RustProxy/docs/SETTINGS.md

Listener and response settings

Configuration and update semantics

GET /api/config returns a revisioned envelope. PUT the entire document with expected_revision. Defaults apply when fields are omitted. Unknown fields are rejected; failed validation/persistence leaves the old snapshot active. Existing backend/route/TLS/ACL data must be retained when changing settings. The panel does this and preserves dirty settings forms across status/language refreshes.

{
  "listeners": {
    "endpoints": [
      {"id":"http", "name":"HTTP", "scope":"public", "enabled":true,
       "binding":{"address":"0.0.0.0:80", "tls":false, "http2":false, "http3":null}},
      {"id":"https", "name":"HTTPS", "scope":"public", "enabled":true,
       "binding":{"address":"0.0.0.0:443", "tls":true, "http2":true,
                  "http2_settings":{"idle_timeout_seconds":300, "max_connection_lifetime_seconds":0, "drain_timeout_seconds":10}}}
    ]
  },
  "server_header": {"mode":"custom", "value":"RustProxy/v0.20.0"},
  "compression": {"gzip":true, "br":true, "zstd":true, "deflate":false, "min_bytes":1024},
  "headers": {
    "request": [{"op":"set", "name":"x-proxy-name", "value":"RustProxy"}],
    "response": [
      {"op":"remove", "name":"x-powered-by"},
      {"op":"set", "name":"x-served-by", "value":"RustProxy"}
    ]
  }
}

This is a settings fragment, not a replacement for the existing routing/vhost document. A complete opt-in example is in examples/cache-dashboard.json.

The dashboard exposes the complete raw JSON editor under Settings -> Manual config. The same card exposes Revision history, which reads the newest 512 retained configuration revisions from SQLite schema 8 and groups them by month/day. Selecting a revision shows timestamp, actor and a bounded path-level before/after diff against the previous retained revision. An older retained revision can be restored from the same dialog; RustProxy validates it through the normal configuration update path and saves it as a new revision, preserving the prior history. The historical /configuration browser route is retained only as a compatibility alias and opens that Settings block; it is no longer a primary-navigation item. Prefer the structured section editors for routine changes so unrelated sections are not republished.

Administration HTTPS

administration is separate from public proxy listeners. It defaults to the startup loopback address and plain HTTP. Persisted address/certificate changes are validated immediately but take effect after process restart. A non-loopback persisted bind is accepted only when administration.tls is true. Plain remote HTTP remains available only when process startup explicitly allows it with --allow-remote-admin.

{
  "administration": {
    "listen": "0.0.0.0:9090",
    "tls": true,
    "certificate_id": "admin-example",
    "allowed_hosts": ["admin.example.com"],
    "session_days": 30
  }
}

certificate_id: null uses data/certs/default.pem and default.key, generated by the application. A selected inventory certificate is loaded from the same private certificate directory. session_days controls the absolute browser-session lifetime and must be 7..30 (default 30). It applies without restart; changing listener/TLS/certificate settings still requires restart. Session cookies are HttpOnly/SameSite=Strict and receive the Secure attribute on HTTPS. When HTTPS is enabled, accidental plain HTTP received on the same administration port receives a permanent redirect to the same authority/path over https://; the plaintext path contains no administration handlers. An empty allowed_hosts accepts valid DNS Host values on the configured HTTPS port as well as valid numeric destination addresses. Once allowed_hosts contains entries it becomes a strict DNS allowlist for browser-facing DNS authorities. An explicitly listed hostname may arrive from a trusted reverse proxy on an external port such as 443 even when the private admin socket is 9090. Direct IP/localhost access is still accepted only on the actual configured admin port. For HTTPS termination in front of a plain local admin socket, the trusted proxy must pass its external Host and scheme; X-Forwarded-Host is accepted only from loopback/configured trusted proxy peers and X-Forwarded-Proto additionally follows the forwarded-proto trust policy. Origin/CSRF comparison and the session cookie Secure flag use that external origin. Use a firewall and normal network policy even with HTTPS.

