config.go

/*
    _____           _____   _____   ____          ______  _____  ------
   |     |  |      |     | |     | |     |     | |       |            |
   |     |  |      |     | |     | |     |     | |       |            |
   | --- |  |      |     | |-----| |---- |     | |-----| |-----  ------
   |     |  |      |     | |     | |     |     |       | |       |
   | ____|  |_____ | ____| | ____| |     |_____|  _____| |_____  |_____


   Licensed under the MIT License <http://opensource.org/licenses/MIT>.

   Copyright © 2020-2024 Microsoft Corporation. All rights reserved.
   Author : <blobfusedev@microsoft.com>

   Permission is hereby granted, free of charge, to any person obtaining a copy
   of this software and associated documentation files (the "Software"), to deal
   in the Software without restriction, including without limitation the rights
   to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   copies of the Software, and to permit persons to whom the Software is
   furnished to do so, subject to the following conditions:

   The above copyright notice and this permission notice shall be included in all
   copies or substantial portions of the Software.

   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
   SOFTWARE
*/

package azstorage

import (
	"errors"
	"fmt"
	"reflect"
	"strings"

	"github.com/Azure/azure-sdk-for-go/sdk/storage/azblob/blockblob"
	"github.com/Azure/azure-storage-fuse/v2/common/config"
	"github.com/Azure/azure-storage-fuse/v2/common/log"

	"github.com/JeffreyRichter/enum/enum"
)

// AuthType Enum
type AuthType int

var EAuthType = AuthType(0).INVALID_AUTH()

func (AuthType) INVALID_AUTH() AuthType {
	return AuthType(0)
}

func (AuthType) KEY() AuthType {
	return AuthType(1)
}

func (AuthType) SAS() AuthType {
	return AuthType(2)
}

func (AuthType) SPN() AuthType {
	return AuthType(3)
}

func (AuthType) MSI() AuthType {
	return AuthType(4)
}

func (AuthType) AZCLI() AuthType {
	return AuthType(5)
}

func (a AuthType) String() string {
	return enum.StringInt(a, reflect.TypeOf(a))
}

func (a *AuthType) Parse(s string) error {
	enumVal, err := enum.ParseInt(reflect.TypeOf(a), s, true, false)
	if enumVal != nil {
		*a = enumVal.(AuthType)
	}
	return err
}

// AccountType Enum
type AccountType int

var EAccountType = AccountType(0).INVALID_ACC()

func (AccountType) INVALID_ACC() AccountType {
	return AccountType(0)
}

func (AccountType) BLOCK() AccountType {
	return AccountType(1)
}

func (AccountType) ADLS() AccountType {
	return AccountType(2)
}

func (f AccountType) String() string {
	return enum.StringInt(f, reflect.TypeOf(f))
}

func (a *AccountType) Parse(s string) error {
	enumVal, err := enum.ParseInt(reflect.TypeOf(a), s, true, false)
	if enumVal != nil {
		*a = enumVal.(AccountType)
	}
	return err
}

// default value for maximum results returned by a list API call
const DefaultMaxResultsForList int32 = 2

