refactor exchange rates data backend, supports multi data source, supports timeout

cmd/initializer.go

@@ -7,6 +7,7 @@ import (
 	"github.com/urfave/cli/v2"
 
 	"github.com/mayswind/lab/pkg/datastore"
+	"github.com/mayswind/lab/pkg/exchangerates"
 	"github.com/mayswind/lab/pkg/log"
 	"github.com/mayswind/lab/pkg/settings"
 	"github.com/mayswind/lab/pkg/utils"
@@ -65,6 +66,13 @@ func initializeSystem(c *cli.Context) (*settings.Config, error) {
 		return nil, err
 	}
 
+	err = exchangerates.InitializeExchangeRatesDataSource(config)
+
+	if err != nil {
+		log.BootErrorf("[initializer.initializeSystem] initializes exchange rates data source failed, because %s", err.Error())
+		return nil, err
+	}
+
 	cfgJson, _ := json.Marshal(getConfigWithNoSensitiveData(config))
 	log.BootInfof("[initializer.initializeSystem] has loaded configuration %s", cfgJson)
 

conf/lab.ini

@@ -109,3 +109,10 @@ enable_register = true
 [data]
 # Set to true to allow users to export their data
 enable_export = true
+
+[exchange_rates]
+# Exchange rates data source, supports "euro_central_bank" currently
+data_source = euro_central_bank
+
+# Requesting exchange rates data timeout (milliseconds), default is 10000 (10 seconds)
+request_timeout = 10000

pkg/api/exchange_rates.go

@@ -1,19 +1,17 @@
 package api
 
 import (
-	"encoding/xml"
 	"io/ioutil"
 	"net/http"
+	"time"
 
 	"github.com/mayswind/lab/pkg/core"
 	"github.com/mayswind/lab/pkg/errs"
+	"github.com/mayswind/lab/pkg/exchangerates"
 	"github.com/mayswind/lab/pkg/log"
-	"github.com/mayswind/lab/pkg/models"
+	"github.com/mayswind/lab/pkg/settings"
 )
 
-// EuroCentralBankExchangeRateUrl represents euro central bank exchange rate date url
-const EuroCentralBankExchangeRateUrl = "https://www.ecb.europa.eu/stats/eurofxref/eurofxref-daily.xml"
-
 // ExchangeRatesApi represents exchange rate api
 type ExchangeRatesApi struct{}
 
@@ -24,8 +22,19 @@ var (
 
 // LatestExchangeRateHandler returns latest exchange rate data
 func (a *ExchangeRatesApi) LatestExchangeRateHandler(c *core.Context) (interface{}, *errs.Error) {
+	dataSource := exchangerates.Container.Current
+
+	if dataSource == nil {
+		return nil, errs.ErrInvalidExchangeRatesDataSource
+	}
+
 	uid := c.GetCurrentUid()
-	resp, err := http.Get(EuroCentralBankExchangeRateUrl)
+
+	client := &http.Client{
+		Timeout: time.Duration(settings.Container.Current.ExchangeRatesRequestTimeout) * time.Millisecond,
+	}
+
+	resp, err := client.Get(dataSource.GetRequestUrl())
 
 	if err != nil {
 		log.ErrorfWithRequestId(c, "[exchange_rates.LatestExchangeRateHandler] failed to request latest exchange rate data for user \"uid:%d\", because %s", uid, err.Error())
@@ -39,25 +48,12 @@ func (a *ExchangeRatesApi) LatestExchangeRateHandler(c *core.Context) (interface
 
 	defer resp.Body.Close()
 	body, err := ioutil.ReadAll(resp.Body)
-	euroCentralBankData := &models.EuroCentralBankExchangeRateData{}
+	latestExchangeRateResponse, err := dataSource.Parse(c, body)
-	err = xml.Unmarshal(body, euroCentralBankData)
 
 	if err != nil {
-		log.ErrorfWithRequestId(c, "[exchange_rates.LatestExchangeRateHandler] failed to parse xml data for user \"uid:%d\", response is %s, because %s", uid, string(body), err.Error())
+		log.ErrorfWithRequestId(c, "[exchange_rates.LatestExchangeRateHandler] failed to parse response for user \"uid:%d\", because %s", uid, err.Error())
-		return nil, errs.ErrFailedToRequestRemoteApi
+		return nil, errs.Or(err, errs.ErrFailedToRequestRemoteApi)
 	}
 
