context helpers, rework logging to support ongoing inheritance

Leaves module logger property as purely an override, pulling logger
information directly from the lifecycle instead.

lifecycle.go

@@ -1,6 +1,7 @@
 package app
 
 import (
+	"context"
 	"errors"
 	"fmt"
 	"log/slog"
@@ -8,19 +9,23 @@ import (
 	"strings"
 )
 
+type contextKey string
+
+const lifecycleContextKey contextKey = "lifecycle"
+
 // LifecycleOpts contains user-exposed options when defining a lifecycle.
 type LifecycleOpts struct {
 	// DisableAutoload disables dependency autoloading (enabled by default).
 	DisableAutoload bool
+
+	// Logger is the logger for the lifecycle. If not set, it will be initialized
+	// by the lifecycle using the default logger (slog.Default).
+	Logger *slog.Logger
 }
 
 // Lifecycle represents the core application structure. Lifecycle manages
 // resources providing an orchestrator for setup and teardown of modules.
 type Lifecycle struct {
-	// Logger is the logger for the lifecycle. If not set, it will be initialized
-	// by the lifecycle itself using the default logger.
-	logger *slog.Logger
-
 	modules []*Module
 	opts    LifecycleOpts
 
@@ -33,46 +38,59 @@ type Lifecycle struct {
 // NewLifecycle creates a new Lifecycle instance with a default logger and the
 // given modules. It panics if any module has a duplicate name.
 func NewLifecycle(modules ...*Module) *Lifecycle {
-	return NewLifecycleL(nil, modules...)
-}
-
-// NewLifecycleL creates a new Lifecycle instance with a specific logger and the
-// given modules. See NewLifecycle for more details.
-func NewLifecycleL(defaultLogger *slog.Logger, modules ...*Module) *Lifecycle {
-	// Use the provided logger or initialize a default one
-	if defaultLogger == nil {
-		defaultLogger = slog.Default()
-	}
-
 	// Ensure modules are unique
 	unique := make(map[string]bool)
 	for _, mod := range modules {
 		if _, exists := unique[mod.name]; exists {
-			panic(fmt.Sprintf("duplicate module name: %s", mod.name))
+			panic(fmt.Sprintf("duplicate module: %s", mod))
 		}
 		unique[mod.name] = true
 	}
 
 	return &Lifecycle{
-		logger:          defaultLogger,
 		modules:         modules,
 		setupTracker:    make(map[string]int),
 		teardownTracker: make(map[string]int),
 	}
 }
 
+// LifecycleToContext adds the Lifecycle to the context.
+func LifecycleToContext(ctx context.Context, lifecycle *Lifecycle) context.Context {
+	if lifecycle == nil {
+		return ctx
+	}
+	return context.WithValue(ctx, lifecycleContextKey, lifecycle)
+}
+
+// LifecycleFromContext retrieves the Lifecycle from the context. Returns nil if not found.
+func LifecycleFromContext(ctx context.Context) *Lifecycle {
+	if lifecycle, ok := ctx.Value(lifecycleContextKey).(*Lifecycle); ok {
+		return lifecycle
+	}
+	return nil
+}
+
 // WithOpts sets the options for the lifecycle.
 func (app *Lifecycle) WithOpts(opts LifecycleOpts) *Lifecycle {
 	app.opts = opts
 	return app
 }
 
+// WithLogger sets the logger for the lifecycle. Panics if the logger is nil.
+func (app *Lifecycle) WithLogger(logger *slog.Logger) *Lifecycle {
+	if logger == nil {
+		panic("logger cannot be nil")
+	}
+	app.opts.Logger = logger
+	return app
+}
+
 // Logger returns the logger for the lifecycle.
 func (app *Lifecycle) Logger() *slog.Logger {
-	if app.logger == nil {
-		panic("lifecycle logger is not initialized")
+	if app.opts.Logger == nil {
+		app.opts.Logger = slog.Default()
 	}
-	return app.logger
+	return app.opts.Logger
 }
 