// Environment variable names
// Here we are not reading MSI_ENDPOINT and MSI_SECRET as they are read by go-sdk directly
// https://github.com/Azure/go-autorest/blob/a46566dfcbdc41e736295f94e9f690ceaf50094a/autorest/adal/token.go#L788
// newServicePrincipalTokenFromMSI : reads them directly from env
const (
	EnvAzStorageAccount                = "AZURE_STORAGE_ACCOUNT"
	EnvAzStorageAccountType            = "AZURE_STORAGE_ACCOUNT_TYPE"
	EnvAzStorageAccessKey              = "AZURE_STORAGE_ACCESS_KEY"
	EnvAzStorageSasToken               = "AZURE_STORAGE_SAS_TOKEN"
	EnvAzStorageIdentityClientId       = "AZURE_STORAGE_IDENTITY_CLIENT_ID"
	EnvAzStorageIdentityResourceId     = "AZURE_STORAGE_IDENTITY_RESOURCE_ID"
	EnvAzStorageIdentityObjectId       = "AZURE_STORAGE_IDENTITY_OBJECT_ID"
	EnvAzStorageSpnTenantId            = "AZURE_STORAGE_SPN_TENANT_ID"
	EnvAzStorageSpnClientId            = "AZURE_STORAGE_SPN_CLIENT_ID"
	EnvAzStorageSpnClientSecret        = "AZURE_STORAGE_SPN_CLIENT_SECRET"
	EnvAzStorageSpnOAuthTokenFilePath  = "AZURE_OAUTH_TOKEN_FILE"
	EnvAzStorageAadEndpoint            = "AZURE_STORAGE_AAD_ENDPOINT"
	EnvAzStorageAuthType               = "AZURE_STORAGE_AUTH_TYPE"
	EnvAzStorageBlobEndpoint           = "AZURE_STORAGE_BLOB_ENDPOINT"
	EnvHttpProxy                       = "http_proxy"
	EnvHttpsProxy                      = "https_proxy"
	EnvAzStorageAccountContainer       = "AZURE_STORAGE_ACCOUNT_CONTAINER"
	EnvAzAuthResource                  = "AZURE_STORAGE_AUTH_RESOURCE"
	EnvAzStorageCpkEncryptionKey       = "AZURE_STORAGE_CPK_ENCRYPTION_KEY"
	EnvAzStorageCpkEncryptionKeySha256 = "AZURE_STORAGE_CPK_ENCRYPTION_KEY_SHA256"
)

type AzStorageOptions struct {
	AccountType             string `config:"type" yaml:"type,omitempty"`
	UseHTTP                 bool   `config:"use-http" yaml:"use-http,omitempty"`
	AccountName             string `config:"account-name" yaml:"account-name,omitempty"`
	AccountKey              string `config:"account-key" yaml:"account-key,omitempty"`
	SaSKey                  string `config:"sas" yaml:"sas,omitempty"`
	ApplicationID           string `config:"appid" yaml:"appid,omitempty"`
	ResourceID              string `config:"resid" yaml:"resid,omitempty"`
	ObjectID                string `config:"objid" yaml:"objid,omitempty"`
	TenantID                string `config:"tenantid" yaml:"tenantid,omitempty"`
	ClientID                string `config:"clientid" yaml:"clientid,omitempty"`
	ClientSecret            string `config:"clientsecret" yaml:"clientsecret,omitempty"`
	OAuthTokenFilePath      string `config:"oauth-token-path" yaml:"oauth-token-path,omitempty"`
	ActiveDirectoryEndpoint string `config:"aadendpoint" yaml:"aadendpoint,omitempty"`
	Endpoint                string `config:"endpoint" yaml:"endpoint,omitempty"`
	AuthMode                string `config:"mode" yaml:"mode,omitempty"`
	Container               string `config:"container" yaml:"container,omitempty"`
	PrefixPath              string `config:"subdirectory" yaml:"subdirectory,omitempty"`
	BlockSize               int64  `config:"block-size-mb" yaml:"block-size-mb,omitempty"`
	MaxConcurrency          uint16 `config:"max-concurrency" yaml:"max-concurrency,omitempty"`
	DefaultTier             string `config:"tier" yaml:"tier,omitempty"`
	CancelListForSeconds    uint16 `config:"block-list-on-mount-sec" yaml:"block-list-on-mount-sec,omitempty"`
	MaxRetries              int32  `config:"max-retries" yaml:"max-retries,omitempty"`
	MaxTimeout              int32  `config:"max-retry-timeout-sec" yaml:"max-retry-timeout-sec,omitempty"`
	BackoffTime             int32  `config:"retry-backoff-sec" yaml:"retry-backoff-sec,omitempty"`
	MaxRetryDelay           int32  `config:"max-retry-delay-sec" yaml:"max-retry-delay-sec,omitempty"`
	HttpProxyAddress        string `config:"http-proxy" yaml:"http-proxy,omitempty"`
	HttpsProxyAddress       string `config:"https-proxy" yaml:"https-proxy,omitempty"`
	FailUnsupportedOp       bool   `config:"fail-unsupported-op" yaml:"fail-unsupported-op,omitempty"`
	AuthResourceString      string `config:"auth-resource" yaml:"auth-resource,omitempty"`
	UpdateMD5               bool   `config:"update-md5" yaml:"update-md5"`
	ValidateMD5             bool   `config:"validate-md5" yaml:"validate-md5"`
	VirtualDirectory        bool   `config:"virtual-directory" yaml:"virtual-directory"`
	MaxResultsForList       int32  `config:"max-results-for-list" yaml:"max-results-for-list"`
	DisableCompression      bool   `config:"disable-compression" yaml:"disable-compression"`
	Telemetry               string `config:"telemetry" yaml:"telemetry"`
	HonourACL               bool   `config:"honour-acl" yaml:"honour-acl"`
	CPKEnabled              bool   `config:"cpk-enabled" yaml:"cpk-enabled"`
	CPKEncryptionKey        string `config:"cpk-encryption-key" yaml:"cpk-encryption-key"`
	CPKEncryptionKeySha256  string `config:"cpk-encryption-key-sha256" yaml:"cpk-encryption-key-sha256"`

