thermograph/infra/ops/ICEBERG-HANDOFF.md

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:

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.