 // Setup initializes all modules in the order they were defined and checks
@@ -81,12 +99,12 @@ func (app *Lifecycle) Logger() *slog.Logger {
 // of the application lifecycle to ensure all resources are cleaned up properly.
 func (app *Lifecycle) Setup() error {
 	for _, mod := range app.modules {
-		if err := app.setupSingle(mod, app.logger); err != nil {
+		if err := app.setupSingle(nil, mod); err != nil {
 			return err
 		}
 	}
 
-	app.logger.Info("Lifecycle modules initialized, backend setup complete",
+	app.Logger().Info("Lifecycle modules initialized, backend setup complete",
 		"modules", mapToString(app.setupTracker))
 
 	return nil
@@ -105,11 +123,11 @@ func (app *Lifecycle) Teardown() error {
 	}
 
 	if err != nil {
-		app.logger.Error("Error tearing down modules", "failures", app.setupCount-app.teardownCount, "error", err)
+		app.Logger().Error("Error tearing down modules", "failures", app.setupCount-app.teardownCount, "error", err)
 		return err
 	}
 
-	app.logger.Info("All modules torn down, backend teardown complete",
+	app.Logger().Info("All modules torn down, backend teardown complete",
 		"modules", mapToString(app.teardownTracker))
 
 	return nil
@@ -120,13 +138,13 @@ func (app *Lifecycle) Teardown() error {
 // but may still be conditionally necessary. Any modules that are already
 // set up are ignored.
 func (app *Lifecycle) Require(modules ...*Module) error {
-	return app.RequireL(app.logger, modules...)
+	return app.require(nil, false, modules...)
 }
 
 // RequireUnique is the same as Require, but it returns an error if any requested
 // module is already set up--rather than ignoring it.
 func (app *Lifecycle) RequireUnique(modules ...*Module) error {
-	return app.RequireUniqueL(app.logger, modules...)
+	return app.require(nil, true, modules...)
 }
 
 // RequireL adds module(s) to the lifecycle with a specific logger and
@@ -135,21 +153,39 @@ func (app *Lifecycle) RequireUnique(modules ...*Module) error {
 // default logger.
 func (app *Lifecycle) RequireL(logger *slog.Logger, modules ...*Module) error {
 	if logger == nil {
-		logger = app.logger
+		return fmt.Errorf("logger cannot be nil")
 	}
+	return app.require(logger, false, modules...)
+}
 
+// RequireUniqueL is the same as RequireL, but it returns an error if any requested
+// module is already set up--rather than ignoring it.
+func (app *Lifecycle) RequireUniqueL(logger *slog.Logger, modules ...*Module) error {
+	if logger == nil {
+		return fmt.Errorf("logger cannot be nil")
+	}
+	return app.require(logger, true, modules...)
+}
+
+// require is a helper function that attempts to add module(s) to the lifecycle
+// and immediately run any setup functions.
+func (app *Lifecycle) require(logger *slog.Logger, unique bool, modules ...*Module) error {
 	if len(modules) == 0 {
 		return fmt.Errorf("no modules to require")
 	}
 
-	for _, mod := range modules {
+	for i, mod := range modules {
 		if mod == nil {
-			return fmt.Errorf("module is nil")
+			return fmt.Errorf("module %d is nil", i)
 		}
 
-		// Check if the module is already set up
+		// Check if the module has already been set up
 		if _, ok := app.setupTracker[mod.name]; ok {
-			app.logger.Warn("module already set up, ignoring", "module", mod.name)
+			if unique {
+				return fmt.Errorf("module %s is already set up, cannot require it again", mod)
+			}
+
+			app.Logger().Warn("module already set up, ignoring", "module", mod)
 			mod.loaded = true
 			mod.logger = logger
 			continue
@@ -159,57 +195,40 @@ func (app *Lifecycle) RequireL(logger *slog.Logger, modules ...*Module) error {
 		app.modules = append(app.modules, mod)
 