	// v1 support
	UseAdls        bool   `config:"use-adls" yaml:"-"`
	UseHTTPS       bool   `config:"use-https" yaml:"-"`
	SetContentType bool   `config:"set-content-type" yaml:"-"`
	CaCertFile     string `config:"ca-cert-file" yaml:"-"`
}

// RegisterEnvVariables : Register environment varilables
func RegisterEnvVariables() {
	config.BindEnv("azstorage.account-name", EnvAzStorageAccount)
	config.BindEnv("azstorage.type", EnvAzStorageAccountType)

	config.BindEnv("azstorage.account-key", EnvAzStorageAccessKey)

	config.BindEnv("azstorage.sas", EnvAzStorageSasToken)

	config.BindEnv("azstorage.appid", EnvAzStorageIdentityClientId)
	config.BindEnv("azstorage.resid", EnvAzStorageIdentityResourceId)

	config.BindEnv("azstorage.tenantid", EnvAzStorageSpnTenantId)
	config.BindEnv("azstorage.clientid", EnvAzStorageSpnClientId)
	config.BindEnv("azstorage.clientsecret", EnvAzStorageSpnClientSecret)
	config.BindEnv("azstorage.oauth-token-path", EnvAzStorageSpnOAuthTokenFilePath)

	config.BindEnv("azstorage.objid", EnvAzStorageIdentityObjectId)

	config.BindEnv("azstorage.aadendpoint", EnvAzStorageAadEndpoint)

	config.BindEnv("azstorage.endpoint", EnvAzStorageBlobEndpoint)

	config.BindEnv("azstorage.mode", EnvAzStorageAuthType)

	config.BindEnv("azstorage.http-proxy", EnvHttpProxy)
	config.BindEnv("azstorage.https-proxy", EnvHttpsProxy)

	config.BindEnv("azstorage.container", EnvAzStorageAccountContainer)

	config.BindEnv("azstorage.auth-resource", EnvAzAuthResource)

	config.BindEnv("azstorage.cpk-encryption-key", EnvAzStorageCpkEncryptionKey)
	config.BindEnv("azstorage.cpk-encryption-key-sha256", EnvAzStorageCpkEncryptionKeySha256)

}

//    ----------- Config Parsing and Validation  ---------------

// formatEndpointProtocol : add the protocol and missing "/" at the end to the endpoint
func formatEndpointProtocol(endpoint string, http bool) string {
	correctedEndpoint := endpoint

