limoli/dbshift-core

package dbshiftcore

import (
    "fmt"
    "os"
    "strconv"
)

const (
    envPathMigrations            = "DBSHIFT_ABS_FOLDER_MIGRATIONS"
    envOptionIsCreateDisabled    = "DBSHIFT_OPTION_IS_CREATE_DISABLED"
    envOptionIsDowngradeDisabled = "DBSHIFT_OPTION_IS_DOWNGRADE_DISABLED"
    envOptionIsUpgradeDisabled   = "DBSHIFT_OPTION_IS_UPGRADE_DISABLED"
)

type configuration struct {
    MigrationsPath string
    Options        configurationOptions
}

type configurationOptions struct {
    IsCreateDisabled    bool
    IsDowngradeDisabled bool
    IsUpgradeDisabled   bool
}

func getConfiguration() (*configuration, error) {
    folderMigrations, err := getEnvVar(envPathMigrations)
    if err != nil {
        return nil, err
    }

    // Check if migrations path exists
    err = checkMigrationPath(folderMigrations)
    if err != nil {
        return nil, err
    }

    // Optional values
    options, err := getOptions()
    if err != nil {
        return nil, err
    }

    return &configuration{
        MigrationsPath: folderMigrations,
        Options:        *options,
    }, nil
}

func checkMigrationPath(migrationsPath string) error {
    _, err := os.Stat(migrationsPath)
    if os.IsNotExist(err) {
        return fmt.Errorf("migrations folder does not exist at %s", migrationsPath)
    }
    return nil
}

func getOptions() (*configurationOptions, error) {
    var err error
    options := configurationOptions{}

    if options.IsCreateDisabled, err = getBooleanOption(envOptionIsCreateDisabled); err != nil {
        return nil, err
    }

    if options.IsDowngradeDisabled, err = getBooleanOption(envOptionIsDowngradeDisabled); err != nil {
        return nil, err
    }

    if options.IsUpgradeDisabled, err = getBooleanOption(envOptionIsUpgradeDisabled); err != nil {
        return nil, err
    }

    return &options, nil
}

func getBooleanOption(envKey string) (bool, error) {
    optionEnv, err := getEnvVar(envKey)
    if err == nil {
        return strconv.ParseBool(optionEnv)
    }
    return false, nil
}

func getEnvVar(key string) (string, error) {
    var err error

    value := os.Getenv(key)
    if value == "" {
        err = fmt.Errorf("%s is not set", key)
    }

    return value, err
}