 		// Run the setup function for the module
-		if err := app.setupSingle(mod, logger); err != nil {
-			return fmt.Errorf("error setting up required module '%s': %w", mod.name, err)
+		if err := app.setupSingle(logger, mod); err != nil {
+			return fmt.Errorf("error setting up required module %s: %w", mod, err)
 		}
 	}
 
-	app.logger.Info("New modules initialized", "all", mapToString(app.setupTracker))
-
+	app.Logger().Info("New modules initialized", "all", mapToString(app.setupTracker))
 	return nil
 }
 
-// RequireUniqueL is the same as RequireL, but it returns an error if any requested
-// module is already set up--rather than ignoring it.
-func (app *Lifecycle) RequireUniqueL(logger *slog.Logger, modules ...*Module) error {
-	// Check if any module is already set up
-	for _, mod := range modules {
-		if mod == nil {
-			return fmt.Errorf("module is nil")
-		}
-
-		if _, ok := app.setupTracker[mod.name]; ok {
-			return fmt.Errorf("module '%s' is already set up, cannot require it again", mod.name)
-		}
-	}
-
-	return app.RequireL(logger, modules...)
-}
-
 // setupSingle is a helper function to set up a single module. Returns an error
 // if the module cannot be set up or if dependencies are not satisfied.
-func (app *Lifecycle) setupSingle(mod *Module, logger *slog.Logger) error {
+func (app *Lifecycle) setupSingle(logger *slog.Logger, mod *Module) error {
 	if mod == nil {
 		return fmt.Errorf("module is nil")
 	}
 
-	// Set the logger for the module
+	// Set the parent lifecycle and logger override
+	mod.lifecycle = app
 	mod.logger = logger
 
 	// Check if all dependencies are satisfied
 	for _, dep := range mod.depends {
 		if _, ok := app.setupTracker[dep]; !ok {
 			if app.opts.DisableAutoload {
-				return fmt.Errorf("dependency '%s' not satisfied for '%s'", dep, mod.name)
+				return fmt.Errorf("dependency %s not satisfied for '%s'", dep, mod)
 			} else {
 				// Attempt to set up the dependency
 				depmod, err := app.getModuleByName(dep)
 				if err != nil {
-					return fmt.Errorf("error getting dependency '%s' for '%s': %w", dep, mod.name, err)
+					return fmt.Errorf("error getting dependency '%s' for %s: %w", dep, mod, err)
 				}
 
-				if err := app.setupSingle(depmod, logger); err != nil {
-					return fmt.Errorf("error setting up dependency '%s' for '%s': %w", dep, mod.name, err)
+				if err := app.setupSingle(logger, depmod); err != nil {
+					return fmt.Errorf("error setting up dependency %s for %s: %w", depmod, mod, err)
 				}
 			}
 		}
@@ -218,7 +237,7 @@ func (app *Lifecycle) setupSingle(mod *Module, logger *slog.Logger) error {
 	if mod.setup != nil {
 		// Run the setup function for the module
 		if err := mod.setup(mod); err != nil {
-			return fmt.Errorf("error initializing '%s': %w", mod.name, err)
+			return fmt.Errorf("error initializing %s: %w", mod, err)
 		}
 	}
 
@@ -238,13 +257,13 @@ func (app *Lifecycle) teardownSingle(mod *Module) error {
 
 	// Check if the module was set up
 	if _, ok := app.setupTracker[mod.name]; !ok {
-		return fmt.Errorf("module '%s' is not set up, cannot tear down", mod.name)
+		return fmt.Errorf("module %s is not set up, cannot tear down", mod)
 	}
 
 	// Run the teardown function for the module
 	if mod.teardown != nil {
 		if err := mod.teardown(mod); err != nil {
-			return fmt.Errorf("error tearing down '%s': %w", mod.name, err)
+			return fmt.Errorf("error tearing down %s: %w", mod, err)
 		}
 	}