Oxygenhub — Specification

The key words MUST, MUST NOT, SHOULD, SHOULD NOT and MAY are to be interpreted as described in RFC 2119.

Table of contents

1. Goals and non-goals
2. How it compares with GitHub
3. Architecture
4. Repositories on the server
5. Accounts, identities and authorization
6. Web interface
7. Proposals and review
8. Issues
9. Releases and tags
10. Notifications
11. Search
12. HTTP API and webhooks
13. Checks and the runner
14. Git interoperability
15. Security
16. Performance and caching
17. Operations: configuration, storage, backup
18. Required changes to Oxygen
19. Milestones
20. Open questions
21. Changelog

1. Goals and non-goals

1. Work like GitHub. A developer who knows GitHub must find repositories, history, diffs, review, issues, releases, tokens and webhooks where they expect them, with the same words where the words still apply. The learning curve is Oxygen's model, not the forge.
2. Show what the model makes possible. Multiple heads, reified conflicts, exact blame, signatures and trust policy, proposals that never go stale, review comments that survive rebases, and approvals that are portable signed objects. Each of these is a first-class page, not a footnote.
3. One binary, one directory. oxygenhub serve links oxy-core, embeds the wire protocol server, renders its own pages, and keeps everything under one data directory with SQLite for hub state. A backup is a copy of that directory. There is no separate database server, job queue, cache server or front-end build.
4. The repository is the source of truth. Everything about code, history, references, signatures and policy lives in the Oxygen object store and is readable with oxy alone. Hub tables hold only what Oxygen has no object for: accounts, sessions, issues, review threads, webhooks and check results. Deleting the hub database loses discussion, never history.
5. Off the shelf where it is not the product. Markdown editing uses EasyMDE, in-browser code editing uses CodeMirror 6, syntax highlighting uses syntect, Markdown rendering uses pulldown-cmark with ammonia sanitising. The hub's own code is the forge logic and the pages.
6. Honest state. A page never shows something the object store does not say. A signature is shown as verified only when the hub verified it against policy; an approval is shown only when the approving seal exists.

Non-goals for 1.0: hosting Git repositories natively (§14 covers mirrors), a marketplace, wikis, project boards, discussions, GitHub Pages, and federation between hubs. The runner is specified separately (§13, docs/runner.md) and is not required for 1.0.

2. How it compares with GitHub

3. Architecture

3.1 One process

oxygenhub is a Rust binary in its own Cargo workspace at ../oxygenhub, depending on oxy-core and oxy-server by path (developer edition) or by version (release). It runs one tokio runtime with:

• an axum router serving pages, static assets, the JSON API, and the wire protocol under every repository's path;
• askama templates compiled into the binary; one hand-written stylesheet, also compiled in and served at /style.css;
• SQLite through sqlx (WAL mode, synchronous=NORMAL, foreign keys on) for hub state, opened from <data>/hub.db;
• a small background worker pool (tokio tasks) for webhooks delivery, notification email, search indexing, Git mirror export and cache warming;
• an in-process cache (§16).

There is no separate front-end build. JavaScript is limited to: the theme cookie, EasyMDE (Markdown editing), CodeMirror 6 (file editing), and small progressive enhancements (history graph hover, keyboard shortcuts, live check status). Every page MUST render and every form MUST work with JavaScript disabled, except the two editors, which degrade to a plain <textarea>.

3.2 Layout on disk

<data>/
  hub.db                      SQLite database (and -wal, -shm)
  hub.toml                    configuration (§17.1), optional; environment overrides
  keys/                       the hub's own identity (delegate key, §5.5) and TLS material
  repos/<owner>/<name>/       one Oxygen repository per directory, bare (§4.1)
  mirrors/<owner>/<name>.git  optional Git mirror (§14)
  assets/<owner>/<name>/      release assets, content addressed by BLAKE3
  cache/                      rebuildable: rendered pages, graph layouts, search index

<owner> and <name> MUST match [A-Za-z0-9][A-Za-z0-9._-]{0,63} and MUST NOT be ., .., or end in .git (reserved for the mirror URL). The reserved top-level path segments are api, static, login, logout, register, settings, explore, search, notifications, new, orgs, admin, style.css, favicon.ico, favicon.svg, health; no owner may take those names.

3.3 Request path

1. Middleware: request id, tracing span, body limits, session cookie decode, CSRF check on unsafe methods (§15.2), rate limits (§15.6).
2. Wire protocol routes /{owner}/{name}/oxy/v1/* go to the embedded oxy-server handlers with the hub's repository resolver and authorizer (§18).
3. Page and API handlers resolve {owner}/{name} to a RepoHandle, check the viewer's role, and run every oxy-core call inside spawn_blocking under the repository's read-write lock (§16.2).
4. Templates receive plain structs; no template touches oxy-core directly.

