# Service accounts: a scoped, non-human credential type This is a design note for a feature, not an implementation plan — it exists to propose the shape before writing code. It's raised directly by `terdut-operator` (a separate repo, no shared code — see its `DESIGN.md` §6, §9, §13), which needs a credential for unattended, repeatable API access and currently has no good one available. Anything automating terdut-server long-term (this operator, CI, future integrations) hits the same gap, so this is written as a general primitive, not operator-specific. ## The problem terdut-server has two credential types today, and neither fits "an unattended process that manages teams/schedules/policies on someone's behalf": - **User API keys** (`api_keys`, `internal/api/users.go`) are always tied to a real `users` row and carry that user's full rights — every team they're a member of, their admin flag if set. There's no `kind`/`service` marker distinguishing "a human's personal automation key" from "a login session," and no way to mint one scoped to less than the full user. - **Integration keys** (`integrations`, `internal/api/*teams*.go`) are team-scoped, but narrowly: they authenticate exactly one inbound Alertmanager webhook call (`POST /api/integrations/{key}/alertmanager`) and nothing else. They're not a general management-API credential and shouldn't become one — overloading a narrow, one-way ingestion credential with broad read/write access would weaken the one property that makes it safe to embed in an Alertmanager config today. The result: any automation that needs to create teams, set escalation policies, manage dead-man switches, or rotate integration keys has to hold a real human admin's or team owner's API key. That key is exactly as powerful as that person logging in — full team access, and full instance access if they're an admin. `terdut-operator`'s design ran directly into this (its DESIGN.md §6): its described bootstrap/rotation flow assumed a repeatable, identity-scoped way to get a credential, and `/api/bootstrap`'s actual behavior (single-shot per install, gated on `COUNT(*) FROM users`, confirmed via `internal/api/users.go` and `charts/terdut-server/templates/bootstrap-job.yaml`) doesn't provide one — it mints exactly one founding admin, once, ever. ## Goals - A credential type that isn't a human: doesn't touch OIDC group sync, login, session, or the `is_admin`/account-management semantics that come with a real `users` row. - Two scopes matching the two shapes automation actually needs: instance-wide (create/list teams — what a server-owning controller needs) and team-scoped (manage one team's escalation policy, dead-man switches, integrations, schedule, OIDC group bindings — what a per-team controller or integration needs). - Repeatable issuance and rotation — unlike `/api/bootstrap`, callable more than once, by anything that already holds admin rights, without destroying and recreating state to get a fresh credential. - Visibly distinct from a human in every place identity shows up (audit trails, timeline entries, UI attribution) — a service account acting on a team should never be indistinguishable from a person. ## Non-goals - Not a general OAuth2/OIDC client-credentials flow — this is a bearer-token primitive matching the shape `api_keys` already uses (SHA-256 hash stored, raw key shown once at creation), not a new auth protocol. - Not replacing integration keys — those stay as the narrow, one-way webhook credential they are today. - Not modeling per-endpoint or per-verb permissions within a scope — `instance` and `team` are the only two scopes for now; finer-grained scoping is future work if a real need shows up. ## Proposed shape ### Schema ```sql CREATE TABLE service_accounts ( id BIGSERIAL PRIMARY KEY, name TEXT NOT NULL UNIQUE, -- e.g. "terdut-operator" scope TEXT NOT NULL CHECK (scope IN ('instance', 'team')), team_id BIGINT REFERENCES teams(id) ON DELETE CASCADE, -- team_id required iff scope = 'team'; NULL iff scope = 'instance' created_by BIGINT REFERENCES users(id), created_at TIMESTAMPTZ NOT NULL DEFAULT now() ); CREATE TABLE service_account_keys ( id BIGSERIAL PRIMARY KEY, service_account_id BIGINT NOT NULL REFERENCES service_accounts(id) ON DELETE CASCADE, key_hash TEXT NOT NULL UNIQUE, name TEXT NOT NULL, -- e.g. "initial", "2026-Q4-rotation" created_at TIMESTAMPTZ NOT NULL DEFAULT now(), last_used_at TIMESTAMPTZ ); ``` Deliberately not a `users` row: no `password_hash`, no `is_admin`, no `user_identities` linkage, so it's structurally impossible for a service account to be pulled into OIDC group sync or password login. Multiple keys per account (mirroring `api_keys`' existing one-user-many-keys shape) so rotation is "mint a new key, revoke the old one," not "recreate the account." ### Endpoints - `POST /api/service-accounts` — instance-scope/admin-only. Body: `{"name": ..., "scope": "instance"|"team", "teamID": ... }` (teamID required iff scope=team, and caller must be that team's owner