lilpacks/reliw

Architecture

RELIW uses a coroutine-per-connection model built on the LEV async I/O runtime. The manager process forks listener processes (IPv4, IPv6, metrics), and each listener runs a lev.run() event loop that accepts connections and spawns a coroutine per client. Redis access uses redis (async Redis client) injected into the request handler context. TLS with SNI is handled by LEV's LITLS integration.

Legacy config field names fork_limit and requests_per_fork are accepted as aliases for connection_limit and requests_per_connection.

1.1 Runtime entry point

The standalone RELIW app entry point is defined in cli/reliw.lua and runs:

local reliw = require("reliw")
math.randomseed(os.time())
local reliw_srv, err = reliw.new()
if not reliw_srv then
	print("failed to init RELIW: " .. tostring(err))
	os.exit(-1)
end
reliw_srv:run()

1.2 Config file location

RELIW reads config JSON from:

1. RELIW_CONFIG_FILE environment variable, if set

2. /etc/reliw/config.json otherwise

1.3 Minimal HTTP config

{
  "ip": "127.0.0.1",
  "port": 8080
}

1.4 Minimal Redis data for one host

Example below serves / for example.com from data_dir/example.com/index.md.

redis-cli -n 13 SET RLW:API:example.com '[["/","home",true]]'
redis-cli -n 13 SET RLW:API:example.com:home '{"methods":{"GET":true,"HEAD":true},"index":"index.md"}'

Create content file:

mkdir -p /www/example.com
printf '# Hello\n' > /www/example.com/index.md

Request:

curl -H 'Host: example.com' http://127.0.0.1:8080/

1.5 Manager inspection API

The reliw.new() manager object exposes read-only inspection helpers:

• has_child_pid(pid) -> boolean

• list_child_pids() -> map of pid -> process_name

• get_process_pids() -> { ipv4 = pid|nil, ipv6 = pid|nil, metrics = pid|nil }

These are intended for runtime introspection and tests, replacing direct reads of internal state tables.

2.1 Top-level server config

Compression defaults:

• compression.enabled = true

• compression.min_size = 4096

• compression.types includes text/html, text/plain, text/css, text/javascript, image/svg+xml, application/json, application/rss+xml

• Encoding selection: prefers gzip when client advertises it, falls back to deflate

• Responses include Vary: Accept-Encoding when compressed

2.2 Redis config (redis)

2.3 Metrics config (metrics)

Metrics process behavior:

• spawned by manager as a dedicated process

• uses reliw.metrics.show

• forces ssl = nil and log_level = 100

• reuses manager-loaded config in memory (no second config-file read during spawn)

2.4 TLS config (ssl)

Server-side TLS config shape:

{
  "ssl": {
    "default": { "cert": "/path/default.crt", "key": "/path/default.key" },
    "hosts": {
      "*.example.org":  { "cert": "/path/_.example.org.crt",  "key": "/path/_.example.org.key" },
      "other-site.com": { "cert": "/path/other-site.com.crt", "key": "/path/other-site.com.key" }
    }
  }
}

Notes:

• ssl.default is required when TLS is enabled.

• ssl.hosts adds SNI contexts for additional hostnames.

• ssl.hosts keys support the *.example.org wildcard syntax to match any single-label subdomain (e.g. api.example.org). Exact hostname entries take priority over wildcard entries when both match.

• RELIW validates that configured cert/key files exist before startup.

3.1 Routing and entry metadata

• ${PREFIX}:API:<host>

  • JSON array of route entries: [pattern, entry_id, exact_match?]

