Skip to main content

core

The runtime engine of the webda.io framework. It manages the full lifecycle of a Webda application: loading configuration, instantiating services, routing HTTP requests, managing sessions, and providing cross-cutting concerns like logging, metrics, and caching.

Architecture​

Architecture

The framework is organized into six layers:

Application Layer​

Responsible for discovering modules, loading configuration, and bootstrapping the runtime.

  • Application -- Scans the project, parses webda.config.json, discovers installed Moddas (service types) and Models, and caches everything for fast startup.
  • UnpackedApplication -- Development-oriented variant that auto-discovers webda.module.json files and creates default services (Router, Registry, CryptoService, SessionManager) when missing.
  • Configuration -- Defines the UnpackedConfiguration schema (version 4) with service definitions, global parameters, and application settings.
  • Runner -- Orchestrates startup: creates Core from Application, initializes all services, and registers SIGINT for graceful shutdown.
  • Application Hooks -- useApplication(), useModel(), useModelId(), useParameters() for accessing application state from anywhere in the call stack.

Core Runtime​

The central orchestrator that manages the service lifecycle and dependency graph.

  • Core -- Creates and initializes services with dependency tracking, maps Models to Stores and BinaryServices, manages the operation registry. Lifecycle: initial -> loading -> initializing -> ready -> stopping -> stopped.
  • InstanceStorage -- AsyncLocalStorage-based context that holds the current Core, Application, Router, and request context. Enables the hooks pattern without passing references through every function call.
  • Core Hooks -- useCore(), useService(), useDynamicService(), useModelStore(), useModelRepository(), getMachineId().
  • Events -- Async event system with lifecycle events: Webda.Init, Webda.Request, Webda.Result, Webda.404, Webda.OperationSuccess, Webda.Configuration.Applied, etc.
  • Errors -- Typed HTTP errors: Unauthorized (401), Forbidden (403), NotFound (404), BadRequest (400), Conflict (409), TooManyRequests (429), Redirect (302), and more.

Services Layer​

All application logic lives in services. Every service extends Service which provides logging, metrics, dependency injection, and event emission.

  • Service -- Base class for all application services. Provides @Inject decorator for DI, @Route for HTTP endpoints, logger per instance, metrics support, and lifecycle hooks (init(), resolve(), stop()).
  • ServiceParameters -- Base configuration class with change watching support. Services declare their config shape by extending this class.
  • CryptoService -- Encryption, JWT signing/verification, key management with rotation support. Pluggable encrypters.
  • BinaryService -- Abstract file/binary storage with metadata, integrity challenges, and model-attribute mapping.
  • ConfigurationService -- Dynamic configuration with hot-reload from external sources (files, Kubernetes ConfigMaps, other services).

Data Layer​

Persistent storage abstraction with query support.

  • Store -- Abstract storage with CRUD, query (via WebdaQL), conditional updates, and event emission (Created, Updated, Deleted). Automatically maps to Models via scoring.
  • MemoryStore -- In-memory implementation with optional file persistence. Used as the default Registry.
  • Registry -- Key-value store for framework internals (crypto keys, service state). Backed by any Store implementation.

HTTP / Request Layer​

Handles incoming HTTP requests and manages user sessions.

  • Router -- Routes HTTP requests to service methods, manages OpenAPI spec generation, request/CORS filters, and model REST endpoints.
  • OperationContext -- Typed request/response context with generic <Input, Parameters, Output>. Provides session access, parameter parsing, header management, and streaming.
  • SessionManager -- Abstract session load/save. Default implementation uses JWT tokens in secure cookies with optional backend storage.

Cross-Cutting Concerns​

Shared infrastructure available to all services.

  • Logger -- Structured logging with per-service context. Backed by @webda/workout.
  • Metrics -- Prometheus integration via prom-client. useMetric() creates Counters, Gauges, and Histograms with automatic service labels.
  • Cache -- Decorator-based caching at four scopes: @ProcessCache() (global), @InstanceCache() (per Core), @SessionCache() (per user), @ContextCache() (per request).
  • Queue -- Message queue consumer pattern with configurable parallelism, retry backoff, and metrics. Extend for SQS, AMQP, etc.
  • Models -- Model registry with built-in types: CoreModel, User, Ident, ACLModel, OwnerModel, RegistryEntry.
  • Execution Context -- AsyncLocalStorage-based context for useContext(), useCurrentUser(), runAsSystem(), runWithContext().