Structured access logging

The Settings -> Logging page is split into Outputs, JSON format and Error log subsections, using the same in-card sub-tab layout and keyboard interaction as Cache. Outputs controls optional external access-log sinks while the existing bounded live ring remains available to the panel. Sink I/O is performed by a bounded background queue; request processing only performs a non-blocking enqueue. Supported destinations:

• JSONL file append, either one combined file such as /var/log/rustproxy/access.jsonl or one file per resolved vhost under a configurable directory (default /var/log/rustproxy/vhosts). Unmatched traffic uses _unmatched.jsonl. The managed systemd service provisions /var/log/rustproxy for the service account and keeps that directory writable under ProtectSystem=strict. Other custom paths still need matching service permissions.
• Logstash TCP using host:port (IP or DNS). Each event is one JSON line.
• Loki HTTP(S) push. Optional bearer credentials are read from an environment variable named by bearer_token_env; the secret itself is not stored in configuration.

logging.format.fields maps output field names to standard event fields; an empty map emits the complete standard event. The panel provides Standard, Nginx-style, ECS-style and Minimal presets plus a visual field selector/renamer with JSON preview. Advanced raw mapping remains available for aliases not representable by the simple builder. Supported mapped sources include vhost, route, cache_effective_enabled, transform_effective_enabled, backend, request/response metadata and cache outcome fields. static_fields adds constant string fields. For low-level protocol_error events, RustProxy always preserves the required diagnostic envelope (event, error kind/detail, time, client/local/TLS/protocol fields, status and outcome) even with a custom mapping, so malformed-traffic records remain searchable in the built-in Logs explorer. Loki labels are separately configurable. /api/status.logging.sinks reports queue capacity, dropped events, successfully delivered events and sink errors.

Hot and cold cache tiers

cache.max_bytes and cache.max_entries bound the HOT RAM tier. max_bytes is charged from retained body backing allocation plus entry metadata rather than only payload length. cache.transient_max_bytes separately bounds in-progress fills and full bodies moving between HOT and COLD; cache.cold_queue_max_bytes additionally caps queued demotions in bytes, and cache.hot_eviction_max_objects bounds one LRU admission attempt. The source defaults are 256 MiB HOT, 16 MiB maximum object, 64 MiB transient and 32 MiB COLD queue. The Settings panel calculates conservative/recommended/performance presets from the lower of host RAM and a finite cgroup memory limit without changing the COLD disk budget. It also warns when HOT + transient is a large fraction of effective RAM, when the additional configured cache budget is large compared with current host/cgroup headroom, when the COLD queue exceeds transient RAM, or when the object ceiling cannot fit in transient RAM. Automatic presets are disabled below 256 MiB effective RAM. On a 2 GiB effective-memory VM the recommended profile selects approximately 400 MiB HOT, 96 MiB transient, 16 MiB maximum object, 48 MiB COLD queue, 6400 HOT entries and a 64-object LRU admission limit. The optional persistent cold tier is controlled by cold_enabled, cold_path, cold_max_bytes, cold_max_entries, cold_gc_interval_seconds, cold_gc_max_delete, cold_after_seconds, cold_on_lru, cold_on_idle and cold_on_shutdown. cold_gc_interval_seconds defaults to 60 and cold_gc_max_delete to 256. Pressure GC starts at roughly 90% of the configured byte/entry budget and cleans toward roughly 80% without deleting more than the configured per-pass cap. cold_path is relative to the RustProxy data directory and cannot contain parent traversal or an absolute path. The two demotion switches independently select LRU-pressure and idle objects; shutdown flush is a best-effort direct write during a graceful restart. Demotions use a small bounded queue and release hot accounting before disk persistence so cold storage does not retain an unnecessary second body buffer in RAM. Cold metadata is readable JSON and bodies are raw .body files; reads are size/SHA-256 checked before promotion to RAM. Since 0.21.0 objects are sharded by the first two SHA-256 hex characters (cache/cold/00/... through ff/...), with shard directories created on first write. The previous flat Cold Cache is intentionally not migrated. Purge operations clear both in-memory indexes and schedule disk cleanup; selective cleanup uses the same GC/eviction path and runs asynchronously.

