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 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).

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

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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	Warn and skip. Patches are verified against stock 57.4 only; on anything else the base install proceeds and the patch tier is skipped with a warning. Forks are the norm in a public audience — refusing outright would block most operators
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.
• On any ServUO version other than stock 57.4, skip the whole tier with a warning and continue with the base install. Do not attempt to apply unverified diffs to an unknown tree.
• 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).

2.3 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).
• 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.

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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.

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.

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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) (git apply + guard)  + config + data  (systemd / Windows SCM)

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

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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), 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) — 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, link#25, servuo-plugins#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) — 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, and it is a reverse proxy. [web] bind defaults to 127.0.0.1, which only works when the site runs on the shard host. The guide's recommended arrangement — already in production on a real domain — is to leave the bind on loopback and put a TLS reverse proxy in front, giving the website the proxied https:// / wss:// URLs in place of the pair the installer prints from the bind address. Four requirements make that work and are stated with an nginx block that satisfies them: forward the WebSocket upgrade (/ws is the whole live feed), pass headers through unmodified (auth is Authorization: Bearer, and a stripped X-UOLink-Version silently skips the mismatch check), do not buffer and allow long-lived connections (the sidecar pings every 30 s, so a ≥60 s read timeout is safe), and do not log query strings (?token= is an accepted auth form). Widening the bind and firewalling the port stays documented as the trusted-LAN alternative, not the default, because on that path the token crosses the network in the clear. [shard] bind is never proxied and never widened — 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.

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 — 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, for the operator 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.

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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.

It does not attempt to detect a reverse proxy, which is the recommended arrangement for a website on another host (INSTALL.md §5). Nothing visible from the sidecar's side says what fronts it, so guessing would produce a confidently wrong https:// URL. The two printed URLs always describe the sidecar itself, and the guide tells the operator to paste their public https:// / wss:// pair instead when there is a proxy. --host accepting a full origin later is a cheap improvement if this proves annoying in practice.

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.

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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:

{
  "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:

{
  "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 POSTs 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 404s 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.

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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.

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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