ROWS

ROWS — Rust Open World Server

ROWS is a single-binary Rust reimplementation of the OWS (Open World Server) game backend. It consolidates the five .NET microservices (PublicAPI, InstanceManagement, CharacterPersistence, GlobalData, Management) into one unified service with both REST and gRPC interfaces.

Architecture

• REST API (Axum) — player-facing endpoints: login, registration, character CRUD, zone connections
• gRPC (Tonic) — internal service-to-service communication and UE5 dedicated server coordination
• RabbitMQ — async job queue for instance lifecycle events (spin-up, shutdown, health checks)
• PostgreSQL — persistent storage for accounts, characters, abilities, world state
• ValKey — session cache and ephemeral game state
• Agones — game server fleet management for UE5 dedicated server instances

Endpoints

Group	Path Prefix	Description
Auth	/api/users/*	Login, register, session management
Characters	/api/characters/*	Character CRUD, class selection
Zones	/api/zones/*	Zone listing, server-to-connect-to
Instance	/api/instance/*	Server instance lifecycle
Global	/api/global/*	Key/value world state
Health	/health, /ready	Liveness and readiness probes
gRPC	Port 50051	Internal service mesh

Production

ROWS is the production game backend. The legacy .NET OWS microservices have been fully removed — all traffic on api.chuckrpg.com routes exclusively to ROWS.

Deployment

ROWS deploys as a single Docker image (ghcr.io/kbve/rows) into the ows Kubernetes namespace. ArgoCD syncs the manifest from apps/kube/ows/manifest/rows-deployment.yaml with auto-prune and self-heal enabled.

The container exposes:

• Port 4322 — REST + gRPC multiplexed (Axum + Tonic on a single port)

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Procedural World — Seed-Based Multi-Zone Architecture

Roadmap

This section describes the planned seed-based procedural world system. Current deployment uses single-zone with ServerDefaultMap=Lvl_ThirdPerson.

Overview

Each game zone is a procedurally generated region driven by a deterministic seed. The same seed always produces identical terrain, foliage, and spawn layouts. This enables:

• One map, many worlds — a single Lvl_Procedural map generates different zones from different seeds
• Elastic scaling — any server pod can host any zone, just give it a seed
• Crash recovery — replace a dead server, give it the same seed, world is identical
• Discovery — new zones are just new seeds, no additional map packaging required

Data Model

The maps table gains a seed column:

ALTER TABLE ows.maps ADD COLUMN seed BIGINT DEFAULT 0;

-- Example zones
INSERT INTO maps (customerguid, mapname, zonename, seed) VALUES
  ('83d88046-...', 'Lvl_Procedural', 'Grassland',    0xA1B2C3D4),
  ('83d88046-...', 'Lvl_Procedural', 'Arctic',       0xDEAD0002),
  ('83d88046-...', 'Lvl_Procedural', 'Desert',       0xCAFE0003),
  ('83d88046-...', 'Lvl_Procedural', 'Marshlands',   0xBEEF0004),
  ('83d88046-...', 'Lvl_PvPArena',   'PvPArena',     0);  -- static map, no seed

ROWS Flow

1. Player → GetServerToConnectTo(zoneName: "Arctic")
2. ROWS → Agones allocate → server starts on Entry
3. ROWS → GetZoneAssignment returns:
   {
     "assigned": true,
     "mapName": "Lvl_Procedural",
     "zoneName": "Arctic",
     "seed": 3735552002,
     "zoneInstanceId": 42
   }
4. Server → ServerTravel("/Game/Procedural/Lvl_Procedural?listen?seed=3735552002")
5. Lvl_Procedural BeginPlay → reads seed → PCG generates Arctic biome
6. Server reports ready → players connect to deterministic world

UE5 Integration

PCG (Procedural Content Generation) Framework:

Layer	Driven By	Examples
Terrain heightmap	Seed + biome type	Mountain ranges, valleys, coastlines
Biome selection	Seed bits [0:7]	Grassland, Arctic, Desert, Marshland, Tropic
Foliage placement	Seed + density rules	Trees, bushes, grass patches
Resource nodes	Seed + spawn tables	Ore veins, herb clusters, fishing spots
Mob spawns	Seed + difficulty curve	Creature type, patrol routes, density
Landmarks	Fixed coordinates	Towns, dungeons, POIs (handcrafted, placed at deterministic positions)
Weather	Seed + time-of-day	Rain cycles, fog density, wind patterns

Hybrid approach:

• Handcrafted landmarks are pre-built actors placed at coordinates derived from the seed
• Procedural fill generates the terrain and natural environment between landmarks
• Biome blending uses seed-derived Voronoi regions for smooth transitions

GameMode seed consumption:

// In Lvl_Procedural's GameMode BeginPlay
FString SeedStr = UGameplayStatics::ParseOption(OptionsString, TEXT("seed"));
int64 Seed = FCString::Atoi64(*SeedStr);
FRandomStream WorldRNG(Seed);

// Feed to PCG subsystem
UPCGSubsystem* PCG = GetWorld()->GetSubsystem<UPCGSubsystem>();
PCG->SetGlobalSeed(Seed);

Zone Travel

Players move between zones via zone portals or world map travel:

Player enters Arctic→Desert portal
  → Client calls SetSelectedCharacterAndGetUserSession
  → Client calls GetServerToConnectTo(zoneName: "Desert")
  → ROWS finds/allocates Desert server (seed: 0xCAFE0003)
  → Client disconnects from Arctic, connects to Desert
  → Character position saved on Arctic, loaded on Desert

Seed Registry

Seeds can be:

• Static — admin-created zones with curated seeds (main world regions)
• Dynamic — player-triggered instanced content (dungeons, events) with random seeds
• Seasonal — time-limited zones that rotate seeds periodically

GET /api/System/SeedRegistry
{
  "zones": [
    { "zoneName": "Grassland",  "seed": 2712847316, "type": "static",  "biome": "grassland" },
    { "zoneName": "Arctic",     "seed": 3735552002, "type": "static",  "biome": "arctic" },
    { "zoneName": "Dungeon_42", "seed": 8827361024, "type": "dynamic", "biome": "cave",  "expires": "2026-04-01T00:00:00Z" }
  ]
}

Implementation Phases

Phase	Scope	Dependencies
Phase 1	Add seed column to maps table, include in GetZoneAssignment response	dbmate migration
Phase 2	Lvl_Procedural map with basic PCG — terrain heightmap from seed	UE5 PCG framework
Phase 3	Biome system — seed bits select biome, PCG generates appropriate flora/fauna	Biome data tables
Phase 4	Handcrafted landmarks — POI actors placed at seed-derived coordinates	Level design
Phase 5	Zone portals — client-side travel between seed-based zones	OWS travel flow
Phase 6	Dynamic instances — player-triggered dungeons with random seeds	Instance lifecycle
Phase 7	Seed registry API — admin tools for zone management	Dashboard integration