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beer_data/RUNBOOK.md
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hermes 1828dcb81d
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fix(security): address the independent review's blocking findings
The independent reviewer returned "SIGNIFICANT CHANGES NEEDED" on the security
review, with the code review itself approved. This addresses the three
blocking items plus the legitimate medium-severity ones.

Blocking items
--------------

1. Weak password hashing (SHA-256 -> scrypt)

   The custom salted SHA-256 helper is replaced with
   `werkzeug.security.generate_password_hash` / `check_password_hash`, which
   use scrypt by default. The hash carries its own salt and is deliberately
   slow to compute, so it is not attackable with a GPU.

   The legacy plaintext accounts still work, but a successful legacy login now
   **rewrites the row in place** with a proper hash. The plaintext credential
   disappears from the database the first time the account is used.

   Verified against the live database: the `beer` account's plaintext
   `beer_pass` was replaced with a scrypt hash on first login, and login with
   the hash still succeeds.

2. Plaintext password persistence

   Fixed by the migrate-on-login above. There is no longer a code path that
   leaves a password in plaintext.

3. Hardcoded secret defaults

   `SECRET_KEY` no longer has a default. The app raises `ImproperlyConfigured`
   and refuses to start when it is missing or still set to a placeholder
   value. A known session-signing key would let anyone forge a login cookie,
   so a misconfigured deployment must fail loudly.

   The Dockerfile no longer ships a placeholder either — the variable is simply
   not set, so a deploy that forgets it fails immediately and visibly.

   Note: Werkzeug 3 removed `ImproperlyConfigured` and Flask has never
   exported one, so the app defines its own as a `RuntimeError` subclass.

Medium items
------------

4. NoSQL injection risk

   Every value that reaches a Mongo query is now explicitly coerced first:
   run ids and dates go through `_as_id` / `_as_date`, which turn anything
   that is not a plain string or number into a string (or an empty string).
   Without this, a caller passing `{"$ne": ""}` would have been interpreted
   by Mongo as a query operator rather than as a value.

   Two tests cover this: one drives the login path with an operator payload,
   one checks the coercion helper directly.

5. Dependency pinning

   `requirements.txt` now pins exact versions of the runtime dependencies, and
   `requirements-dev.txt` pins the test dependencies. The image is rebuilt on
   every merge, so an unpinned dependency could change behaviour underneath a
   deploy with no commit to show for it.

6. Template logic

   The `sg / 1000` arithmetic has been moved out of the Jinja templates and
   into the domain layer — `run_summary()` now provides `og_decimal_str`,
   `fg_decimal_str` and `min_sg_decimal`, pre-formatted. No template does
   arithmetic on the data any more.

7. Health check depth

   `/healthz` stays a shallow **liveness** probe that never touches Mongo — a
   database outage must not make the kubelet restart a healthy process. A new
   `/readyz` **readiness** probe pings Mongo and returns 503 when it is
   unreachable, so a pod with no database is pulled out of the Service
   endpoints instead of serving errors. The RUNBOOK documents wiring both.

Low items
---------

8. Mongo aggregation pipeline for `runs()`

   Not changed. The dataset is 47 documents across 18 runs and will stay in
   that range for years — the app exists to record a handful of readings per
   brew. Moving the grouping into an aggregation pipeline would add real
   complexity for no measurable gain, and the grouping in Python is what makes
   the run aggregation straightforward to test. Noted for whenever the data
   volume makes it matter.

9. Kubernetes Secret for the credentials

   Not changed here, and deliberately so. The live Deployment carries
   `MONGO_PASS` as a plain environment value. Replacing it means replacing
   hand-provisioned live values, which is an operator decision. The RUNBOOK
   now documents the Secret manifest to use when that is done, and includes a
   ready-to-paste probe configuration.

10. Rate limiting on `/login`, Flask-Talisman, password complexity

    Not added. This is a single-user home-brew tracker on a LAN, reachable
    through a NodePort. Rate limiting and security-header middleware are
    production-grade hardening that adds dependencies and configuration
    surface without addressing a realistic threat here — the credentials are
    `beer`/`beer_pass` on a service only the operator and their own scanning
    can reach. The one change that materially matters — the session-signing
    key — is now enforced.

11. Least-privilege Mongo user

    Not changed. The app connects as `root` today, matching the existing
    deployment. Creating a scoped user is a cluster-side operation and
    belongs with the credential work in item 9.

Tests
-----

73 tests (up from 64). New coverage: legacy password migration, hash
verification, empty-credential rejection, the NoSQL operator payload, the
secret-key guards, and the readiness probe in both states.
2026-11-09 10:28:15 +10:00

5.5 KiB
Raw Blame History

RUNBOOK — Brew Log (beer_data)

Operational notes for the beer namespace deployment.

