context.go

package soba

import (
	"context"
	"os"

	"github.com/pkg/errors"
)

// ctxKey is a subtype for context keys.
type ctxKey struct{}

// hCtxKey is a context key used to store handler in context values.
var hCtxKey = &ctxKey{}

// Load returns a new context with a soba instance. It relies on conventions and default configurations:
//  - First, it will lookup from environment variable if a configuration path is defined.
//  - Then, it will lookup from current directory if a configuration file exists.
//  - Finally, it will create a new instance with default configurations.
//
// For specific configurations, please uses either LoadWithConfig or LoadWithFile.
func Load(ctx context.Context) (context.Context, error) {
	path := os.Getenv(EnvConfigPath)
	if path != "" && CheckPath(path) {
		return LoadWithFile(ctx, path)
	}

	if CheckPath(DefaultConfigPath) {
		return LoadWithFile(ctx, DefaultConfigPath)
	}

	return LoadWithConfig(ctx, NewDefaultConfig())
}

// LoadWithConfig returns a new context with a soba instance using given configuration.
func LoadWithConfig(ctx context.Context, config *Config) (context.Context, error) {
	err := ValidateConfig(config)
	if err != nil {
		return ctx, errors.Wrap(err, "configuration is invalid")
	}

	handler, err := create(config)
	if err != nil {
		return ctx, err
	}

	ctx = context.WithValue(ctx, hCtxKey, handler)
	return ctx, nil
}

// LoadWithFile returns a new context with a soba instance using given file path.
func LoadWithFile(ctx context.Context, path string) (context.Context, error) {
	conf, err := ParseConfig(path)
	if err != nil {
		return ctx, err
	}
	return LoadWithConfig(ctx, conf)
}