	// If the pvtEndpoint does not have protocol mentioned in front, pvtEndpoint parsing will fail while
	// creating URI also the string shall end with "/"
	if correctedEndpoint != "" {
		if !(strings.HasPrefix(correctedEndpoint, "https://") ||
			strings.HasPrefix(correctedEndpoint, "http://")) {
			if http {
				correctedEndpoint = "http://" + correctedEndpoint
			} else {
				correctedEndpoint = "https://" + correctedEndpoint
			}
		}

		if correctedEndpoint[len(correctedEndpoint)-1] != '/' {
			correctedEndpoint = correctedEndpoint + "/"
		}
	}

	return correctedEndpoint
}

// formatEndpointAccountType : format the endpoint to match the account type
func formatEndpointAccountType(endpoint string, account AccountType) string {
	// TODO : Modify this method when file share support is merged
	correctedEndpoint := endpoint
	if strings.Contains(correctedEndpoint, ".blob.") {
		if account == EAccountType.ADLS() {
			correctedEndpoint = strings.Replace(correctedEndpoint, ".blob.", ".dfs.", 1)
		}
	} else if strings.Contains(correctedEndpoint, ".dfs.") {
		if account == EAccountType.BLOCK() {
			correctedEndpoint = strings.Replace(correctedEndpoint, ".dfs.", ".blob.", 1)
		}
	}

	return correctedEndpoint
}

func validateMsiConfig(opt AzStorageOptions) error {
	v := make(map[string]bool, 3)
	if opt.ApplicationID != "" {
		v[opt.ApplicationID] = true
	}
	if opt.ObjectID != "" {
		v[opt.ObjectID] = true
	}
	if opt.ResourceID != "" {
		v[opt.ResourceID] = true
	}
	if len(v) > 1 {
		return errors.New("client ID, object ID and MSI resource ID are mutually exclusive and zero or one of the inputs need to be provided")
	}
	return nil
}

// ParseAndValidateConfig : Parse and validate config
func ParseAndValidateConfig(az *AzStorage, opt AzStorageOptions) error {
	log.Trace("ParseAndValidateConfig : Parsing config")

	// Validate account name is present or not
	if opt.AccountName == "" {
		return errors.New("account name not provided")
	}
	az.stConfig.authConfig.AccountName = opt.AccountName

	// Validate account type property
	if opt.AccountType == "" {
		opt.AccountType = "block"
	}

	if config.IsSet(compName + ".use-adls") {
		if opt.UseAdls {
			az.stConfig.authConfig.AccountType = az.stConfig.authConfig.AccountType.ADLS()
		} else {
			az.stConfig.authConfig.AccountType = az.stConfig.authConfig.AccountType.BLOCK()
		}
	} else {
		var accountType AccountType
		err := accountType.Parse(opt.AccountType)
		if err != nil {
			log.Err("ParseAndValidateConfig : Failed to parse account type %s", opt.AccountType)
			return errors.New("invalid account type")
		}

		if accountType == EAccountType.INVALID_ACC() {
			log.Err("ParseAndValidateConfig : Invalid account type %s", opt.AccountType)
			return errors.New("invalid account type")
		}

		az.stConfig.authConfig.AccountType = accountType
	}

	if opt.BlockSize != 0 {
		if opt.BlockSize > blockblob.MaxStageBlockBytes {
			log.Err("ParseAndValidateConfig : Block size is too large. Block size has to be smaller than %s Bytes", blockblob.MaxStageBlockBytes)
			return errors.New("block size is too large")
		}
		az.stConfig.blockSize = opt.BlockSize * 1024 * 1024
	}

	// Validate container name is present or not
	err := config.UnmarshalKey("mount-all-containers", &az.stConfig.mountAllContainers)
	if err != nil {
		log.Err("ParseAndValidateConfig : Failed to detect mount-all-container")
	}

	if !az.stConfig.mountAllContainers && opt.Container == "" {
		return errors.New("container name not provided")
	}

	az.stConfig.container = opt.Container

	if config.IsSet(compName + ".use-https") {
		opt.UseHTTP = !opt.UseHTTPS
	}

	if opt.CPKEnabled {
		if opt.CPKEncryptionKey == "" || opt.CPKEncryptionKeySha256 == "" {
			log.Err("ParseAndValidateConfig : CPK key or CPK key sha256 not provided")
			return errors.New("CPK key or key sha256 not provided")
		}
		az.stConfig.cpkEnabled = opt.CPKEnabled
		az.stConfig.cpkEncryptionKey = opt.CPKEncryptionKey
		az.stConfig.cpkEncryptionKeySha256 = opt.CPKEncryptionKeySha256
	}

