Codevault initial commit

internal/config/config.go

@@ -0,0 +1,74 @@
+package config
+
+import (
+	"errors"
+	"fmt"
+	"os"
+	"strings"
+
+	"go.uber.org/multierr"
+	"gopkg.in/yaml.v3"
+)
+
+var ErrLoggingDisabled error = errors.New("logging is disabled")
+
+type Config struct {
+	Environment   Environment         `yaml:"environment"`
+	Server        ServerConfig        `yaml:"server"`
+	Database      DatabaseConfig      `yaml:"database"`
+	RateLimit     RateLimitConfig     `yaml:"rate_limit"`
+	Observability ObservabilityConfig `yaml:"observability"`
+}
+
+func (c *Config) Validate() error {
+	var err error
+
+	err = addValidationError(err, "environment validation error", c.Environment.PreprocessAndValidate())
+	err = addValidationError(err, "server section validation error", c.Server.Validate())
+	err = addValidationError(err, "database section validation error", c.Database.Validate())
+	err = addValidationError(err, "rate_limit section validation error", c.RateLimit.Validate())
+	err = addValidationError(err, "observability section validation error", c.Observability.Validate())
+
+	return err
+}
+
+func ReadConfig(path string) (Config, error) {
+	var c Config
+	yamlFile, err := os.ReadFile(path)
+	if err != nil {
+		return c, fmt.Errorf("could not read config: %w", err)
+	}
+	err = yaml.Unmarshal(yamlFile, &c)
+	if err != nil {
+		return c, fmt.Errorf("could not parse yaml: %w", err)
+	}
+	return c, nil
+}
+
+type Environment string
+
+var (
+	ProductionEnvironment  Environment = "production"
+	DevelopmentEnvironment Environment = "development"
+)
+
+func (e *Environment) PreprocessAndValidate() error {
+	preprocessed := strings.ToLower(string(*e))
+	switch preprocessed {
+	case string(ProductionEnvironment), "prod":
+		*e = ProductionEnvironment
+		return nil
+	case string(DevelopmentEnvironment), "dev":
+		*e = DevelopmentEnvironment
+		return nil
+	default:
+		return fmt.Errorf("invalid Environment value: '%v'", *e)
+	}
+}
+
+func addValidationError(err error, text string, validationError error) error {
+	if validationError == nil {
+		return err
+	}
+	return multierr.Append(err, fmt.Errorf("%s: %w", text, validationError))
+}