docs/installer/PLAN.md

# Runic Gateway Installer — plan

Status: **Phase 0 complete.** Every prerequisite in another repo has landed, the installer repo
publishes the bundle manifest, and [`INSTALL.md`](INSTALL.md) now specifies the operator-facing run
— so *what* the installer installs and *what using it looks like* both exist ahead of the binary.
No installer code exists yet; **Phase 1 is next.** This document is the design of record; it
supersedes the informal overview it grew out of, which described a ServUO integration that does not
match how `servuo-plugins` actually ships (see
[Corrections](#corrections-to-the-original-overview)).

| Phase 0 item | State |
|---|---|
| 0.1 `servuo-plugins` release workflow | ✅ Merged — [servuo-plugins#7](https://gitea.whitlocktech.com/RunicGateway/servuo-plugins/pulls/7) + [#8](https://gitea.whitlocktech.com/RunicGateway/servuo-plugins/pulls/8); first overlay release is [`v0.1.1`](https://gitea.whitlocktech.com/RunicGateway/servuo-plugins/releases/tag/v0.1.1) |
| 0.2 `link` installable (data paths + `--print-config`) | ✅ Merged — [link#24](https://gitea.whitlocktech.com/RunicGateway/link/pulls/24) (docs half [docs#84](https://gitea.whitlocktech.com/RunicGateway/docs/pulls/84)); released as [`v1.1.0`](https://gitea.whitlocktech.com/RunicGateway/link/releases/tag/v1.1.0) |
| 0.3 Bundle CI in the installer repo | ✅ Merged — [installer#3](https://gitea.whitlocktech.com/RunicGateway/installer/pulls/3), plus the dispatch step in each component ([link#25](https://gitea.whitlocktech.com/RunicGateway/link/pulls/25), [servuo-plugins#9](https://gitea.whitlocktech.com/RunicGateway/servuo-plugins/pulls/9)). First bundle: [`2026.08.04`](https://gitea.whitlocktech.com/RunicGateway/installer/src/branch/main/bundles/current.json) |
| 0.4 This file + `INSTALL.md` | ✅ Merged — [docs#87](https://gitea.whitlocktech.com/RunicGateway/docs/pulls/87). [`INSTALL.md`](INSTALL.md) is the operator guide, written before the binary because it *is* the specification of the run |
| — Repo bootstrap (governance + CI) | ✅ [`RunicGateway/installer`](https://gitea.whitlocktech.com/RunicGateway/installer) created; workflows merged ([installer#1](https://gitea.whitlocktech.com/RunicGateway/installer/pulls/1), [#2](https://gitea.whitlocktech.com/RunicGateway/installer/pulls/2)) |

---

## 1. Purpose

Take a stock ServUO installation and configure it for Runic Gateway with minimal manual steps, while
keeping the components separated and independently maintainable.

The installer handles environment detection, ServUO overlay deployment, the optional stock-file
patch tier, uo-link installation and service registration, version tracking, diagnostics, and
updates from Gitea releases.

**It is a deployment tool, not a hosted bootstrapper.** There is no `curl | bash`, no installer
service, and no hosted bootstrap script. Artifacts are downloaded from a Gitea release page and run.

**It does not replace ServUO startup behavior.** ServUO keeps running through its existing
release/start scripts. The installer never writes a launcher.

### Decisions locked

| Question | Decision |
|---|---|
| Audience | **Public** — any ServUO operator, not just shards we run |
| Code signing | **Unsigned.** `SHA256SUMS` is the trust anchor; SmartScreen/Gatekeeper warnings are expected and documented, as with most self-hosted tooling |
| Language | **Rust** — single static binary per OS, reuses the cross-compile pattern already proven in `link/.gitea/workflows/release.yml` |
| Plugin source | **Release tarball artifact** — no git and no Gitea credentials on the shard host |
| Composition | **Published bundle manifest** (§7.1). CI names an exact, protocol-checked combination of component versions; the installer fetches it at run time and `--bundle <tag>` pins one. Component releases regenerate JSON, not the installer binary |
| Token handoff | **Print token + prefilled admin URL** at the end of the run |
| Repo | **New repo**, `RunicGateway/installer`. It deploys *both* other components, so living inside `link/` would invert the dependency |
| ServUO version | **57.4 is the only supported version.** The patch tier's gate is content, not a version string: a patch applies where the lines it edits are still stock and is handed to the operator where they are not (§2.2.1). Forks and hand-edited trees are the norm in a public audience, so a non-57.4 tree is still *allowed* to attempt the tier — but **unsupported, untested and not guaranteed**, behind a loud banner, a defaulted-to-no prompt and its own opt-in flag (§2.2.2) |
| Uninstall | **Never touches the ServUO tree.** Removes uo-link and its service entry, then *prints* the overlay files to delete and the patch hunks to revert. Reverting is the operator's call |

---

## 2. Corrections to the original overview

These are not wording nits — each one changes what the installer has to do.

### 2.1 There is no `RunicGateway.dll` and no `Plugins/` directory

The plugin ships as **C# source** and ServUO compiles it at boot. The real deployable is
`servuo-plugins/overlay/`, which mirrors the server root:

```
overlay/
├── Config/Bridge.cfg
└── Scripts/
    ├── Scripts.csproj                 # Phase 0 — whole-file overwrite of a stock file
    └── Custom/Bridge/*.cs             # 22 files
```

So the plugin step is a hash-compare file sync, not a DLL drop — mechanically easier than the
overview assumed. The sting is that **a successful copy does not mean a working bridge.** Per
`link/SHARD_PREREQS.md`, `ScriptCompiler.Compile()` shells out to `dotnet build`, prints the output,
**ignores the exit code**, and reloads the existing `Scripts.dll`. A broken script build is
invisible: the shard boots clean on stale code. Diagnostics must therefore verify *post-boot* state,
never treat "files copied" as success.

