117 lines
2.7 KiB
Go
117 lines
2.7 KiB
Go
// File: lixenwraith/config/builder.go
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package config
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import (
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"errors"
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"fmt"
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"os"
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)
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// Builder provides a fluent interface for building configurations
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type Builder struct {
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cfg *Config
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opts LoadOptions
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defaults any
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prefix string
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file string
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args []string
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err error
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}
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// NewBuilder creates a new configuration builder
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func NewBuilder() *Builder {
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return &Builder{
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cfg: New(),
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opts: DefaultLoadOptions(),
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args: os.Args[1:],
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}
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}
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// WithDefaults sets the struct containing default values
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func (b *Builder) WithDefaults(defaults any) *Builder {
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b.defaults = defaults
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return b
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}
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// WithPrefix sets the prefix for struct registration
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func (b *Builder) WithPrefix(prefix string) *Builder {
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b.prefix = prefix
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return b
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}
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// WithEnvPrefix sets the environment variable prefix
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func (b *Builder) WithEnvPrefix(prefix string) *Builder {
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b.opts.EnvPrefix = prefix
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return b
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}
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// WithFile sets the configuration file path
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func (b *Builder) WithFile(path string) *Builder {
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b.file = path
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return b
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}
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// WithArgs sets the command-line arguments
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func (b *Builder) WithArgs(args []string) *Builder {
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b.args = args
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return b
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}
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// WithSources sets the precedence order for configuration sources
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func (b *Builder) WithSources(sources ...Source) *Builder {
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b.opts.Sources = sources
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return b
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}
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// WithEnvTransform sets a custom environment variable transformer
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func (b *Builder) WithEnvTransform(fn EnvTransformFunc) *Builder {
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b.opts.EnvTransform = fn
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return b
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}
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// WithEnvWhitelist limits which paths are checked for env vars
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func (b *Builder) WithEnvWhitelist(paths ...string) *Builder {
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if b.opts.EnvWhitelist == nil {
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b.opts.EnvWhitelist = make(map[string]bool)
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}
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for _, path := range paths {
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b.opts.EnvWhitelist[path] = true
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}
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return b
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}
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// Build creates the Config instance with all specified options
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func (b *Builder) Build() (*Config, error) {
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if b.err != nil {
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return nil, b.err
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}
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// Register defaults if provided
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if b.defaults != nil {
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if err := b.cfg.RegisterStruct(b.prefix, b.defaults); err != nil {
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return nil, fmt.Errorf("failed to register defaults: %w", err)
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}
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}
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// Load configuration
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if err := b.cfg.LoadWithOptions(b.file, b.args, b.opts); err != nil {
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// The error might be non-fatal (e.g., file not found).
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// Return the config object so it can be used with other sources.
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return b.cfg, err
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}
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return b.cfg, nil
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}
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// MustBuild is like Build but panics on error
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func (b *Builder) MustBuild() *Config {
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cfg, err := b.Build()
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if err != nil {
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// Ignore ErrConfigNotFound as it is not a fatal error for MustBuild.
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// The application can proceed with defaults/env vars.
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if !errors.Is(err, ErrConfigNotFound) {
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panic(fmt.Sprintf("config build failed: %v", err))
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}
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}
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return cfg
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} |