better cache management

.github/workflows/lint.yml

@@ -19,18 +19,18 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
-      - name: pick reporter
-        run: |
-          if [ "${{ github.event_name }}" = pull_request ]; then
-            echo "REPORTER=gitea-pr-review" >> "$GITHUB_ENV"
-          else
-            echo "REPORTER=local" >> "$GITHUB_ENV"
-          fi
-
       - name: run linters
         run: nix run -L .#ci -- lint . "$RUNNER_TEMP/findings"
 
       - name: report findings
+        if: always()
         env:
-          REVIEWDOG_GITHUB_API_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          REVIEWDOG_GITEA_API_TOKEN: ${{ secrets.GITEA_TOKEN }}
-        run: nix run -L .#ci -- lint-report "$REPORTER" "$RUNNER_TEMP/findings"
+          GITEA_ADDRESS: ${{ github.server_url }}
+        run: |
+          if [ "${{ github.event_name }}" = pull_request ]; then
+            nix run -L .#ci -- lint-report gitea-pr-review "$RUNNER_TEMP/findings"
+          else
+            nix run -L .#ci -- lint-summary "$RUNNER_TEMP/findings" \
+              | tee -a "$GITHUB_STEP_SUMMARY"
+          fi

ci.nix

@@ -3,6 +3,7 @@
 # runner's own nix, not a pinned one).
 pkgs.writers.writePython3Bin "ci" {
   flakeIgnore = [ "E501" ];
+  libraries = [ pkgs.python3Packages.subprocess-tee ];
   makeWrapperArgs = [
     "--prefix"
     "PATH"

ci.py

@@ -6,6 +6,7 @@ import json
 import os
 import re
 import subprocess
+import subprocess_tee
 import sys
 import urllib.request
 from collections import Counter
@@ -17,7 +18,7 @@ def run(*args, **kw):
 
 
 def nix(*args):
-    return run("nix", "--extra-experimental-features", "nix-command flakes", "-L", *args, check=True, stdout=subprocess.PIPE).stdout
+    return subprocess_tee.run(("nix", "--extra-experimental-features", "nix-command flakes", "-L", *args), check=True, text=True).stdout
 
 
 def git(*args, check=True):
@@ -362,10 +363,63 @@ def lint_report(args):
 
     codes = [reviewdog(f"{args.dir}/{name}", flags)
              for name, flags in LINTERS
-             if os.path.getsize(f"{args.dir}/{name}") > 0]
+             if os.path.isfile(f"{args.dir}/{name}") and os.path.getsize(f"{args.dir}/{name}") > 0]
     sys.exit(1 if any(codes) else 0)
 
 
+def has_findings(path):
+    return os.path.isfile(path) and os.path.getsize(path) > 0
+
+
+def fmt_rdjsonl(path):
+    lines = []
+    with open(path) as f:
+        for raw in f:
+            rec = json.loads(raw)
+            loc = rec["location"]
+            r = loc.get("range", {}).get("start")
+            pos = f"{loc['path']}:{r['line']}:{r['column']}" if r else loc["path"]
+            lines.append(f"- `{pos}`: {rec['message']}")
+    return "\n".join(lines)
+
+
+def fmt_errfmt(path):
+    lines = []
+    with open(path) as f:
+        for raw in f:
+            parts = raw.strip().split(">", 1)
+            if len(parts) == 2:
+                lines.append(f"- `{parts[0]}:{parts[1].split(':', 3)[-1].strip()}`" if ":" in parts[1] else f"- `{raw.strip()}`")
+            elif raw.strip():
+                lines.append(f"- `{raw.strip()}`")
+    return "\n".join(lines)
+
+
+def lint_summary(args):
+    sections = []
+    d = args.dir
+
+    if has_findings(f"{d}/nixfmt.diff"):
+        with open(f"{d}/nixfmt.diff") as f:
+            sections.append(f"## nixfmt\n\n```diff\n{f.read().rstrip()}\n```")
+
+    if has_findings(f"{d}/statix.errfmt"):
+        sections.append(f"## statix\n\n{fmt_errfmt(f'{d}/statix.errfmt')}")
+
+    if has_findings(f"{d}/deadnix.rdjsonl"):
+        sections.append(f"## deadnix\n\n{fmt_rdjsonl(f'{d}/deadnix.rdjsonl')}")
+
+    if has_findings(f"{d}/cycles.rdjsonl"):
+        sections.append(f"## systemd ordering cycles\n\n{fmt_rdjsonl(f'{d}/cycles.rdjsonl')}")
+
+    if sections:
+        print("\n\n".join(["# Lint findings"] + sections))
+        sys.exit(1)
+    else:
+        print("No lint findings.")
+        sys.exit(0)
+
+
 def post_comment(args):
     body = args.marker + "\n" + Path(args.body_file).read_text()
     pr = os.environ["PR"]
@@ -438,6 +492,7 @@ def main():
     command("vulnix", vulnix, "ref", "body_out")
     command("lint", lint, "target", "out")
     command("lint-report", lint_report, "reporter", "dir")
+    command("lint-summary", lint_summary, "dir")
     command("post-comment", post_comment, "marker", "body_file")
     command("upsert-issue", upsert_issue, "label", "title", "body_file")
     command("close-issue", close_issue, "label")