Version 0.22 adds foreground fill collapsing (collapse_enabled, collapse_wait_timeout_ms, collapse_timeout_fallback), detailed stale-if-error policy (stale_if_error_timeout, stale_if_error_connection, stale_if_error_dns, stale_if_error_tls, stale_if_error_statuses) and opt-in proactive refresh (proactive_refresh_enabled, proactive_refresh_before_expiry_seconds, proactive_refresh_percent, proactive_refresh_max_inflight). Defaults preserve the previous stale-if-error behavior; proactive refresh is disabled by default. Selective PURGE/BAN is an operational API/panel action rather than persisted configuration. See CACHE.md for request-collapse, Range and invalidation semantics.

Static-response transformation

transform is a formal identity-response stage between the upstream response and shared cache storage. transform.enabled is the global kill switch, but every vhost must also set its own transform.enabled=true; vhosts stay disabled by default even when the global engine is enabled. Global defaults enable JavaScript and CSS transformation and leave HTML, SVG and JSON off. extensions controls extension-based detection and max_body_bytes (1 KiB..32 MiB, 2 MiB default) bounds aggregation/decoding.

The pipeline is origin -> decode supported Content-Encoding -> transform -> cache identity representation -> client compression. JavaScript/CSS can be enabled normally; HTML minification, SVG optimization and JSON compaction are independent optional formats. Recognition uses safe configured extensions and known Content-Type values. Binary/image formats outside those explicit transform types are not transformed.

Origin Cache-Control: no-transform always disables transformation. When bytes change, RustProxy removes representation-specific length/digest/encoding metadata and creates a new strong rustproxy-* ETag for the transformed representation. The original origin ETag/Last-Modified are kept separately and used for origin revalidation, so a proxy ETag is never sent upstream as though it validated the original object. The transformed identity body is what enters cache, preventing repeated minification on every HIT.

Global TLS protocol and cipher policy

tls.policy is the global baseline inherited by every TLS host. It controls TLS 1.2, TLS 1.3 and optional rustls cipher-suite names. An empty cipher_suites list uses the ring provider defaults. Settings shows both the currently effective cipher suites and the complete selectable suite inventory. At least one protocol version and one compatible effective suite are required. This policy is also used by administration HTTPS. HTTP/3 requires TLS 1.3 and a TLS 1.3 suite. Vhosts can narrow TCP TLS with tls_policy; when a vhost has HTTP/3 enabled on a selected H3-capable listener it must match the global policy because QUIC TLS is shared per UDP listener. Available suite names are exposed in authenticated status for the Settings editor.

Listeners: saved intent, not hot rebinding

When an HTTP, HTTPS or administration address was explicitly supplied by systemd/CLI (or the corresponding service environment variable), that exact startup bind is a process contract: the panel shows it as locked and configuration updates cannot remove, disable or change it. If an address was not explicitly supplied at startup, listener entries remain freely addable/removable/editable subject to normal validation.

listeners.endpoints is the only persisted frontend socket configuration. Each endpoint has a stable id/name, an informational scope label, an enabled flag and one primary binding containing IP:port, TLS, HTTP/2 plus its optional lifecycle settings, and optional HTTP/3 settings. Optional additional_addresses reuse that same transport policy on up to 15 further addresses. When more than one address is configured every address must be explicit; 0.0.0.0 and :: are rejected so a multi-IP selection cannot silently mean every interface. IP/port and transport capability belong here, not inside a vhost. IPv6 uses [address]:port.

A vhost references endpoints through frontend.listener_ids. Listener changes are restart-required because they alter TCP/UDP sockets or TLS ALPN capability. The listener editor owns the HTTP/2/H2C and HTTP/3 enable/disable switches. An H2/H2C row links to HTTP connections -> HTTP/2 for idle, absolute-lifetime and graceful-drain limits; an enabled H3 row links to HTTP connections -> HTTP/3 for advertisement, connection, stream and idle-timeout limits. Both tuning pages are listener-scoped and do not own protocol enablement. Vhost H2/H3 switches only narrow the protocols already enabled by the selected endpoints; they never create a protocol that Settings disabled.