Request Flow​

HTTP Request
    |
    v
HttpContext (parse headers, cookies, body)
    |
    v
OperationContext / WebContext (typed I/O)
    |
    v
SessionManager.load() (JWT from cookie)
    |
    v
Router.execute() (match route, run filters)
    |
    v
Service method (business logic)
    |
    v
SessionManager.save() (persist if dirty)
    |
    v
HTTP Response

Hooks API​

The hooks pattern provides access to framework singletons from any point in the call stack, powered by AsyncLocalStorage:

HookReturnsUse case
useCore()CoreAccess the runtime engine
useApplication()ApplicationAccess project metadata and configuration
useService(name)Typed serviceGet a named service ("Registry", "CryptoService", etc.)
useDynamicService(name)ServiceGet a service by arbitrary name
useModel(name)ModelDefinitionGet a model class with metadata
useModelId(object)stringGet the model identifier for an instance
useModelStore(name)IStoreGet the store assigned to a model
useModelRepository(name)RepositoryGet the repository for a model
useContext()ContextGet the current request context
useCurrentUser()UserGet the authenticated user
useCurrentUserId()stringGet the user ID or "system"
useLogger(class)LoggerGet a logger with class context
useMetric(type, config)Counter/Gauge/HistogramCreate a prometheus metric
useParameters()Configuration["parameters"]Get global configuration parameters
getMachineId()stringGet a stable machine identifier

Dependency Injection​

Services declare dependencies with the @Inject decorator:

import { Service, Inject } from "@webda/core";

class MyService extends Service {
  // Inject by service name
  @Inject("CryptoService")
  crypto: CryptoService;

  // Inject from a parameter value
  @Inject("params:storeName", "Registry")
  store: Store;

  // Optional injection
  @Inject("NotificationService", undefined, true)
  notifications?: NotificationService;
}

Configuration​

Applications are configured via webda.config.json (version 4):

{
  "version": 4,
  "parameters": {
    "routePrefix": "/api",
    "metrics": { "prefix": "myapp_" }
  },
  "services": {
    "MyStore": {
      "type": "MemoryStore",
      "model": "MyApp/MyModel"
    },
    "MyService": {
      "type": "MyApp/MyService",
      "storeName": "MyStore"
    }
  }
}

Events​

Services emit typed async events. Subscribe with on():

// Core lifecycle events
useCoreEvents("Webda.Init", () => { /* framework ready */ });
useCoreEvents("Webda.Request", ({ context }) => { /* new request */ });

// Store events
myStore.on("Store.Created", ({ object }) => { /* model created */ });
myStore.on("Store.Updated", ({ object }) => { /* model updated */ });
myStore.on("Store.Deleted", ({ object }) => { /* model deleted */ });

Error Handling​

Throw typed HTTP errors from services:

import * as WebdaError from "@webda/core";

throw new WebdaError.NotFound("User not found");
throw new WebdaError.Forbidden("Insufficient permissions");
throw new WebdaError.BadRequest("Invalid input", "VALIDATION_ERROR");
throw new WebdaError.Redirect("https://example.com/new-location");

Ecosystem​

@webda/core is the foundation. The full framework includes:

PackagePurpose
@webda/modelsModel base classes, relations, repositories
@webda/compilerTypeScript compiler with schema generation
@webda/tsc-esmESM-aware TypeScript compiler, decorators
@webda/utilsUtilities (debounce, dirty tracking, state machines)
@webda/workoutLogging infrastructure
@webda/testMulti-framework test decorators (vitest, jest, mocha, bun)
@webda/qlWebdaQL query language
@webda/cloudeventsCloudEvents filtering
@webda/cacheCaching decorators
@webda/serializeSerialization framework
@webda/content-mapperJSON Schema generator

Deep-dive sub-pages​

  • Architecture — 6-layer overview with diagram
  • Service Lifecycle — resolve → init → run → stop
  • Services — Service, @Bean, @Inject, ServiceParameters
  • Stores — Store contract, query interface, events
  • Context — WebContext, sessions, request lifecycle
  • Routing — @Route, @Operation, REST auto-generation
  • Events — Core.on, store events, @On decorator
  • Errors — WebdaError hierarchy and HTTP status mapping
  • Logging — useLog + @webda/workout integration
  • CLI — webda runtime commands

CoreFeatures​

CoreServices​

Other​