sum

README

sum

Wire once, run anywhere. An application framework that unifies HTTP, data, configuration, and services into a single lifecycle.

Compose and Run

// Register services by contract type
k := sum.Start()
sum.Register[UserService](k, &userImpl{})
sum.Register[OrderService](k, &orderImpl{})
sum.Freeze(k)

// Retrieve anywhere by type
userSvc := sum.MustUse[UserService](ctx)

Services, configuration, and data stores—all wired through one registry, resolved by type.

Install

go get github.com/zoobzio/sum

Requires Go 1.24 or later.

Quick Start

package main

import (
    "context"
    "log"

    "github.com/zoobzio/sum"
)

type Greeter interface {
    Greet(name string) string
}

type greeterImpl struct{}

func (g *greeterImpl) Greet(name string) string {
    return "Hello, " + name
}

func main() {
    // Initialize service and registry
    svc := sum.New(sum.ServiceConfig{Host: "localhost", Port: 8080})
    k := sum.Start()

    // Register services
    sum.Register[Greeter](k, &greeterImpl{})
    sum.Freeze(k)

    // Use services anywhere
    greeter := sum.MustUse[Greeter](context.Background())
    log.Println(greeter.Greet("World"))

    // Run with graceful shutdown
    if err := svc.Run(); err != nil {
        log.Fatal(err)
    }
}

Capabilities

Capability	Description	Documentation
Service Registry	Type-safe service locator with guards	Registry
Lifecycle Management	Singleton service with graceful shutdown	Service
Configuration	Load and register config via fig	Config
Typed Events	Emit and listen with type-safe payloads	Event
Data Stores	Database, KV, and object storage helpers	Database

Why sum?

• Type-safe service registry — Register and retrieve services by contract type, not strings. Compile-time safety, zero casting.
• Unified lifecycle — One Run() handles startup, signal handling, and graceful shutdown.
• Integrated data catalog — Databases, KV stores, and buckets register automatically with the data catalog for observability.
• Typed events — Define events once with Event[T], emit and listen with full type safety.
• Minimal ceremony — No annotations, no reflection magic, no code generation. Just Go.

The Ecosystem

sum builds on the zoobzio toolkit:

Package	Purpose
rocco	HTTP engine with OpenAPI
slush	Service registry core
capitan	Event/signal system
fig	Configuration loading
grub	Database/KV/Object storage
scio	Data catalog

Documentation

• Learn: Overview · Quickstart · Concepts · Architecture
• Guides: Testing · Troubleshooting · Service Registry · Events · Data Stores
• Reference: API · Types · pkg.go.dev

Contributing

Contributions welcome—see CONTRIBUTING.md for guidelines.

License

MIT License - see LICENSE

Documentation

Overview

Package sum provides an applications framework for Go.

Index

• Variables
• func Bucket[C, M any](k Key, provider grub.BucketProvider, name string, ...) error
• func Config[T any](ctx context.Context, k Key, provider fig.SecretProvider) error
• func Database[C, M any](k Key, db *sqlx.DB, table, keyCol string, renderer astql.Renderer, ...) error
• func Freeze(k Key)
• func MustUse[T any](ctx context.Context) T
• func Store[C, M any](k Key, provider grub.StoreProvider, name string, ...) error
• func Use[T any](ctx context.Context) (T, error)
• type Event
  • func NewDebugEvent[T any](signal capitan.Signal) Event[T]
  • func NewErrorEvent[T any](signal capitan.Signal) Event[T]
  • func NewEvent[T any](signal capitan.Signal, level capitan.Severity) Event[T]
  • func NewInfoEvent[T any](signal capitan.Signal) Event[T]
  • func NewWarnEvent[T any](signal capitan.Signal) Event[T]
  • func (e Event[T]) Emit(ctx context.Context, data T)
  • func (e Event[T]) Listen(callback func(context.Context, T)) *capitan.Listener
  • func (e Event[T]) ListenOnce(callback func(context.Context, T)) *capitan.Listener
• type Guard
• type Handle
  • func Register[T any](k Key, impl T) *Handle[T]
• type Key
  • func Start() Key
• type Service
  • func New(cfg ServiceConfig) *Service
  • func (s *Service) Catalog() *scio.Scio
  • func (s *Service) Config() ServiceConfig
  • func (s *Service) Engine() *rocco.Engine
  • func (s *Service) Handle(endpoints ...rocco.Endpoint)
  • func (s *Service) Run() error
  • func (s *Service) Shutdown(ctx context.Context) error
  • func (s *Service) Start() error
  • func (s *Service) Tag(name, description string)
• type ServiceConfig
• type ServiceInfo
  • func Services(k Key) ([]ServiceInfo, error)

Variables

var (
	ErrNotFound     = slush.ErrNotFound
	ErrAccessDenied = slush.ErrAccessDenied
	ErrInvalidKey   = slush.ErrInvalidKey
)

Error re-exports from slush.

var (
	SignalRegistered capitan.Signal = slush.SignalRegistered
	SignalAccessed   capitan.Signal = slush.SignalAccessed
	SignalDenied     capitan.Signal = slush.SignalDenied
	SignalNotFound   capitan.Signal = slush.SignalNotFound
)

Signal re-exports from slush.

var (
	KeyInterface capitan.Key = slush.KeyInterface
	KeyImpl      capitan.Key = slush.KeyImpl
	KeyError     capitan.Key = slush.KeyError
)

Field key re-exports from slush.