-	latestExchangeRateResponse := euroCentralBankData.ToLatestExchangeRateResponse()
-
-	if latestExchangeRateResponse == nil {
-		log.ErrorfWithRequestId(c, "[exchange_rates.LatestExchangeRateHandler] failed to parse latest exchange rate data for user \"uid:%d\", response is %s,", uid, string(body))
-		return nil, errs.ErrFailedToRequestRemoteApi
-	}
-
-	latestExchangeRateResponse.ExchangeRates = append(latestExchangeRateResponse.ExchangeRates, &models.LatestExchangeRate{
-		Currency: "EUR",
-		Rate:     "1",
-	})
-
 	return latestExchangeRateResponse, nil
 }

pkg/errs/setting.go

@@ -4,8 +4,9 @@ import "net/http"
 
 // Error codes related to settings
 var (
-	ErrInvalidProtocol     = NewSystemError(SystemSubcategorySetting, 0, http.StatusInternalServerError, "invalid server protocol")
+	ErrInvalidProtocol                = NewSystemError(SystemSubcategorySetting, 0, http.StatusInternalServerError, "invalid server protocol")
-	ErrInvalidLogMode      = NewSystemError(SystemSubcategorySetting, 1, http.StatusInternalServerError, "invalid log mode")
+	ErrInvalidLogMode                 = NewSystemError(SystemSubcategorySetting, 1, http.StatusInternalServerError, "invalid log mode")
-	ErrGettingLocalAddress = NewSystemError(SystemSubcategorySetting, 2, http.StatusInternalServerError, "failed to get local address")
+	ErrGettingLocalAddress            = NewSystemError(SystemSubcategorySetting, 2, http.StatusInternalServerError, "failed to get local address")
-	ErrInvalidUuidMode     = NewSystemError(SystemSubcategorySetting, 3, http.StatusInternalServerError, "invalid uuid mode")
+	ErrInvalidUuidMode                = NewSystemError(SystemSubcategorySetting, 3, http.StatusInternalServerError, "invalid uuid mode")
+	ErrInvalidExchangeRatesDataSource = NewSystemError(SystemSubcategorySetting, 4, http.StatusInternalServerError, "invalid exchange rates data source")
 )

pkg/exchangerates/euro_central_bank_datasource.go

@@ -0,0 +1,103 @@
+package exchangerates
+
+import (
+	"encoding/xml"
+
+	"github.com/mayswind/lab/pkg/core"
+	"github.com/mayswind/lab/pkg/errs"
+	"github.com/mayswind/lab/pkg/log"
+	"github.com/mayswind/lab/pkg/models"
+)
+
+const euroCentralBankExchangeRateUrl = "https://www.ecb.europa.eu/stats/eurofxref/eurofxref-daily.xml"
+const euroCentralBankDataSource = "European Central Bank"
+const euroCentralBankBaseCurrency = "EUR"
+
+// EuroCentralBankDataSource defines the structure of exchange rates data source of euro central bank
+type EuroCentralBankDataSource struct {
+	ExchangeRatesDataSource
+}
+
+// EuroCentralBankExchangeRateData represents the whole data from euro central bank
+type EuroCentralBankExchangeRateData struct {
+	XMLName          xml.Name                        `xml:"Envelope"`
+	AllExchangeRates []*EuroCentralBankExchangeRates `xml:"Cube>Cube"`
+}
+
+// EuroCentralBankExchangeRates represents the exchange rates data from euro central bank
+type EuroCentralBankExchangeRates struct {
+	Date          string                         `xml:"time,attr"`
+	ExchangeRates []*EuroCentralBankExchangeRate `xml:"Cube"`
+}
+
+// EuroCentralBankExchangeRate represents the exchange rate data from euro central bank
+type EuroCentralBankExchangeRate struct {
+	Currency string `xml:"currency,attr"`
+	Rate     string `xml:"rate,attr"`
+}
+
+// ToLatestExchangeRateResponse returns a view-object according to original data from euro central bank
+func (e *EuroCentralBankExchangeRateData) ToLatestExchangeRateResponse() *models.LatestExchangeRateResponse {
+	if len(e.AllExchangeRates) < 1 {
+		return nil
+	}
+
+	latestEuroCentralBankExchangeRate := e.AllExchangeRates[0]
+
+	if len(latestEuroCentralBankExchangeRate.ExchangeRates) < 1 {
+		return nil
+	}
+
+	exchangeRates := make([]*models.LatestExchangeRate, len(latestEuroCentralBankExchangeRate.ExchangeRates))
+
+	for i := 0; i < len(latestEuroCentralBankExchangeRate.ExchangeRates); i++ {
+		exchangeRates[i] = latestEuroCentralBankExchangeRate.ExchangeRates[i].ToLatestExchangeRate()
+	}
+
+	latestExchangeRateResp := &models.LatestExchangeRateResponse{
+		DataSource:    euroCentralBankDataSource,
+		Date:          latestEuroCentralBankExchangeRate.Date,
+		BaseCurrency:  euroCentralBankBaseCurrency,
+		ExchangeRates: exchangeRates,
+	}
+
+	return latestExchangeRateResp
+}
+
+// ToLatestExchangeRate returns a data pair according to original data from euro central bank
+func (e *EuroCentralBankExchangeRate) ToLatestExchangeRate() *models.LatestExchangeRate {
+	return &models.LatestExchangeRate{
+		Currency: e.Currency,
+		Rate:     e.Rate,
+	}
+}
+
+// GetRequestUrl returns the euro central bank data source url
+func (e *EuroCentralBankDataSource) GetRequestUrl() string {
+	return euroCentralBankExchangeRateUrl
+}
+
+// Parse returns the common response entity according to the euro central bank data source raw response
+func (e *EuroCentralBankDataSource) Parse(c *core.Context, content []byte) (*models.LatestExchangeRateResponse, error) {
+	euroCentralBankData := &EuroCentralBankExchangeRateData{}
+	err := xml.Unmarshal(content, euroCentralBankData)
+
+	if err != nil {
+		log.ErrorfWithRequestId(c, "[euro_central_bank_datasource.Parse] failed to parse xml data, content is %s, because %s", string(content), err.Error())
+		return nil, errs.ErrFailedToRequestRemoteApi
+	}
+
+	latestExchangeRateResponse := euroCentralBankData.ToLatestExchangeRateResponse()
+
+	if latestExchangeRateResponse == nil {
+		log.ErrorfWithRequestId(c, "[euro_central_bank_datasource.Parse] failed to parse latest exchange rate data, content is %s", string(content))
+		return nil, errs.ErrFailedToRequestRemoteApi
+	}
+
+	latestExchangeRateResponse.ExchangeRates = append(latestExchangeRateResponse.ExchangeRates, &models.LatestExchangeRate{
+		Currency: euroCentralBankBaseCurrency,
+		Rate:     "1",
+	})
+
+	return latestExchangeRateResponse, nil
+}

