haproxy-manager-base/CLAUDE.md

# CLAUDE.md

This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.

## Development Commands

### Testing
- **API Testing**: `./scripts/test-api.sh` - Tests all API endpoints with optional authentication
- **Certificate Request Testing**: `./scripts/test-certificate-request.sh` - Tests certificate generation endpoints
- **Stick-table contract**: `python3 scripts/test-stick-table-contract.py` - offline; holds the templates' `store` clauses, `STICK_TABLE_FIELD_CONTRACT`, and every consumer to each other. Run it after touching any `stick-table` line.
- **Runtime-map contract**: `python3 scripts/test-runtime-map-contract.py` - offline; asserts the runtime map commands are `@1`-prefixed, reference the map by FILE PATH (never `#<id>`), carry the value `1`, and that every captured rejection is classified as a failure. Run it after touching any `add map`/`del map`/`clear map` path.
- **Certificate destruction safety**: `python3 scripts/test-cert-write-safety.py` - offline; asserts a live `.pem` is never truncated, removed, or its certbot lineage deleted while any configured domain still references it (one bundle serves many names, so `ssl_cert_path` is routinely shared). Run it after touching any `os.remove`/`certbot delete`/PEM-write path.
- **API thread-pool safety**: `python3 scripts/test-gunicorn-socket-timeouts.py` - runs REAL gunicorn (~60s); asserts a silent/half-written client cannot pin a gthread pool thread (per-connection socket timeout, `HAPROXY_MGR_CLIENT_TIMEOUT`), 2050 never-sending connections are reaped (`HAPROXY_MGR_FIRST_BYTE_TIMEOUT`), slowloris header drips are cut (`HAPROXY_MGR_HEADER_DEADLINE`, counted from enqueue), 40 reconnecting drippers cannot starve legit requests, the :8000 peer filter (`HAPROXY_MGR_API_ALLOWED_PEERS`) refuses non-allowed peers, slow legit requests are not cut off, the wedge watchdog (`HAPROXY_MGR_WEDGE_SECONDS`) replaces a fully stuck worker, and an in-process call to a stalled upstream times out. Run it after touching `haproxy_gunicorn_worker.py`, start-up.sh's gunicorn lines, or upgrading gunicorn (the worker overrides gthread internals: `enqueue_req`, `accept`, `on_client_socket_readable`, `murder_keepalived`, `handle`, `handle_request`).
- **WAF body inspection**: `python3 scripts/test-waf-body-inspection.py` - offline (runs in the image build); pins `option http-buffer-request`, the `X-WHP-WAF-Body` complete/partial stamp (strip -> stamp -> SPOE -> strip), `tune.bufsize` against the 100 ms SPOE fail-open budget and the 65535-byte SPOP frame cap, and Coraza's body limits in `coraza-spoa/config.yaml`. Run it after touching the Coraza block, `tune.bufsize`, or the SPOE engine.
- **Superseded-cert retirement**: covered by the same file (`TestRetirementRules`, `TestSanOverlapRetirement`). A new bundle retires any OTHER pem/lineage sharing ANY name (CN or SAN) with it - the pem moved to `cert-retired/`, the lineage's live+archive+renewal moved TOGETHER to `/etc/letsencrypt/retired/<stamp>/` (leaving archive/ behind makes certbot refuse the name forever), never deleted; the bundle's own `--cert-name` lineage is `live/<primary>` exactly and is never retired - unless that cert is still the only valid one for a name this edge serves (`retirement_blockers()`). `GET /api/capabilities` advertises this to WHP, which must not use whole-site re-bundling without it. Expired pems already in the crt dir are moved to `cert-retired/` by `cert_retire_expired_pems` (never the last pem, never `default_self_signed_cert.pem`). Expired lineages are never published (`cert_is_expired` in `cert-publish-lib.sh`, `leaf_is_expired()` in Python). Fixtures: `scripts/test-fixtures/san-certs/`.
- **Manual Testing**: Run `curl` commands against `http://localhost:8000` endpoints as shown in README.md

### Reading stick tables (and why it is easy to get silently wrong)

`/tmp/haproxy-cli` is HAProxy's **master** CLI socket. Worker commands
(`show table`, `show map`, `add map`, ...) need an `@1` prefix. Without it
HAProxy answers `Unknown command: 'show', ...` **and socat still exits 0** — so
an exit-status check passes and the help text gets parsed as data. Always use
`haproxy_cli(cmd, worker=True)` in Python, which inspects the response body.

