hyperhive/nix/modules/hive-ci.nix

242 lines
9.5 KiB
Nix

{
pkgs,
lib,
config,
...
}:
let
cfg = config.services.hyperhive.forge.ci;
forgeCfg = config.services.hyperhive.forge;
# hive-c0re writes its own admin token here on first forge startup.
# The token has read:admin + write:admin scopes — sufficient to call
# the runner registration-token API endpoint.
coreTokenPath = "/var/lib/hyperhive/forge-core-token";
# Oneshot run before gitea-runner-hive.service starts.
#
# The nixpkgs gitea-actions-runner module uses tokenFile as a systemd
# EnvironmentFile (sets TOKEN= in the environment). EnvironmentFile is
# loaded before any ExecStartPre, so the file MUST exist at service start —
# an ExecStartPre override is too late. We solve this with:
# 1. tmpfiles: pre-create /run/hive-ci/runner-token with TOKEN=placeholder
# 2. hive-ci-register.service (this script): on first boot only,
# fetch the real token from forge and overwrite with TOKEN=<real>.
# 3. gitea-runner-hive.service: After=hive-ci-register.service
#
# On subsequent boots: .runner credentials file exists so the nixpkgs
# register step exits early — TOKEN value in the EnvironmentFile is
# irrelevant (placeholder is fine).
registerScript = pkgs.writeShellScript "hive-ci-register" ''
set -euo pipefail
TOKEN_FILE=/run/hive-ci/runner-token
CORE_TOKEN=$(cat /run/hive-ci/core-token)
FORGE_URL="http://127.0.0.1:${toString forgeCfg.httpPort}"
# Retry up to 30s for forge to come up (containers autoStart in parallel).
for i in $(seq 1 30); do
REG_TOKEN=$(${pkgs.curl}/bin/curl -sf \
"$FORGE_URL/api/v1/admin/runners/registration-token" \
-H "Authorization: token $CORE_TOKEN" \
| ${pkgs.jq}/bin/jq -r .token) && break
sleep 1
done
if [ -z "''${REG_TOKEN:-}" ] || [ "$REG_TOKEN" = "null" ]; then
echo "hive-ci: failed to fetch runner registration token from forge" >&2
exit 1
fi
# Write in EnvironmentFile format: TOKEN=<value>.
# File is already 0600 (set by tmpfiles on boot).
echo "TOKEN=$REG_TOKEN" > "$TOKEN_FILE"
'';
in
{
# Forgejo Actions runner in a `hive-ci` nixos-container.
# Shares host netns (same as hive-forge), so the runner reaches
# the forge at `http://127.0.0.1:<httpPort>` without extra plumbing.
# Container is non-ephemeral: the runner's registered credentials
# survive restarts (gitea-actions-runner writes them to its stateDir
# on first registration and reuses them on every subsequent start).
#
# Auto-registration: on first boot a oneshot service fetches a runner
# registration token from the forge's admin API using the core token
# hive-c0re writes to /var/lib/hyperhive/forge-core-token. No manual
# token handling needed — `forge.ci.enable = true` is the full operator
# bootstrap.
#
# Nix builds inside the container use the shared /nix/store (standard
# nixos-container behaviour) with sandbox-fallback = true, because
# nspawn containers can't create the user-namespaces that nix sandboxing
# requires. See docs/gotchas.md.
options.services.hyperhive.forge.ci = {
enable = lib.mkOption {
type = lib.types.bool;
default = false;
example = true;
description = ''
Run a Forgejo Actions runner in a `hive-ci` nixos-container.
Grouped under `services.hyperhive.forge` because the runner is
tightly coupled to the forge instance it registers against.
Disabled by default; `services.hyperhive.forge.enable = true` is
a prerequisite (enforced by assertion).
On first start the container auto-registers against hive-forge using
hive-c0re's admin token no manual token provisioning needed.
Runner credentials are persisted in the container's state dir and
reused on every subsequent boot.
'';
};
name = lib.mkOption {
type = lib.types.str;
default = "hive-ci";
example = "prod-hive";
description = ''
Runner name as shown in the Forgejo admin panel. Defaults to
"hive-ci"; override when multiple hives share a Forgejo instance.
'';
};
concurrency = lib.mkOption {
type = lib.types.ints.positive;
default = 1;
example = 4;
description = ''
Maximum number of workflow jobs the runner executes in parallel.