### 2.2 Stock ServUO files *are* modified — by an optional tier

`servuo-plugins/patches/` holds unified diffs against stock ServUO 57.4, plus two `.cs` files that
can only be copied *after* their patch lands (they reference symbols the patch introduces):

| Patch | Target | Companion file | Rebuild required |
|---|---|---|---|
| `playervendor-sale-eventsink.patch` | `Server/EventSink.cs` | `BridgeVendorSale.cs` | **Core** — `dotnet build ServUO.sln`; the dynamic script build is not enough |
| `playervendor-sale-gump.patch` | `Scripts/Gumps/PlayerVendorGumps.cs` | (same unit as above) | script build |
| `commandlogging-event.patch` | `Scripts/Commands/Logging.cs` | `BridgeModerationAudit.cs` | script build |

Plus `overlay/Scripts/Scripts.csproj`, which overwrites a stock file (Phase 0 — it fixes the silent
ServUO build bug above).

This is the hardest part of the installer. `git apply` against a hand-modified shard will fail, and
most real shards are hand-modified. Therefore:

- The patch tier is **opt-in and skippable**. The base install must complete without it.
- Always dry-run (`git apply --check`) before applying, and report per-patch.
- When skipped or failed, say plainly what is lost: **no `vendor.sale` events, no in-game moderation
  audit forwarding**.
- The `EventSink.cs` patch must warn loudly that a **core solution rebuild** is required, not just a
  shard restart.
- Record applied patches in `install.json`, **and cache the applied `.patch` files** next to it
  (`/etc/runicgateway/patches/`, `%ProgramData%\RunicGateway\patches\`). Re-runs stay idempotent,
  and uninstall can print the exact hunks offline long after the release tarball is gone (§5,
  Phase 4).

#### 2.2.1 A whole-file hash mismatch is not a verdict — check the region

A file-level hash compare answers "is this entire file stock?", which is the wrong question. The
patches touch three small regions of three large files; an operator who added a custom command to
`Logging.cs` or a hook to `EventSink.cs` has changed the file's hash without going anywhere near the
lines the patch edits. Refusing on the file hash alone hands most real shards a manual patch job
they did not need. So the decision is made in three rungs, cheapest and safest first, and only the
last one gives up:

| Rung | Test | Outcome |
|---|---|---|
| **0 — already applied** | The hunk's *post*-patch text appears in the file | No-op, recorded as applied. Keeps re-runs idempotent |
| **1 — file is stock** | Whole-file hash matches the patch's pre-image (`index <old>..<new>` in the diff — `git hash-object` on the target reproduces it) | Apply verbatim with `git apply` |
| **2 — region is stock** | File differs, but every hunk's stock-side region is still byte-identical | Apply hunk-by-hunk at the matched offsets |
| **3 — region is modified** | Anything else | **Do not touch the file.** Print the path, the hunks and what is lost; the operator patches by hand |

Rung 2 is the semantic review, and it needs no new metadata: a unified diff already carries the
stock text of the region it edits — the context lines plus the `-` lines *are* the pre-image. For
each hunk the installer reconstructs that block and searches the target file for it, under these
rules:

- **Exact match, not fuzzy.** Only line-ending (CRLF/LF) and trailing-whitespace normalization is
  allowed. No `patch --fuzz`, no context reduction: dropping context to force a match is precisely
  how a patch lands in the wrong method.
- **Exactly one occurrence, or it fails.** Zero means the region moved or was edited. More than one
  means the anchor is ambiguous and the installer cannot know which the author meant. Both are
  rung 3.
- **Line numbers are advisory.** The hunk header's offsets are used only to prefer the nearest
  candidate when reporting; the match itself is by content, since insertions above the region shift
  every number below it.
- **All-or-nothing per patch file.** If one hunk of a patch reaches rung 3, none of that patch's
  hunks are applied. A half-patched `EventSink.cs` compiles against a companion `.cs` that expects
  the whole thing, and a partial apply is harder for an operator to unpick than an untouched file.
- **Rung 0 is checked first and is also all-or-nothing.** A file where some hunks are already
  present and others are not is a hand-merge in progress, not an idempotent re-run — that is
  rung 3.

#### 2.2.2 Non-57.4 is allowed, unsupported, and must say so loudly

The rung ladder replaces the blanket ServUO-version gate. The old rule skipped the entire tier on
anything other than stock 57.4 on the grounds that unverified diffs must not be applied to an
unknown tree — but forks are the norm (§1), so that rule skipped the tier for most of the audience.
Content matching gives a stronger guarantee than a version string does: on a non-57.4 tree, rung 1
is simply unavailable (its pre-image hash cannot be trusted), the tier goes straight to rung 2, and
a hunk lands only where the surrounding lines are still character-for-character the ones the patch
was written against.

**That is a mechanical safety guarantee about where text lands. It is not a support commitment, and
the installer must never let the two be confused.** Runic Gateway is designed, built and tested
against **stock ServUO 57.4**. On anything else the patch tier is **unsupported, untested, and not
guaranteed to work** — a hunk can match textually and still be wrong for a tree whose surrounding
behaviour has diverged, and neither the shard's silent script build (§2.1) nor the installer will
tell you that. So:

- **The disclaimer is unmissable, not a footnote.** On a non-57.4 tree the tier prints a banner
  before it is even offered — that 57.4 is the only supported version, that the operator is on their
  own here, and that a bad outcome may not surface until the shard is running.
- **It is off by default and takes an explicit, separate yes.** The interactive prompt defaults to
  **no** on a non-57.4 tree, and `--patches` alone is **not** consent: an unattended run must pass
  `--patches-unsupported-servuo` as well. A flag an operator had to look up cannot be hit by
  accident in a script copied from somewhere else.
- **The label follows the install.** `install.json` records the detected version and the fact that
  the tier ran unsupported; `doctor` shows that row on every subsequent run, not just at install
  time; and the uninstall report carries it too. An operator who inherits this shard six months
  later must be able to see it without being told.
- **It is the first thing quoted back in a bug report.** The tier's summary line names the detected
  version, so a pasted install log answers "which ServUO?" before anyone asks.