The administration listener is independent and cannot share a frontend port. Bindings must be valid local unicast/wildcard addresses; conflicting overlapping endpoints are rejected rather than silently widened.

Server and other client headers

server_header.mode is preserve (default), hide, or custom. Custom values are nonempty, bounded to 256 bytes and validated against header injection. Preserve means retain the result of origin/global/route rules; it does not add a missing header. Hide/custom take final precedence, including proxy-generated errors.

Global and route headers.response apply to client responses; headers.request apply only upstream. Each scope/direction supports up to 32 ordered set/append/remove rules. Remove has no value. Global rules precede route rules. Multiple Set-Cookie values remain distinct. Admin-session cookie names are never forwarded or set by public proxy rules. Transport, framing and trusted forwarding/identity fields are protected. Cache diagnostic fields are owned by the cache controls, not generic rules.

Global response rules also cover generated errors; route-specific rules apply only after an origin route response exists. Client policy changes use hot configuration publication and invalidate the RAM cache. In-flight exchanges retain their old snapshot; no mixed-version configuration is applied midway through a response.

Compression

All four flags default false. min_bytes defaults to 1024 (valid 32..1048576). The library's default small-body/content-type predicate is also retained; actual minimum for a known-size body is at least that default. Unknown-length text bodies can be streamed without pre-buffering merely to discover their size.

Accept-Encoding quality negotiation is delegated to tower-http. Text, JSON, JavaScript, XML, SVG and wasm are eligible; already encoded, SSE, range, upgrade, HEAD/204/304 and privacy-sensitive responses are excluded. Cookies/authorization bypass even when an origin marks a response public. Origin no-transform/privacy exclusions cannot be defeated by deleting a response header in the editor. Cached identity bodies can be streamed through compression on HIT; origin encodings are passed through without recompression.

Vary: Accept-Encoding is added by compression; content length is removed for the transformed body. Strong ETags are weakened, and identity-body content digests and Accept-Ranges are removed. Encoders use their fastest preset; there is no panel compression-quality slider in this release. Real binary interoperability tests are still an acceptance requirement, not a result of this packaging session.

Diagnostics and units

Samples run off the traffic path roughly every two seconds. CPU and network rates need two successful samples. Host CPU is aggregate; process CPU uses 100% per busy logical CPU and can exceed 100%. Neither is normalized to a container CPU quota. Host memory is MemTotal minus MemAvailable. RSS/FDs/threads and process I/O come from procfs. Network rates sum non-loopback interfaces in the process network namespace, not just RustProxy traffic. Load average is OS scope, not latency.

The process's cgroup v2 memory files are read at the standard mount location when available. Linux keeps the existing /proc/cgroup metric names, units and behavior. FreeBSD/OpenBSD/NetBSD use native system interfaces where the same metric is available; unknown or unsupported values remain null rather than being fabricated. Snapshot timestamps and sample age are shown; cache counters and proxy request metrics are separate from OS resource metrics. The dashboard history is browser-local and resets on reload/sign-out. No time-series database, disk utilization chart or Windows/macOS OS sampler is implemented.

HTTP/2 compatibility and per-vhost settings

HTTP/2 lifecycle settings are listener-scoped under listeners.endpoints[].binding.http2_settings:

• idle_timeout_seconds (default 300) retires only a truly unused H2 connection; active streams and current frame I/O postpone it.
• max_connection_lifetime_seconds (default 0) is an independent absolute lifetime; 0 disables this limit.
• drain_timeout_seconds (default 10) bounds how long accepted streams may finish after retirement begins.

Idle and lifetime retirement both send GOAWAY, stop accepting new streams, drain already accepted streams and then close TCP. RFC 8441 WebSocket/H2 Extended CONNECT streams are counted as active until their response body/tunnel ends. The same settings apply to TLS H2 and cleartext H2C on that named listener.

For backward compatibility, the top-level http2 object is still accepted as the fallback for an H2/H2C listener that has no explicit binding.http2_settings. The structured UI writes explicit per-listener settings; operators should treat the top-level object and PUT /api/config/http2 as legacy compatibility surfaces rather than the preferred configuration path.