3.4 Crate layout

oxygenhub/
  Cargo.toml            workspace: crates/hub (binary), crates/hub-api (types shared with clients)
  crates/hub/src/
    main.rs             CLI: serve, init, admin (§17.3)
    config.rs           hub.toml and environment
    db/                 sqlx migrations and queries, one module per table group
    repos/              RepoHandle, locks, cache, bare repository operations
    auth/               sessions, passwords, TOTP, tokens, identity linking
    web/                page handlers, one module per area (repo, change, proposal, issue, …)
    api/                JSON handlers
    protocol.rs         embedding oxy-server
    render/             markdown, syntax highlighting, diff rendering, graph layout
    jobs/               background workers
  templates/            askama; base.html, style.css, one file per page
  assets/               wordmark, favicons, vendored EasyMDE and CodeMirror bundles
  migrations/           sqlx migrations
  docs/                 this file, runner.md, deploy.md

4. Repositories on the server

4.1 Bare repositories

A hosted repository is an Oxygen repository directory with no working copy checked out and no user workspace. oxy-core today always keeps one working-copy change per workspace; the hub never snapshots, commits from a checkout, or touches files outside .oxy/. The directory contains only .oxy/. §18 lists the small change that lets Repo::open skip working-copy bookkeeping for such a directory.

Creation: Repo::init under <data>/repos/<owner>/<name> with a fresh repository id, then an initial row in repositories. Import: a client oxy push into an empty hub repository; or, for Git, §14.

Deletion moves the directory to <data>/trash/<owner>/<name>-<timestamp> and a job removes it after trash_days (default 30). Renames are a directory move under the repository's write lock plus a redirects row so old URLs resolve for 90 days.

4.2 Forks

A fork copies the object store (hard links where the file system allows, otherwise a copy) and records forked_from. Because objects are content addressed and repository ids differ, a proposal from a fork carries the changes across repositories by hash; the hub fetches missing objects from the fork's store directly, never over the network.

4.3 The default bookmark

Each repository has a default bookmark (main unless changed). It is what the repository page, tree, file views and search show, and the target every proposal picks first.

4.4 Visibility

public (readable by anyone including anonymous clients), internal (readable by every signed-in account), private (readable by collaborators). Wire protocol reads obey the same rule: a private repository answers 404 to an unauthorized client, not 401, so its existence is not disclosed.

5. Accounts, identities and authorization

5.1 Accounts

An account has a username (same grammar as an owner name), a display name, an email (verified before it is used for anything), an Argon2id password hash, an optional TOTP secret, a session salt (rotating it signs out every session), and a set of linked Oxygen identities (§5.3). The first account created becomes the site administrator. Registration is open, invitation only, or closed, per configuration.

Sessions are a signed cookie oxyhub=<username>.<mac> where mac = HMAC-SHA256(cookie_key, "session:" || username || ":" || session_salt), HttpOnly, Secure when served over HTTPS, SameSite=Lax. Password changes and "sign out everywhere" rotate the salt. Passkeys (WebAuthn) are planned for 1.0 as a second factor or password replacement.

5.2 Organisations and teams

An organisation is an owner with members and teams. Roles on an organisation: owner, member. Roles on a repository, whether personal or organisational: read, triage (manage issues and proposals without writing), write, maintain (settings except deletion and secrets), admin. Teams hold members and receive repository roles as a unit. An organisation's default repository role for members is configurable.

5.3 Linked identities

An Oxygen identity is a signed object holding an Ed25519 + ML-DSA-65 key pair's public halves (spec §14.2). An account links an identity by uploading the identity object (oxy identity export) and proving possession: the hub issues a 32-byte challenge and the client signs it with oxy identity sign-challenge (§18); the hub verifies both signatures. A linked key is what makes a pushed change this account's change: author attribution in every page comes from the change's signing key, not from who held the token that pushed it. A change signed by an unlinked key shows its KeyId and "unlinked key" rather than a user name.

An identity can be linked to at most one account. Rotation (oxy identity rotate) produces a new identity whose object names the old key; the hub accepts the rotated identity for the same account without a new challenge when the rotation is signed by the old key.

5.4 Authentication for the wire protocol

push requires one of:

1. Authorization: Bearer <token> with a personal access token holding repo:write on that repository;
2. an HTTP signature (spec §15.1): the client signs a server challenge with its identity key and the key is linked to an account with write. Reference implementation support is a §18 item; until then tokens are the only method.

Reads on public repositories are anonymous. Reads on internal and private repositories require the same credentials with repo:read.

