config.go

package main

import (
	"errors"
	"log"
	"os"
	"os/user"
	"path/filepath"

	"github.com/caarlos0/env/v7"
	"github.com/joho/godotenv"
	"github.com/oracle/oci-go-sdk/v65/common"
	"github.com/oracle/oci-go-sdk/v65/core"
)

type config struct {
	Region             string  `env:"OCI_REGION"`
	UserID             string  `env:"OCI_USER_ID"`
	TenancyID          string  `env:"OCI_TENANCY_ID"`
	KeyFingerprint     string  `env:"OCI_KEY_FINGERPRINT"`
	PrivateKeyFilename string  `env:"OCI_PRIVATE_KEY_FILENAME"`
	SubnetID           string  `env:"OCI_SUBNET_ID"`
	ImageID            string  `env:"OCI_IMAGE_ID"`
	OCPUS              float32 `env:"OCI_OCPUS"`
	MemoryInGbs        float32 `env:"OCI_MEMORY_IN_GBS"`
	Shape              string  `env:"OCI_SHAPE"`
	MaxInstances       int     `env:"OCI_MAX_INSTANCES" envDefault:"1"`
	SSHPublicKey       string  `env:"OCI_SSH_PUBLIC_KEY"`

	// Optional
	AvailabilityDomains []string `env:"OCI_AVAILABILITY_DOMAIN" envSeparator:","`
	BootVolumeSizeInGbs int64    `env:"OCI_BOOT_VOLUME_SIZE_IN_GBS"`
	BootVolumeId        string   `env:"OCI_BOOT_VOLUME_ID"`
}

func (cfg config) validate() error {
	if cfg.BootVolumeId != "" && cfg.BootVolumeSizeInGbs != 0 {
		return errors.New("OCI_BOOT_VOLUME_ID and OCI_BOOT_VOLUME_SIZE_IN_GBS cannot be used together")
	}
	if cfg.BootVolumeId != "" && len(cfg.AvailabilityDomains) == 0 {
		return errors.New("OCI_AVAILABILITY_DOMAIN must be specified as string if using OCI_BOOT_VOLUME_ID")
	}
	return nil
}

func (cfg config) buildConfigProvider() (common.ConfigurationProvider, error) {
	pkPath, _ := expand(cfg.PrivateKeyFilename)
	pk, err := os.ReadFile(pkPath)
	if err != nil {
		return nil, err
	}

	cp := common.NewRawConfigurationProvider(cfg.TenancyID, cfg.UserID, cfg.Region, cfg.KeyFingerprint, string(pk), nil)
	if err != nil {
		return nil, err
	}

	ok, err := common.IsConfigurationProviderValid(cp)
	if err != nil {
		return nil, err
	}
	if ok {
		return cp, nil
	}
	log.Println("The config specified in .env is not valid, trying the default oci config")
	cp = common.DefaultConfigProvider()
	return cp, nil
}

func loadConfig() (config, error) {
	err := godotenv.Load() // load .env file
	if err != nil {
		return config{}, err
	}

	cfg := config{}
	if err := env.Parse(&cfg); err != nil {
		return config{}, err
	}

	err = cfg.validate()
	if err != nil {
		return config{}, err
	}

	return cfg, nil
}

func buildSourceDetails(cfg config) core.InstanceSourceDetails {
	if cfg.BootVolumeId != "" {
		return core.InstanceSourceViaBootVolumeDetails{
			BootVolumeId: &cfg.BootVolumeId,
		}
	}

	var bootVolume *int64
	if cfg.BootVolumeSizeInGbs > 0 {
		bootVolume = &cfg.BootVolumeSizeInGbs
	}
	return core.InstanceSourceViaImageDetails{
		ImageId:             &cfg.ImageID,
		BootVolumeSizeInGBs: bootVolume,
	}
}

func expand(path string) (string, error) {
	if len(path) == 0 || path[0] != '~' {
		return path, nil
	}

	usr, err := user.Current()
	if err != nil {
		return "", err
	}
	return filepath.Join(usr.HomeDir, path[1:]), nil
}