containers/common/overseer.nix

@@ -381,6 +381,6 @@ let
         };
       };
     };
-  hostAddr = c.hostAddr;
+  inherit (c) hostAddr;
 in
 c

containers/server-n0/git.nix

@@ -55,7 +55,8 @@ in
     net.expose.tcp = [ 3000 ];
   };
 
-  ci-runner = mkVm {
+  ci-runner =
+    mkVm {
       name = "ci-runner";
       includedInTests = false;
       net.access = [
@@ -75,6 +76,12 @@ in
           source = "${ciRunnerData}/nix-rw-store";
           mountPoint = "/nix/.rw-store";
         }
+        {
+          proto = "virtiofs";
+          tag = "nix-db";
+          source = "${ciRunnerData}/nix-db";
+          mountPoint = "/nix/var/nix/db";
+        }
         {
           proto = "virtiofs";
           tag = "docker-data";
@@ -152,22 +159,33 @@ in
               "flakes"
             ];
             max-jobs = "auto";
+            substituters = [ "https://microvm.cachix.org" ];
+            trusted-public-keys = [ "microvm.cachix.org-1:oXnBc6hRE3eX5rSYdRyMYXnfzcCxC7yKPTbZXALsqys=" ];
           };
 
-        nix.gc = {
+          nix.settings = {
-          automatic = true;
+            min-free = 5 * 1024 * 1024 * 1024;
-          dates = "daily";
+            max-free = 10 * 1024 * 1024 * 1024;
-          options = "--delete-older-than 14d";
           };
           # nix.optimise.automatic = true; - doesn't work with microvm.writableStoreOverlay
 
+          services.openssh = {
+            enable = true;
+            settings = {
+              PermitRootLogin = "yes";
+              PermitEmptyPasswords = "yes";
+            };
+          };
+          users.users.root.initialHashedPassword = "";
           services.journald.extraConfig = "ForwardToConsole=yes";
 
           virtualisation.containerd.enable = true;
-        virtualisation.containerd.settings.plugins."io.containerd.snapshotter.v1.overlayfs".mount_options = [ "userxattr" ];
+          virtualisation.containerd.settings.plugins."io.containerd.snapshotter.v1.overlayfs".mount_options =
+            [ "userxattr" ];
 
           virtualisation.docker.enable = true;
           virtualisation.docker.extraOptions = "--containerd /run/containerd/containerd.sock";
+          virtualisation.docker.daemon.settings.exec-opts = [ "native.cgroupdriver=cgroupfs" ];
           systemd.services.docker.wants = [ "containerd.service" ];
           systemd.services.docker.after = [ "containerd.service" ];
 
@@ -201,5 +219,15 @@ in
             };
           };
         };
+    }
+    // {
+      hostConfig = {
+        systemd.tmpfiles.rules = [
+          "d ${ciRunnerData}/nix-rw-store 0755 server server -"
+          "d ${ciRunnerData}/nix-db 0755 server server -"
+          "d ${ciRunnerData}/docker 0755 server server -"
+          "d ${ciRunnerData}/runner-state 0755 server server -"
+        ];
+      };
     };
 }

containers/server-n0/nginx.nix

@@ -210,6 +210,6 @@ let
     };
     inherit (setup) containerConfig;
   };
-  hostAddr = c.hostAddr;
+  inherit (c) hostAddr;
 in
 c