or a system admin). Returns the account plus its first raw key (shown once, same pattern as `POST /api/users/{id}/api-keys`). Safe to call again with the same `name` — see "idempotent lookup" below — unlike `/api/bootstrap`, which is inherently one-shot by design (it's answering "does any user exist yet," a question with no analogue once one already does). - `POST /api/service-accounts/{id}/keys` — mint an additional key on an existing account (self-service-equivalent: instance admin for `instance` scope, team owner or system admin for `team` scope). Enables rotation without recreating the account or losing its identity/audit history. - `DELETE /api/service-accounts/{id}/keys/{keyID}` — revoke one key, mirroring `DELETE /api/users/{id}/api-keys/{keyID}`. - `GET /api/service-accounts?name=` — look up an existing account by name. This is what turns "I tried to create my account and got a conflict" into a normal flow instead of an error: a controller that expects to have already registered itself calls this first, and only falls through to `POST` if nothing comes back. ### Auth middleware **Revised** (this section originally described an aspiration that didn't match what shipped — `TEAM-LOOKUP.md` already caught one instance of that, and a fuller audit found three more; this is the corrected, as-built description, not the original proposal). `internal/api/middleware.go`'s dual resolution (`Authorization: Bearer` → `apiKeyUser()`, or session cookie → `sessionUser()`) and the service-account path (`serviceAccountFor()`) both resolve into one `Caller` type (`internal/api/caller.go`), not two parallel, un-unified context representations the way an earlier version of this server kept them. Every authorization predicate reads `Caller`'s methods: - `Caller.IsAdmin()` — true **only** for a human system administrator, never for a service account of either scope, under any circumstance. `AdminOnly` and `requireSelfOrAdmin` key on this alone — user management (`POST /api/users`, `PUT /api/users/{id}/admin`, etc.) and `GET/PUT /api/admin/settings` stay human-only, forever. The original text here claimed an instance-scoped service account satisfies `AdminOnly` "for team-creation/listing purposes" — that was never true of the shipped code (`TEAM-LOOKUP.md` caught the listing half; the creation half was always a separate, bespoke check in `handleCreateTeam`, not `AdminOnly` itself) and is not being made true now. Don't widen `AdminOnly`: every time this has come up, the fix has been a narrower, purpose-built capability instead (`?name=` lookups for teams and service accounts; now `terdut-operator`'s own invite-minting feature for the one real gap this boundary left — how a human ever gets a first login on a no-OIDC, operator-managed install. See the bottom of "What this unblocks.") - `Caller.IsInstanceServiceAccount()` — true only for an instance-scoped service account, never for a human (including a human admin). `handleCreateTeam` uses exactly this: a human creates a team by being a human (and becomes its owner); an instance-scoped service account creates one with no human owner at all. The two paths are not interchangeable, so this predicate deliberately does not also admit a human admin. - `Caller.Role(teamID)`/`TeamIDs()` — a human's real `team_members` rows, or a team-scoped service account's single synthetic owner membership (`serveAsServiceAccount`). This is what makes `requireTeamMember`/ `requireTeamOwner` treat a team-scoped service account as owner-equivalent for that one team, with no separate branch needed in either function. - `Caller.ServiceAccountID()` — used by `OperatorModeBlock` ("any service account passes") and by `callerMayManageServiceAccount`'s self-rotation check. - `Caller.AsHuman()` — the accessor every handler that needs a real `user_id` to act on behalf of must call and check, instead of reading a user off context unconditionally. Before the `Caller` type existed, four handlers did the latter and silently misbehaved for a service-account caller: `handleMe` and `handleTestNotification` 500'd (a zero-value user id that matches no row), `handleDismissOnboarding` silently no-op'd (`UPDATE ... WHERE id = 0` affects nothing, still returns 204), and `handleCreateInvite` wrote that same zero value into `invites.created_by` — a real foreign-key violation, not just a wrong answer, since that column is nullable but was never passed as `nil`. All four now call `AsHuman()` and return an explicit 403 ("this endpoint is for human accounts only") or, for the invite case, leave `created_by` `NULL` the same way `handleCreateServiceAccount` already did for the analogous situation. **Team scope is owner-equivalent for every `requireTeamOwner` endpoint, membership and invites included — by design, not by an unclosed gap.