5.5 Two authorities, one answer

The hub's roles decide who may reach a repository, open issues, create proposals, edit settings, and attempt a push. The repository's Oxygen trust policy (spec §14.5) decides which keys may update which references and whether conflicts may land on them. Both must agree for a push to succeed; the hub MUST NOT bypass or reimplement policy, and it MUST run the same receive_push validation oxy-core runs everywhere else.

A repository with no policy accepts any reference update from any account with write. The settings page says so plainly and offers to create a policy. Policy editing in the browser produces a policy proposal: a signed policy object that roots sign with oxy policy sign from their own clients; the hub collects signatures until the threshold is met, then applies the update as an ordinary push. The hub never holds a root key.

The hub has one identity of its own, the hub delegate key, generated at init and published at /.well-known/oxyhub-key. It is used only to sign changes the hub itself creates on behalf of a signed-in user (web edits, §6.9; proposal landings, §7.6). Such a change carries the user's linked key as author and the hub key as signer, which the author-or-delegate rule (spec §14.4) accepts only when the user's identity object lists the hub key as a delegate: the user opts in once with oxy identity delegate add <hub key> and re-links the rotated identity (§5.3). Policy is then checked exactly as for the user's own signature, since a rule that names the author covers the author's delegates (spec §14.5). If the user has not delegated, or the policy does not authorise them for the reference, the hub refuses the action and shows the client recipe. Delegation is per user and revocable by the user alone (oxy identity delegate remove); the hub never needs a policy entry of its own.

5.6 Personal access tokens

Tokens are 32 random bytes, shown once, stored as BLAKE3 hashes, with a name, an optional expiry, and scopes: repo:read, repo:write, repo:admin, issues:write, proposals:write, user:read, hooks:admin, optionally restricted to listed repositories. Tokens authenticate the API and the wire protocol; they never authenticate the pages.

6. Web interface

6.1 Theme

The visual language follows the RetroPlay Network's shape (dark by default, Barlow for text and Press Start 2P for the wordmark and first columns, square corners, thin --line rules, a --panel header and footer, a full-width --band navigation bar with the active tab underlined in --acc) with the palette taken from the Oxygen mark shared with the VS Code extension: the mark's cyan #00F0FF to blue #0072FF gradient on #070c18, so --acc is cyan, --acc-2 blue, and the band a deep blue. The mark itself is the logo in the header, the footer and the favicon; the wordmark beside it reads OXYGENHUB. The stylesheet starts from retroplay-manager/templates/style.css lines 1–171 (tokens, shell, band, tabs, main, tables, forms, footer) and adds forge components; the store, showcase and game components are not carried over.

The theme is dark, light, or auto (follow the system's prefers-color-scheme, and change with it), chosen with the switch in the header (it cycles) or under Settings → Appearance, and kept in a theme cookie for a year; dark when unset. A script in the page head applies it before first paint. Syntax highlighting uses the highlighter's scope names as classes prefixed sy-, so no scope can collide with the page's own classes.

Tokens (dark default, light under :root[data-theme="light"]):

--bg  --panel  --soft  --ink  --mute  --line  --dim
--acc  --band  --band-ink  --band-line  --now  --now-ink
--ok  --bad  --warn (new: #ffb347 dark / #b8651b light)
--add  --del  --add-ink  --del-ink   (new: diff backgrounds and text)
--m1 … --m5   (kept for signature status colours: root, signed, sealed, unsigned, invalid)

Theme selection: cookie theme=light|dark|auto; auto follows prefers-color-scheme. The <head> sets data-theme before paint exactly as retroplay-manager does. Fonts are vendored under /static/fonts/ rather than loaded from Google, so a hub on a private network paints without internet access.

The logo is assets/icons/oxygenhub.svg, a copy of the extension's oxygen.svg (two linked rings, the molecule), inlined in the header at 22px beside the wordmark.

6.2 Page shell

header (wordmark, global search box, "+" menu for new repository/issue/proposal, notifications bell with unread count, avatar menu) · .band (Repositories · Explore · Proposals · Issues · Notifications, with admin links pushed right) · repository .tabs (Code · Changes · Proposals · Issues · Releases · Trust · Settings, each with a count pill) · main at 1180px max (wider than retroplay's 980 because diffs need it; tree and file pages use 100% with 22px gutters) · footer.

Every page has a <title> of the form <thing> · <owner>/<name> · Oxygenhub.

6.3 Pages

6.4 Repository overview

The default bookmark's tree at the root, the rendered README.md (or README, README.txt) below it, and a right column: description and topics, clone URL with copy button (oxy clone https://…/{owner}/{name}), heads count with a link when more than one, bookmarks, tags, latest release, collaborators, license detected from LICENSE, and the trust badge: policy, no policy, or policy expired.