The version is detected and reported everywhere; it just no longer *silently* decides. A refusal
becomes an informed choice, which is the point — but it stays visibly the operator's choice.

**What the installer records.** `install.json` stores, per patch, which rung applied it
(`stock-hash`, `region-match`, `already-present`) and the hunk offsets it matched. `doctor` and
`uninstall` report that: a `region-match` apply on a modified file is a different support story from
a clean apply to a stock tree, and the operator should be able to see which one they have without
re-deriving it.

### 2.3 Config paths collide with what the sidecar actually reads

The sidecar reads `$UOLINK_CONFIG`, else `sidecar.toml` in the **working directory**
(`link/sidecar/src/config.rs`), with keys `[shard].bind`, `[web].bind`, `[web].auth_token`,
`[store].path`. The overview proposed a `config.toml` with `[updates]`, `[link]`, `[servuo]` — keys
the sidecar cannot read.

Two files, two owners:

| File | Owner | Contents |
|---|---|---|
| `/etc/runicgateway/sidecar.toml` | uo-link | The sidecar's own schema, unchanged. Service sets `UOLINK_CONFIG` to this path |
| `/etc/runicgateway/install.json` | installer | Deployed versions, file hashes, applied patches, ServUO path, timestamps |

**Working-directory trap:** the sidecar wrote both `sidecar.toml` and `uo-link.db` relative to CWD.
Under `C:\Program Files\` that fails or silently lands in VirtualStore. Phase 0.2 fixed the second
half in the sidecar — a relative `[store].path` now resolves against the directory holding
`sidecar.toml`, so pinning the config alone is enough to put the database somewhere deterministic —
but the config path itself is still CWD-relative by default, and "deterministic" is not the same as
"where this install wants it". The service definitions therefore still pin `UOLINK_CONFIG` and
`UOLINK_DB_PATH` explicitly:

- Linux: config `/etc/runicgateway/sidecar.toml`, db `/var/lib/runicgateway/uo-link.db`, dedicated
  service user
- Windows: binary under `%ProgramFiles%\RunicGateway\`, **data under `%ProgramData%\RunicGateway\`**

### 2.4 The token handoff was missing entirely

The whole point is the website reaching the sidecar, and today that is manual and undocumented in
the install flow: the sidecar generates a token on first run and logs it, then a human pastes base
URL, WS URL, token, and protocol version into Admin → Shard, where it is AES-GCM encrypted and
becomes write-only. This is the largest "I installed it and nothing happened" failure mode.

The installer closes it by printing a copy-paste block at the end of a successful run — see §6.

Phase 0.2 supplied the missing half of that: `uo-link-sidecar --print-config` provisions the config
if absent and prints the resolved settings — token, both binds, `ws_path`, protocol version, db
path — as JSON. The installer reads the block it prints out of that one call. **It never parses the
log**, which was the alternative and would have made the handoff depend on a log format that is not
a contract.

### 2.5 `deploy.ps1` cannot be the cross-platform deployer

It is PowerShell-only; a Linux ServUO host running .NET typically has no `pwsh`. It also hard-throws
when the ServUO process is running — correct behavior, and the installer must inherit it (detect and
refuse, rather than corrupt a live `Scripts.dll`). The installer reimplements the sync natively; it
is a short hash-compare-and-copy that never deletes.

`deploy.ps1` **stays** in `servuo-plugins` as the developer-facing tool. The installer is for
operators.

### 2.6 Prerequisites the overview assumed away

- **`servuo-plugins` had no release workflow.** Only `link` did. "Pull latest repository" is replaced
  by a release tarball, which had to be built first — Phase 0 item 1, now in review
  ([servuo-plugins#7](https://gitea.whitlocktech.com/RunicGateway/servuo-plugins/pulls/7)).
- **arm64 is not buildable today.** `link/release.yml` cross-compiles only
  `x86_64-unknown-linux-gnu` and `x86_64-pc-windows-gnu`. An arm64 `.deb` needs another cross
  toolchain.
- **The compat matrix has no home.** `PROTOCOL_VERSION` lives in `link/sidecar/src/main.rs`. The
  sidecar publishes it via `X-UOLink-Version` and `/health`, and the website stores an expected
  value — but the *plugin's* protocol version is not queryable before boot. Phase 0 item 1 gives it
  a home: `servuo-plugins/overlay.toml`, declared into the overlay manifest. See §7.0 / §7.1.

