3
0
Fork 0
forked from mirrors/nixpkgs
nixpkgs/nixos/modules/services/continuous-integration/github-runner.nix
pennae 2e751c0772 treewide: automatically md-convert option descriptions
the conversion procedure is simple:

 - find all things that look like options, ie calls to either `mkOption`
   or `lib.mkOption` that take an attrset. remember the attrset as the
   option
 - for all options, find a `description` attribute who's value is not a
   call to `mdDoc` or `lib.mdDoc`
 - textually convert the entire value of the attribute to MD with a few
   simple regexes (the set from mdize-module.sh)
 - if the change produced a change in the manual output, discard
 - if the change kept the manual unchanged, add some text to the
   description to make sure we've actually found an option. if the
   manual changes this time, keep the converted description

this procedure converts 80% of nixos options to markdown. around 2000
options remain to be inspected, but most of those fail the "does not
change the manual output check": currently the MD conversion process
does not faithfully convert docbook tags like <code> and <package>, so
any option using such tags will not be converted at all.
2022-07-30 15:16:34 +02:00

335 lines
12 KiB
Nix

{ config, pkgs, lib, ... }:
with lib;
let
cfg = config.services.github-runner;
svcName = "github-runner";
systemdDir = "${svcName}/${cfg.name}";
# %t: Runtime directory root (usually /run); see systemd.unit(5)
runtimeDir = "%t/${systemdDir}";
# %S: State directory root (usually /var/lib); see systemd.unit(5)
stateDir = "%S/${systemdDir}";
# %L: Log directory root (usually /var/log); see systemd.unit(5)
logsDir = "%L/${systemdDir}";
# Name of file stored in service state directory
currentConfigTokenFilename = ".current-token";
in
{
options.services.github-runner = {
enable = mkOption {
default = false;
example = true;
description = ''
Whether to enable GitHub Actions runner.
Note: GitHub recommends using self-hosted runners with private repositories only. Learn more here:
<link xlink:href="https://docs.github.com/en/actions/hosting-your-own-runners/about-self-hosted-runners"
>About self-hosted runners</link>.
'';
type = lib.types.bool;
};
url = mkOption {
type = types.str;
description = lib.mdDoc ''
Repository to add the runner to.
Changing this option triggers a new runner registration.
IMPORTANT: If your token is org-wide (not per repository), you need to
provide a github org link, not a single repository, so do it like this
`https://github.com/nixos`, not like this
`https://github.com/nixos/nixpkgs`.
Otherwise, you are going to get a `404 NotFound`
from `POST https://api.github.com/actions/runner-registration`
in the configure script.
'';
example = "https://github.com/nixos/nixpkgs";
};
tokenFile = mkOption {
type = types.path;
description = lib.mdDoc ''
The full path to a file which contains the runner registration token.
The file should contain exactly one line with the token without any newline.
The token can be used to re-register a runner of the same name but is time-limited.
Changing this option or the file's content triggers a new runner registration.
'';
example = "/run/secrets/github-runner/nixos.token";
};
name = mkOption {
# Same pattern as for `networking.hostName`
type = types.strMatching "^$|^[[:alnum:]]([[:alnum:]_-]{0,61}[[:alnum:]])?$";
description = lib.mdDoc ''
Name of the runner to configure. Defaults to the hostname.
Changing this option triggers a new runner registration.
'';
example = "nixos";
default = config.networking.hostName;
defaultText = literalExpression "config.networking.hostName";
};
runnerGroup = mkOption {
type = types.nullOr types.str;
description = lib.mdDoc ''
Name of the runner group to add this runner to (defaults to the default runner group).
Changing this option triggers a new runner registration.
'';
default = null;
};
extraLabels = mkOption {
type = types.listOf types.str;
description = lib.mdDoc ''
Extra labels in addition to the default (`["self-hosted", "Linux", "X64"]`).
Changing this option triggers a new runner registration.
'';
example = literalExpression ''[ "nixos" ]'';
default = [ ];
};
replace = mkOption {
type = types.bool;
description = lib.mdDoc ''
Replace any existing runner with the same name.
Without this flag, registering a new runner with the same name fails.
