exchange rate data source supports requesting multi url

pkg/api/exchange_rates.go

@@ -3,12 +3,14 @@ package api
 import (
 	"io/ioutil"
 	"net/http"
+	"sort"
 	"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"
 )
 
@@ -34,26 +36,65 @@ func (a *ExchangeRatesApi) LatestExchangeRateHandler(c *core.Context) (interface
 		Timeout: time.Duration(settings.Container.Current.ExchangeRatesRequestTimeout) * time.Millisecond,
 	}
 
-	resp, err := client.Get(dataSource.GetRequestUrl())
+	urls := dataSource.GetRequestUrls()
+	exchangeRateResps := make([]*models.LatestExchangeRateResponse, 0, len(urls))
 
-	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())
-		return nil, errs.ErrFailedToRequestRemoteApi
+	for i := 0; i < len(urls); i++ {
+		resp, err := client.Get(urls[i])
+
+		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())
+			return nil, errs.ErrFailedToRequestRemoteApi
+		}
+
+		if resp.StatusCode != 200 {
+			log.ErrorfWithRequestId(c, "[exchange_rates.LatestExchangeRateHandler] failed to get latest exchange rate data response for user \"uid:%d\", because response code is not 200", uid)
+			return nil, errs.ErrFailedToRequestRemoteApi
+		}
+
+		defer resp.Body.Close()
+		body, err := ioutil.ReadAll(resp.Body)
+		exchangeRateResp, err := dataSource.Parse(c, body)
+
+		if err != nil {
+			log.ErrorfWithRequestId(c, "[exchange_rates.LatestExchangeRateHandler] failed to parse response for user \"uid:%d\", because %s", uid, err.Error())
+			return nil, errs.Or(err, errs.ErrFailedToRequestRemoteApi)
+		}
+
+		exchangeRateResps = append(exchangeRateResps, exchangeRateResp)
 	}
 
-	if resp.StatusCode != 200 {
-		log.ErrorfWithRequestId(c, "[exchange_rates.LatestExchangeRateHandler] failed to get latest exchange rate data response for user \"uid:%d\", because response code is not 200", uid)
-		return nil, errs.ErrFailedToRequestRemoteApi
+	lastExchangeRateResponse := exchangeRateResps[len(exchangeRateResps)-1]
+	allExchangeRatesMap := make(map[string]string)
+
+	for i := 0; i < len(exchangeRateResps); i++ {
+		exchangeRateResp := exchangeRateResps[i]
+
+		for j := 0; j < len(exchangeRateResp.ExchangeRates); j++ {
+			exchangeRate := exchangeRateResp.ExchangeRates[j]
+			allExchangeRatesMap[exchangeRate.Currency] = exchangeRate.Rate
+		}
 	}
 
-	defer resp.Body.Close()
-	body, err := ioutil.ReadAll(resp.Body)
-	latestExchangeRateResponse, err := dataSource.Parse(c, body)
+	allExchangeRatesMap[lastExchangeRateResponse.BaseCurrency] = "1"
+	allExchangeRates := make(models.LatestExchangeRateSlice, 0, len(allExchangeRatesMap))
 
-	if err != nil {
-		log.ErrorfWithRequestId(c, "[exchange_rates.LatestExchangeRateHandler] failed to parse response for user \"uid:%d\", because %s", uid, err.Error())
-		return nil, errs.Or(err, errs.ErrFailedToRequestRemoteApi)
+	for currency, rate := range allExchangeRatesMap {
+		allExchangeRates = append(allExchangeRates, &models.LatestExchangeRate{
+			Currency: currency,
+			Rate:     rate,
+		})
 	}
 
-	return latestExchangeRateResponse, nil
+	sort.Sort(allExchangeRates)
+
+	finalExchangeRateResponse := &models.LatestExchangeRateResponse{
+		DataSource:    lastExchangeRateResponse.DataSource,
+		ReferenceUrl:  lastExchangeRateResponse.ReferenceUrl,
+		UpdateTime:    lastExchangeRateResponse.UpdateTime,
+		BaseCurrency:  lastExchangeRateResponse.BaseCurrency,
+		ExchangeRates: allExchangeRates,
+	}
+
+	return finalExchangeRateResponse, nil
 }

pkg/exchangerates/euro_central_bank_datasource.go

@@ -42,26 +42,30 @@ type EuroCentralBankExchangeRate struct {
 }
 
 // ToLatestExchangeRateResponse returns a view-object according to original data from euro central bank
-func (e *EuroCentralBankExchangeRateData) ToLatestExchangeRateResponse() *models.LatestExchangeRateResponse {
+func (e *EuroCentralBankExchangeRateData) ToLatestExchangeRateResponse(c *core.Context) *models.LatestExchangeRateResponse {
 	if len(e.AllExchangeRates) < 1 {
+		log.ErrorfWithRequestId(c, "[euro_central_bank_datasource.ToLatestExchangeRateResponse] all exchange rates is empty")
 		return nil
 	}
 
 	latestEuroCentralBankExchangeRate := e.AllExchangeRates[0]
 
 	if len(latestEuroCentralBankExchangeRate.ExchangeRates) < 1 {
+		log.ErrorfWithRequestId(c, "[euro_central_bank_datasource.ToLatestExchangeRateResponse] exchange rates is empty")
 		return nil
 	}
 