---

## 3. Distribution model

Components are published as Gitea release artifacts. Operators download from the release page
(browser, `curl`/`wget`, or `scp` to the server) and run the binary.

```
Runic Gateway Installer v1.0.0
├── runicgateway-installer-windows-x86_64.exe
├── runicgateway-installer-linux-x86_64
└── SHA256SUMS

uo-link v1.1.0                        (existing release, extended)
├── uo-link-sidecar-windows-x86_64.exe
├── uo-link-sidecar-linux-x86_64
├── runicgateway-link_<ver>_amd64.deb        (Phase 5)
└── SHA256SUMS

servuo-plugins v<ver>                 (new release, Phase 0)
├── runicgateway-overlay-<ver>.tar.gz         # overlay/ + patches/ + manifest.json
└── SHA256SUMS
```

Binding those together is the **bundle manifest** (§7.1) — published by the installer repo's CI, not
by any component, and the thing the installer actually resolves against.

```bash
scp runicgateway-installer-linux-x86_64 user@server:/tmp/
chmod +x runicgateway-installer-linux-x86_64
sudo ./runicgateway-installer-linux-x86_64
```

### Unsigned-binary posture

Because releases are unsigned, trust is anchored on checksums and the operator's own verification.
The docs must state this up front rather than let users discover it as a scary dialog:

- Every release publishes `SHA256SUMS`; the install docs lead with the verification command for both
  OSes.
- Windows will show a SmartScreen "unrecognized app" prompt. Documented, with the exact click path.
- The installer verifies the SHA256 of everything **it** downloads (overlay tarball, sidecar binary)
  against the release's `SHA256SUMS` and refuses on mismatch. Self-verification is not optional just
  because the installer itself is unsigned.
- Revisit signing if it ever becomes affordable; the release layout should not have to change.

---

## 4. Component architecture

```
                 Runic Gateway Installer  (Rust, one binary per OS)
                                │
                ┌───────────────┴────────────────┐
                ▼                                ▼
      ServUO integration                      uo-link
                │                                │
       ┌────────┴────────┐              ┌────────┴────────┐
       ▼                 ▼              ▼                 ▼
  overlay sync    patch tier (opt-in)  binary install   service registration
  (never deletes) (per-region rungs)   + config + data  (systemd / Windows SCM)
```

Each component keeps its own lifecycle. ServUO's existing startup process is untouched.

---

## 5. Phases

### Phase 0 — prerequisites (no installer code)

Repo work that must land before an installer can exist.

1. **`servuo-plugins`: add `.gitea/workflows/release.yml`.** Retarget the release *engine* half of
   `link/release.yml` (its header comment explicitly anticipates this — the plan/release steps
   consume only `{version, changelog, artifacts}`). The adapter half produces
   `runicgateway-overlay-<ver>.tar.gz` containing `overlay/`, `patches/`, and a `manifest.json`
   (version, commit, per-file SHA256, declared protocol version, minimum ServUO version).

   As built ([servuo-plugins#7](https://gitea.whitlocktech.com/RunicGateway/servuo-plugins/pulls/7)),
   with three deviations from `link`'s copy that each fell out of the repo rather than being chosen:

   - **No build gates, structural gates instead.** Nothing in that repo can be compiled without
     ServUO reference assemblies, so CI asserts what it honestly can: `Bridge.cfg` and the Bridge
     scripts present, `Scripts.csproj` present (its absence ships code that never compiles while
     ServUO reports success — §2.1), every `.patch` parseable via `git apply --stat`, and each
     patch's companion `.cs` present.
   - **No bump commit, so no push to `main`.** `link` writes the version into `Cargo.toml` because
     the binary embeds it; the tarball embeds nothing but the generated manifest, so the tag *is*
     the version. That workflow needs no branch-protection exception.
   - **`overlay.toml` at the repo root** holds the declared `protocol` and the ServUO compatibility
     values, read by CI into the manifest. It exists because the number needs one maintained home —
     see §7 for why the plugin cannot simply be asked.

   The tarball uses a **fixed** top-level directory, `runicgateway-overlay/`, not a versioned one:
   the installer looks for `overlay/`, `patches/` and `manifest.json` at known paths rather than
   parsing the version it is trying to read. Member order, mtime and ownership are pinned, so a
   given tree yields a byte-identical tarball and its checksum moves only when its contents do.
2. **`link`: make the sidecar installable.** Confirm/settle default data paths, and add a way to
   read back config non-interactively (e.g. `--print-config` emitting JSON: bind addresses, token,
   protocol version, db path) so the installer does not have to scrape logs for the token.

   As built ([link#24](https://gitea.whitlocktech.com/RunicGateway/link/pulls/24)) — the sidecar
   had **no CLI at all** before this, so the shape was chosen rather than inherited:

   - **Four flags, hand-rolled:** `--print-config`, `--config <PATH>`, `--version`, `--help`. No
     argument-parsing crate — it would be larger than the code it replaced — and deliberately no
     flags that duplicate a config key, so `sidecar.toml` stays the single place settings live.
     An unrecognized argument exits `2`; silently ignoring a typo'd flag would start a sidecar that
     is not the one the installer asked for.
   - **`--print-config` performs first-run setup rather than only reporting.** It runs the same
     load path a normal start does, so a missing config file is written and a blank token is
     generated and saved. That collapses "provision the sidecar" and "find out its token" into one
     non-interactive call — which is exactly the sequence §6 needs. `config_created` and
     `token_generated` say whether *this* run did either, because the values alone cannot
     distinguish a fresh install from a re-read of an existing one, and a re-run must not report a
     token as newly minted.
   - **The document is the whole of stdout.** The log subscriber writes to stdout, so it is not
     started in this mode. `ws_path` is emitted from the same constant the route is registered
     with, so the installer's WebSocket URL cannot drift from the server's.
   - **Relative `[store].path` now anchors to the config file's directory, not the CWD** — see
     §2.3, which this half-closes on the sidecar side. Absolute paths are used as written; parent
     directories are created; `:memory:` and `file:` URIs are left alone.
   - **The db path is handed to sqlx as a path, not a `sqlite://` URL.** The URL spelling is
     parsed as one: it percent-decodes the path and splits it on `?`, so an installed path
     containing `%20` opened a different file than the operator named.
   - **No platform data directories are compiled in.** That is the "settle" half of this item, and
     the answer is that the *installer* owns layout (§2.3) and pins `UOLINK_CONFIG` /
     `UOLINK_DB_PATH` in the service definition. Baking `/etc` and `%ProgramData%` defaults into
     the binary would give the same paths two owners and break `cargo run` in a working tree.
3. **Bundle CI in the installer repo** (§7). Compose job (read both repos' latest releases → run the
   two gates → publish `bundle.json`), the nightly cron, and the dispatch step appended to each
   component's release workflow. This must exist before Phase 1 is useful, since the installer
   resolves what to install *from* the bundle.

