# Deploying hsa-app

The app runs as a **user systemd service** (no sudo). Deployment is driven by
git tags:

- **Release tags `X.Y.Z`** (e.g. `1.2.0`) — CI builds + tests, stages the binary
  into `~/hsa-app/releases/hsa-app-V<tag>/hsa`, then **activates** it: points the
  `~/hsa-app/hsa` symlink at that release and restarts the service.
- **Pre-release tags** (anything else, e.g. `0.0.0a2`) — built, tested, and
  staged into `releases/`, but **not** activated. Nothing goes live.

The symlink decouples "what's on disk" from "what's running," so activating a
staged pre-release or rolling back is just a symlink repoint + restart (see
below).

## Layout on the host

Mutable state (DB, env, config) lives at the top of `~/hsa-app/` and survives
every deploy. Only the binaries live under `releases/`.

```
~/hsa-app/
  hsa_app.sh                     # launcher: sources env file, exec's the binary
  hsa_app.env                    # environment (KEY=VALUE)
  config.json
  hsa.db, hsa.db-shm, hsa.db-wal # SQLite state
  releases/
    hsa-app-V0.0.0a0/hsa
    hsa-app-V0.0.1/hsa
  hsa -> releases/hsa-app-V0.0.1/hsa   # current symlink, swapped on deploy
```

## The current symlink

Create/repoint it **from inside `~/hsa-app`** so the relative target resolves
against the link's own directory (running `ln -s` from `~` produces a broken
link that points at `~/hsa-app/hsa-app/...`):

```bash
cd ~/hsa-app
chmod +x releases/hsa-app-V<tag>/hsa
ln -sfn releases/hsa-app-V<tag>/hsa hsa   # -f replace, -n don't follow existing link
ls -l hsa                                  # target must resolve (not broken)
```

This same `ln -sfn` + `chmod +x` is what the CI deploy step runs on each tag.

## Install the service (once)

Save [hsa_app.service](hsa_app.service) to `~/.config/systemd/user/hsa_app.service`,
then:

```bash
loginctl enable-linger "$USER"     # run the service without an active login session
systemctl --user daemon-reload
systemctl --user enable --now hsa_app
systemctl --user status hsa_app
journalctl --user -u hsa_app -f    # follow logs
```

### Why these choices

- **User service** (`systemctl --user`) — no sudo, matches the home-dir deploy.
  `enable-linger` lets it start at boot / stay up without an interactive login.
- **`Type=exec`** — `hsa_app.sh` ends in `exec "$BIN"`, so the binary becomes the
  unit's main process; signals and exit codes propagate correctly.
- **`WorkingDirectory=%h/hsa-app`** — relative paths in the env file resolve here.
  The launcher's comment recommends absolute paths for `DB_PATH` / `STORAGE_DIR` /
  `BACKUP_DIR` / `CONFIG_PATH`; either works.
- **ExecStart passes the env file as `$1`** — matches `hsa_app.sh`'s first-arg
  precedence, so no `/etc/hsa-app/...` file is needed. `%h` expands to the home dir.
- The launcher defaults its binary to `./hsa` next to itself (`~/hsa-app/hsa`, the
  symlink), so a restart after a symlink swap runs the new release automatically.

## Deploy a tagged release

Push a release tag `X.Y.Z` — CI builds, stages, and activates it automatically.
To manually activate a staged pre-release (or any release) from the host:

```bash
cd ~/hsa-app
chmod +x releases/hsa-app-V<tag>/hsa
ln -sfn releases/hsa-app-V<tag>/hsa hsa
systemctl --user restart hsa_app
```

## Roll back

Every release stays under `releases/`, so rollback is a symlink repoint:

```bash
cd ~/hsa-app
ln -sfn releases/hsa-app-V<old-tag>/hsa hsa
systemctl --user restart hsa_app
```