Files
config/builder.go

110 lines
2.4 KiB
Go

// File: lixenwraith/config/builder.go
package config
import (
"fmt"
"os"
)
// Builder provides a fluent interface for building configurations
type Builder struct {
cfg *Config
opts LoadOptions
defaults interface{}
prefix string
file string
args []string
err error
}
// NewBuilder creates a new configuration builder
func NewBuilder() *Builder {
return &Builder{
cfg: New(),
opts: DefaultLoadOptions(),
args: os.Args[1:],
}
}
// WithDefaults sets the struct containing default values
func (b *Builder) WithDefaults(defaults interface{}) *Builder {
b.defaults = defaults
return b
}
// WithPrefix sets the prefix for struct registration
func (b *Builder) WithPrefix(prefix string) *Builder {
b.prefix = prefix
return b
}
// WithEnvPrefix sets the environment variable prefix
func (b *Builder) WithEnvPrefix(prefix string) *Builder {
b.opts.EnvPrefix = prefix
return b
}
// WithFile sets the configuration file path
func (b *Builder) WithFile(path string) *Builder {
b.file = path
return b
}
// WithArgs sets the command-line arguments
func (b *Builder) WithArgs(args []string) *Builder {
b.args = args
return b
}
// WithSources sets the precedence order for configuration sources
func (b *Builder) WithSources(sources ...Source) *Builder {
b.opts.Sources = sources
return b
}
// WithEnvTransform sets a custom environment variable transformer
func (b *Builder) WithEnvTransform(fn EnvTransformFunc) *Builder {
b.opts.EnvTransform = fn
return b
}
// WithEnvWhitelist limits which paths are checked for env vars
func (b *Builder) WithEnvWhitelist(paths ...string) *Builder {
if b.opts.EnvWhitelist == nil {
b.opts.EnvWhitelist = make(map[string]bool)
}
for _, path := range paths {
b.opts.EnvWhitelist[path] = true
}
return b
}
// Build creates the Config instance with all specified options
func (b *Builder) Build() (*Config, error) {
if b.err != nil {
return nil, b.err
}
// Register defaults if provided
if b.defaults != nil {
if err := b.cfg.RegisterStruct(b.prefix, b.defaults); err != nil {
return nil, fmt.Errorf("failed to register defaults: %w", err)
}
}
// Load configuration
if err := b.cfg.LoadWithOptions(b.file, b.args, b.opts); err != nil {
return nil, err
}
return b.cfg, nil
}
// MustBuild is like Build but panics on error
func (b *Builder) MustBuild() *Config {
cfg, err := b.Build()
if err != nil {
panic(fmt.Sprintf("config build failed: %v", err))
}
return cfg
}