   As built ([installer#3](https://gitea.whitlocktech.com/RunicGateway/installer/pulls/3),
   [link#25](https://gitea.whitlocktech.com/RunicGateway/link/pulls/25),
   [servuo-plugins#9](https://gitea.whitlocktech.com/RunicGateway/servuo-plugins/pulls/9)) —
   `installer/.gitea/workflows/bundle.yml`, with the decisions §7 had left open:

   - **Bundles are committed to the installer repo, not published as releases** — see §7.1 for
     where and why. That was the one genuinely open question here, and the deciding factor is that
     this repo's *own* releases are the installer binaries.
   - **Gate 1 reads the sidecar's protocol from source at the release tag**, not from the binary.
     `--print-config` (Phase 0.2) would answer authoritatively, but only for releases from `v1.1.0`
     onward, and `--bundle <tag>` has to be able to recompose a bundle from an older pair. Reading
     `sidecar/src/main.rs` at the tag the release was built from works uniformly, needs no execution
     of a downloaded artifact, and does not provision a throwaway config whose auth token would then
     be sitting in a CI log. A constant that has moved or been renamed is a hard failure — treating
     "could not read" as "matches" is exactly how a mismatched pair would ship.
   - **Gate 2 records the hash CI computed itself**, after verifying the download against the
     publishing repo's `SHA256SUMS`. It also asserts the reverse direction — an asset with *no*
     `SHA256SUMS` entry — because `sha256sum -c` silently passes over a file the sums file does not
     mention, which would put an unverified artifact in the bundle.
   - **Release metadata is read anonymously**, on purpose: those are exactly the requests the
     shipped installer makes on a host with no Gitea credentials, so a repo flipped to private
     fails CI here instead of on an operator's machine.
   - **An unrecognized asset name is a hard failure.** link's binaries are mapped onto platform keys
     by suffix; adding a target (aarch64, macOS) to its release workflow therefore reddens this job
     rather than silently omitting the new binary from every bundle.
   - **A run that changes nothing writes nothing** — the comparison excludes `bundle` and
     `generated`, which are metadata about the run. Without that the nightly cron would commit a
     dated duplicate of the same matrix every morning.

   The workflow's compose steps were run against the live releases before merge, producing the
   first bundle (`2026.08.04`: link `v1.1.0` + overlay `v0.1.1`, protocol 3), which is committed so
   the manifest exists ahead of the binary that reads it.
4. **`docs`: this file, plus `docs/installer/INSTALL.md`** (the operator-facing guide) once the
   shape is settled.

   As built ([`INSTALL.md`](INSTALL.md)) — written *before* the binary on purpose. Everything it
   installs is already released (items 1–3), so the guide is not speculation about a tool that
   might exist; it is the specification of what the run asks, where it writes, what it prints, and
   what the operator does next. Phase 1–4 implement it.

   - **It is useful before the installer exists.** Appendix A is the same deployment done by hand —
     bundle fetch, tarball verify + overlay copy, the optional patch tier, `--print-config`
     provisioning, and a systemd unit / `sc create` service — composed from the released artifacts'
     actual contents and the sidecar's config and CLI source rather than from memory. That appendix
     doubles as **Phase 1's acceptance test**: walking it end to end on a real shard is what proves
     the automated path has nothing left to discover.
   - **The installer does not install itself.** §5's `runicgateway doctor` sketch implied a name on
     `PATH`; nothing places one there, and adding self-installation would give the tool a second
     lifecycle to manage. The guide names the downloaded artifact, says to keep it, and shortens it
     in later examples.
   - **The flag surface got fixed here**, because a guide cannot describe a run in the abstract:
     `--verify`, `--bundle`, `--purge` were already named by §5/§7; `--servuo`, `--patches` /
     `--no-patches`, `--host`, `--site-url` and `--yes` are the remainder, chosen so every prompt
     in §6's handoff has a non-interactive equivalent and an unattended install is expressible.
   - **A modified `Bridge.cfg` must survive an update** — see Phase 1, where this changes the sync
     rule inherited from `deploy.ps1`.
   - **Remote-website deployments needed an answer.** `[web] bind` defaults to `127.0.0.1`, which
     only works when the site runs on the shard host. The guide says to widen it, firewall it to
     the website's address, and front it with TLS or a VPN off a trusted network — because the
     token is always required but travels as a plain bearer token over HTTP. `[shard] bind` stays
     on loopback, since that socket carries inbound commands *into* the game.

### Phase 1 — installer core

- ServUO root detection and validation (`ServUO.exe`, `Scripts/`, `Config/`), with version detection
  and an explicit refusal when the ServUO process is running.
- Overlay sync: fetch tarball → verify SHA256 → hash-compare against the server tree → add/change,
  **never delete**. Port of `deploy.ps1` semantics including its `-Verify` dry run (`--verify`).
- **One deviation from `deploy.ps1`: an operator-modified `Config/Bridge.cfg` is reported, not
  overwritten.** `deploy.ps1` overwrites every file whose hash differs, which is right for a
  developer redeploying their own tree and wrong for an operator who has set `LinkUrl`,
  `PublicConnectAddress` and sweep intervals — an `update` would silently revert the shard's entire
  configuration. `install.json` records the hash deployed, so the installer can distinguish "the
  operator edited this" from "the overlay moved on" (§7.0) and act only on the second. The rule is
  specific to `Bridge.cfg`: it is the only file in the overlay that is *meant* to be edited in
  place, and it carries no code, so a stale copy cannot break the build. Every `.cs` file and
  `Scripts.csproj` still overwrite unconditionally.
- Write `install.json`: component, version, source commit, per-file hashes, applied patches,
  timestamp.
- Idempotent re-runs; a second run with no upstream change reports "unchanged" and writes nothing.