  • exact_match (true) means strict equality; otherwise query:match(pattern) is used

• ${PREFIX}:API:<host>:<entry_id>

  • JSON object containing entry metadata

Common metadata fields:

• Required:

  • methods map, for example { "GET": true, "POST": true }

• Optional:

  • file: explicit file path

  • index: appended when query ends with /

  • try_extensions: try .lua, .dj, .md if file is missing

  • gsub: { "pattern": "...", "replacement": "..." } query remap

  • title, css_file, favicon_file

  • cache_control (for example max-age=3600)

  • path_cache: if true and file is set, RELIW checks ${PREFIX}:FILES:<host>:<query> for a pre-computed response before loading the handler. On a cache hit the handler is skipped entirely. The handler is responsible for writing that key (fields: content, hash, size, mime, title) and calling EXPIRE. Cache invalidation is performed by DEL-ing the key.

  • auth: see auth section

  • rate_limit: see rate-limiting section

  • error: status-specific image/html override map

3.2 Content and templates

• ${PREFIX}:FILES:<host>:<filename> (hash)

  • fields: content, hash, size, mime, title

  • cache TTL: 3600 seconds

• ${PREFIX}:FILES:<host>:<query> (hash, same fields)

  • written by Lua handlers that use path_cache: true

  • key uses the request URL path (e.g. /std/fs) rather than the handler filename

  • TTL is set by the handler; recommended to match cache_control

• ${PREFIX}:TITLES:<host> (hash)

  • optional per-file title override

• ${PREFIX}:DATA:<host>:<name> (string)

  • user data; fallback key: ${PREFIX}:DATA:__:<name>

  • template.lua is used as page template override if present

  • ACME HTTP-01 challenge payloads can be provisioned at ${PREFIX}:DATA:<host>:.well-known/acme-challenge/<token>

3.3 Auth/session keys

• ${PREFIX}:USERS:<host> (hash)

  • field: username

  • value: JSON { "pass": "<hex_hmac>", "salt": "<salt>" }

• ${PREFIX}:SESSIONS:<host>:<token> (string with TTL)

  • value: username

3.4 Proxy metadata schema

• ${PREFIX}:PROXY:<host> (JSON object)

  • target (required): upstream host

  • scheme (optional): http (default) or https

  • port (optional): defaults to 80/443 by scheme

  • tls_cafile, tls_capath, tls_handshake_timeout (optional)

  • tls_insecure, tls_no_verify, no_verify_mode (optional bools; any true enables no-verify mode)

3.5 WAF and control channels

• ${PREFIX}:WAF (hash)

  • field __: global rule set JSON

  • field <host>: per-host rule set JSON

• ${PREFIX}:WAFFERS (Pub/Sub channel)

  • receives blocked IP value from WAF branch

• ${PREFIX}:CTL (Pub/Sub channel)

  • generic control messages from store:send_ctl_msg

3.6 Metrics and rate-limit keys

• ${PREFIX}:METRICS:<host>:total (hash: status_code -> count)

• ${PREFIX}:METRICS:<host>:by_method (hash: method -> count)

• ${PREFIX}:METRICS:<host>:by_request (hash: query -> count; internal, 24h TTL)

• ${PREFIX}:METRICS:<host>:timing (hash: <name>_sum / <name>_count pairs)

  • request_sum / request_count — total handler duration

  • proxy_sum / proxy_count — upstream proxy round-trip (proxied vhosts only)

  • content_sum / content_count — content fetch + rendering

• ${PREFIX}:METRICS:<host>:waf_blocks (hash: rule_source -> count)

  • "global" — blocks from the global WAF rule set (__)

  • "<hostname>" — blocks from a per-host WAF rule set

• ${PREFIX}:METRICS:misdirected (string counter — total 421 responses for non-configured vhosts)

• ${PREFIX}:LIMITS:<host>:<method>:<query>:<ip> (string counter with TTL)

5.1 Host and query hardening

Host validation:

• accepts DNS name, localhost, IPv4, bracketed IPv6

• rejects malformed ports, comma-separated host lists, control chars, unbracketed IPv6

Query validation:

• requires leading /

• rejects control chars and backslashes

• rejects encoded traversal separators (%2e, %2f, %5c)

• percent-decodes and rejects .. segments

5.2 Auth flow

metadata.auth supports three paths:

• login endpoint mode (metadata.auth.login == true)

  • GET: returns login form

  • POST: parses body form fields login and password

  • successful auth: sets rlw_session_token=<token>; secure; HttpOnly and 303 redirect

  • failed/malformed auth body: deterministic 401

• logout endpoint mode (metadata.auth.logout == true)

  • clears rlw_session_token and rlw_redirect, returns 303 to /

• allowlist mode (metadata.auth is a username list)

  • unauthenticated request: 302 to /login and sets rlw_redirect=<query>

5.3 Proxy routing behavior

If ${PREFIX}:PROXY:<host> exists, RELIW proxies request and skips local content flow.