** An earlier version of this document flagged this as "acknowledged rather than closed," kept in check only by the social convention that nobody *builds* automation against those two routes. That convention is retired: `terdut-operator`'s `TerdutTeam` controller now mints and revokes its own team's invite link through exactly this capability (its existing team-scoped credential, `POST`/`DELETE /api/teams/{teamID}/invites`), which is the real fix for the human-onboarding gap below — not a narrower carve-out of this capability. `service_accounts_test.go`'s `TestServiceAccount_TeamScopeManagesItsOwnInvites` pins it. **A team-scoped account can also mint another service account scoped to its own team** (`handleCreateServiceAccount`'s `callerOwnsTeam` branch, which a team-scoped caller already satisfies for its own team via the synthetic membership above). Kept, not restricted, for the same reason: a team-scoped credential is that team's owner's reach, full stop — carving this one capability out while leaving membership/invites alone would be an arbitrary asymmetry. Pinned by `TestServiceAccount_TeamScopeCanMintAnotherAccountForItsOwnTeam`. **`callerMayManageServiceAccount` gained the one load-bearing fix this redesign exists for:** an instance-scoped service account may manage (mint/revoke a key on) *any* team-scoped account, not only one admin, that team's human owner, or the account itself. `handleCreateServiceAccount` already let an instance-scoped caller *create* a team-scoped account for any team; this closes the gap where adopting or rotating one it didn't just create in the same call — exactly `terdut-operator`'s documented adopt-on-409 crash-window recovery (its own `DESIGN.md` §5) — 403'd forever instead of succeeding (`terdut-operator#3`). Pinned by `TestServiceAccount_InstanceScopeAdoptsAnExistingTeamScopedAccountsKey`. Anywhere identity is recorded for a human (incident timeline `acknowledged_by`/`assigned_to`, audit-relevant fields), a service-account caller is still coerced into a bare `user_id` of `0` today — `Caller`'s new `Identity()` accessor exists for exactly this follow-up, but wiring it in needs a schema migration (an actor-attribution column distinct from `user_id`) and is deliberately out of scope here. Tracked separately, not by this document. ## What this unblocks Directly resolves `terdut-operator` DESIGN.md §6's two broken assumptions: 1. **Bootstrap becomes single-purpose again.** `/api/bootstrap` mints exactly the founding human admin, once. The operator's actual first-reconcile flow: call `/api/bootstrap` only on a genuinely empty install; otherwise (or immediately after, if it won the bootstrap race) call `GET /api/service-accounts?name=terdut-operator`, and `POST` one if it doesn't exist yet. From then on the operator never touches `/api/bootstrap` again. 2. **Rotation becomes real.** `POST /api/service-accounts/{id}/keys` + revoke the old one — no destructive DB-level workaround, no re-triggering a single-shot endpoint that can't fire twice. 3. **Cross-namespace credential mirroring is no longer needed at all.** `terdut-operator`'s current design holds every credential — instance- and team-scoped alike — privately in the operator's own namespace, never in the namespace of the CR each one authenticates for; reconciliation happens entirely inside the operator's controller loop, so no CR owner ever needs read access to a terdut-server credential regardless of same- or cross-namespace `serverRef`. Team scoping is still what bounds the blast radius of any individual credential: a leaked team-scoped key exposes exactly one team's resources, never the whole server, which is what makes holding many credentials in one place (the operator's namespace) an acceptable trade rather than reintroducing the mirrored design's server-admin-equivalent-everywhere problem. 4. **A human can get a first login on a no-OIDC, operator-managed install — without ever touching `AdminOnly` or `/api/admin/settings`.** This was filed as `terdut-server#23` ("no API path to create a human login after bootstrap") and diagnosed, at the time, as this server needing to let a service account through `AdminOnly`. It doesn't: the fix lives entirely in `terdut-operator`, because a team-scoped credential was *already* owner-equivalent for `POST /api/teams/{teamID}/invites`, and invite redemption (`POST /api/signup` with an `invite` token) bypasses `signup_mode` entirely — `terdut-operator` just never grew a feature to use either fact. Its `TerdutTeam` controller now mints and surfaces one via its own existing team-scoped credential (`spec.invite`, `status.inviteSecretRef`, see that repo's own docs), so a human joins a CRD-managed team by a real invite link, the same way anyone else would. `terdut-server#23` is closed with this note once that feature ships — its named routes stay human-only, correctly, not a gap. ## Suggested sequencing Land this before `terdut-operator` implements any bootstrap/credential-handling code — that code would otherwise be written against the current one-shot, user-only credential model as a known-temporary workaround, which is wasted effort on a repo that currently has zero implementation to begin with.