### Phase 2 — uo-link install and service

- Linux: binary → `/usr/bin/runicgateway-link`, config → `/etc/runicgateway/sidecar.toml`, db →
  `/var/lib/runicgateway/`, systemd unit with a dedicated user, `enable` + `start`.
- Windows: `%ProgramFiles%\RunicGateway\`, data in `%ProgramData%\RunicGateway\`, service
  registration with automatic start and restart-on-failure.
- Both: `UOLINK_CONFIG` and `UOLINK_DB_PATH` pinned in the service definition (§2.3).
- Token surfacing (§6): run the installed binary once as
  `uo-link-sidecar --print-config --config <the pinned path>` **before** registering the service.
  That both writes the config the service will read and returns the token to print, so the service
  never starts against a config that does not exist yet.

### Phase 3 — patch tier (opt-in)

Everything in §2.2. Detect applicability, dry-run, apply, record, warn about the core rebuild, and
degrade loudly rather than silently.

The rung ladder of §2.2.1 is the bulk of the work here: parse each `.patch` into hunks, reconstruct
each hunk's pre- and post-image blocks, and resolve the file through rungs 0–3 before writing
anything. The unsupported-version path (§2.2.2) is part of this phase, not a later polish — the
banner, the defaulted-to-no prompt, the `--patches-unsupported-servuo` flag, and the unsupported
marker carried into `install.json`, `doctor` and the uninstall report. Two pieces carry the risk and want direct tests — the hunk parser (headers, `\ No newline
at end of file`, CRLF files) and the uniqueness rule (a region that appears twice must fail, not
pick the first). Fixtures are cheap: the three stock 57.4 files, each with a hand edit far from the
patched region (must reach rung 2), an edit inside it (must reach rung 3), and an already-patched
copy (must reach rung 0).

### Phase 4 — diagnostics and updates

`runicgateway doctor` — the command that makes the whole thing supportable:

```
✓ ServUO found            /opt/ServUO  (57.4)
✓ Overlay in sync         24 files, all hashes match install.json
⚠ Patch tier              1 of 3 applied (region-match) — vendor.sale unavailable
✓ uo-link installed       1.1.0
✓ Service                 running, enabled
✓ Sidecar reachable       127.0.0.1:8080  /health ok
✓ Protocol                sidecar 3 = overlay manifest 3
✗ Shard connected         no shard has dialed in since boot
```

The last check matters most: it is the only thing that distinguishes "files copied" from "the bridge
actually works" (§2.1).

Three of those rows are answered by the sidecar's own CLI rather than by inspecting the filesystem:
`--version` prints `uo-link-sidecar <ver> (protocol <n>)`, and `--print-config` gives the config and
db paths the *installed service* resolves — so `doctor` reports what the binary would actually do,
not what `install.json` believes it was told to do. The protocol row compares that number against
the overlay manifest's declared one (§7.0).

`runicgateway update` — resolves the current bundle (§7.1), then acts asymmetrically by component,
deliberately:

- **uo-link**: compare the bundle's version against what is installed → download → verify checksum →
  replace binary → restart service.
- **plugin overlay**: download the bundle's overlay tarball → verify → re-sync (leaving a modified
  `Bridge.cfg` alone — Phase 1) → record commit → tell the operator ServUO must restart (the
  installer does not restart the shard).

Because both come from one bundle, an update always moves to a combination whose protocol versions
were checked together, rather than to two independently-latest artifacts that may disagree.

`runicgateway uninstall` — **removes only what it exclusively owns, and never edits the ServUO
tree.** The installer cannot know what the operator has changed in those files since deployment, so
a clever automatic revert risks silently eating their work. It removes and it reports:

| Action | Scope |
|---|---|
| Removed | uo-link binary, its service entry (systemd unit / Windows service), `install.json` and the cached patch set |
| Kept | `sidecar.toml` and `uo-link.db` (config and history survive; `--purge` to drop them) |
| **Printed, not done** | Every overlay file deployed into the ServUO tree, listed by path, for the operator to delete |
| **Printed, not done** | The exact hunks each applied patch added to `EventSink.cs`, `PlayerVendorGumps.cs`, `Logging.cs`, rendered from the cached `.patch` files — with the rung that applied each one (§2.2.1), since a `region-match` apply means the surrounding file was already the operator's — for them to revert by hand |

The printed report is also written to a file, so it survives the terminal scrollback of a long
uninstall.

### Phase 5 — packaging polish

`.deb` packaging, Windows MSI, arm64 cross build, and optional automated backup before upgrade.
Deliberately last: v1 can register services directly (`sc create` / a written systemd unit) and ship
plain binaries. Nothing in Phases 1–4 should have to change to add these.

---

## 6. Token handoff (the end of a successful run)

```
Runic Gateway is installed.

One manual step remains — connect the website to this sidecar:

  Base URL          http://<this-host>:8080
  WebSocket URL     ws://<this-host>:8080/ws
  Protocol version  3
  Auth token        4f9c...   (also in /etc/runicgateway/sidecar.toml)

Paste these into  Admin → Shard  on your Runic Gateway site:
  https://<your-site>/admin/shard

The token is write-only once saved — the site will never show it back to you.
```

Every value in that block except the host and the site URL comes from one
`uo-link-sidecar --print-config` call (§2.4): `web.auth_token`, `protocol`, and `web.bind` +
`web.ws_path` for the two URLs. Only the **host** is substituted — `web.bind` is frequently
`0.0.0.0`, which is not something to hand a website — so the installer composes the URLs from the
host it detects or prompts for, rather than echoing the bind address.