pkg/exchangerates/exchange_rates_datasource.go

@@ -0,0 +1,15 @@
+package exchangerates
+
+import (
+	"github.com/mayswind/lab/pkg/core"
+	"github.com/mayswind/lab/pkg/models"
+)
+
+// ExchangeRatesDataSource defines the structure of exchange rates data source
+type ExchangeRatesDataSource interface {
+	// GetRequestUrl returns the data source url
+	GetRequestUrl() string
+
+	// Parse returns the common response entity according to the data source raw response
+	Parse(c *core.Context, content []byte) (*models.LatestExchangeRateResponse, error)
+}

pkg/exchangerates/exchange_rates_datasource_container.go

@@ -0,0 +1,26 @@
+package exchangerates
+
+import (
+	"github.com/mayswind/lab/pkg/errs"
+	"github.com/mayswind/lab/pkg/settings"
+)
+
+// ExchangeRatesDataSourceContainer contains the current exchange rates data source
+type ExchangeRatesDataSourceContainer struct {
+	Current ExchangeRatesDataSource
+}
+
+// Initialize a exchange rates data source container singleton instance
+var (
+	Container = &ExchangeRatesDataSourceContainer{}
+)
+
+// InitializeExchangeRatesDataSource initializes the current exchange rates data source according to the config
+func InitializeExchangeRatesDataSource(config *settings.Config) error {
+	if config.ExchangeRatesDataSource == settings.EuroCentralBankDataSource {
+		Container.Current = &EuroCentralBankDataSource{}
+		return nil
+	}
+
+	return errs.ErrInvalidExchangeRatesDataSource
+}