Stick-table entries are `name=value` / `name(window_ms)=value` pairs, not fixed
columns; the first token is an allocation pointer (`0x...:`), not the key. Parse
by NAME, and treat a missing field as an ERROR — never default it to `0`. The
`web` table stores only `conn_cur`, `conn_rate`, `http_req_rate`,
`http_err_rate`; it holds **no history and no counter of past blocks**. What was
actually denied/tarpitted is in the edge access log on the **host** at
`/var/log/haproxy.log` (shipped 2026.08.8), not in any stick table.

This is written down because `/api/security/stats` and `show-tarpit-ips.sh`
reported "Scan Count"/"BLOCKED" figures parsed from `gpc0`/`gpc1` — fields no
stick table has ever stored — for their entire existence. See the header of
`haproxy_tarpit_config.txt` and the contract test.

### Changing a runtime map (`add map` / `del map`)

Same socket, two more ways to fail silently — and both were live in
`add_ip_to_runtime_map()`/`remove_ip_from_runtime_map()` for their whole
existence:

* **Reference the map by FILE PATH, never `#<id>`.** Ids are assigned at
  config-parse time and move on every config regeneration (on whp01
  `blocked_ips.map` is 37, `trusted_ips.map` is 10 — there is no id 0). Use
  `add map /etc/haproxy/blocked_ips.map <ip> 1`.
* **A mutation answers NOTHING on success**, so an empty body is the only
  success — any output at all is a rejection. Worse, `@1 add map #0 <ip> 1`
  *also* answers nothing and adds nothing, so the body cannot prove an add
  worked. **Read it back** with `@1 get map <path> <key>`.
* Entries must carry the value `1`; haproxy.cfg matches with
  `map_ip(...,0) -m int gt 0`, so a valueless entry does not block.

In Python use `haproxy_cli(cmd, worker=True, expect_empty=True)` for mutations
and `runtime_map_lookup()` / `runtime_map_keys()` to verify. The runtime map is
only a fast path: `/etc/haproxy/blocked_ips.map` is authoritative and HAProxy
re-reads it on reload, so a failed runtime command must degrade to
"enforced on reload" and be reported, never swallowed.

### Running the Application
- **Docker Build**: `docker build -t haproxy-manager .`
- **Local Development**: `python haproxy_manager.py` (requires HAProxy, certbot, and dependencies installed)
- **Container Run**: See README.md for various docker run configurations

### Monitoring and Debugging
- **Error Monitoring**: `./scripts/monitor-errors.sh` - Monitor application error logs
- **External Monitoring**: `./scripts/monitor-errors-external.sh` - External monitoring script
- **Health Check**: `curl http://localhost:8000/health`
- **Log Files**: 
  - `/var/log/haproxy-manager.log` - General application logs
  - `/var/log/haproxy-manager-errors.log` - Error logs for alerting

## Architecture Overview

### Core Components

1. **haproxy_manager.py** - Main Flask application providing:
   - RESTful API for HAProxy configuration management
   - SQLite database integration for domain/backend storage
   - Let's Encrypt certificate automation
   - HAProxy configuration generation from Jinja2 templates
   - Optional API key authentication via `HAPROXY_API_KEY` environment variable

2. **Database Schema** - SQLite database with three main tables:
   - `domains` - Domain configurations with SSL settings
   - `backends` - Backend service definitions linked to domains  
   - `backend_servers` - Individual servers within backend groups

3. **Template System** - Jinja2 templates for HAProxy configuration generation:
   - `hap_header.tpl` - Global HAProxy settings, defaults, and HTTP/2 tuning
   - `hap_backend.tpl` - Backend server definitions
   - `hap_listener.tpl` - Frontend listener configurations with rate limiting
   - `hap_letsencrypt.tpl` - SSL certificate configurations
   - `hap_security_tables.tpl` - Stats frontend and security stick tables
   - Template override support for custom backend configurations

4. **Certificate Management** - Automated SSL certificate handling:
   - Let's Encrypt integration with certbot
   - Self-signed certificate fallback for development
   - Certificate renewal automation via cron
   - Certificate download endpoints for external services

### Configuration Flow

1. Domain added via `/api/domain` endpoint → Database updated
2. `generate_config()` function → Reads database, renders Jinja2 templates → Writes `/etc/haproxy/haproxy.cfg`
3. HAProxy reload via socket API (`/tmp/haproxy-cli`) or process restart
4. SSL certificate generation via Let's Encrypt or self-signed fallback