A named TLS listener with binding.http2: true advertises H2 capability and always retains HTTP/1.1 fallback. binding.http2: false makes that listener HTTP/1.1-only. Cleartext H2 uses binding.h2c: true. Changing listener transport capability or H2 lifecycle settings requires restart.

A vhost can additionally set http2_enabled: false. RustProxy reads TLS ClientHello and SNI before committing to ALPN, so a vhost that disables H2 gets HTTP/1.1-only ALPN even while another hostname on the same listener keeps H2. http3_enabled is the equivalent per-vhost H3 opt-out. The panel enables these switches only when a selected listener provides the protocol. No failed application request is replayed to downgrade.

Vhosts have their own backend pool, health/keepalive/affinity controls, ACL and security/custom response headers. See VHOSTS.md. Global Server policy still takes final precedence. There is no per-vhost compression algorithm override.

The reported SizeAbove(u16) compilation error is removed by a custom u64 predicate, not a cast or panic-producing conversion. Compression thresholds retain the full 32..1048576-byte setting range. Known body length/Content-Length is compared exactly; unknown streaming lengths are eligible without buffering the full body. Actual compression execution still requires the compiler-enabled acceptance suite.

Management in 0.3.0

Settings contains a direct Security shortcut (accounts, sessions and host ACLs) and a vhost shortcut (SSL, headers, cache and pages). Compact is the default density; Dense and Comfortable change spacing/control sizes without browser zoom or logo redesign. The preference is local to the browser, not a global proxy setting.

Global Pages configures error overrides, direct-IP and unknown-host responses. See MANAGEMENT.md for inheritance, allowed statuses and security implications. Access logs have moved out of the dashboard into a separate modal/docked window. Filters stay above the scrollable rows; counts and exports use the same selection.

Named listeners, forwarding and diagnostics (0.4.0)

As of 0.8.0, the vhost editor no longer asks for a free-form listener IP. Configure listener IP/port/protocol once in this Settings section, then select named endpoints in the vhost. The pre-production inline/global listener format is no longer accepted. This separates socket intent from host routing and avoids duplicating listening IP configuration across vhosts.

listeners.endpoints is the only proxy-listener configuration. Each record has id, name, scope, enabled and a binding with address, tls, http2, optional http2_settings, h2c and optional http3. Scope is only a label. A vhost uses frontend.listener_ids; every reference must exist. Conflicting protocols on shared sockets are rejected. Changes to effective transport plans need restart, including H2 lifecycle and H3 limits. The UI shows saved named entries and actual bound transports separately.

forwarding controls trusted CIDRs and forwarded-proto acceptance. diagnostic_headers exposes only request_id (false initially). Vhosts can override the diagnostic policy and Server policy; absent/null means inherit. Runtime/cache/static/error responses pass through the same final header policy.

See INTEGRATIONS_040.md and HTTP3.md for complete JSON, limits and security details.

0.5.0 changes (override earlier baseline examples)

A named TLS listener with omitted http3 uses default H3 limits. Explicit null is persisted as disabled. Overlapping named sockets must match protocols AND H3 limits; the error identifies owners and remedies. A changed binding requires restart, including UDP protocol/limit changes. Check UDP port availability before upgrading.

The diagnostic control is request_id (false by default). The removed hide_mock_origin field is not accepted; use normal response-header removal for X-Mock-Origin. Existing custom Server values remain unchanged.

Cache decision/object inspection is under Cache, separate from Overview. Basic manual certificate issuance is under Certificates; TSIG is never a configuration field. See CACHE_DIAGNOSTICS.md and ACME_RFC2136.md for exact scopes and limits.

0.6 navigation and exporter

The Settings page now has eight switching cards: Listeners, Response, Cache, Headers, Forwarding, Pages, Prometheus and Security. Unsaved values remain in place while switching; switching alone never writes configuration. Security is not a separate sidebar item. Use arrow keys/Home/End in the tab bar.

The Prometheus card controls enabled, bind IP/port, URL path, client CIDRs, bearer-token environment variable name and optional collectors, including the bounded Traffic analytics collector. Only the variable name is exported; supply the actual secret to the service separately. See PROMETHEUS.md for immediate revocation, restart rules and scrape configuration.