A repository whose default bookmark has more than one head shows a --warn strip: "main has 3 heads; the tree below is their union" with a link to the bookmarks page. Conflicts in that state show a --bad strip linking to the conflicts page.

6.5 Tree

Directory rows show name, the last change touching the entry (message and relative time, from log_for_path, computed lazily per row over the API so a large directory paints immediately), size, and mode glyphs (executable, symlink, subrepository). A subrepository row links to its pin: another hub repository at a state, or a Git URL at a SHA.

6.6 File view and blame

Text files render with syntect line highlighting, line numbers as anchors (#L12, #L12-L20 selects a range), a "raw", "history", "blame", "edit" toolbar, and the file's last change. Markdown renders by default with a toggle to source. Images and PDFs render inline; other binaries offer download. Files above render_limit (default 2 MiB) show the first part and a download link.

Blame uses Repo::blame: every line is exact, because each line is an atom with one authoring change. The gutter shows the change's short hash, author and age, grouped into runs, with the change's signature glyph. Blame is exact through rebase and squash, so there is no "ignore revs" file.

6.7 History

A dependency graph, not a parent chain. The default view lists the bookmark's changes newest first with lanes drawn between a change and its dependencies (the same layout algorithm as the VS Code extension's webview, ported to Rust and rendered server side as SVG). Heads are marked. Filters: author, path, date, signed/unsigned, message text. Each row: short hash, message first line, author (name, or KeyId when unlinked), relative time, signature glyph, bookmark and tag chips, a conflict chip when the change introduces one.

?path= gives the history of one path.

6.8 Change page

Header: full hash, message, author identity (linked account or KeyId), timestamp, signature status with the policy rule that admitted it (or "unsigned", or "invalid"), seals covering it, the bookmarks and tags containing it. Body: dependencies and dependents as chips, the change's edits as a diff (unified or split, per-user preference), atom counts, and the raw change (oxy show --json) behind a details block.

Actions for write: open a proposal containing this change, tag it, copy hash. Describing, abandoning, squashing and rebasing are client operations and are not offered here.

6.8.1 Diffs

Every diff (change, compare, proposal files) shows each file as a collapsible section, open unless it has more than 400 rows. Within a block of changed lines, removals come first and each is paired with the addition in the same position; a pair similar enough (at least 40% of its tokens shared, tokens being identifiers, whitespace runs and single other characters) marks the tokens that changed. ?w=1 hides whitespace-only changes: a pair equal once whitespace is removed is shown as one unchanged line. With scripts, a toolbar switches between unified and split (side by side, pairs opposite each other) views, remembered in a diff cookie, and collapses or expands every file.

6.9 Web edit

CodeMirror 6 with the file's language mode. Saving creates a change with the given message signed by the hub delegate on behalf of the user (§5.5) and adds it to the chosen bookmark, or to a new bookmark plus a proposal, exactly as GitHub's "propose changes" flow. The hub refuses with a clear message when the user has not delegated to the hub key (§5.5) or the policy does not authorise them for the target. Binary files and files over render_limit cannot be edited in the browser.

6.10 Conflicts page

For each bookmark whose state has conflicts: the file (or tree entry), the conflict kind, and each side with the change that produced it and its content, rendered with the same marker structure oxy checkout writes. A "resolve in browser" action opens the file's conflict markers in the editor (§6.9) and commits a resolution change through the delegate. Otherwise the page gives the two-line client recipe.

6.11 Trust page

The current policy (serial, expiry, roots, threshold, rules with their patterns, thresholds and allow_conflicts), the policy history, the hub delegate key with its fingerprint and which collaborators have delegated to it, every linked account's keys that the policy names, revoked keys, and a verification summary computed from oxy verify: counts of signed, sealed, unsigned and invalid changes, with a list of invalid ones. Policy proposals awaiting root signatures are listed with who has signed and a download of the proposal file.

6.12 Pushes page

The hub keeps its own log of every reference update it accepted or refused: time, account, key, reference, old and new state, force flag, the result and reason. This is the answer to "who moved main and when" and is the hub's audit trail for history; it is not the repository's operation log, which is per workspace.

6.13 Keyboard and accessibility

/ focuses search, g c / g p / g i jump to Code, Proposals, Issues, ? shows the sheet. Every interactive element is reachable by keyboard; colour is never the only carrier of meaning (glyphs accompany every status colour); contrast meets WCAG AA in both themes.

7. Proposals and review

7.1 Definition

A proposal is a request to add a set of changes to a target bookmark of a repository. It is identified by a per-repository number, like a pull request. Its source is either a bookmark of the same repository or of a fork, in which case the proposal's changes are those in the source bookmark's state not in the target's; or an explicit list of change hashes (from the change page or the API).