containers/server-n0/ssh.nix

@@ -61,27 +61,16 @@ let
       net ? { },
       resources ? { },
       traits ? [ ],
-      isolation ? { },
     }:
     mkContainer {
       inherit name;
       inherit net resources;
       svc.autoStart = true;
-      isolation = { nixDaemon = nixDaemon; } // isolation;
+      isolation.nixDaemon = nixDaemon;
       traits = [ sshTrait ] ++ traits;
       packages = with pkgs; [ tmux ] ++ packages;
       miscProperties = self._sshpiperRegister routingInfo;
     };
-
-  kvmTrait = {
-    containerConfig =
-      { pkgs, ... }:
-      {
-        users.users.runner.extraGroups = [ "wheel" ];
-        security.sudo.wheelNeedsPassword = false;
-        environment.systemPackages = [ pkgs.qemu_kvm ];
-      };
-  };
 in
 {
   ssh-admin = mkSsh {
@@ -132,25 +121,6 @@ in
       mem = "16G";
       cpu = 65;
     };
-    traits = [ kvmTrait ];
-    isolation.allowedDevices = [
-      {
-        node = "/dev/kvm";
-        modifier = "rw";
-      }
-      {
-        node = "/dev/vhost-net";
-        modifier = "rw";
-      }
-      {
-        node = "/dev/net/tun";
-        modifier = "rwm";
-      }
-    ];
-    isolation.additionalCapabilities = [
-      "CAP_NET_ADMIN"
-      "CAP_MKNOD"
-    ];
     routingInfo = [
       {
         username = "autumn";

dsl.nix

@@ -228,17 +228,6 @@ rec {
     : systemd-nspawn user namespacing; see `--private-users=` in
       systemd-nspawn(1). Bind mounts always go through idmapped `--bind`.
 
-    `isolation.allowedDevices`
-    : List of `{ node; modifier; }` host devices to grant the container's
-      cgroup access to; see `containers.<name>.allowedDevices` in the NixOS
-      manual. nspawn bind-mounts a handful of devices (`/dev/kvm`,
-      `/dev/net/tun`, ...) into the container itself once the cgroup allows it -
-      this doesn't need a matching `resources.fs` bind mount.
-
-    `isolation.additionalCapabilities`
-    : Extra Linux capabilities granted to the container; see
-      `containers.<name>.additionalCapabilities` in the NixOS manual.
-
     `miscProperties`
     : Arbitrary data attached to the result. Used for cross-container discovery
       via `collectContainers`.
@@ -283,8 +272,6 @@ rec {
       bindMounts = resources.fs or { };
       allowsNixDaemon = isolation.nixDaemon or false;
       privateUsers = isolation.privateUsers or "pick";
-      allowedDevices = isolation.allowedDevices or [ ];
-      additionalCapabilities = isolation.additionalCapabilities or [ ];
 
       allowInternet = hasInternetAccess access;
       allBindMounts = builtins.foldl' (acc: t: acc // (t.resources.fs or { })) { } traits // bindMounts;
@@ -381,12 +368,7 @@ rec {
       kind = "nspawn";
       miscProperties = flattenMiscProp self miscProperties;
       nixosContainer = {
-        inherit
+        inherit autoStart privateUsers;
-          autoStart
-          privateUsers
-          allowedDevices
-          additionalCapabilities
-          ;
         bindMounts = { };
         extraFlags = bindMountExtraFlags;
         privateNetwork = true;
@@ -572,7 +554,10 @@ rec {
               Gateway = hostAddr;
             };
             networkConfig.DNS = [ hostAddr ];
-            networkConfig.Domains = [ "~." "containers" ];
+            networkConfig.Domains = [
+              "~."
+              "containers"
+            ];
             linkConfig.RequiredForOnline = if allowInternet then "routable" else "degraded";
           };
           networking.enableIPv6 = false;

flake.nix

@@ -129,11 +129,10 @@
     {
       nixosConfigurations = lib.mapAttrs (_: host: host.hostCfg) allHosts;
 
-      inspect = lib.mapAttrs
+      inspect = lib.mapAttrs (
-        (name: host:
+        name: host:
-          pkgs.writeText "inspect-${name}.json"
+        pkgs.writeText "inspect-${name}.json" (builtins.toJSON (introspect.hostReport { inherit host; }))
-            (builtins.toJSON (introspect.hostReport { inherit host; })))
+      ) allHosts;
-        allHosts;
 
       packages.${system} = customPkgs // {
         inherit ci;

tests/server-n0/integration.py

@@ -205,12 +205,7 @@ with subtest("(isolation): edges are one-way"):
     server.fail(ct_connect("git", ADDR["nginx"], 443, timeout=2))
 
 with subtest("(isolation): host access allowlist"):
-    server.succeed(
+    server.succeed(ct_connect("overseer", HOST_ADDR["overseer"], HOST_EXPORTER_PORT))
-        net_cmd(
-            "overseer",
-            f"{CURL} -sf --max-time 5 http://{HOST_ADDR['overseer']}:{HOST_EXPORTER_PORT}/metrics >&2",
-        )
-    )
     for port in (HOST_EXPORTER_PORT, HOST_CADVISOR_PORT):
         server.fail(ct_connect("git", HOST_ADDR["git"], port, timeout=2))
         server.fail(ct_connect("git", HOST_ADDR["overseer"], port, timeout=2))