# Iceberg: implementing the agent-queryable service

Handoff spec for whoever builds the Iceberg layer. The Postgres equivalent is
already shipped (`infra/ops/dbq.sh`) — **mirror it**. This document is the
contract, the environment facts you'll trip over, and how the result gets
verified.

## Definition of done

`infra/ops/iceberg.sh` exists and behaves like `dbq.sh`:

```sh
infra/ops/iceberg.sh prod -c "select count(*) from <namespace>.<table>"
infra/ops/iceberg.sh dev  -c "show tables"
echo "select 1" | infra/ops/iceberg.sh beta -f -
```

An agent (or operator) can query Iceberg in any environment, read-only, with no
new network exposure and no interactive steps.

## The contract (non-negotiable)

1. **Same interface shape as `dbq.sh`** — `iceberg.sh <dev|beta|prod> [flags]
   "<sql>"`. Extra flags pass through to the engine; **stdin is forwarded** so
   `-f -` works. Non-interactive, deterministic, safe to call from CI.
2. **Read-only enforced by the system, not by convention.** A dedicated
   read-only identity — not an admin/superuser credential. You must be able to
   *demonstrate* a refused write (see Acceptance).
3. **No new network endpoints.** Run the engine where the data is already
   reachable (containerised), rather than publishing ports or opening firewall
   rules. See the prod constraint below — this is not negotiable, it's physics.
4. **Env-keyed dispatch, names resolved at call time.** Prod is Docker Swarm;
   task container names change on **every redeploy**. Resolve via
   `docker ps --filter name=…`; never hardcode a container name.
5. **No secrets in the repo** or in workflow files.

## Environment facts you need

- Monorepo `emi/thermograph` (domain dirs: `backend/ frontend/ infra/
  observability/`). Ops tooling lives in `infra/ops/`.
- Environments: **dev** = LAN compose stack on the dev machine; **beta** =
  `75.119.132.91`; **prod** = `169.58.46.181`. SSH as `agent` with
  `~/.ssh/thermograph_agent_ed25519` (passwordless sudo on both boxes).
- **Prod runs Docker Swarm.** Its app database sits on the overlay network
  `thermograph_internal` (`10.0.2.0/24`), which **the prod host itself cannot
  route to**. Consequence, learned the hard way: `ssh -L` tunnelling works for
  beta but is *impossible* for prod. Any design that depends on a tunnel or a
  published port will fail on prod — that's why `dbq.sh` execs into the
  container instead. Assume the same for anything you deploy there.
- The overlay is `attachable=true`, and the **dev machine is a Swarm worker** in
  the prod cluster (NodeAddr `10.10.0.3`) — so `docker run --network
  thermograph_internal …` from the dev box is a plausible route to prod-side
  services. Untested; verify before relying on it.
- WireGuard mesh: prod `10.10.0.1`, beta `10.10.0.2`, dev `10.10.0.3`.
- `rclone` and `age` are already installed on prod and beta.
- Reference implementation to copy: **`infra/ops/dbq.sh`** + `infra/ops/README.md`.

## Storage — almost certainly your warehouse

Contabo Object Storage (S3-compatible), already provisioned and in use:

- Endpoint `https://eu2.contabostorage.com` · bucket `era5-thermograph` ·
  region `default` · ~2 TB · **private** (keep it that way).
- ⚠️ **Contabo requires PATH-STYLE addressing.** Set
  `force_path_style=true` / `s3.path-style-access=true` (whatever your engine's
  FileIO calls it) and `region=default`. Virtual-host-style addressing **fails**.
  This is validated, not theoretical.
- ⚠️ **The `backups/` prefix is in use** by the nightly backup jobs (prod DB +
  Forgejo). Put Iceberg data under its own prefix (e.g. `iceberg/` or
  `warehouse/`). Do not write outside your prefix.
- Credentials already exist — **reuse them, don't mint new ones silently**:
  - SOPS vault: `infra/deploy/secrets/{prod,beta}.yaml` as `THERMOGRAPH_S3_*`
    (rendered to `/etc/thermograph.env` at deploy by
    `infra/deploy/render-secrets.sh`).
  - Forgejo Actions secrets: `S3_ENDPOINT`, `S3_BUCKET`, `S3_ACCESS_KEY`,
    `S3_SECRET_KEY`.
  - If read-only S3 keys are needed for the query identity, ask the operator to
    mint a scoped keypair rather than reusing the read-write one.

## Secrets handling

- Host-side: SOPS + age. Recipient `age1xx4dzs0dxlwvkv9sjuqzsphl7lfrxannkfken374yu2qvvcte9sqzktqt2`;
  the private key is on each host at `/etc/thermograph/age.key` and on the
  operator's machine at `~/.config/sops/age/keys.txt`.
- CI-side: Forgejo Actions secrets.
- ⚠️ **beta gotcha:** `/etc/thermograph.env` on beta is `agent:agent 0640` — the
  `deploy` user **cannot read it**. If your service or job runs as `deploy` on
  beta, pull credentials from Actions secrets instead, or change the ownership
  deliberately and say so.

## Decisions you must make — and report back

1. **Catalog**: REST (Lakekeeper / Nessie / Polaris), JDBC-on-Postgres, Hive, or
   filesystem/hadoop — and where it runs per environment.
2. **Engine**: DuckDB + iceberg extension, Trino, Spark, or pyiceberg. Prefer the
   lightest that satisfies the contract; it must run containerised and headless.
3. **Warehouse location**: bucket + prefix, and whether environments are isolated
   by separate prefixes, namespaces, or buckets.
4. **Read-only mechanism**: scoped S3 keys? catalog RBAC? engine restricted mode?
   State which, and how a write is refused.
5. **Where the engine runs** for each env (local container on dev, on the box for
   beta/prod, or attached to the overlay) — consistent with constraint #3.

## Acceptance criteria

The work is accepted when all of these are demonstrated with pasted output:

- [ ] `infra/ops/iceberg.sh <env> -c "<select>"` returns rows for **each**
      environment that has data (explicitly state any env that doesn't yet).
- [ ] **A write/DDL attempt is refused by the system**, with the error pasted.
      The Postgres bar to match:
      `create table` on prod → `ERROR:  permission denied for schema public`.
- [ ] **No new exposure**: `sudo ss -ltnp` on prod and beta shows no new
      listening port; no new ufw rules; no Swarm `EndpointSpec` publish added.
      State this explicitly.
- [ ] Non-interactive: extra flags pass through, stdin (`-f -`) works.
- [ ] Prod container/task resolution is dynamic (survives a redeploy).
- [ ] `infra/ops/README.md` updated with an Iceberg section: usage examples and
      the *why* (same style as the Postgres rationale).

## Anti-goals

- ❌ Publishing catalog/engine/DB ports publicly, or adding firewall holes.
- ❌ Any design requiring a persistent SSH tunnel (**prod cannot be tunnelled**).
- ❌ Querying with an admin/superuser/read-write credential.
- ❌ Secrets committed to the repo or pasted into workflow files.
- ❌ Writing outside your own S3 prefix (`backups/` is live and load-bearing).

## Questions to route back to the operator

Anything that would require: minting new cloud credentials, opening a port,
changing firewall/Swarm configuration, or writing to a shared prefix. Don't
improvise on those — ask.