-	exchangeRates := make([]*models.LatestExchangeRate, len(latestEuroCentralBankExchangeRate.ExchangeRates))
+	exchangeRates := make(models.LatestExchangeRateSlice, 0, len(latestEuroCentralBankExchangeRate.ExchangeRates))
 
 	for i := 0; i < len(latestEuroCentralBankExchangeRate.ExchangeRates); i++ {
-		exchangeRates[i] = latestEuroCentralBankExchangeRate.ExchangeRates[i].ToLatestExchangeRate()
+		exchangeRate := latestEuroCentralBankExchangeRate.ExchangeRates[i]
+		exchangeRates = append(exchangeRates, exchangeRate.ToLatestExchangeRate())
 	}
 
 	timezone, err := time.LoadLocation(euroCentralBankDataUpdateDateTimezone)
 
 	if err != nil {
+		log.ErrorfWithRequestId(c, "[euro_central_bank_datasource.ToLatestExchangeRateResponse] failed to get timezone, timezone name is %s", euroCentralBankDataUpdateDateTimezone)
 		return nil
 	}
 
@@ -69,6 +73,7 @@ func (e *EuroCentralBankExchangeRateData) ToLatestExchangeRateResponse() *models
 	updateTime, err := time.ParseInLocation(euroCentralBankDataUpdateDateFormat, updateDateTime, timezone)
 
 	if err != nil {
+		log.ErrorfWithRequestId(c, "[euro_central_bank_datasource.ToLatestExchangeRateResponse] failed to parse update date, datetime is %s", updateDateTime)
 		return nil
 	}
 
@@ -91,9 +96,9 @@ func (e *EuroCentralBankExchangeRate) ToLatestExchangeRate() *models.LatestExcha
 	}
 }
 
-// GetRequestUrl returns the euro central bank data source url
-func (e *EuroCentralBankDataSource) GetRequestUrl() string {
-	return euroCentralBankExchangeRateUrl
+// GetRequestUrls returns the euro central bank data source urls
+func (e *EuroCentralBankDataSource) GetRequestUrls() []string {
+	return []string{euroCentralBankExchangeRateUrl}
 }
 
 // Parse returns the common response entity according to the euro central bank data source raw response
@@ -106,17 +111,12 @@ func (e *EuroCentralBankDataSource) Parse(c *core.Context, content []byte) (*mod
 		return nil, errs.ErrFailedToRequestRemoteApi
 	}
 
-	latestExchangeRateResponse := euroCentralBankData.ToLatestExchangeRateResponse()
+	latestExchangeRateResponse := euroCentralBankData.ToLatestExchangeRateResponse(c)
 
 	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

@@ -7,8 +7,8 @@ import (
 
 // ExchangeRatesDataSource defines the structure of exchange rates data source
 type ExchangeRatesDataSource interface {
-	// GetRequestUrl returns the data source url
-	GetRequestUrl() string
+	// GetRequestUrl returns the data source urls
+	GetRequestUrls() []string
 
 	// Parse returns the common response entity according to the data source raw response
 	Parse(c *core.Context, content []byte) (*models.LatestExchangeRateResponse, error)

pkg/models/exchange_rate.go

@@ -1,12 +1,14 @@
 package models
 
+import "strings"
+
 // LatestExchangeRateResponse returns a view-object which contains latest exchange rate
 type LatestExchangeRateResponse struct {
-	DataSource    string                `json:"dataSource"`
-	ReferenceUrl  string                `json:"referenceUrl"`
-	UpdateTime    int64                 `json:"updateTime"`
-	BaseCurrency  string                `json:"baseCurrency"`
-	ExchangeRates []*LatestExchangeRate `json:"exchangeRates"`
+	DataSource    string                  `json:"dataSource"`
+	ReferenceUrl  string                  `json:"referenceUrl"`
+	UpdateTime    int64                   `json:"updateTime"`
+	BaseCurrency  string                  `json:"baseCurrency"`
+	ExchangeRates LatestExchangeRateSlice `json:"exchangeRates"`
 }
 
 // LatestExchangeRate represents a data pair of currency and exchange rate
@@ -14,3 +16,21 @@ type LatestExchangeRate struct {
 	Currency string `json:"currency"`
 	Rate     string `json:"rate"`
 }
+
+// LatestExchangeRateSlice represents the slice data structure of LatestExchangeRate
+type LatestExchangeRateSlice []*LatestExchangeRate
+
+// Len returns the count of items
+func (c LatestExchangeRateSlice) Len() int {
+	return len(c)
+}
+
+// Swap swaps two items
+func (c LatestExchangeRateSlice) Swap(i, j int) {
+	c[i], c[j] = c[j], c[i]
+}
+
+// Less reports whether the first item is less than the second one
+func (c LatestExchangeRateSlice) Less(i, j int) bool {
+	return strings.Compare(c[i].Currency, c[j].Currency) < 0
+}