### Key Design Patterns

- **Template-driven configuration**: HAProxy config generated from modular Jinja2 templates
- **Database-backed state**: All configuration persisted in SQLite for reliability
- **API-first design**: All operations exposed via REST endpoints
- **Process monitoring**: Health checks and automatic HAProxy restart capabilities
- **Comprehensive logging**: Operation logging with error alerting support

### Authentication & Security

- Optional API key authentication controlled by `HAPROXY_API_KEY` environment variable
- All API endpoints (except `/health` and `/`) require Bearer token when API key is set
- Certificate private keys combined with certificates in HAProxy-compatible format
- Default backend page for unmatched domains instead of exposing HAProxy errors

### Rate Limiting & Connection Limits (hap_listener.tpl)

- **Stick table**: `type ip size 200k expire 10m` tracking `conn_cur`, `conn_rate(10s)`, `http_req_rate(10s)`, `http_err_rate(30s)`
- Tracks real client IP via `var(txn.real_ip)` to work correctly behind Cloudflare/proxies
- **Rate limit thresholds**:
  - Tarpit at 3000 req/10s (300 req/s)
  - Hard block (deny) at 5000 req/10s (500 req/s)
  - Connection rate limit: 500/10s
  - Concurrent connection limit: 500
  - Error rate limit: 100/30s
- **Whitelist bypasses** (exempt from rate limits):
  - `is_local` — RFC1918 private address ranges
  - `is_trusted_ip` — source IPs listed in `trusted_ips.list`
  - `is_whitelisted` — real IPs (from proxy headers) matched in `trusted_ips.map`

### Trusted IP Whitelist Files

- `trusted_ips.list` — Source IP whitelist for rate limit bypass (one CIDR/IP per line)
- `trusted_ips.map` — Real IP whitelist for proxy-header matching (format: `<IP> 1`)
- Both files are baked into the Docker image via `COPY` in the Dockerfile
- Ship as comment-only templates (no real IPs). Add trusted IPs locally and do **not** commit them — this repo is mirrored publicly. Entries persist in the `/etc/haproxy` named volume across recreates

### Timeout Hardening (hap_header.tpl)

- `timeout http-request`: 300s -> 30s (slowloris protection)
- `timeout connect`: 120s -> 10s
- `timeout client`: 10m -> 5m
- `timeout http-keep-alive`: 120s -> 30s

### HTTP/2 Protection (hap_header.tpl)

- `tune.h2.fe.max-total-streams 2000` — limits total streams per HTTP/2 connection
- `tune.h2.fe.glitches-threshold 50` — CVE-2023-44487 Rapid Reset protection

### Stats Frontend (hap_security_tables.tpl)

- HAProxy stats page bound to `127.0.0.1:8404` (localhost only, accessible inside container)
- Template: `templates/hap_security_tables.tpl`

### Deployment Context

- Designed to run as Docker container with persistent volumes for certificates and configurations
- Exposes ports 80 (HTTP), 443 (HTTPS), and 8000 (management API/UI)
- Stats page on port 8404 (localhost only inside container)
- Management interface on port 8000 should be firewall-protected in production
- Dockerfile HEALTHCHECK runs `scripts/healthcheck.sh`: port 8000 `/health` (4s max) AND port 80 (HAProxy). WHP's `lib-edge-container.sh` passes its own `--health-cmd`, which REPLACES the image's; it must call `/haproxy/scripts/healthcheck.sh` or the fleet never probes :8000
- **The :8000 API refuses peers other than 127.0.0.1/::1 and the container's default gateway** (`HAPROXY_MGR_API_ALLOWED_PEERS`, default `127.0.0.1,::1,gateway`; ports via `HAPROXY_MGR_PEER_FILTER_PORTS`, default `8000`). haproxy-manager shares `client-net` with every tenant container; host callers arrive from the gateway via docker-proxy. Only effective with the WHP `-p 127.0.0.1:8000:8000` publish (a 0.0.0.0 publish lets a tenant hairpin through the host and arrive from the gateway). A sidecar that must call :8000 directly needs its IP added
- gunicorn uses `haproxy_gunicorn_worker.TimeoutThreadWorker` (gthread + client socket timeout + first-byte deadline + total header deadline + wedge watchdog). Stock gthread leaves client sockets blocking with NO timeout; `--timeout` only watches the main thread's heartbeat
- Supports deployment on servers with git directory at `/root/whp` and web file sync via rsync to `/docker/whp/web/`
- HAProxy is version 3.0.11