configuration-management

name	configuration-management
description	Use when adding or changing NanoProxy configuration — the env-driven struct config in pkg/config (caarlos0/env/v10), struct-tag defaults, and validation. Note real env vars (ADDR, ADDR_HTTP, TOR_ENABLED, USER_STORE_PATH).

Configuration Management

Expertise in managing environment-based configuration for NanoProxy using struct-based parsing and environment variables.

When to use this skill

• Setting up NanoProxy configuration
• Adding new configuration options
• Handling environment variables
• Implementing configuration validation
• Managing configuration defaults

Expertise areas

• Struct-based configuration parsing
• Environment variable handling
• Default values and validation
• Type conversion for config values
• Runtime configuration usage

Key files

• pkg/config/config.go - Configuration implementation (uses caarlos0/env/v10)
• nanoproxy.go - Main entry point with config usage

Notes specific to NanoProxy

• Config is env-driven only (no JSON/YAML files). The SOCKS5 listen address is ADDR (default :1080) and the HTTP proxy listen address is ADDR_HTTP (default :8080). Credentials are stored at USER_STORE_PATH (BoltDB).
• Always confirm the actual env tags in pkg/config/config.go before documenting or referencing them.

Common tasks

Defining configuration structure

Use struct tags to define configuration from environment variables.

Parsing environment variables

Use the caarlos0/env library to automatically parse the struct from the environment.

Setting defaults

Define default values in struct tags via envDefault.

Validating configuration

Validate configuration values after parsing.

Example patterns

Configuration struct

type Config struct {
    Addr           string `env:"ADDR" envDefault:":1080"`
    AddrHTTP       string `env:"ADDR_HTTP" envDefault:":8080"`
    TOREnabled     bool   `env:"TOR_ENABLED" envDefault:"false"`
    UserStorePath  string `env:"USER_STORE_PATH"`
    LogLevel       string `env:"LOG_LEVEL" envDefault:"info"`
}

Parsing configuration

cfg := &Config{}
if err := env.Parse(cfg); err != nil {
    logger.Fatal().Err(err).Msg("failed to parse config")
}

// Validate
if cfg.Addr == "" && cfg.AddrHTTP == "" {
    logger.Fatal().Msg("at least one proxy address must be configured")
}

Testing approach

• Test with various environment variable combinations
• Test default value usage
• Test type conversion
• Test validation logic
• Test missing required values
• Test invalid value formats
• Test environment variable overrides

Performance considerations

• Parse config once at startup
• Cache config values
• Avoid frequent environment variable reads

Security considerations

• Never log sensitive values (passwords, secrets)
• Validate all config values
• Use environment variables for secrets
• Document required vs optional values

References

• caarlos0/env GitHub repository
• Go struct tags documentation

Related skills

• credential-management - Handling persisted proxy users and admin-auth flows
• socks5-protocol - Using config in SOCKS5 setup
• http-proxy - Using config in HTTP proxy setup