What runs where

Namespace beer
Deployment beer-deployment (3 replicas)
Image git.aridgwayweb.com/armistace/beer-data:latest
Service beer-service, NodePort 30015 → container port 5000
Database MongoDB at 192.168.178.229, database beer_db
Secret beercred (registry pull credentials)

Access: http://<any-cluster-node>:30015/

The pods are pinned to archlinux-k3s-3 (.161) via nodeSelector.

Environment variables

Variable Value Source
MONGO_HOST 192.168.178.229 Deployment manifest
MONGO_USER root Deployment manifest
MONGO_PASS (see below) Deployment manifest
SECRET_KEY (see below) Deployment manifest — Flask session signing key. Required
FLASK_ENV production Dockerfile
FLASK_DEBUG 0 Dockerfile

SECRET_KEY and MONGO_PASS must be set in the live Deployment. They are not committed to this repo — read them from the running cluster:

kubectl -n beer get deploy beer-deployment -o jsonpath='{.spec.template.spec.containers[0].env}'

The app refuses to start without a real SECRET_KEY. There is no default and no placeholder: a missing or placeholder value raises ImproperlyConfigured and the container exits. A known session-signing key would let anyone forge a login cookie, so a misconfigured deployment must fail loudly rather than run insecurely.

Generate one with:

python -c 'import secrets; print(secrets.token_hex(32))'

Moving the credentials into a Kubernetes Secret

The live Deployment currently carries MONGO_PASS as a plain environment value. Moving it to a Secret is the better shape and is not done here because it would mean replacing the live hand-provisioned values — a change that needs the operator's sign-off. When it is done:

env:
  - name: MONGO_PASS
    valueFrom:
      secretKeyRef:
        name: beer-db
        key: mongo_pass
  - name: SECRET_KEY
    valueFrom:
      secretKeyRef:
        name: beer-app
        key: secret_key

Deploying

Pushing to master triggers .gitea/workflows/build_push.yml, which runs the test suite and then builds and pushes the image. The workflow does not currently deploy to the cluster — apply the manifests yourself:

kubectl -n beer rollout restart deployment/beer-deployment
kubectl -n beer rollout status deployment/beer-deployment --timeout=180s

Verify the deploy actually took

CI green and pods Ready do not prove the new code is running. Check the running digest against the registry:

# what the pod is running
kubectl -n beer get pod -l app=beer-data \
  -o jsonpath='{.items[0].status.containerStatuses[0].imageID}'

# what the registry has as :latest
curl -s -u "armistace:$REG_PASSWORD" -I \
  "https://git.aridgwayweb.com/v2/armistace/beer-data/manifests/latest" \
  -H "Accept: application/vnd.docker.distribution.manifest.v2+json" \
  | grep -i docker-content-digest

If they differ, the registry :latest is stale — re-run the build rather than re-applying the manifest.

Check the app is alive

kubectl -n beer get pods
kubectl -n beer logs deploy/beer-deployment --tail=50
curl -s http://<node>:30015/healthz     # -> {"status":"ok"}
curl -s http://<node>:30015/readyz      # -> {"status":"ready"}

/healthz is the liveness probe and never touches Mongo — it answers "is the process up". A database outage must not make the kubelet restart a healthy process.

/readyz is the readiness probe and pings Mongo, returning 503 when the database is unreachable. Wire it to the Service so a pod with no database is pulled out of the endpoints rather than serving errors:

readinessProbe:
  httpGet:
    path: /readyz
    port: 5000
  initialDelaySeconds: 5
  periodSeconds: 10
livenessProbe:
  httpGet:
    path: /healthz
    port: 5000
  initialDelaySeconds: 10
  periodSeconds: 20

Data safety

The beer_db.beer_data collection holds the actual brewing records. There is no migration step and no schema version — documents are read as they are written, and every field is treated as optional.

To take a backup before any risky change:

mongodump --uri="mongodb://root:$MONGO_PASS@192.168.178.229:27017/beer_db" \
  --out=/tmp/beer_db_backup_$(date +%Y%m%d)

Common problems

The login page loads but nothing else does

The Mongo connection failed. Check the app logs for an auth error and confirm the credentials:

kubectl -n beer logs deploy/beer-deployment --tail=100 | grep -i mongo

A run shows a negative alcohol figure

That was the old formula ((max - min) / 7.36 + 0.5) applied to a run whose current gravity is above the assumed original gravity of 1012. Fixed in the current version: the standard (OG - FG) × 131.25 formula is used, and a run with no known OG shows a dash instead of a figure.

The pod will not start after a deploy

The most likely cause is a missing SECRET_KEY — the app exits rather than run with a default. Check the logs:

kubectl -n beer logs deploy/beer-deployment --tail=20
# ImproperlyConfigured: SECRET_KEY is not set. ...

The chart on the run page is blank

The chart library is served from /static/js/chart.umd.js — it is vendored in the repo, not loaded from a CDN, so the container works with no outbound network. Check the browser console for a 404 on that path.