Scheduler fails on NixOS: invalid OnCalendar format, hardcoded /usr/bin/perl, macOS-only PATH

[KaminariOS]

Environment

• OS: NixOS (Linux, systemd-based)
• opencode: 1.2.26
• opencode-scheduler: latest

Problem

The scheduler plugin generates systemd timer/service units that fail immediately on NixOS with:

Failed to start opencode-job-....timer: Unit ... has a bad unit file setting.

There are three distinct bugs, all in src/index.ts:

---

Bug 1: Invalid OnCalendar format (line 841)

Function: cronToSystemdCalendars

The generated calendar spec includes a leading * as a day-of-week field:

OnCalendar=* *-*-* 08:00:00

systemd does not accept * as a day-of-week prefix. The correct format when no specific day is constrained is simply:

OnCalendar=*-*-* 08:00:00

systemd logs confirm:

Failed to parse calendar specification, ignoring: * *-*-* 08:00:00
Timer unit lacks value setting. Refusing.

Root cause — line 841:

calendars.push(`${dowValue} *-${monthValue}-${domValue} ${hourValue}:${minuteValue}:00`)

When dowValue is "*", it produces an invalid spec. The day-of-week prefix should only be included when it's an actual day name (Mon, Tue, etc.).

Proposed fix:

const prefix = dowValue === "*" ? "" : `${dowValue} `;
calendars.push(`${prefix}*-${monthValue}-${domValue} ${hourValue}:${minuteValue}:00`);

---

Bug 2: Hardcoded /usr/bin/perl (lines 1052, 1160, 1412)

The ExecStart in generated systemd service units hardcodes /usr/bin/perl:

ExecStart="/usr/bin/perl" "/home/.../.config/opencode/scheduler/supervisor.pl" "..."

On NixOS, perl lives in the Nix store (e.g., /nix/store/...-perl-5.x.y/bin/perl) or is available via /run/current-system/sw/bin/perl. /usr/bin/perl does not exist.

This affects:

• createSystemdService (line 1160) — Linux
• createLaunchdPlist (line 1052) — macOS
• createCronEntry (line 1412) — fallback

Proposed fix: Detect the perl path dynamically at job creation time:

import { execSync } from "child_process";

function findPerl(): string {
  try {
    return execSync("command -v perl", { encoding: "utf-8" }).trim();
  } catch {
    return "/usr/bin/perl"; // fallback
  }
}

---

Bug 3: macOS-only PATH in generated units (lines 663-673)

Function: getEnhancedPath

function getEnhancedPath(): string {
  const paths = [
    "/opt/homebrew/bin",
    "/usr/local/bin",
    "/usr/bin",
    "/bin",
    "/usr/sbin",
    "/sbin",
  ]
  return paths.join(":")
}

This is used as Environment="PATH=..." in the systemd service unit (line 1170). On NixOS, none of these contain any user tools — binaries are in /nix/store/..., ~/.nix-profile/bin, /run/current-system/sw/bin, etc.

Even if bug 2 were fixed to use a bare perl command, it would still fail because PATH doesn't include any NixOS paths.

Proposed fix: Capture and embed the current process.env.PATH (which contains the correct paths at plugin load time), with the hardcoded paths as fallbacks:

function getEnhancedPath(): string {
  const fallbackPaths = [
    "/opt/homebrew/bin",
    "/usr/local/bin",
    "/usr/bin",
    "/bin",
    "/usr/sbin",
    "/sbin",
  ];

  const currentPath = process.env.PATH || "";
  if (currentPath) {
    // Deduplicate: append fallbacks that aren't already present
    const existing = new Set(currentPath.split(":"));
    const extras = fallbackPaths.filter((p) => !existing.has(p));
    return [currentPath, ...extras].join(":");
  }

  return fallbackPaths.join(":");
}

---

Workaround

For anyone hitting this on NixOS, you can manually fix the generated units after job creation:

1. Fix the timer — remove the leading * from OnCalendar:

   OnCalendar=*-*-* 08:00:00

2. Fix the service — update ExecStart to use the NixOS perl path:

   ExecStart=/run/current-system/sw/bin/perl ...

3. Fix PATH:

   Environment="PATH=/run/current-system/sw/bin:/home/<user>/.nix-profile/bin:/nix/var/nix/profiles/default/bin:/usr/bin:/bin"

4. Reload and enable:

   systemctl --user daemon-reload
   systemctl --user enable --now <timer-unit>

Reproduction

# On NixOS, any schedule_job call will fail:
# opencode scheduler creates the units, then runs:
#   systemctl --user start <timer>
# which immediately fails with "bad unit file setting"

[Nvious1]

I can confirm I also see the OnCalendar bug on my system.

Environment
- OS: Ubuntu 26.04 LTS
- Kernel: Linux 7.0.0-27-generic x86_64
- systemd: 259
- Node: v24.18.0
- OpenCode 1.17.13
- OpenCode Scheduler 1.3.0

Symptom

Any job whose cron leaves the day-of-week field unspecified (e.g. */10 * * * *) produces a timer that never fires. systemctl --user status <timer> shows Loaded: bad-setting and the journal logs:

Fix for me — omit the DOW token when it's *:

for (const dowValue of dowValues) {
 const dowPrefix = dowValue === "*" ? "" : `${dowValue} `;
 calendars.push(`${dowPrefix}*-${monthValue}-${domValue} ${hourValue}:${minuteValue}:00`);
}