Glyph as a DJED Layer 2 cell

Public

Glyph runs as a Layer 2 cell on the DJED platform. That means a few specific things — and disclaiming what it does not mean is just as useful.

What “cell” means here

A DJED cell is a single product unit (a Rust + React app, in Glyph’s case) that consumes a fixed contract of shared infrastructure from DJED. Glyph’s contract is declared in /opt/glyph/cell-manifest.yaml and validated against the platform’s cell-manifest.schema.json:

Identity

Name: glyph
Version: ${GLYPH_VERSION:-0.1.0}
Contract version: 2.1
Maintainer: alexbayerl
Repository: https://github.com/alexbayerl/glyph

Runtime

Runtime: compose
Site type: product
Compose: cloud/cell/compose.yml
Caddy site: glyph.caddy
Domains: ${GLYPH_DOMAIN:-glyph.naburis.cloud}

Health

/livez: /livez
/readyz: /readyz
/healthz: /startupz
Interval: 30s
Timeout: 10s

Resources

Memory limit: 2048M
CPU limit: 1.5
Memory reservation: 512M

Backing services

Postgres database: glyph
Postgres extensions: uuid-ossp
Redis prefix: glyph
Redis maxmemory: 64mb
OIDC scopes: openid, profile, email

Source: /opt/glyph/cell-manifest.yaml. Contract: cell-manifest.schema.json in DJED.

Everything else — Postgres, PgBouncer, Redis, MinIO, Zitadel, Caddy, Prometheus, log shipping, certificates — is shared infrastructure that DJED runs once for the whole platform. Glyph owns its application; the platform owns its substrate.

What this buys

No re-implementing infra per cell. Glyph does not run its own database server, message broker, or OIDC provider. It connects to the platform’s.
Identity is one place. Zitadel issues every JWT; every cell verifies through djed-auth. Roles like admin mean the same thing across cells.
Caddy is one place. Every cell ships a *.caddy site file that Caddy includes; security headers, CORS, rate limits, and OIDC callbacks come from shared snippets in /opt/djed/caddy/snippets/.
Atomic deploys per cell. A Glyph release does not touch any other cell. The blast radius of a bad deploy is one cell.

What this costs

You cannot ignore the contract. If Glyph’s cell-manifest.yaml lies about its health endpoints or its OIDC scopes, the platform catches it and refuses to deploy.
Tenant isolation is partly the cell’s problem. PgBouncer and shared Postgres deliver per-cell databases by default; Glyph also enforces row-level security inside its tables (see migrations/010_security_hardening.sql).
One dependency contract version per cell. Bumping the cell-contract version is a coordinated platform change.

Where the docs gate fits

These docs themselves are part of the cell. They live at glyph.naburis.cloud/docs, are built from this repo, and use the platform’s OIDC for the admin-tier gate:

_glyph_docs_session cookie carrying an admin role from Zitadel.

The same gate snippet (cell_docs_admin_gate) lives in /opt/djed/caddy/snippets/ and is intended to be imported by every cell that wants tier-gated docs. Source: ADR-001.

The reusable Caddy snippet (cell_docs_admin_gate) lives in /opt/djed/caddy/snippets/ so any future cell can adopt the same docs pattern in one import line. See ADR-001.