'';
default = false;
};
extraPackages = mkOption {
type = types.listOf types.package;
description = lib.mdDoc ''
Extra packages to add to `PATH` of the service to make them available to workflows.
'';
default = [ ];
};
package = mkOption {
type = types.package;
description = lib.mdDoc ''
Which github-runner derivation to use.
'';
default = pkgs.github-runner;
defaultText = literalExpression "pkgs.github-runner";
};
};
config = mkIf cfg.enable {
warnings = optionals (isStorePath cfg.tokenFile) [
''
`services.github-runner.tokenFile` points to the Nix store and, therefore, is world-readable.
Consider using a path outside of the Nix store to keep the token private.
''
];
systemd.services.${svcName} = {
description = "GitHub Actions runner";
wantedBy = [ "multi-user.target" ];
wants = [ "network-online.target" ];
after = [ "network.target" "network-online.target" ];
environment = {
HOME = runtimeDir;
RUNNER_ROOT = runtimeDir;
};
path = (with pkgs; [
bash
coreutils
git
gnutar
gzip
]) ++ [
config.nix.package
] ++ cfg.extraPackages;
serviceConfig = rec {
ExecStart = "${cfg.package}/bin/runsvc.sh";
# Does the following, sequentially:
# - If the module configuration or the token has changed, purge the state directory,
# and create the current and the new token file with the contents of the configured
# token. While both files have the same content, only the later is accessible by
# the service user.
# - Configure the runner using the new token file. When finished, delete it.
# - Set up the directory structure by creating the necessary symlinks.
ExecStartPre =
let
# Wrapper script which expects the full path of the state, runtime and logs
# directory as arguments. Overrides the respective systemd variables to provide
# unambiguous directory names. This becomes relevant, for example, if the
# caller overrides any of the StateDirectory=, RuntimeDirectory= or LogDirectory=
# to contain more than one directory. This causes systemd to set the respective
# environment variables with the path of all of the given directories, separated
# by a colon.
writeScript = name: lines: pkgs.writeShellScript "${svcName}-${name}.sh" ''
set -euo pipefail
STATE_DIRECTORY="$1"
RUNTIME_DIRECTORY="$2"
LOGS_DIRECTORY="$3"
${lines}
'';
currentConfigPath = "$STATE_DIRECTORY/.nixos-current-config.json";
runnerRegistrationConfig = getAttrs [ "name" "tokenFile" "url" "runnerGroup" "extraLabels" ] cfg;
newConfigPath = builtins.toFile "${svcName}-config.json" (builtins.toJSON runnerRegistrationConfig);
newConfigTokenFilename = ".new-token";
runnerCredFiles = [
".credentials"
".credentials_rsaparams"
".runner"
];
unconfigureRunner = writeScript "unconfigure" ''
differs=
# Set `differs = 1` if current and new runner config differ or if `currentConfigPath` does not exist
${pkgs.diffutils}/bin/diff -q '${newConfigPath}' "${currentConfigPath}" >/dev/null 2>&1 || differs=1
# Also trigger a registration if the token content changed
${pkgs.diffutils}/bin/diff -q \
"$STATE_DIRECTORY"/${currentConfigTokenFilename} \
${escapeShellArg cfg.tokenFile} \
>/dev/null 2>&1 || differs=1
if [[ -n "$differs" ]]; then
echo "Config has changed, removing old runner state."
echo "The old runner will still appear in the GitHub Actions UI." \
"You have to remove it manually."
