BCZLMSJP/63N+pZsK8er87Zem7IFGdkyruDs6UVDZSM=";
+  };
+
+  vendorHash = "sha256-hn2cMKhLl5qsm4sZErs6PXTs8yajowxw9a9vtHe5cAk=";
+
+  # FIXME: tests fail due to read-only nix store
+  doCheck = false;
+
+  excludedPackages = [ "docs/node-mixin" ];
+
+  ldflags = [
+    "-s"
+    "-w"
+    "-X github.com/prometheus/common/version.Version=${version}"
+    "-X github.com/prometheus/common/version.Revision=${rev}"
+    "-X github.com/prometheus/common/version.Branch=unknown"
+    "-X github.com/prometheus/common/version.BuildUser=nix@nixpkgs"
+    "-X github.com/prometheus/common/version.BuildDate=unknown"
+  ];
+
+  passthru.tests = { inherit (nixosTests.prometheus-exporters) node; };
+
+  meta = with lib; {
+    description = "Prometheus exporter for machine metrics";
+    homepage = "https://github.com/prometheus/node_exporter";
+    changelog = "https://github.com/prometheus/node_exporter/blob/v${version}/CHANGELOG.md";
+    mainProgram = "node_exporter";
+    license = licenses.asl20;
+    maintainers = with maintainers; [ benley fpletz globin Frostman ];
+  };
+}