The installer prompts for the site URL only to build that link; it never contacts the website. A
future "installer registers itself with the website" flow (claim code + authenticated endpoint) is
explicitly **out of scope** — it is real backend work in a security-sensitive area and can be added
later without changing anything here.

The printed token is a secret in transit: `--print-config` output must go to the operator's
terminal and the config file, never into an installer log file or a support bundle.

---

## 7. Version tracking, the bundle, and release orchestration

Three components version independently, bound by a protocol contract:

- **sidecar** — `PROTOCOL_VERSION` in `link/sidecar/src/main.rs`, exposed on `/health` and as
  `X-UOLink-Version` on every response; a mismatch is rejected `409`.
- **website** — stores an expected protocol version in `uoLinkConfig` (admin-managed).
- **plugin overlay** — has no queryable version before ServUO boots. The overlay release
  `manifest.json` declares it, and `install.json` records what was deployed.

### 7.0 The overlay manifest

Shipped inside every `runicgateway-overlay-<ver>.tar.gz`, generated by that repo's release workflow:

```json
{
  "component": "servuo-plugins-overlay",
  "version":   "0.1.0",
  "commit":    "968b526…",
  "repo":      "RunicGateway/servuo-plugins",
  "protocol":  3,
  "servuo": { "min_version": "57.4", "patches_verified_against": "57.4" },
  "files":  { "overlay/Config/Bridge.cfg": "32718424…", "patches/…": "…" }
}
```

`version` and `commit` come from the release engine; `protocol` and the `servuo` block are read from
`servuo-plugins/overlay.toml`; `files` is a SHA256 per shipped file.

Two of these carry weight beyond documentation:

- **`protocol` is a hand-maintained declaration, and has to be.** The plugin announces no version on
  the wire and none is queryable before ServUO boots, so nothing in CI can derive it — which makes
  this line the only thing §7.1's gate 1 has to compare the sidecar against. The duty is stated in
  `overlay.toml` and in that repo's README: **bump it in the same PR that changes the emitters**, the
  way `link` bumps `PROTOCOL_VERSION`.
- **`files` is what makes `doctor` able to tell "the operator edited a deployed file" from "the
  overlay moved on"** (§5, Phase 4). The installer copies these hashes into `install.json` at deploy
  time; a later mismatch against *both* the manifest and `install.json` means upstream changed, a
  mismatch against `install.json` alone means local edits.

`min_version` and `patches_verified_against` are separate on purpose. The base overlay only *adds*
files and is expected to work broadly; the patch tier diffs stock ServUO files and is verified
against exactly one version (§2.2).

### 7.1 The bundle manifest

**The bundle is the compat matrix.** Rather than the installer hardcoding versions or blindly
resolving "latest", CI publishes a small manifest naming an exact, checked combination:

```json
{
  "schema": 1,
  "bundle": "2026.08.04",
  "generated": "2026-08-04T16:07:13Z",
  "protocol": 3,
  "link": {
    "repo": "RunicGateway/link", "tag": "v1.1.0", "version": "1.1.0", "protocol": 3,
    "assets": {
      "linux-x86_64":   { "name": "uo-link-sidecar-linux-x86_64",       "url": "…", "sha256": "27d491ef…" },
      "windows-x86_64": { "name": "uo-link-sidecar-windows-x86_64.exe", "url": "…", "sha256": "fbefd886…" }
    }
  },
  "overlay": {
    "repo": "RunicGateway/servuo-plugins", "tag": "v0.1.1", "version": "0.1.1",
    "commit": "3a52abb…", "protocol": 3,
    "servuo": { "min_version": "57.4", "patches_verified_against": "57.4" },
    "asset": { "name": "runicgateway-overlay-0.1.1.tar.gz", "url": "…", "sha256": "75dc6d6c…" }
  }
}
```

Note `link.assets` is a **map keyed by platform**, not the single `sha256` this section originally
sketched: link publishes a Linux binary and a Windows `.exe`, and the installer runs on both, so one
hash could only ever have described one of them. `schema` versions this document's shape and is
independent of `protocol` and of either component's release version — all three move separately.

The installer fetches the current bundle at run time; `--bundle <tag>` pins an older one for a
reproducible install. Because the bundle is data, **a new `link` release regenerates ~30 lines of
JSON and leaves the installer binary untouched** — operators do not re-download the installer to
pick up a sidecar patch, and the installer does not accumulate releases whose code is byte-identical.

Two gates run at compose time, both cheap and both worth it:

1. The sidecar's `PROTOCOL_VERSION` must equal the overlay manifest's declared protocol version.
   This is the check that catches an `edge`/`main` protocol mismatch before it reaches an operator.
   The two halves are read from different places because they *are* different: the overlay's from
   `manifest.json` inside the tarball (the only statement of it that exists — §7.0), the sidecar's
   from `sidecar/src/main.rs` at the release tag (see Phase 0 item 3 for why not from the binary).
2. Every referenced asset must exist and its SHA256 must match the publishing repo's `SHA256SUMS`.
   The hash recorded in the bundle is the one CI computed from the asset it downloaded, *after* that
   check — and the installer verifies every download against it. These artifacts are deliberately
   unsigned (§3), so the checksum is the whole trust anchor; a hash copied from a file nobody
   verified would make the chain decorative.