A proposal records: number, title, description (Markdown), author, target bookmark, source (bookmark and repository, or explicit hashes), state (draft, open, landed, closed), reviewers requested, labels, and the projected state (§7.2).

7.2 Projected state

Whenever the proposal or its target changes, a job computes the projected state: the union of the target's heads and the proposal's changes, loaded through oxy-core exactly as a client's oxy merge would. From it the page shows:

• the changes to be added, in dependency order, with signature status;
• the diff between the target's state and the projected state;
• conflicts the landing would reify, each with its sides, in the same rendering as §6.10;
• files touched, and check results for the projected state hash (§13).

Because changes commute, a projected state is stale only when the target has moved; the job then recomputes it. There is no "update branch" button because there is nothing to update. If the recomputation shows a new conflict, the proposal is marked conflicted and the author and reviewers are notified.

7.3 Review comments

A comment is attached to the proposal (general), to a file, or to an atom: (ChangeHash, index) plus the change that introduced the line. Rendering places it at the atom's current position in the projected state; if the atom is gone (deleted by a later change in the proposal), the comment shows in the file's "resolved lines" section rather than disappearing. When the author squashes or rebases, the correspondence the rewrite recorded maps the old atom to the new one, and the comment follows. Comments are Markdown (EasyMDE), threaded, and resolvable.

7.4 Reviews and approvals

A review is comment, request changes, or approve. An approval MUST be backed by a seal attestation (spec §14.4, kind = seal) over the proposal's change hashes, signed with a key linked to the reviewer's account. Private keys never enter the browser, so the reviewer signs from a client: oxy seal --proposal <url> or oxy seal <hashes> (§18, a new command; the seal object already exists in the model) signs and pushes the seal; the hub matches the seal to the proposal and records the approval. The page shows the command ready to copy. An approval not yet backed by a seal is shown as "approval pending signature" and does not count towards requirements.

Landing requirements per repository (settings): N approvals, approvals from code owners (.oxyowners in the target state, GitHub CODEOWNERS syntax), required checks green on the projected state, no conflicts (or conflicts allowed, matching the policy rule's allow_conflicts), and no outstanding "request changes".

7.5 Stacked proposals

A change may depend on changes in another open proposal. The page shows "depends on #12" and lands only after #12 has landed, or lands both when the user chooses "land with dependencies" and holds the rights for each.

7.6 Landing

Landing sets the target bookmark to the projected state's heads: a reference update with a fresh ref attestation. It is performed by:

1. the hub delegate key on behalf of the user landing, when that user has delegated to it (§5.5), the policy authorises them for the target, and they hold write; or
2. a client: oxy proposal land <url> (§18) fetches the proposal's changes, sets the bookmark locally and pushes with the user's own key. The hub notices the push, sees the proposal's changes are now in the target, and marks it landed.

The landed state hash is recorded. Nothing is rewritten: the changes keep their hashes, so links to them stay valid and check results carry over. "Squash on land" is offered as a client-side option only, since it rewrites signed changes.

7.7 Closing and reopening

closed keeps everything; the source bookmark may be deleted on close if the user asks. A proposal whose changes all appear in the target through another route is marked landed automatically with a note.

8. Issues

Per-repository numbered issues sharing the number space with proposals (as GitHub does), with title, Markdown body, author, assignees, labels (name, colour, description), a milestone (title, due date, description, open/closed), state (open, closed with reason completed or not planned), comments, lock, and pin. Issue templates come from .oxyhub/ISSUE_TEMPLATE/*.md in the default state.

Cross references: #12 links an issue or proposal; owner/name#12 across repositories; a 12-hex-or-longer token links a change when it resolves; closes #12 in a change message closes the issue when the change lands on the default bookmark. Every reference creates a timeline entry on the target.

Import from GitHub or GitLab is a 1.x item.

9. Releases and tags

Tags come from the repository (spec §10): a name, the state, and a signed attestation when the tagger signed. The tags page lists them with signature status. A release attaches to a tag: notes (Markdown, generated draft from the changes since the previous release), assets (uploaded files, content addressed, size limited by asset_limit), a pre-release flag, and a latest marker. Source archives (.tar.zst, .zip) of the tagged state are generated on demand and cached.

10. Notifications

Events: proposal opened, review requested, review submitted, comment on a thread you are in, mention (@name), landing, check failed on your proposal, issue assigned, policy proposal awaiting your signature, push refused. Each becomes an inbox item (/notifications, with unread count in the header) and, when the account chooses, an email through lettre with a per-account SMTP-independent unsubscribe link. Watching a repository subscribes to all its events; participating in a thread subscribes to it.

