feat(core): initial implementation — launcher, logz, xerrors, valid

Introduces `code.nochebuena.dev/einherjar/core` — the foundational implementation
module of the Einherjar framework. Provides four sub-packages that together cover
every service's baseline needs: lifecycle management, structured logging, typed
errors, and struct validation.

- launcher: Launcher interface — three-phase managed lifecycle (OnInit → BeforeStart
  hooks → OnStart → OS signal wait → OnStop in reverse). Accepts
  lifecycle.Component and logging.Logger from contracts. Prints an ASCII art banner
  at startup (EINHERJAR_BANNER=off to suppress). Banner includes core version via
  runtime/debug.ReadBuildInfo() and a loaded-module list for every registered
  component that implements observability.Identifiable. Config struct with
  EINHERJAR_COMPONENT_STOP_TIMEOUT env tag (caarlos0/env syntax, default 15s).

- logz: Logger implementation backed by log/slog. Returns contracts/logging.Logger.
  Detects errs.CodedError and errs.ContextualError (from contracts/errs) to enrich
  log records automatically — replaces the private duck-typed bridge from micro-lib.
  Context helpers: WithRequestID, WithField, WithFields, GetRequestID. Config struct
  with EINHERJAR_LOG_LEVEL (default INFO) and EINHERJAR_LOG_JSON (default false) env
  tags (caarlos0/env syntax); programmatic-only fields StaticArgs and Writer carry no
  tags.

- xerrors: Typed error codes with context enrichment. Complete gRPC canonical set
  (16 codes) plus HTTP 410 ErrGone. Adds ErrOutOfRange, ErrAborted, ErrDataLoss
  over micro-lib. One convenience constructor per code. *Err declares compile-time
  satisfaction of errs.CodedError and errs.ContextualError.

- valid: Struct validation wrapping go-playground/validator/v10. Validator interface
  + MessageProvider interface with full built-in tag coverage (~150 tags) in both
  DefaultMessages (English) and SpanishMessages (Spanish). Backend fully hidden;
  returns *xerrors.Err with ErrInvalidInput or ErrInternal. FieldLevel interface
  abstracts the backend's field-level access for custom validators.
  WithCustomValidator registers custom validation tags at construction time;
  OverrideProvider chains a tag→handler map with a fallback MessageProvider for
  custom tag messages without re-implementing built-ins.

Compliance test enforces CT-6 (at most one exported TypeSpec per file via AST) and
verifies behavioural correctness of all four sub-packages, including custom validator
registration and OverrideProvider composition. Compile-time var _ assertions prove
interface satisfaction.

docs: ADR-001 (core module composition), ADR-002 (logz contracts/errs adoption),
ADR-003 (Config naming convention and caarlos0/env tag standard)
This commit is contained in:
2026-05-29 15:45:12 +00:00
commit 38a415c2ab
33 changed files with 3868 additions and 0 deletions

162
launcher/launcher.go Normal file
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package launcher
import (
"context"
"os"
"os/signal"
"sync"
"syscall"
"time"
"code.nochebuena.dev/einherjar/contracts/lifecycle"
"code.nochebuena.dev/einherjar/contracts/logging"
"code.nochebuena.dev/einherjar/contracts/observability"
)
// Launcher manages the application lifecycle: init → assemble → start → wait → shutdown.
type Launcher interface {
// Append adds one or more components. Registered in the order they are appended;
// shutdown runs in reverse order.
Append(components ...lifecycle.Component)
// BeforeStart registers hooks that run after all OnInit calls and before all OnStart
// calls. Use for dependency injection wiring.
BeforeStart(hooks ...Hook)
// Run executes the full application lifecycle. Blocks until an OS shutdown signal is
// received or Shutdown is called. Returns an error if any lifecycle step fails.
// The caller is responsible for calling os.Exit(1) when needed.
Run() error
// Shutdown triggers a graceful shutdown and waits for Run to return.
// ctx controls the caller-side wait timeout — it does NOT override
// Config.ComponentStopTimeout for individual components.
// Safe to call multiple times (idempotent).
Shutdown(ctx context.Context) error
}
var _ Launcher = (*launcher)(nil)
// New returns a Launcher configured by opts. The zero value of Config is valid.
func New(logger logging.Logger, opts ...Config) Launcher {
o := Config{ComponentStopTimeout: defaultComponentStopTimeout}
if len(opts) > 0 {
if opts[0].ComponentStopTimeout > 0 {
o.ComponentStopTimeout = opts[0].ComponentStopTimeout
}
}
return &launcher{
logger: logger,
opts: o,
components: make([]lifecycle.Component, 0),
shutdownCh: make(chan struct{}),
doneCh: make(chan struct{}),
}
}
type launcher struct {
logger logging.Logger
opts Config
components []lifecycle.Component
beforeStart []Hook
shutdownCh chan struct{}
doneCh chan struct{}
shutdownOnce sync.Once
}
func (l *launcher) Append(components ...lifecycle.Component) {
l.components = append(l.components, components...)
}
func (l *launcher) BeforeStart(hooks ...Hook) {
l.beforeStart = append(l.beforeStart, hooks...)
}
// Run executes the full application lifecycle:
// 1. Prints the startup banner (unless EINHERJAR_BANNER=off).
// 2. OnInit for all components (in registration order).
// 3. BeforeStart hooks (in registration order).
// 4. OnStart for all components (in registration order).
// 5. Blocks until an OS signal or Shutdown() is called.
// 6. stopAll — OnStop for all components (in reverse order).
func (l *launcher) Run() error {
var ids []observability.Identifiable
for _, c := range l.components {
if id, ok := c.(observability.Identifiable); ok {
ids = append(ids, id)
}
}
printBanner(ids)
defer close(l.doneCh)
l.logger.Info("launcher: starting init phase (OnInit)")
for _, c := range l.components {
if err := c.OnInit(); err != nil {
return err
}
}
l.logger.Info("launcher: running assembly hooks (BeforeStart)")
for _, hook := range l.beforeStart {
if err := hook(); err != nil {
return err
}
}
l.logger.Info("launcher: starting components (OnStart)")
for _, c := range l.components {
if err := c.OnStart(); err != nil {
l.logger.Error("launcher: OnStart failed, triggering shutdown", err)
l.stopAll()
return err
}
}
l.logger.Info("launcher: application ready")
quit := make(chan os.Signal, 1)
signal.Notify(quit, os.Interrupt, syscall.SIGTERM)
defer signal.Stop(quit)
select {
case s := <-quit:
l.logger.Info("launcher: termination signal received", "signal", s.String())
case <-l.shutdownCh:
l.logger.Info("launcher: programmatic shutdown requested")
}
l.stopAll()
return nil
}
func (l *launcher) Shutdown(ctx context.Context) error {
l.shutdownOnce.Do(func() {
close(l.shutdownCh)
})
select {
case <-l.doneCh:
return nil
case <-ctx.Done():
return ctx.Err()
}
}
func (l *launcher) stopAll() {
l.logger.Info("launcher: stopping all components")
for i := len(l.components) - 1; i >= 0; i-- {
done := make(chan struct{})
go func(c lifecycle.Component) {
if err := c.OnStop(); err != nil {
l.logger.Error("launcher: error during OnStop", err)
}
close(done)
}(l.components[i])
select {
case <-done:
case <-time.After(l.opts.ComponentStopTimeout):
l.logger.Error("launcher: component OnStop timed out", nil)
}
}
l.logger.Info("launcher: all components stopped")
}