	// Validate endpoint
	if opt.Endpoint == "" {
		log.Warn("ParseAndValidateConfig : account endpoint not provided, assuming the default .core.windows.net style endpoint")
		if az.stConfig.authConfig.AccountType == EAccountType.BLOCK() {
			opt.Endpoint = fmt.Sprintf("%s.blob.core.windows.net", opt.AccountName)
		} else if az.stConfig.authConfig.AccountType == EAccountType.ADLS() {
			opt.Endpoint = fmt.Sprintf("%s.dfs.core.windows.net", opt.AccountName)
		}
	}
	az.stConfig.authConfig.Endpoint = opt.Endpoint
	az.stConfig.authConfig.Endpoint = formatEndpointProtocol(az.stConfig.authConfig.Endpoint, opt.UseHTTP)
	az.stConfig.authConfig.Endpoint = formatEndpointAccountType(az.stConfig.authConfig.Endpoint, az.stConfig.authConfig.AccountType)

	az.stConfig.authConfig.ActiveDirectoryEndpoint = opt.ActiveDirectoryEndpoint
	az.stConfig.authConfig.ActiveDirectoryEndpoint = formatEndpointProtocol(az.stConfig.authConfig.ActiveDirectoryEndpoint, false)

	// If subdirectory is mounted, take the prefix path
	az.stConfig.prefixPath = removeLeadingSlashes(opt.PrefixPath)

	// Block list call on mount for given amount of time
	az.stConfig.cancelListForSeconds = opt.CancelListForSeconds

	az.stConfig.telemetry = opt.Telemetry

	httpProxyProvided := opt.HttpProxyAddress != ""
	httpsProxyProvided := opt.HttpsProxyAddress != ""

	// Set whether to use http or https and proxy
	if opt.UseHTTP {
		az.stConfig.authConfig.UseHTTP = true
		if httpProxyProvided {
			az.stConfig.proxyAddress = opt.HttpProxyAddress
		} else if httpsProxyProvided {
			az.stConfig.proxyAddress = opt.HttpsProxyAddress
		}
	} else {
		if httpsProxyProvided {
			az.stConfig.proxyAddress = opt.HttpsProxyAddress
		} else {
			if httpProxyProvided {
				log.Err("ParseAndValidateConfig : `http-proxy` Invalid : must set `use-http: true` in your config file")
				return errors.New("`http-proxy` Invalid : must set `use-http: true` in your config file")
			}
		}
	}
	log.Info("ParseAndValidateConfig : using the following proxy address from the config file: %s", az.stConfig.proxyAddress)

	err = ParseAndReadDynamicConfig(az, opt, false)
	if err != nil {
		return err
	}

	log.Debug("ParseAndValidateConfig : Getting auth type")
	if opt.AuthMode == "" {
		// Based on other config decide the auth mode
		// for e.g. if sas token is set then mode shall be set to sas and if key is set then authmode shall be key
		opt.AuthMode = autoDetectAuthMode(opt)
		log.Debug("ParseAndValidateConfig : Auth type %s", opt.AuthMode)
	}

	var authType AuthType
	err = authType.Parse(opt.AuthMode)
	if err != nil {
		log.Err("ParseAndValidateConfig : Invalid auth type %s", opt.AccountType)
		return errors.New("invalid auth type")
	}