11. Search

Global search box with scopes: repositories (name, description, topics), issues and proposals (FTS5 over title, body and comments), changes (message FTS5 over the default bookmark's state, indexed on push), accounts, and code. Code search in 1.0 is a per-repository substring and regular-expression search over the default state's text files, run with a time budget and a result cap, cached per state hash. A trigram index is a 1.x item.

12. HTTP API and webhooks

12.1 API

JSON under /api/v1, bearer tokens, application/json, RFC 7807 problem responses, cursor pagination (?after=), ETags on cacheable resources, and rate limits per token. Resources mirror the pages: /repos/{owner}/{name}, /bookmarks, /changes/{hash}, /tree/{ref}/{path}, /file/{ref}/{path}, /blame, /history, /compare, /conflicts, /proposals, /proposals/{n}/comments|reviews|checks|land, /issues, /labels, /milestones, /releases, /tags, /trust, /pushes, /hooks, /checks, /user, /users/{name}, /orgs/{name}, /search. Shapes reuse oxy --json shapes wherever one exists (change, status, blame, diff) so tools written against the CLI work against the hub. crates/hub-api holds the types with serde derives and is what the runner and the VS Code extension will link.

12.2 Webhooks

Per repository and per organisation: a URL, a secret, an event selection, active flag, and delivery log with redelivery. Payloads are JSON with X-Oxyhub-Event, X-Oxyhub-Delivery, and X-Oxyhub-Signature: blake3-keyed=<hex> computed as keyed BLAKE3 over the body. Events: push (reference updated: old and new state, heads, changes), proposal (opened, edited, review requested, landed, closed, conflicted), review, comment, issue, release, check, policy. Deliveries retry with backoff up to 24 hours.

13. Checks and the runner

13.1 Checks

A check is a result attached to a state hash: name, status (queued, running, passed, failed, cancelled, skipped), a summary, a URL, timing, and an optional signed seal from the checker's key over the changes in that state, which makes a passed check a verifiable object. Checks are created through the API (POST /repos/{o}/{n}/checks) by any token with checks:write, so any CI system can report, and required checks for landing (§7.4) are matched by name against the projected state's hash. The proposal page streams check status updates over server-sent events.

Because a state is content addressed, the hub deduplicates: a check that passed for a state hash is shown for every proposal and bookmark that reaches that same state.

13.2 Oxygen Runner (later; docs/runner.md)

The runner is a separate Rust program and a separate specification, not required for hub 1.0. The hub side is only §13.1 plus a runner scope for tokens and a job-claim API. The runner's design principles, recorded here so the hub does not close doors:

1. Pipelines are typed, validated documents, not templated YAML. The definition lives in the repository (.oxy/ci/*.kdl), has a schema, and is validated by oxyrun check and by the hub on push before anything runs. Errors point at a line. There is no string templating stage; parameters are typed values.
2. Same execution locally and remotely. oxyrun runs the pipeline on a laptop in the same OCI container image with the same inputs and produces the same result. "Works on CI but not here" is a bug in the runner.
3. Content-addressed steps and images. A step references an action by an Oxygen state hash or a Git SHA, never a mutable tag; images by digest. The hub refuses a definition that pins nothing. Actions are ordinary Oxygen repositories with signed tags, so uses is verifiable.
4. Proposals from outsiders run with no secrets. There is no pull_request_target. Secrets are bound to named environments; an environment lists who may deploy to it and whether a proposal may use it, and using one from a proposal needs an explicit approval by a maintainer on that projected state.
5. Results are seals. A green job is a seal over the state's changes signed by the runner's key, admitted by policy as a checker. It is the same object §13.1 stores, verifiable by any client offline.
6. The state is the unit, not the commit. A job runs on a state hash and is cached by it. Two proposals reaching the same state run once.
7. Structured logs, streamed and kept. Log lines carry step, timestamp and level; the UI groups and folds them; retention is configurable; artefacts are content addressed.
8. Caches keyed by content. Cache entries are keyed by the BLAKE3 of the declared inputs, never by a hand-written key string.
9. No implicit shell. Each step declares its program and arguments; a sh step is explicit about the shell and set -eu is on by default.
10. Runners are cattle. A runner registers with a token, claims jobs over a long-poll API, runs each in a fresh container or VM, and reports; no state survives a job. Runner groups and labels select where jobs run.

14. Git interoperability

A repository may enable a Git mirror: on every landing on selected bookmarks the hub runs oxy git export into <data>/mirrors/<owner>/<name>.git and serves it read-only over Git's smart HTTP protocol at /{owner}/{name}.git (implemented with the git binary's http-backend behind the hub's authorization, since reimplementing pack negotiation is not the product). This lets GitHub Actions runners, IDEs and tooling that only speak Git read hosted Oxygen repositories. Pushing to a mirror is refused with a message pointing at oxy.

