multi: init fiat backends with proxy if provided

This commit adds support for the coindesk backends to be initialized
with a socks proxy if one is provided.

accounting/config.go

@@ -96,6 +96,9 @@ type CommonConfig struct {
 	// Categories is a set of custom categories which should be added to the
 	// report.
 	Categories []CustomCategory
+
+	// SocksProxy is the URL to be used as a proxy for http requests.
+	SocksProxy string
 }
 
 // NewOnChainConfig returns an on chain config from the lnd services provided.

accounting/conversions.go

@@ -34,7 +34,7 @@ func invertMsat(msat int64) int64 {
 // individual price points from this data.
 func getConversion(ctx context.Context, startTime, endTime time.Time,
 	disableFiat bool, fiatBackend fiat.PriceBackend,
-	granularity *fiat.Granularity) (usdPrice, error) {
+	granularity *fiat.Granularity, socksProxy string) (usdPrice, error) {
 
 	// If we don't want fiat values, just return a price which will yield
 	// a zero price and timestamp.
@@ -49,7 +49,9 @@ func getConversion(ctx context.Context, startTime, endTime time.Time,
 		return nil, err
 	}
 
-	fiatClient, err := fiat.NewPricePriceSource(fiatBackend, granularity)
+	fiatClient, err := fiat.NewPricePriceSource(
+		fiatBackend, granularity, socksProxy,
+	)
 	if err != nil {
 		return nil, err
 	}

accounting/off_chain.go

@@ -45,7 +45,7 @@ func OffChainReport(ctx context.Context, cfg *OffChainConfig) (Report, error) {
 	// or a no-op function if we do not want prices.
 	getPrice, err := getConversion(
 		ctx, cfg.StartTime, cfg.EndTime, cfg.DisableFiat,
-		cfg.FiatBackend, cfg.Granularity,
+		cfg.FiatBackend, cfg.Granularity, cfg.SocksProxy,
 	)
 	if err != nil {
 		return nil, err

accounting/on_chain.go

@@ -21,7 +21,7 @@ func OnChainReport(ctx context.Context, cfg *OnChainConfig) (Report, error) {
 	// or a no-op function if we do not want prices.
 	getPrice, err := getConversion(
 		ctx, cfg.StartTime, cfg.EndTime, cfg.DisableFiat,
-		cfg.FiatBackend, cfg.Granularity,
+		cfg.FiatBackend, cfg.Granularity, cfg.SocksProxy,
 	)
 	if err != nil {
 		return nil, err

fiat/coindesk_api.go

@@ -20,24 +20,25 @@ const (
 )
 
 // coinDeskAPI implements the fiatBackend interface.
-type coinDeskAPI struct{}
+type coinDeskAPI struct {
+	httpClient *http.Client
+}
 
 type coinDeskResponse struct {
 	Data map[string]float64 `json:"bpi"`
 }
 
 // queryCoinDesk constructs and sends a request to coindesk to query historical
 // price information.
-func queryCoinDesk(start, end time.Time) ([]byte, error) {
+func (c *coinDeskAPI) queryCoinDesk(start, end time.Time) ([]byte, error) {
 	queryURL := fmt.Sprintf("%v?start=%v&end=%v",
 		coinDeskHistoryAPI, start.Format(coinDeskTimeFormat),
 		end.Format(coinDeskTimeFormat))
 
 	log.Debugf("coindesk url: %v", queryURL)
 
 	// Query the http endpoint with the url provided
-	// #nosec G107
-	response, err := http.Get(queryURL)
+	response, err := c.httpClient.Get(queryURL)
 	if err != nil {
 		return nil, err
 	}
@@ -77,7 +78,7 @@ func (c *coinDeskAPI) rawPriceData(ctx context.Context, start,
 	end time.Time) ([]*USDPrice, error) {
 
 	query := func() ([]byte, error) {
-		return queryCoinDesk(start, end)
+		return c.queryCoinDesk(start, end)
 	}
 