find "$STATE_DIRECTORY/" -mindepth 1 -delete
# Copy the configured token file to the state dir and allow the service user to read the file
install --mode=666 ${escapeShellArg cfg.tokenFile} "$STATE_DIRECTORY/${newConfigTokenFilename}"
# Also copy current file to allow for a diff on the next start
install --mode=600 ${escapeShellArg cfg.tokenFile} "$STATE_DIRECTORY/${currentConfigTokenFilename}"
fi
'';
configureRunner = writeScript "configure" ''
if [[ -e "$STATE_DIRECTORY/${newConfigTokenFilename}" ]]; then
echo "Configuring GitHub Actions Runner"
token=$(< "$STATE_DIRECTORY"/${newConfigTokenFilename})
RUNNER_ROOT="$STATE_DIRECTORY" ${cfg.package}/bin/config.sh \
--unattended \
--disableupdate \
--work "$RUNTIME_DIRECTORY" \
--url ${escapeShellArg cfg.url} \
--token "$token" \
--labels ${escapeShellArg (concatStringsSep "," cfg.extraLabels)} \
--name ${escapeShellArg cfg.name} \
${optionalString cfg.replace "--replace"} \
${optionalString (cfg.runnerGroup != null) "--runnergroup ${escapeShellArg cfg.runnerGroup}"}
# Move the automatically created _diag dir to the logs dir
mkdir -p "$STATE_DIRECTORY/_diag"
cp -r "$STATE_DIRECTORY/_diag/." "$LOGS_DIRECTORY/"
rm -rf "$STATE_DIRECTORY/_diag/"
# Cleanup token from config
rm "$STATE_DIRECTORY/${newConfigTokenFilename}"
# Symlink to new config
ln -s '${newConfigPath}' "${currentConfigPath}"
fi
'';
setupRuntimeDir = writeScript "setup-runtime-dirs" ''
# Link _diag dir
ln -s "$LOGS_DIRECTORY" "$RUNTIME_DIRECTORY/_diag"
# Link the runner credentials to the runtime dir
ln -s "$STATE_DIRECTORY"/{${lib.concatStringsSep "," runnerCredFiles}} "$RUNTIME_DIRECTORY/"
'';
in
map (x: "${x} ${escapeShellArgs [ stateDir runtimeDir logsDir ]}") [
"+${unconfigureRunner}" # runs as root
configureRunner
setupRuntimeDir
];
# Contains _diag
LogsDirectory = [ systemdDir ];
# Default RUNNER_ROOT which contains ephemeral Runner data
RuntimeDirectory = [ systemdDir ];
# Home of persistent runner data, e.g., credentials
StateDirectory = [ systemdDir ];
StateDirectoryMode = "0700";
WorkingDirectory = runtimeDir;
InaccessiblePaths = [
# Token file path given in the configuration
cfg.tokenFile
# Token file in the state directory
"${stateDir}/${currentConfigTokenFilename}"
];
# By default, use a dynamically allocated user
DynamicUser = true;
KillMode = "process";
KillSignal = "SIGTERM";
# Hardening (may overlap with DynamicUser=)
# The following options are only for optimizing:
# systemd-analyze security github-runner
AmbientCapabilities = "";
CapabilityBoundingSet = "";
# ProtectClock= adds DeviceAllow=char-rtc r
DeviceAllow = "";
NoNewPrivileges = true;
PrivateDevices = true;
PrivateMounts = true;
PrivateTmp = true;
PrivateUsers = true;
ProtectClock = true;
ProtectControlGroups = true;
ProtectHome = true;
ProtectHostname = true;
ProtectKernelLogs = true;
ProtectKernelModules = true;
ProtectKernelTunables = true;
ProtectSystem = "strict";
RemoveIPC = true;
RestrictNamespaces = true;
RestrictRealtime = true;
RestrictSUIDSGID = true;
UMask = "0066";
ProtectProc = "invisible";
SystemCallFilter = [
"~@clock"
"~@cpu-emulation"
"~@module"
"~@mount"
"~@obsolete"
"~@raw-io"
"~@reboot"
"~capset"
"~setdomainname"
"~sethostname"
];
RestrictAddressFamilies = [ "AF_INET" "AF_INET6" "AF_UNIX" "AF_NETLINK" ];
# Needs network access
PrivateNetwork = false;
# Cannot be true due to Node
MemoryDenyWriteExecute = false;
# The more restrictive "pid" option makes `nix` commands in CI emit
# "GC Warning: Couldn't read /proc/stat"
# You may want to set this to "pid" if not using `nix` commands
ProcSubset = "all";
# Coverage programs for compiled code such as `cargo-tarpaulin` disable
# ASLR (address space layout randomization) which requires the
# `personality` syscall
# You may want to set this to `true` if not using coverage tooling on
# compiled code
LockPersonality = false;
};
};
};
}