#### Where bundles are published

Committed to the installer repo under `bundles/`, so the installer's fetch is a plain anonymous
`GET` against a public repo — the shard host has no Gitea credentials (§1):

```
bundles/current.json          → …/RunicGateway/installer/raw/branch/main/bundles/current.json
bundles/bundle-<tag>.json     → …/raw/branch/main/bundles/bundle-2026.08.04.json   (--bundle)
```

Every bundle is kept forever, so `--bundle` stays reproducible. Tags are UTC dates; a second bundle
on the same day — a sidecar release in the morning and an overlay release in the afternoon is the
normal way that happens — becomes `2026.08.04.2`, so one tag always names exactly one matrix.

**Not one Gitea release per bundle**, which was the obvious alternative. This repo's own releases
are the installer *binaries*, and `/releases/latest` returns whichever release is newest regardless
of kind — interleaving bundle releases would make "latest" intermittently resolve to a release
carrying no installer binary. Committing also yields a reviewable diff and a git history of the
compat matrix, and needs no new branch-protection exception: `release.yml`'s version-bump commit
already requires the CI user to be able to push to `main`.

### 7.2 What triggers a bundle

| Trigger | Why |
|---|---|
| `link` publishes a release | Its release job `POST`s to the installer repo's workflow-dispatch endpoint as its final step |
| `servuo-plugins` publishes a release | Same. Phase 0 item 1 gave it the release workflow; the dispatch step was left as a marked TODO until there was something to dispatch, and landed with the bundle CI it calls (item 3) — a step that `404`s on every release is worse than no step |
| Nightly cron on the installer repo | Recomputes from whatever the latest releases actually are, so a missed or failed dispatch self-heals instead of silently pinning operators to a stale sidecar |

`repository_dispatch` is deliberately avoided — support for it is uncertain on this Gitea version,
whereas dispatching an existing `workflow_dispatch` workflow via the API works today.

**A failed dispatch is a warning, never a failed release.** By the time that step runs the component
release is published and correct; failing the job would misreport it. This also keeps the dispatch
from becoming a new hard credential requirement — `REGISTRY_TOKEN` having write on the installer
repo is a nicety, and without it the nightly cron picks the release up anyway. A dropped dispatch
costs latency, not correctness, which is the whole reason the cron exists.

### 7.3 Stale-overlay handling: dispatch, don't wait

Each component **self-releases on merge to its own `main`**, using the same conventional-commit
engine. Note that "updated since the last release" must mean *releasable* commits — the engine sets
`RELEASE=false` when nothing but `docs:`/`chore:` has landed, so a docs typo correctly does **not**
cut an overlay release, and the bundle keeps using the existing one.

The compose job's copy of that rule additionally **excludes merge commits**, whose subject is
`Merge pull request '<the real subject>'`. Without that, every squash-free merge of a `feat:` branch
would be counted twice, and worse, a merge of a `docs:` branch whose *title* happens to quote a
`fix:` would be read as releasable — re-dispatching, every night, a release workflow that correctly
declines to run.

So by the time the installer's CI looks, the release normally already exists. If it finds
`servuo-plugins` main ahead of its latest release *with* releasable commits, it:

1. fires that repo's release workflow via workflow-dispatch and **does not wait for it**,
2. composes this bundle from the assets that exist right now,
3. writes a loud warning into the job summary.

The new overlay release lands minutes later on its own and the nightly cron folds it into the next
bundle. This gets the automation without the flaky part: dispatching another repo's workflow is
fine — that workflow still runs its own gates — but *polling* it is not, because Gitea's dispatch
endpoint returns no run handle, so the job would have to guess which run is its own and hold a
runner idle meanwhile. The warning exists so a genuinely broken release workflow surfaces once
rather than being silently retriggered every night forever.

### 7.4 Open risk

**Settled as of the v3 cutover.** Protocol work landed on `edge` branches and the `edge → main`
cutover has now merged, so `main` speaks protocol 3 consistently across the repos. The rule it
motivated stands regardless and is not a temporary measure: **the installer hardcodes no protocol
version anywhere.** It reads what the artifacts declare, and §7.1's gate 1 is what stops a
mismatched pair from being published as a bundle — which is the mechanism that will matter at the
*next* protocol bump, not just this one. See `docs/link/v3.md`.

---

## 8. Open questions

1. **Windows service mechanism** — `sc create` against the plain console binary (simplest, works
   today), a bundled WinSW/NSSM shim, or a native `--service` mode in the sidecar using the
   `windows-service` crate (cleanest, but changes `link`). Recommendation: `sc create` for v1,
   revisit if restart semantics prove inadequate.
2. **Does the installer manage ServUO stop/start?** Currently it refuses while ServUO runs and tells
   the operator to restart afterward. Offering to stop/start would be friendlier but means owning
   another shard's process lifecycle, and the shard's own start scripts vary.
3. **Co-location assumption** — the shard dials out to the sidecar on loopback `127.0.0.1:7788`, so
   sidecar and ServUO must share a host. Should the installer support installing only uo-link on a
   different host, or hard-assume co-location?
Resolved and moved into §1 / §2.2 / §5: uninstall scope, and minimum ServUO version.

**Resolved — branch targeting for the new repo** (was question 4). The v3 cutover landed:
`servuo-plugins#6` merged, so that repo's `main` and `edge` agree at protocol 3. The release
workflow targets `main`, and the installer repo starts clean on `main`. §7.4's caution still applies
in principle — the installer hardcodes no protocol version, it reads what the artifacts declare —
but the specific `edge`/`main` disagreement that motivated it is gone.

---

## 9. Administrator experience

Before:

```
find plugins → copy files → edit ServUO → download bridge → start bridge
→ configure startup → find the token → troubleshoot paths
```

After:

```
download artifact → verify checksum → run installer → select ServUO directory
→ install components → paste 4 values into Admin → Shard → start ServUO normally
```