 	// CoinDesk uses a granularity of 1 day and does not include the current

fiat/prices.go

@@ -3,6 +3,8 @@ package fiat
 import (
 	"context"
 	"errors"
+	"net/http"
+	"net/url"
 	"sort"
 	"time"
 
@@ -91,18 +93,57 @@ var priceBackendNames = map[PriceBackend]string{
 	CoinDeskPriceBackend: "coindesk",
 }
 
+var priceBackendProxySupport = map[PriceBackend]bool{
+	CoinCapPriceBackend:  false,
+	CoinDeskPriceBackend: true,
+}
+
 // String returns the string representation of a price backend.
 func (p PriceBackend) String() string {
 	return priceBackendNames[p]
 }
 
 // NewPricePriceSource returns a PriceSource which can be used to query price
 // data.
-func NewPricePriceSource(backend PriceBackend, granularity *Granularity) (
-	*PriceSource, error) {
+func NewPricePriceSource(backend PriceBackend, granularity *Granularity,
+	proxy string) (*PriceSource, error) {
+
+	// If no specific backend is specified then choose a default backend
+	// based on whether or not a proxy is specified.
+	if backend == UnknownPriceBackend {
+		if proxy != "" {
+			backend = CoinDeskPriceBackend
+		} else {
+			backend = CoinCapPriceBackend
+		}
+	}
+
+	// Check that the proxy flag is not set for a price backend that does
+	// not support requests through a socks proxy.
+	if proxy != "" && !priceBackendProxySupport[backend] {
+		return nil, errors.New("can't use a socks proxy for the " +
+			"given backend")
+	}
+
+	httpClient := http.DefaultClient
+	if proxy != "" {
+		// Parse socks proxy URL string to a URL type
+		socksProxyURL, err := url.Parse("socks5://" + proxy)
+		if err != nil {
+			return nil, err
+		}
+
+		// Set up a custom HTTP transport to use the proxy and
+		// create the client
+		httpClient = &http.Client{
+			Transport: &http.Transport{
+				Proxy: http.ProxyURL(socksProxyURL),
+			},
+		}
+	}
 
 	switch backend {
-	case UnknownPriceBackend, CoinCapPriceBackend:
+	case CoinCapPriceBackend:
 		if granularity == nil {
 			return nil, errGranularityRequired
 		}
@@ -112,7 +153,9 @@ func NewPricePriceSource(backend PriceBackend, granularity *Granularity) (
 
 	case CoinDeskPriceBackend:
 		return &PriceSource{
-			impl: &coinDeskAPI{},
+			impl: &coinDeskAPI{
+				httpClient: httpClient,
+			},
 		}, nil
 	}
 
@@ -133,7 +176,7 @@ type PriceRequest struct {
 
 // GetPrices gets a set of prices for a set of timestamps.
 func GetPrices(ctx context.Context, timestamps []time.Time,
-	backend PriceBackend, granularity Granularity) (
+	backend PriceBackend, granularity Granularity, socksProxy string) (
 	map[time.Time]*USDPrice, error) {
 
 	if len(timestamps) == 0 {
@@ -152,7 +195,7 @@ func GetPrices(ctx context.Context, timestamps []time.Time,
 	// timestamp if we have 1 entry, but that's ok.
 	start, end := timestamps[0], timestamps[len(timestamps)-1]
 
-	client, err := NewPricePriceSource(backend, &granularity)
+	client, err := NewPricePriceSource(backend, &granularity, socksProxy)
 	if err != nil {
 		return nil, err
 	}

frdrpc/rpcserver.go

@@ -443,7 +443,7 @@ func (s *RPCServer) ExchangeRate(ctx context.Context,
 	}
 
 	prices, err := fiat.GetPrices(
-		ctx, timestamps, fiatBackend, *granularity,
+		ctx, timestamps, fiatBackend, *granularity, "",
 	)
 	if err != nil {
 		return nil, err