pkg/models/exchange_rate.go

@@ -1,10 +1,5 @@
 package models
 
-import "encoding/xml"
-
-const euroCentralBankDataSource = "European Central Bank"
-const euroCentralBankBaseCurrency = "EUR"
-
 // LatestExchangeRateResponse returns a view-object which contains latest exchange rate
 type LatestExchangeRateResponse struct {
 	DataSource    string                `json:"dataSource"`
@@ -18,57 +13,3 @@ type LatestExchangeRate struct {
 	Currency string `json:"currency"`
 	Rate     string `json:"rate"`
 }
-
-// EuroCentralBankExchangeRateData represents the whole data from euro central bank
-type EuroCentralBankExchangeRateData struct {
-	XMLName          xml.Name                        `xml:"Envelope"`
-	AllExchangeRates []*EuroCentralBankExchangeRates `xml:"Cube>Cube"`
-}
-
-// EuroCentralBankExchangeRates represents the exchange rates data from euro central bank
-type EuroCentralBankExchangeRates struct {
-	Date          string                         `xml:"time,attr"`
-	ExchangeRates []*EuroCentralBankExchangeRate `xml:"Cube"`
-}
-
-// EuroCentralBankExchangeRate represents the exchange rate data from euro central bank
-type EuroCentralBankExchangeRate struct {
-	Currency string `xml:"currency,attr"`
-	Rate     string `xml:"rate,attr"`
-}
-
-// ToLatestExchangeRateResponse returns a view-object according to original data from euro central bank
-func (e EuroCentralBankExchangeRateData) ToLatestExchangeRateResponse() *LatestExchangeRateResponse {
-	if len(e.AllExchangeRates) < 1 {
-		return nil
-	}
-
-	latestEuroCentralBankExchangeRate := e.AllExchangeRates[0]
-
-	if len(latestEuroCentralBankExchangeRate.ExchangeRates) < 1 {
-		return nil
-	}
-
-	exchangeRates := make([]*LatestExchangeRate, len(latestEuroCentralBankExchangeRate.ExchangeRates))
-
-	for i := 0; i < len(latestEuroCentralBankExchangeRate.ExchangeRates); i++ {
-		exchangeRates[i] = latestEuroCentralBankExchangeRate.ExchangeRates[i].ToLatestExchangeRate()
-	}
-
-	latestExchangeRateResp := &LatestExchangeRateResponse{
-		DataSource:    euroCentralBankDataSource,
-		Date:          latestEuroCentralBankExchangeRate.Date,
-		BaseCurrency:  euroCentralBankBaseCurrency,
-		ExchangeRates: exchangeRates,
-	}
-
-	return latestExchangeRateResp
-}
-
-// ToLatestExchangeRate returns a data pair according to original data from euro central bank
-func (e EuroCentralBankExchangeRate) ToLatestExchangeRate() *LatestExchangeRate {
-	return &LatestExchangeRate{
-		Currency: e.Currency,
-		Rate:     e.Rate,
-	}
-}

pkg/settings/setting.go

@@ -62,6 +62,11 @@ const (
 	InternalUuidGeneratorType string = "internal"
 )
 
+// Exchange rates data source types
+const (
+	EuroCentralBankDataSource string = "euro_central_bank"
+)
+
 const (
 	defaultAppName string = "lab"
 
@@ -81,6 +86,8 @@ const (
 	defaultSecretKey                 string = "lab"
 	defaultTokenExpiredTime          int    = 604800 // 7 days
 	defaultTemporaryTokenExpiredTime int    = 300    // 5 minutes
+
+	defaultExchangeRatesDataRequestTimeout int = 10000 // 10 seconds
 )
 
 // DatabaseConfig represents the database setting config
@@ -156,6 +163,10 @@ type Config struct {
 
 	// Data
 	EnableDataExport bool
+
+	// Exchange Rates
+	ExchangeRatesDataSource     string
+	ExchangeRatesRequestTimeout int
 }
 
 // LoadConfiguration loads setting config from given config file path
@@ -223,6 +234,12 @@ func LoadConfiguration(configFilePath string) (*Config, error) {
 		return nil, err
 	}
 
+	err = loadExchangeRatesConfiguration(config, cfgFile, "exchange_rates")
+
+	if err != nil {
+		return nil, err
+	}
+
 	return config, nil
 }
 
@@ -392,6 +409,18 @@ func loadDataConfiguration(config *Config, configFile *ini.File, sectionName str
 	return nil
 }
 
+func loadExchangeRatesConfiguration(config *Config, configFile *ini.File, sectionName string) error {
+	if getConfigItemStringValue(configFile, sectionName, "data_source") == EuroCentralBankDataSource {
+		config.ExchangeRatesDataSource = EuroCentralBankDataSource
+	} else {
+		return errs.ErrInvalidExchangeRatesDataSource
+	}
+
+	config.ExchangeRatesRequestTimeout = getConfigItemIntValue(configFile, sectionName, "request_timeout", defaultExchangeRatesDataRequestTimeout)
+
+	return nil
+}
+
 func getWorkingPath() (string, error) {
 	workingPath := os.Getenv(labWorkDirEnvName)