	az.stConfig.authConfig.ObjectID = opt.ObjectID

	switch authType {
	case EAuthType.KEY():
		az.stConfig.authConfig.AuthMode = EAuthType.KEY()
		if opt.AccountKey == "" {
			return errors.New("storage key not provided")
		}
		az.stConfig.authConfig.AccountKey = opt.AccountKey
	case EAuthType.SAS():
		az.stConfig.authConfig.AuthMode = EAuthType.SAS()
		if opt.SaSKey == "" {
			return errors.New("SAS key not provided")
		}
		az.stConfig.authConfig.SASKey = sanitizeSASKey(opt.SaSKey)
	case EAuthType.MSI():
		az.stConfig.authConfig.AuthMode = EAuthType.MSI()
		err := validateMsiConfig(opt)
		if err != nil {
			return err
		}
		az.stConfig.authConfig.ApplicationID = opt.ApplicationID
		az.stConfig.authConfig.ResourceID = opt.ResourceID
	case EAuthType.SPN():
		az.stConfig.authConfig.AuthMode = EAuthType.SPN()
		if opt.ClientID == "" || (opt.ClientSecret == "" && opt.OAuthTokenFilePath == "") || opt.TenantID == "" {
			//lint:ignore ST1005 ignore
			return errors.New("Client ID, Tenant ID or Client Secret not provided")
		}
		az.stConfig.authConfig.ClientID = opt.ClientID
		az.stConfig.authConfig.ClientSecret = opt.ClientSecret
		az.stConfig.authConfig.TenantID = opt.TenantID
		az.stConfig.authConfig.OAuthTokenFilePath = opt.OAuthTokenFilePath
	case EAuthType.AZCLI():
		az.stConfig.authConfig.AuthMode = EAuthType.AZCLI()

	default:
		log.Err("ParseAndValidateConfig : Invalid auth mode %s", opt.AuthMode)
		return errors.New("invalid auth mode")
	}
	az.stConfig.authConfig.AuthResource = opt.AuthResourceString

	// Retry policy configuration
	// A user provided value of 0 doesn't make sense for MaxRetries, MaxTimeout, BackoffTime, or MaxRetryDelay.

	az.stConfig.maxRetries = 5     // Max number of retry to be done  (default 4) (v1 : 0)
	az.stConfig.maxTimeout = 900   // Max timeout for any single retry (default 1 min) (v1 : 60)
	az.stConfig.backoffTime = 4    // Delay before any retry (exponential increase) (default 4 sec)
	az.stConfig.maxRetryDelay = 60 // Maximum allowed delay before retry (default 120 sec) (v1 : 1.2)

	if opt.MaxRetries != 0 {
		az.stConfig.maxRetries = opt.MaxRetries
	}
	if opt.MaxTimeout != 0 {
		az.stConfig.maxTimeout = opt.MaxTimeout
	}
	if opt.BackoffTime != 0 {
		az.stConfig.backoffTime = opt.BackoffTime
	}
	if opt.MaxRetryDelay != 0 {
		az.stConfig.maxRetryDelay = opt.MaxRetryDelay
	}

	if config.IsSet(compName + ".set-content-type") {
		log.Warn("unsupported v1 CLI parameter: set-content-type is always true in blobfuse2.")
	}
	if config.IsSet(compName + ".ca-cert-file") {
		log.Warn("unsupported v1 CLI parameter: ca-cert-file is not supported in blobfuse2. Use the default ca cert path for your environment.")
	}
	if config.IsSet(compName + ".debug-libcurl") {
		log.Warn("unsupported v1 CLI parameter: debug-libcurl is not applicable in blobfuse2.")
	}

