Scaffold vault-plugin-secrets-arrstack engine
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Mint dynamic arrproxy machine tokens via arrproxy's bearer-gated admin API
so Terraform-driven *arr onboarding can issue and revoke per-role tokens
non-interactively.

- Add backend, config, roles, creds paths and the arrstack_token secret
- Call POST/DELETE /api/admin/tokens with a vault:arrstack:<role> subject
- Enforce apps as a non-empty subset of sonarr/radarr/prowlarr
- Cap lease renewal at the arrproxy token's fixed expiry
- Add table-driven unit tests against a fake arrproxy admin server
- Add Makefile, nfpm packaging, and pre-commit/build/test/release pipelines
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# vault-plugin-secrets-arrstack
Vault/OpenBao secrets engine minting dynamic arrproxy per-user API tokens
A dynamic secrets engine that mints **arrproxy machine tokens** on both
**HashiCorp Vault** and **[OpenBao](https://openbao.org)**.
[arrproxy](https://git.unkin.net/unkin/arrproxy) fronts the *arr apps
(Sonarr / Radarr / Prowlarr) behind a single OAuth-gated proxy that brokers
per-caller API tokens. Its human path derives scope from OAuth identity headers,
so a non-interactive caller cannot use it. This engine calls arrproxy's
bearer-gated **admin API** (`/api/admin/tokens`) instead, so Terraform-driven
*arr onboarding can mint and revoke machine tokens without a human in the loop.
Each minted token is:
- **scoped to a subset of apps** (`apps`: any of `sonarr`, `radarr`, `prowlarr`)
- **subject-namespaced** as `vault:arrstack:<role>` (arrproxy requires the prefix)
- **bound to a Vault lease** — revoking the lease disables the token in arrproxy
## Vault and OpenBao
OpenBao is a fork of Vault and keeps its plugin protocol compatible, so the
**same plugin binary** registers and runs on either engine unchanged — the CLI
commands below are identical apart from `vault` vs `bao`.
## How it works
The backend authenticates to arrproxy's admin API with the admin bearer token
and manages tokens through `POST /api/admin/tokens` (mint) and
`DELETE /api/admin/tokens/{id}` (revoke). Each minted token is wrapped in a
Vault lease, so Vault owns the token's lifecycle: revoke disables it, renew
extends it up to the token's fixed expiry.
```
┌────────┐ read creds/<role> ┌────────────────────────┐ POST /api/admin/tokens ┌──────────┐
│ client │ ──────────────────► │ vault + arrstack plugin │ ───────────────────────► │ arrproxy │
└────────┘ ◄── machine token ─└────────────────────────┘ ◄──── {id, token} ────── └──────────┘
```
## Usage
```sh
# 1. Enable the engine
vault secrets enable -path=arrstack vault-plugin-secrets-arrstack
# 2. Configure the connection to arrproxy's admin API
vault write arrstack/config \
base_url=https://arrstack.unkin.net \
admin_token=$ARRPROXY_ADMIN_TOKEN \
ca_cert=@traefik-external-ca.pem # optional
# 3. Define a role: which apps, what TTLs
vault write arrstack/roles/media \
apps="sonarr,radarr" \
ttl=1h \
max_ttl=24h
# 4. Mint a scoped, time-limited machine token
vault read arrstack/creds/media
# Key Value
# --- -----
# lease_id arrstack/creds/media/AbC...
# lease_duration 1h
# apps [radarr sonarr]
# id tok-...
# subject vault:arrstack:media
# token arr_...
# 5. Revoking the lease disables the token in arrproxy
vault lease revoke arrstack/creds/media/AbC...
```
### Example roles
| Role | `apps` | Use |
| ---------- | ----------------------------- | ------------------------------------ |
| `sonarr` | `sonarr` | a token that only reaches Sonarr |
| `radarr` | `radarr` | a token that only reaches Radarr |
| `prowlarr` | `prowlarr` | a token that only reaches Prowlarr |
| `all` | `sonarr,radarr,prowlarr` | a token that reaches all three apps |
```sh
vault write arrstack/roles/sonarr apps="sonarr" ttl=1h max_ttl=24h
vault write arrstack/roles/radarr apps="radarr" ttl=1h max_ttl=24h
vault write arrstack/roles/prowlarr apps="prowlarr" ttl=1h max_ttl=24h
vault write arrstack/roles/all apps="sonarr,radarr,prowlarr" ttl=1h max_ttl=24h
```
## Paths
| Path | Ops | Description |
| ---------------- | ------------------ | ------------------------------------------------- |
| `config` | read/write/delete | arrproxy connection (`base_url`, `admin_token`) |
| `roles/<name>` | read/write/delete | Constraints for minted tokens |
| `roles/` | list | List configured roles |
| `creds/<name>` | read | Mint a machine token for the role |
### Config fields
| Field | Type | Description |
| ------------------------- | -------- | ------------------------------------------------------------------- |
| `base_url` | string | arrproxy base URL, e.g. `https://arrstack.unkin.net` |
| `admin_token` | string | arrproxy admin bearer token (write-only, never returned on read) |
| `ca_cert` | string | PEM CA to verify the arrproxy TLS cert; empty uses the system store |
| `request_timeout_seconds` | int | HTTP timeout for admin API calls (default 30) |
### Role fields
| Field | Type | Description |
| --------- | -------- | ------------------------------------------------------------------ |
| `apps` | list | Non-empty subset of `sonarr`/`radarr`/`prowlarr` |
| `ttl` | duration | Default lease TTL |
| `max_ttl` | duration | Maximum lease TTL |
## TTL and renewal
At mint time the effective initial lease TTL is sent to arrproxy as
`ttl_seconds`, so the arrproxy token is given a **fixed expiry** at that point
(`expires_at` in the mint response, which the engine stores). Because that
expiry is fixed and arrproxy does not extend an already-issued token, a lease
renewal can never push the lease past the token's expiry: the renew callback
honours the role's `max_ttl` but **caps the renewed TTL at the remaining time to
the token's expiry**, and an already-expired token is not extended. For a
longer-lived token, issue a new one (or set a larger role `ttl`).
## Development
```sh
make build # build the plugin into ./dist
make test # unit tests (race-enabled)
make lint # go vet
make fmt # gofmt
make rpm # build the binary and package the Vault + OpenBao RPMs
```
### Releasing
Versioning is tag-driven; pushing a `v*` tag runs the release pipeline, which
builds the binary, packages the Vault (`/opt/vault-plugins`) and OpenBao
(`/opt/openbao-plugins`) RPMs, prints the binary `sha256` for Puppet plugin
registration, and uploads the RPMs to the artifactapi `rpm-internal` repo.
```sh
make patch # v0.1.0 -> v0.1.1
make minor # v0.1.1 -> v0.2.0
make major # v0.2.0 -> v1.0.0
```