Import from Git: oxy git import at repository creation from an uploaded bundle or a URL, keeping the mapping so later oxy git fetch keeps the imported bookmark following the Git branch.

15. Security

15.1 Threat model

An anonymous internet user, a signed-in user attempting to exceed their role, a collaborator with write attempting to move a reference the policy forbids, a malicious repository content author (Markdown, file names, huge objects), and a compromised hub host. The last is bounded by design: the hub holds no root keys, approvals are user-signed seals, history is signed by authors, so a compromised hub can deny service and forge hub-only data (issues, comments) but cannot forge history, approvals or policy without detection.

15.2 Web

CSRF: every unsafe form carries a token bound to the session (HMAC(cookie_key, "csrf:" || session mac)), and the Origin header is checked when present. Cookies are HttpOnly, SameSite=Lax, Secure over HTTPS. Content Security Policy: default-src 'self', no inline scripts except the theme snippet by hash, img-src 'self' data:; rendered Markdown is sanitised by ammonia with an allow-list; rendered HTML files are never served inline (raw file responses use Content-Disposition: attachment and X-Content-Type-Options: nosniff) except images with sniffed, allow-listed types. Path parameters are validated before touching the file system; paths inside repositories are resolved against the object store, never the disk.

15.3 Passwords, sessions, tokens

Argon2id with the defaults of the argon2 crate, per-password salt; TOTP with a 30-second step and one-step drift; recovery codes; sessions as in §5.1; tokens stored as BLAKE3 hashes and compared in constant time; login rate limited per account and per address; all session-changing actions logged in the audit log.

15.4 Repository content

Object sizes are bounded by the wire protocol server's body limits (per push and per object); rendering is bounded by render_limit and by time budgets; archives are streamed; symlinks in trees are shown, never followed on the server; subrepository pins are displayed, never fetched by the hub.

15.5 Keys and TLS

The hub delegate key lives in <data>/keys/ with mode 0600. Its identity object is published at /.well-known/oxyhub-key so policy holders can admit it. TLS: the hub serves HTTPS itself with the configured certificate, or plain HTTP behind a terminating proxy, or on the developer edition a self-signed certificate it generates at init (with rcgen) whose CA is downloadable from the trust page and usable with OXY_CA.

15.6 Rate limits and abuse

Per address for anonymous requests, per account and per token otherwise, with separate budgets for pages, API, search and the wire protocol; registration and login have their own. Administrators can ban accounts and block addresses.

16. Performance and caching

16.1 Targets

Repository overview and tree pages in under 100 ms on a warm hub for a repository of 100 000 changes; a change page in under 200 ms; a projected state for a 50-change proposal in under 2 s; wire protocol throughput limited by disk and network, not the hub.

16.2 Locks and blocking

Every oxy-core call runs on the blocking pool. Each repository has a tokio::sync::RwLock: pushes, landings, web edits and mirror exports take the write lock; page reads take the read lock. oxy-core itself is single-threaded per Repo, so a Repo is opened per request and dropped after; store handles are cheap to open because packs are memory mapped.

16.3 Caches

Keyed by state hash, so they never go stale: loaded State objects (LRU by memory), tree listings, rendered file views, blame, history graph layouts per bookmark head set, projected states per proposal, archives, code search results. Keyed by object hash: rendered Markdown, syntax highlighted files. Keyed by repository: bookmark and tag lists, invalidated by the push path. ETag and Cache-Control: private, max-age=0, must-revalidate on pages; immutable on content-addressed responses (raw files by hash, archives by state).

16.4 Large repositories

History pages paginate by cursor; the graph renders a window of 100 changes with lazy extension; log_for_path for tree rows is fetched per row after the page paints and cached per (state, path). The projected state job uses load_state on the target and applies only the proposal's changes on top.

17. Operations: configuration, storage, backup

17.1 Configuration

hub.toml in the data directory; every key overridable by OXYHUB_<SECTION>_<KEY>:

[server]
bind = "0.0.0.0:7300"          # plain HTTP
tls_bind = "0.0.0.0:7343"      # HTTPS, when tls.cert and tls.key (or self_signed) are set
base_url = "https://earth.andymccall.xyz:7343"
behind_proxy = false            # trust X-Forwarded-* when true

[tls]
self_signed = true              # developer edition; otherwise cert = "...", key = "..."

