52 lines
1.4 KiB
Markdown
52 lines
1.4 KiB
Markdown
# Application Configuration with Cobra + Viper
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→ See `samber/cc-skills-golang@golang-cli` skill for complete Cobra+Viper setup, flag binding, precedence rules, and configuration layering.
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## Where Config Lives
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```
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myapp/
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├── cmd/myapp/
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│ ├── main.go # Entry point
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│ ├── root.go # Root command + Viper init
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│ ├── serve.go # Subcommand with flags
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│ └── config.go # Config struct + loader
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└── configs/
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└── config.yaml # Default config file
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```
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## Config Struct
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Define configuration as a struct with `mapstructure` tags matching your YAML keys:
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```go
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// cmd/myapp/config.go
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package main
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import (
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"fmt"
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"github.com/spf13/viper"
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)
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type Config struct {
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Port int `mapstructure:"port"`
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Host string `mapstructure:"host"`
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LogLevel string `mapstructure:"log-level"`
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Database struct {
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DSN string `mapstructure:"dsn"`
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MaxConn int `mapstructure:"max-conn"`
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} `mapstructure:"database"`
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}
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func loadConfig() (Config, error) {
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var cfg Config
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if err := viper.Unmarshal(&cfg); err != nil {
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return Config{}, fmt.Errorf("unmarshaling config: %w", err)
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}
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return cfg, nil
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}
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```
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Configuration MUST be loaded from env vars, files, or flags — NEVER hardcoded. Sensitive values MUST come from env vars or secret managers, NEVER config files.
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