the-daily-epub/docs/runbooks/cdn-rollout.md

# Runbook — putting daily.hallada.net behind Cloudflare

**Written:** 2026-09-04 for the production host. Steps 1–2 happen in the Cloudflare
and registrar dashboards; steps 3–6 are on the server as an operator with `sudo`.
The origin-side changes (the `Cache-Control` matrix and `daily-epub cdn purge`)
ship in the same release, so deploy the new binary before step 5.

Read the whole thing before starting step 1: a nameserver change is the one step
that cannot be undone in seconds.

## 0. What the origin already does

The app decides what is cacheable; Cloudflare is configured only to obey it.

| route | `Cache-Control` |
|---|---|
| `/`, `/issues`, `/issues/{date}`, `/feed.xml`, `/issues.json` (anonymous) | `public, max-age=300, s-maxage=86400` |
| the same pages with a `daily_session=` cookie | `private, no-store` |
| `/robots.txt` | `public, max-age=86400` |
| `/static/*?v=<hash>` | `public, max-age=31536000, immutable` |
| `/static/*` with no `?v=` | `public, max-age=3600` |
| `/files/epub/*`, `/files/xtc/*`, `/opds*` (every status, 401 and 404 included) | `private, no-store` |
| `/dashboard*`, `/login`, `/account`, error pages, anything else | `no-store` |

Two facts follow from that table and matter for every choice below:

- The edge is allowed to hold a public page for a **day** (`s-maxage=86400`).
  That is only correct because `generate` purges the whole zone right after it
  publishes. If the purge is broken, the site serves yesterday's paper until the
  day elapses. Step 5 is not optional.
- Anything gated by a cookie or Basic auth already says `private, no-store`, so
  even a misconfigured cache-everything rule cannot make a download public. The
  cookie bypass rule in step 3 is defence in depth, not the only defence.

## 1. Move DNS to Cloudflare

The Free plan has no partial (CNAME) setup, so this is a full nameserver move:
Cloudflare becomes authoritative for the entire `hallada.net` zone, not just this
host. Everything else in the zone must survive the move unchanged.

1. Export the current zone from Route 53 as BIND:

   ```sh
   ZONE=$(aws route53 list-hosted-zones-by-name --dns-name hallada.net. \
        --query 'HostedZones[0].Id' --output text | cut -d/ -f3)
   aws route53 list-resource-record-sets --hosted-zone-id "$ZONE" > /tmp/hallada-net.json
   ```

   The AWS CLI has no BIND exporter; the console's **Export zone file** button on
   the hosted zone does produce one. Keep both files — the JSON is the rollback
   reference.

2. In Cloudflare, **Add a site** → `hallada.net` → Free plan → **Import DNS
   records** and upload the BIND file. Then read the imported list against the
   export line by line. Pay attention to `MX`, `TXT` (SPF/DKIM/DMARC), and any
   `CNAME` used for verification: those must all stay **DNS only** (grey cloud).

3. Set **only** the `daily` record to **Proxied** (orange cloud). Nothing else in
   the zone should be proxied — proxying an MX target or a mail-related host
   breaks it.

4. Change the nameservers at the registrar to the two Cloudflare assigns.
   Propagation is usually minutes and can be hours. Cloudflare emails when the
   zone goes active.

5. Before the switch, drop the TTL on the `daily` record (60 s) so a rollback is
   quick. Verify afterwards:

   ```sh
   dig +short NS hallada.net
   dig +short daily.hallada.net           # Cloudflare anycast addresses once proxied
   dig +short MX hallada.net              # unchanged
   ```

## 2. Zone settings

Under the zone's **SSL/TLS**, **Speed** and **Scrape Shield** sections:

- **SSL/TLS → Overview → Full (strict)**. The origin has a real Let's Encrypt
  certificate, so there is no reason to accept anything weaker. *Flexible* would
  make Cloudflare talk plain HTTP to the origin and would break the redirect in
  the nginx `:80` server block into a loop.
- **Caching → Configuration → Browser Cache TTL → Respect Existing Headers.**
  This one is easy to miss and quietly wrong: the default (**4 hours**) *raises*
  the `max-age` Cloudflare sends to browsers, so the deliberate 5-minute browser
  age on the public pages would become 4 hours and a reader's tab would show a
  stale paper long after a purge.
- **Speed → Optimization → Rocket Loader: OFF.**
- **Scrape Shield → Email Address Obfuscation: OFF.**
  Both inject a Cloudflare-hosted script into the HTML. The site's CSP is
  `script-src 'self'`, so the browser blocks the injected script and the page
  either breaks or logs CSP violations on every load. There is nothing to gain:
  the site has no email addresses in its markup and its own JS is two small
  files.
- **Do not enable Web Analytics with automatic injection** — same reason, it is
  an injected third-party script. If analytics are wanted later, they have to be
  first-party and listed in the CSP.
- **Always Use HTTPS: ON** is fine and lets the origin's `:80` block stay as a
  backstop.

## 3. Cache Rules

**Caching → Cache Rules.** Order matters: rule 1 must sit above rule 2.

**Rule 1 — "Bypass cache for signed-in readers"**

- When incoming requests match: `http.cookie contains "daily_session="`
- Then: **Bypass cache**

The origin already sends `private, no-store` to a cookie-bearing request, but
this makes the bypass a property of the request rather than of the response, so
nothing is ever *looked up* in a shared cache for a signed-in reader.

**Rule 2 — "Cache by origin headers"**

- When incoming requests match: `http.host eq "daily.hallada.net"`
- Then: **Eligible for cache**
- **Edge TTL:** *Use cache-control header if present, bypass cache if not*
- **Browser TTL:** *Respect origin*

That Edge TTL mode is the whole point of the origin work: a response with
`s-maxage` is cached for exactly that long, and a response with `no-store` (or
one that somehow arrives with no policy at all) is not cached. It is the reason
the `security_headers` middleware defaults unknown routes to `no-store` — with
this mode, "no header" means "do not cache" rather than "cache for 2 hours".

Leave **Cache Key** at its default. Do not add "Ignore query string": the
`?v=<hash>` on `/static/*` is what makes the immutable one-year `max-age` safe.

## 4. Lock the origin to Cloudflare

Once traffic arrives through the edge, direct hits on the origin's port 443
should stop. Either is enough; the first is simpler.

- **Firewall:** allow 443 only from the published Cloudflare ranges.

  ```sh
  { curl -s https://www.cloudflare.com/ips-v4; echo; \
    curl -s https://www.cloudflare.com/ips-v6; echo; } \
  | awk 'NF {print $0}' \
  | xargs -I{} sudo ufw allow proto tcp from {} to any port 443 comment 'cloudflare'
  sudo ufw delete allow 443/tcp        # remove the open rule last
  ```

  Keep a way in that does not depend on this (SSH from your own address) before
  removing the open rule.

- **Authenticated Origin Pulls** (SSL/TLS → Origin Server) instead: install
  Cloudflare's client CA on the origin and add `ssl_client_certificate` +
  `ssl_verify_client on` to the nginx server block. Stronger, but one more
  certificate to keep track of.

Also apply the nginx changes from the README's *Reverse proxy* section now:
the `include /etc/nginx/snippets/cloudflare-real-ip.conf;` (generated from
Cloudflare's published ranges, `real_ip_header CF-Connecting-IP;` at the end) and
`proxy_set_header X-Forwarded-For $remote_addr;` in place of
`$proxy_add_x_forwarded_for`. Without the first, every request looks like it came
from Cloudflare and the login throttle becomes global; without the second, a
client could forge the throttle key. Then:

```sh
sudo nginx -t && sudo systemctl reload nginx
```

Check a login attempt from a phone on cellular and one from the LAN land in
different throttle buckets, and that `journalctl -u daily-epub` shows real client
addresses rather than Cloudflare's.

## 5. Configure the purge

Create the API token in the Cloudflare dashboard: **My Profile → API Tokens →
Create Token → Custom token**, with the single permission **Zone → Cache Purge →
Purge**, **Zone Resources → Include → Specific zone → hallada.net**. Nothing
else — the app makes exactly one API call. Copy the token once; it is not shown
again. The zone id is on the zone's **Overview** page.

