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The publishability gate caught internal tooling names and developer paths but nothing site-specific, so roughly sixty leaks reached the wiki: the site name in ten documents, real fleet hostnames in the collector and GE-Enforce examples, an internal database name through the whole import guide, imaging-share paths, and a maintainer's username as the Deciders line of every ADR and inside a generated curl example. None of it is a security matter on an air-gapped fleet. It matters because these pages are read by engineers at other plants, and a document that names one site throughout reads as that site's notes rather than a product's documentation - which is exactly what it then gets treated as. Examples now use neutral hostnames, the site is "the reference site" where the distinction carries meaning, and ADRs are decided by "ShopDB maintainers". The gate carries all of these patterns, so the next one fails a build. Two documents leave docs/ because they were never written for an outside reader. PROJECT-REVIEW.md is an internal health memo pinned to a commit from July, whose headline finding (an untracked playbook) has since been fixed - it is history, and git holds it. PILOT-DEPLOY.md is one site's own cutover runbook, complete with a "re-measure before publishing" placeholder; it moves next to the loader it belongs to, in scripts/site_imports/wjf/. ADR-015 is AMENDED rather than rewritten. Its enforcement section still said report-only and its backlog still listed hardcodes that are now cleared, which left the record contradicting itself. The amendment says what changed and why the report-only period ended; the original text stays, because what the decision looked like when it was taken is the part worth keeping. Also corrects llms.txt's response envelope, which had errors at the top level and pagination at meta.total. Both are nested one deeper, so anything written against that description read undefined on every error it tried to handle.
93 lines
5.3 KiB
Markdown
93 lines
5.3 KiB
Markdown
# ADR-004: Deployment topology (per-site instances)
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- **Status:** ACCEPTED
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- **Date:** 2026-05-08
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- **Deciders:** ShopDB maintainers
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## Context
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shopdb-flask manages shop-floor inventory. If multiple GE Aerospace sites adopt it, the deployment can take one of two shapes:
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| Model | How it works |
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| **Per-site instances** | Each site runs its own Flask + MySQL + Vue stack. Each site has its own DB, its own users, its own enabled-plugin list, its own deploy. Sites are isolated. |
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| **Multi-tenant single instance** | One central Flask + MySQL + Vue stack serves all sites. A `siteid` foreign key on every asset partitions data. Auth distinguishes which site a user belongs to. |
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The codebase today is single-tenant per deployment. There is no `siteid` column, no tenant filter, no cross-site auth model. Plugins can be enabled / disabled but only globally for the running instance.
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## Decision
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**PROPOSED:** **Per-site instances.** Each adopting site runs its own dedicated stack. The framework does not support multi-tenancy.
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Each site:
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- Owns its database (own credentials, own backup policy, own retention). The
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database charset is part of the contract: it must be **utf8mb4**
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(`utf8mb4_unicode_ci`). The migration chain creates every table utf8mb4, and
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the connection pins `?charset=utf8mb4`. A site that creates the database with
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a different default charset (older MySQL defaults to latin1) gets a schema
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that silently diverges from every other site. See `docs/DEPLOY.md`.
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- Picks its own enabled plugins
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- Configures its own JWT secret, CORS allowlist, Zabbix integration, Active Directory binding
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- Deploys at its own cadence
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The framework provides:
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- A `Dockerfile` and `docker-compose.yml` template suitable for a single-site deploy
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- A `.env.example` listing all required environment variables
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- A `docs/DEPLOY.md` walking through a fresh-site install
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## Consequences
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### Positive
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- Simpler code: no tenant filter on every query, no cross-tenant auth, no shared-state partitioning bugs.
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- Sites are independent. A schema change at one site does not affect another. A plugin crash at one site does not blast radius to other sites.
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- Clear ownership: each site's IT team owns their own stack and data. Compliance and audit boundaries match operational boundaries.
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- Aligns with how GE Aerospace sites already operate (independent IT, independent shop floors).
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### Negative / cost
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- No cross-site reporting out of the box. If GE corporate ever wants a fleet-wide view, it has to be built on top (e.g., a roll-up dashboard that queries each site's API). That layer is out of scope for the framework.
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- Each site administers its own stack. Higher operational overhead than a single central instance, but each site already runs its own infrastructure.
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- Updates require visiting each site's deploy. Fine for the current adoption model; revisit if dozens of sites adopt.
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### Neutral
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- No `siteid` column needed. The existence of one DB per site is the partition.
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## Alternatives considered
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1. **Multi-tenant single instance.** Lower operational overhead at scale, easier cross-site reporting, but adds significant code complexity and risk: every query needs a tenant filter, auth gets complex, schema migrations affect every site at once, and a bug at one site can leak data across sites. Rejected for v1; revisit if and only if more than five sites adopt and operational overhead becomes painful.
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2. **Hybrid: per-site DB but central app server.** Adds the operational complexity of multi-tenancy without isolating the failure domain (one app crash = all sites down). Rejected.
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## Migration strategy (resolved)
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Deploys run two commands: `flask db upgrade` then `flask plugin upgrade-all`
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(lean/ADR-014 sites add an optional `flask plugin prune-schema` at initial
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provisioning). The core Alembic chain applied by `flask db upgrade` creates the
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full core AND bundled-plugin schema through the chain head (this includes
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migration `7c04_fold_plugin_schema`). But every bundled plugin still carries its
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own Alembic chain per ADR-008: `flask plugin upgrade-all` stamps each plugin's
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own chain (the `alembic_version_<plugin>` tables) and applies any plugin-specific
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migrations added after the ownership cutover. The earlier Phase 7B state that
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folded everything into core with no per-plugin chains was superseded by ADR-008's
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per-plugin ownership. A fresh `flask db upgrade` reproduces the live core schema
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exactly (verified on a scratch DB).
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External (out-of-tree) plugins per ADR-003 ship their own migrations too; the
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framework runs the same per-plugin chain mechanism (ADR-008) for both bundled and
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external plugins.
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## Open questions
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- Should the framework provide an optional **read-only fleet roll-up** mode where a "central" instance can pull aggregate metrics from each site's API? Defer. Out of scope for v1.
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- Backup strategy per site: framework recommendation, or each site decides? Framework should publish a recommended backup runbook (mysqldump + offsite copy) but not enforce.
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- Auth federation: each site has its own user table, or sites can share an LDAP / SSO? Recommend documenting the LDAP config knob in `.env.example` so sites can plug in their own auth without code change.
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## References
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- `shopdb/config.py` (currently single-tenant, no `siteid`)
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- ADR-001 (asset model is per-site, not cross-site)
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- ADR-003 (plugin distribution per site)
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