Current proxy behavior:

• upstream connect over TCP; TLS wrap+handshake when scheme == "https"

• rewrites:

  • Host -> upstream host

  • Origin/Referer -> upstream origin

  • adds X-Forwarded-Host, X-Forwarded-Proto, X-Forwarded-For

• response handling:

  • supports chunked responses with chunk extensions

  • normalizes content length

  • rewrites CORS allow-origin to original origin/host

  • ensures proxied Set-Cookie includes Secure

5.4 ETag and method semantics

• For content responses, ETag is generated from SHA-256 of content.

• Conditional behavior:

  • GET + matching If-None-Match -> 304 with empty body

  • HEAD -> 200 with empty body, includes ETag/content-length

  • non-GET/HEAD does not use ETag short-circuit

5.5 Content rendering

Markdown and Djot (text/markdown, text/djot):

• Content is rendered to HTML by the bundled markdown module.

• If the rendered HTML begins with an <h1> element, its text is automatically extracted and used as the page title (overriding any metadata.title or RLW:TITLES value). The <h1> is then stripped from the body so it is not duplicated alongside the <header> section injected by the page template.

• If no <h1> is present, the title falls back to metadata.title, then to the RLW:TITLES:<host> Redis hash, then to empty string.

• When the request Accept header includes text/markdown, the raw source is returned as-is with the original MIME type (no rendering or title extraction).

Lua handlers (application/lua):

• The .lua file is loaded once, cached as bytecode in RLW:FILES:<host>:<filename>, and executed on every request as handler(method, query, args, headers, body).

• The handler may return (content, status) — RELIW wraps content with the page template — or (content, status, headers_table) — RELIW uses headers_table directly and skips template wrapping.

• When path_cache: true is set in entry metadata, RELIW checks RLW:FILES:<host>:<query> before invoking the handler. If a cached response is present it is served immediately without handler execution.

7.1 Logs

Main listener and metrics process both emit structured logs via std.logger.

Access-style request logs include:

• vhost, method, query, status, process, size, time

• client_ip (always present; socket peer address)

• plus configured log_headers if present in request

• optional forwarded context when present:

  • forwarded_for (from request x-forwarded-for)

  • forwarded_real_ip (from request x-real-ip when different from client_ip)

Important explicit log events:

• store init failed

• invalid host header

• invalid query

• blocked by WAF

• proxy startup/errors and metrics store init failures

7.2 Metrics endpoint

Metrics listener:

• GET /metrics -> Prometheus text format

• any other path -> 404

Exported families:

• http_requests_total{host="<host>",code="<status>"} <count>

• http_requests_by_method{host="<host>",method="<method>"} <count>

• http_waf_blocks_total{host="<host>",rule="<source>"} <count>

  • rule is "global" for global WAF rules, or the domain name for per-host rules

• http_misdirected_total <count> (requests to non-configured vhosts)

• http_request_duration_seconds_sum{host="<host>"} <seconds> (summary)

• http_request_duration_seconds_count{host="<host>"} <count>

• http_proxy_duration_seconds_sum{host="<host>"} <seconds> (summary, proxied vhosts only)

• http_proxy_duration_seconds_count{host="<host>"} <count>

• http_content_duration_seconds_sum{host="<host>"} <seconds> (summary)

• http_content_duration_seconds_count{host="<host>"} <count>

All metrics commands per request are batched into a single Redis pipeline.