	log.Info("ParseAndValidateConfig : account %s, container %s, account-type %s, auth %s, prefix %s, endpoint %s, MD5 %v %v, virtual-directory %v, disable-compression %v, CPK %v",
		az.stConfig.authConfig.AccountName, az.stConfig.container, az.stConfig.authConfig.AccountType, az.stConfig.authConfig.AuthMode,
		az.stConfig.prefixPath, az.stConfig.authConfig.Endpoint, az.stConfig.validateMD5, az.stConfig.updateMD5, az.stConfig.virtualDirectory, az.stConfig.disableCompression, az.stConfig.cpkEnabled)
	log.Info("ParseAndValidateConfig : use-HTTP %t, block-size %d, max-concurrency %d, default-tier %s, fail-unsupported-op %t, mount-all-containers %t", az.stConfig.authConfig.UseHTTP, az.stConfig.blockSize, az.stConfig.maxConcurrency, az.stConfig.defaultTier, az.stConfig.ignoreAccessModifiers, az.stConfig.mountAllContainers)
	log.Info("ParseAndValidateConfig : Retry Config: retry-count %d, max-timeout %d, backoff-time %d, max-delay %d",
		az.stConfig.maxRetries, az.stConfig.maxTimeout, az.stConfig.backoffTime, az.stConfig.maxRetryDelay)

	log.Info("ParseAndValidateConfig : Telemetry : %s, honour-ACL %v, disable-symlink %v", az.stConfig.telemetry, az.stConfig.honourACL, az.stConfig.disableSymlink)

	return nil
}

// ParseAndReadDynamicConfig : On config change read only the required config
func ParseAndReadDynamicConfig(az *AzStorage, opt AzStorageOptions, reload bool) error {
	log.Trace("ParseAndReadDynamicConfig : Reparsing config")

	// If block size and max concurrency is configured use those
	// A user provided value of 0 doesn't make sense for BlockSize, or MaxConcurrency.
	if opt.BlockSize != 0 {
		az.stConfig.blockSize = opt.BlockSize * 1024 * 1024
	}

	if opt.MaxConcurrency != 0 {
		az.stConfig.maxConcurrency = opt.MaxConcurrency
	}

	// Populate default tier
	if opt.DefaultTier != "" {
		az.stConfig.defaultTier = getAccessTierType(opt.DefaultTier)
	}

	az.stConfig.ignoreAccessModifiers = !opt.FailUnsupportedOp
	az.stConfig.validateMD5 = opt.ValidateMD5
	az.stConfig.updateMD5 = opt.UpdateMD5

	if config.IsSet(compName + ".virtual-directory") {
		az.stConfig.virtualDirectory = opt.VirtualDirectory
	} else {
		az.stConfig.virtualDirectory = true
	}

	if config.IsSet(compName+".max-results-for-list") && opt.MaxResultsForList > 0 {
		az.stConfig.maxResultsForList = opt.MaxResultsForList
	} else {
		az.stConfig.maxResultsForList = DefaultMaxResultsForList
	}

	if config.IsSet(compName + ".disable-compression") {
		az.stConfig.disableCompression = opt.DisableCompression
	} else {
		az.stConfig.disableCompression = DisableCompression
	}

	if config.IsSet(compName + ".honour-acl") {
		az.stConfig.honourACL = opt.HonourACL
	} else {
		az.stConfig.honourACL = false
	}

	if config.IsSet("attr_cache.no-symlinks") {
		err := config.UnmarshalKey("attr_cache.no-symlinks", &az.stConfig.disableSymlink)
		if err != nil {
			az.stConfig.disableSymlink = true
			log.Err("ParseAndReadDynamicConfig : Failed to unmarshal attr_cache.no-symlinks")
		}
	} else {
		// by default symlink will be disabled
		az.stConfig.disableSymlink = true
	}

	// Auth related reconfig
	switch opt.AuthMode {
	case "sas":
		az.stConfig.authConfig.AuthMode = EAuthType.SAS()
		if opt.SaSKey == "" {
			return errors.New("SAS key not provided")
		}

		oldSas := az.stConfig.authConfig.SASKey
		az.stConfig.authConfig.SASKey = sanitizeSASKey(opt.SaSKey)

		if reload {
			log.Info("ParseAndReadDynamicConfig : SAS Key updated")

			if err := az.storage.UpdateServiceClient("saskey", az.stConfig.authConfig.SASKey); err != nil {
				az.stConfig.authConfig.SASKey = oldSas
				_ = az.storage.UpdateServiceClient("saskey", az.stConfig.authConfig.SASKey)
				return errors.New("SAS key update failure")
			}
		}
	}

	return nil
}