Files
Linux_post_install/DOC/SYSTEMD.md
T
Your Name 025971ca1e feat: multi-platform alerting + shared system.env config with dynamic help values
- lib/notify.sh: route notify_send to every platform in NOTIFY_PLATFORM
  (notify.env, default telegram; comma-separated = send to all). New
  platforms need only a bin/pos-communication-<p> sender implementing
  'send <value> [--markdown]' (Matrix/Synapse ready)
- pos-communication-telegram: add --markdown as alias for --parse-mode
  markdown to match the sender contract
- lib/common.sh: load_system_env() — shared ~/.config/linux_post_install/
  system.env for pos-system-* tools (env exported > file > default)
- pos-system-health/backup: load system.env and show effective dynamic
  values (NOTIFY_PLATFORM, HEALTH_BACKUP_MAX_AGE_DAYS, BACKUP_SERVICE_ROOTS)
  in --help
- config/system.env + config/notify.env templates copied by postinstall
- systemd/pos-health.service: EnvironmentFile for both configs so the
  daily digest honors them
2026-08-06 02:37:56 -04:00

124 lines
4.6 KiB
Markdown

# Systemd & Shell Integration Reference
The units installed and enabled by `postinstall.sh`, plus the `pos` bash completion.
- [Services](#services)
- [`autostart.service`](#autostartservice)
- [`ssh-agent.service`](#ssh-agentservice)
- [`pos-health.service`](#pos-healthservice)
- [Feature-flag gating](#feature-flag-gating)
- [Bash completion](#bash-completion)
---
## Services
`postinstall.sh` copies every `systemd/*.service` (and `systemd/*.timer`) to `/etc/systemd/system/`, runs `systemctl daemon-reload`, then enables each one (see the gating rule below).
### autostart.service
**Purpose:** run `features/autostart.sh` at boot (after the network is online) and keep retrying if it fails.
```ini
[Unit]
Description=My Linux Autostart Script
After=network-online.target
Wants=network-online.target
[Service]
Type=simple
ExecStart=/usr/local/bin/autostart.sh
Restart=on-failure
RestartSec=10
[Install]
WantedBy=multi-user.target
```
**Configuration:** point `ExecStart` at your boot script. Because the target script is a *feature*, this unit is only **enabled** when the `autostart` flag is set — the file is still copied, but a skipped feature leaves the unit present-but-disabled.
### ssh-agent.service
**Purpose:** a system-wide SSH agent, one shared socket for all sessions (so `pos ssh load-keys` and everyday ssh work without per-login agents).
```ini
[Unit]
Description=SSH Authentication Agent
After=network.target
[Service]
Type=simple
ExecStartPre=mkdir -p /run/ssh-agent
ExecStart=/usr/bin/ssh-agent -D -a /run/ssh-agent/socket
ExecStartPost=/bin/sh -c 'chmod 666 /run/ssh-agent/socket'
ExecStopPost=/bin/sh -c 'rm -f /run/ssh-agent/socket'
Restart=on-failure
[Install]
WantedBy=multi-user.target
```
**Configuration:** socket at `/run/ssh-agent/socket` (world-readable/writable). `~/.bashrc` (set by `postinstall.sh`) exports `SSH_AUTH_SOCK` to it. Not gated on any feature flag.
### pos-health.service
**Purpose:** daily "health digest" — runs `pos system health --send --markdown` at 08:00 and sends the report to the configured notify platform(s).
```ini
[Unit]
Description=POS Health digest (daily report via configured notify platforms)
After=network-online.target
Wants=network-online.target
[Service]
Type=oneshot
User=__POS_USER__
EnvironmentFile=-%h/.config/linux_post_install/system.env
EnvironmentFile=-%h/.config/linux_post_install/notify.env
ExecStart=/usr/local/bin/pos system health --send --markdown
[Timer]
OnCalendar=*-*-* 08:00:00
Persistent=true
```
The service is `Type=oneshot` and is driven **only** by its companion `pos-health.timer` (`WantedBy=timers.target`); the service itself is never enabled directly.
**Configuration:** `postinstall.sh` substitutes `__POS_USER__` with the installing user (`${SUDO_USER:-$USER}`) so the digest uses that user's real notify config. The `EnvironmentFile=` lines load `system.env` (health/backup settings) and `notify.env` (`NOTIFY_PLATFORM`). The timer is enabled only when a Telegram config (`~/.config/linux_post_install/telegram.env`) already exists — otherwise postinstall warns and skips; re-run postinstall after configuring a notify platform to install it.
---
## Feature-flag gating
The systemd loop in `postinstall.sh` special-cases two units:
```bash
if [ "$svc_name" = "autostart.service" ] && ! flag_is_set autostart; then
warn "autostart feature not installed — skipping autostart.service (run ./install.sh --feature)"
continue
fi
if [ "$svc_name" = "pos-health.service" ]; then
# substitute User= and enable pos-health.timer only if Telegram is configured
fi
```
- `autostart.service` is **enabled** only when the `autostart` feature flag is set (`./install.sh --feature` or `flag-set autostart`). See [SCRIPTS.md → lib/flags.sh](SCRIPTS.md#libflagssh--feature-flags).
- `pos-health.service` is **not** enabled at all — `postinstall.sh` enables `pos-health.timer` instead, and only when a Telegram config already exists.
---
## Bash completion
**File:** `completions/pos.bash`
**Purpose:** tab-completion for the `pos` CLI.
### How it works
- **Dynamically discovers** subcommands by listing executable `pos-*` files next to the `pos` binary — no hard-coded command list, so new tools complete automatically.
- Works with the `bash-completion` package (`_init_completion`) and falls back to a manual init if it isn't loaded.
- Provides completion for the first two words of `pos <category> <command>`.
### Configuration
Installed by `postinstall.sh` to `/usr/local/share/bash-completion/completions/pos.bash` and sourced from `~/.bashrc`. To load it manually: `source completions/pos.bash` (or copy into `/etc/bash_completion.d/`).