Functions

func Bucket

func Bucket[C, M any](k Key, provider grub.BucketProvider, name string, factory func(*grub.Bucket[M]) C) error

Bucket creates a grub.Bucket[M], passes it to the factory to obtain a C implementation, registers C with the service locator, and registers the atomic with scio.

func Config

func Config[T any](ctx context.Context, k Key, provider fig.SecretProvider) error

Config loads configuration of type T via fig and registers it with the service locator. Pass nil for provider if secrets are not needed. Retrieve the configuration later with Use[T](ctx).

func Database

func Database[C, M any](k Key, db *sqlx.DB, table, keyCol string, renderer astql.Renderer, factory func(*grub.Database[M]) C) error

Database creates a grub.Database[M], passes it to the factory to obtain a C implementation, registers C with the service locator, and registers the atomic with scio.

func Freeze

func Freeze(k Key)

Freeze prevents further service registration. Panics if key is invalid.

func MustUse

func MustUse[T any](ctx context.Context) T

MustUse retrieves a service by its contract type T. Panics if the service is not registered or a guard fails.

func Store

func Store[C, M any](k Key, provider grub.StoreProvider, name string, factory func(*grub.Store[M]) C) error

Store creates a grub.Store[M], passes it to the factory to obtain a C implementation, registers C with the service locator, and registers the atomic with scio.

func Use

func Use[T any](ctx context.Context) (T, error)

Use retrieves a service by its contract type T. Runs all registered guards with the provided context. Returns ErrNotFound if not registered, ErrAccessDenied if a guard fails.

Types

type Event

type Event[T any] struct {
	// Signal is the underlying capitan signal.
	Signal capitan.Signal

	// Key is the typed key for extracting event data.
	Key capitan.GenericKey[T]
	// contains filtered or unexported fields
}

Event provides bidirectional access to a signal with typed data. Use Emit to dispatch events and Listen to register callbacks.

func NewDebugEvent

func NewDebugEvent[T any](signal capitan.Signal) Event[T]

NewDebugEvent creates an Event that emits at Debug level.

func NewErrorEvent

func NewErrorEvent[T any](signal capitan.Signal) Event[T]

NewErrorEvent creates an Event that emits at Error level.

func NewEvent

func NewEvent[T any](signal capitan.Signal, level capitan.Severity) Event[T]

NewEvent creates an Event with the given signal and severity level. The variant is derived automatically from T via sentinel.

func NewInfoEvent

func NewInfoEvent[T any](signal capitan.Signal) Event[T]

NewInfoEvent creates an Event that emits at Info level.

func NewWarnEvent

func NewWarnEvent[T any](signal capitan.Signal) Event[T]

NewWarnEvent creates an Event that emits at Warn level.

func (Event[T]) Emit

func (e Event[T]) Emit(ctx context.Context, data T)

Emit dispatches an event with the configured severity level.

func (Event[T]) Listen

func (e Event[T]) Listen(callback func(context.Context, T)) *capitan.Listener

Listen registers a callback for this event. Returns a Listener that can be closed to unregister.

func (Event[T]) ListenOnce

func (e Event[T]) ListenOnce(callback func(context.Context, T)) *capitan.Listener

ListenOnce registers a callback that fires only once, then automatically unregisters. Returns a Listener that can be closed early to prevent the callback from firing.

type Guard

type Guard = slush.Guard

Guard is a validation function that permits or denies service access.

type Handle

type Handle[T any] = slush.Handle[T]

Handle configures a registered service with optional guards.

func Register

func Register[T any](k Key, impl T) *Handle[T]

Register registers a service implementation for the contract type T. Returns a Handle for optional guard configuration. Panics if Start has not been called, key is invalid, or registry is frozen.

type Key

type Key = slush.Key

Key grants the capability to register services.

func Start

func Start() Key

Start initializes the service registry and returns a Key for registration. Panics if called more than once.

type Service

type Service struct {
	// contains filtered or unexported fields
}

Service wraps a rocco engine and scio catalog, providing application lifecycle.

func New

func New(cfg ServiceConfig) *Service

New creates or returns the singleton Service. Subsequent calls return the existing instance, ignoring the provided config.

func (*Service) Catalog

func (s *Service) Catalog() *scio.Scio

Catalog returns the scio data catalog for advanced usage.

func (*Service) Config

func (s *Service) Config() ServiceConfig

Config returns the service configuration.

func (*Service) Engine

func (s *Service) Engine() *rocco.Engine

Engine returns the underlying rocco engine for advanced usage.

func (*Service) Handle

func (s *Service) Handle(endpoints ...rocco.Endpoint)

Handle registers endpoints with the underlying engine.

func (*Service) Run

func (s *Service) Run() error

Run starts the service and blocks until a shutdown signal is received. Handles SIGINT and SIGTERM, then performs graceful shutdown with a 30 second timeout.

func (*Service) Shutdown

func (s *Service) Shutdown(ctx context.Context) error

Shutdown gracefully stops the service.

func (*Service) Start

func (s *Service) Start() error

Start begins serving. This method blocks until shutdown.

func (*Service) Tag

func (s *Service) Tag(name, description string)

Tag registers an OpenAPI tag with a description.

type ServiceConfig

type ServiceConfig struct {
	Host string
	Port int
}

ServiceConfig defines the service configuration.

type ServiceInfo

type ServiceInfo = slush.ServiceInfo

ServiceInfo describes a registered service for enumeration.

func Services

func Services(k Key) ([]ServiceInfo, error)

Services returns information about all registered services. Returns ErrInvalidKey if the key is invalid.