[registration]
mode = "invite"                 # open | invite | closed

[limits]
render_limit = "2MiB"
asset_limit = "512MiB"
push_body_limit = "4GiB"

[email]
smtp = "smtp://…"               # optional
from = "Oxygenhub <hub@example>"

[mirror]
git = "/usr/bin/git"

[retention]
trash_days = 30
webhook_log_days = 30

17.2 Storage

SQLite in WAL mode; migrations embedded and applied at start; PRAGMA user_version guards downgrades. Repositories are ordinary Oxygen repositories; oxy gc runs per repository as a nightly job with the retention the repository settings choose.

17.3 Command line

oxygenhub init  --data DIR [--admin NAME]      create the data directory, keys, database, first admin
oxygenhub serve --data DIR                     run
oxygenhub admin --data DIR user|repo|token …   offline administration
oxygenhub backup --data DIR --to FILE          consistent snapshot: sqlite backup API plus repos and assets as tar.zst
oxygenhub check --data DIR                     verify every repository's objects and signatures, report

17.4 Backup and restore

backup uses SQLite's online backup API for the database and copies repos/, assets/, keys/ and hub.toml; cache/ is excluded. Restore is extraction plus serve. Because objects are content addressed, a repository directory copied while a push is in flight is still valid up to its last committed reference update.

17.5 Developer edition on Earth

Earth (earth.andymccall.xyz, Ubuntu 26.04, x86_64, 4 cores, 31 GiB, Docker, ports 22, 6400, 6670, 7842, 8080 in use) runs the developer edition as a systemd service under a dedicated oxygenhub system user with <data> = /home/oxygenhub/data, HTTP on 7300 and HTTPS on 7343 with a self-signed certificate. Source is synchronised from the development machine with rsync (the Oxygen workspace and the hub) and built on Earth with a rustup toolchain installed for the claude account; docs/deploy.md gives the exact steps. Once the hub runs, oxygen, oxygen-vscode and oxygenhub are pushed to it as its first repositories and become their own remotes; that fulfils the self-hosting rule without any Git involvement.

18. Required changes to Oxygen

Each is small and lives in the Oxygen workspace, tracked in its docs/plan.md:

1. Bare repositories. Repo::open_bare(dir): open a .oxy/ with no workspace; refuse working-copy operations with a clear error. oxy init --bare.
2. Server embedding. oxy-server exposes router_with(resolver, authorizer) where the resolver maps a path (possibly owner/name) to a repository directory and the authorizer decides read and push per request, so the hub embeds it instead of copying handlers. Repository names with one / allowed when the resolver permits.
3. Challenge signing. oxy identity sign-challenge <bytes> and oxy_core::identity::verify_challenge, for linking keys (§5.3) and HTTP signature authentication (§5.4).
4. Seal command. oxy seal <hash>.. signs a seal attestation over the given changes with the identity key and pushes it on the next push (the seal object and its verification exist, spec §14.4; today only the sync path creates seals). oxy seal --proposal <url> fetches the hash list from the hub API first.
5. Landing from a client. oxy proposal land <url> and oxy proposal show <url> as thin API clients.
6. Delegate signing of hub-created changes. A library entry point to build and sign a change from an edit set with author = user key, signer = hub key, without a workspace (used by web edits, browser conflict resolution and landings). oxy identity delegate add|remove already exists.
7. History for the hub. Repo::log_window(heads, cursor, limit) for paginated history, and a graph::layout module shared with the CLI so both draw the same lanes.
8. Push hook. receive_push reports, per accepted reference, the old and new state and the list of newly stored changes, for the pushes log and webhooks.
9. Machine interface. oxy verify --json already exists; add oxy policy propose output as a downloadable proposal file (it exists as a file format, spec §14.5) and oxy tag list --json is already present.

19. Milestones

20. Open questions

1. Seal signing UX. Requiring oxy seal from a client for every approval is honest but slower than a button. A browser-held signing key (WebAuthn prf extension deriving an Ed25519 key) could sign approvals in the browser with hardware backing; ML-DSA-65 in the browser is heavier. Decide after 0.3 ships with the client flow.
2. Delegate key custody. One hub key delegated to by many users means one key whose compromise lets an attacker sign as any of them (still subject to policy and to each user's revocation). Per-user delegate keys held by the hub would narrow that blast radius at the cost of a key per user. Decide before 0.6.
3. Postgres. SQLite is enough for one host; an organisation-scale hub may want Postgres. sqlx keeps the option open, but every query would need to be dialect-clean. Decide when someone needs it.
4. Comment anchoring for lines that are not atoms. Comments on deleted lines and on binary files fall back to file anchors; is that good enough?
5. Pipeline language. KDL is the current choice for .oxy/ci; Starlark would give loops and functions at the cost of a real evaluator. Settle in docs/runner.md.
6. Federation. Proposals across hubs (a fork on another hub) are natural in a content-addressed model and out of scope for 1.0.

21. Changelog

• Draft 0.1 (2026-09-27): initial specification.