In `/etc/daily-epub/config.toml`:

```toml
[cdn]
provider = "cloudflare"
cloudflare_zone_id = "…"
purge_after_publish = true
```

and in the systemd environment file (the one the units already load, mode `0600`,
owned by `daily-epub`):

```
DAILY_EPUB_CDN__API_TOKEN=…
```

Setting `provider` without both the zone id and the token is a **config error**:
the app refuses to start rather than publishing into a stale edge. Confirm and
then purge by hand:

```sh
sudo systemctl restart daily-epub
sudo -u daily-epub daily-epub --config /etc/daily-epub/config.toml config check | grep '^cdn'
# cdn: cloudflare · zone … · token present · purge_after_publish true
sudo -u daily-epub daily-epub --config /etc/daily-epub/config.toml cdn purge
# purged the whole cloudflare cache (id …)
```

`cdn purge` takes no run lock and touches neither the database nor the publish
directories, so it is safe to run at any time, including during a `generate`.

From then on `generate` purges the whole zone after every successful publish. The
purge is *purge everything* on purpose: a new issue also changes the previous
issue's page (its "latest" nav marker moves), `/issues`, `/feed.xml` and
`/issues.json`, and a per-URL list of that set would rot. A purge failure is
logged at `warn` and never fails the run — so check for it after the first live
run:

```sh
journalctl -u daily-epub-generate.service --since today | grep -i 'purge'
```

## 6. Verify

Anonymous public page — expect `HIT` on the second request (the first fills the
edge) and the origin's own two-part `Cache-Control`:

```sh
curl -sI https://daily.hallada.net/ | grep -iE 'cf-cache-status|cache-control|age'
curl -sI https://daily.hallada.net/ | grep -i cf-cache-status     # HIT
```

Signed in — the cookie rule must take it out of the cache entirely:

```sh
curl -sI -H 'Cookie: daily_session=whatever' https://daily.hallada.net/ \
  | grep -iE 'cf-cache-status|cache-control'
# cf-cache-status: BYPASS (DYNAMIC is also acceptable)
# cache-control: private, no-store
```

Static assets — versioned URLs should settle on `HIT`:

```sh
curl -s https://daily.hallada.net/ | grep -o '/static/app.css?v=[0-9a-f]*'
curl -sI 'https://daily.hallada.net/static/app.css?v=<hash>' \
  | grep -iE 'cf-cache-status|cache-control'
# cf-cache-status: HIT
# cache-control: public, max-age=31536000, immutable
```

Downloads and OPDS — never cached, at any status:

```sh
curl -sI https://daily.hallada.net/opds | grep -iE 'cf-cache-status|cache-control'
curl -sI https://daily.hallada.net/files/epub/does-not-exist.epub \
  | grep -iE 'cf-cache-status|cache-control'
# cache-control: private, no-store   (cf-cache-status: BYPASS or DYNAMIC)
```

The dashboard and the login page:

```sh
curl -sI https://daily.hallada.net/login | grep -iE 'cf-cache-status|cache-control'
# cache-control: no-store
```

Finally, the end-to-end check the whole exercise is about: run a `generate`, then
immediately `curl -sI https://daily.hallada.net/ | grep -i cf-cache-status` and
confirm it reads `MISS` (the purge emptied the edge) and that the page shows the
new issue.

## Rollback

- **Cache misbehaving:** turn on **Development Mode** (Caching → Configuration)
  for a three-hour edge bypass while you look, or **Purge Everything**. Neither
  needs a deploy.
- **Something worse:** set the `daily` DNS record back to **DNS only** (grey
  cloud). Traffic goes straight to the origin again within the record's TTL, and
  nothing about the origin's behaviour depends on Cloudflare being there — the
  `Cache-Control` headers are correct without it, and `cdn.provider` can be
  removed from the config at leisure.
- **Full retreat:** point the registrar's nameservers back at Route 53. The
  hosted zone still exists unless it was deleted; do not delete it until the
  Cloudflare setup has run for a few weeks.