Each job gets its own temporary working directory; multiple parallel
jobs share the container's nix store and cargo registry cache.
Higher values trade memory + CPU headroom for throughput.
'';
};
labels = lib.mkOption {
type = lib.types.listOf lib.types.str;
default = [ "hive-ci:host" ];
example = [
"hive-ci:host"
"nix:host"
];
description = ''
Runner labels in `<name>:<scheme>` format. The `host` scheme runs
commands directly in the container (no docker/podman). Workflow
files target this runner with `runs-on: [hive-ci]`.
'';
};
package = lib.mkOption {
type = lib.types.package;
default = pkgs.gitea-actions-runner;
defaultText = lib.literalExpression "pkgs.gitea-actions-runner";
description = "gitea-actions-runner package.";
};
};
config = lib.mkIf cfg.enable {
assertions = [
{
assertion = forgeCfg.enable;
message = ''
services.hyperhive.forge.ci.enable = true requires
services.hyperhive.forge.enable = true the runner registers
against the hive-forge Forgejo instance.
'';
}
];
containers.hive-ci = {
autoStart = true;
ephemeral = false;
# Shared host netns: runner reaches hive-forge at localhost.
privateNetwork = false;
bindMounts = {
# Core token — used by hive-ci-register.service on first boot.
# Read-only: the container only reads it, never modifies it.
"/run/hive-ci/core-token" = {
hostPath = coreTokenPath;
isReadOnly = true;
};
};
config =
{ pkgs, lib, ... }:
{
system.stateVersion = "26.05";
# nspawn containers can't create user-namespaces, so nix
# sandboxing always fails. Fall back to unsandboxed builds.
# See docs/gotchas.md.
nix.settings.sandbox-fallback = lib.mkForce true;
nix.settings.experimental-features = [
"nix-command"
"flakes"
];
# package is top-level on gitea-actions-runner, not per-instance.
services.gitea-actions-runner.package = cfg.package;
services.gitea-actions-runner.instances.hive = {
enable = true;
name = cfg.name;
url = "http://127.0.0.1:${toString forgeCfg.httpPort}";
# EnvironmentFile providing TOKEN= for the nixpkgs register step.
# Pre-created by tmpfiles (placeholder); overwritten with the real
# token by hive-ci-register.service on first boot only.
tokenFile = "/run/hive-ci/runner-token";
labels = cfg.labels;
settings = {
runner.capacity = cfg.concurrency;
# Generous timeout for cold-cache nix builds.
runner.timeout = "3h";
};
};
# Pre-create the EnvironmentFile so gitea-runner-hive.service can
# always load it. The nixpkgs module sets EnvironmentFile=tokenFile
# which systemd loads before any ExecStartPre — the file must exist
# at service-start time. On first boot hive-ci-register.service
# overwrites this placeholder with the real token before the runner
# starts. On subsequent boots the placeholder is harmless because
# the nixpkgs register step exits early when .runner already exists.
#
# Note: `f` doesn't create parent directories, but /run/hive-ci/
# is guaranteed to exist by the time container systemd starts:
# nspawn creates mount-point directories for all bindMounts before
# launching the container's init. So the dir is there when
# systemd-tmpfiles-setup.service runs.
systemd.tmpfiles.rules = [
"f /run/hive-ci/runner-token 0600 root root - TOKEN=placeholder"
];
# Oneshot that fetches a runner registration token from the forge
# admin API and writes it to the EnvironmentFile. Runs only on
# first boot (ConditionPathExists gates on .runner absence) and
# before gitea-runner-hive.service via the After= dependency below.
systemd.services.hive-ci-register = {
description = "Register hive-ci runner against Forgejo (first boot)";
serviceConfig = {
Type = "oneshot";
RemainAfterExit = true;
ExecStart = registerScript;
};
# Only needed before .runner credentials exist.
unitConfig.ConditionPathExists = "!/var/lib/gitea-runner/hive/.runner";
};
# Runner must start after the register oneshot so the EnvironmentFile
# contains the real token on first boot.
systemd.services."gitea-runner-hive".after = [ "hive-ci-register.service" ];
systemd.services."gitea-runner-hive".wants = [ "hive-ci-register.service" ];
# git is required by the runner's checkout step.
# Everything else (nix, rust tools) is either part of NixOS
# by default or pulled in hermetically by nix flake check.
# curl/jq in the register script use absolute store paths.
environment.systemPackages = [ pkgs.git ];
};
};
};
}