linter: Enable error checking linter (#766)

* golangci: Enable err checking linter to expose unchecked errors.

* gct: handle errors across the board

* gct: handle errors NOTE: Found bug in FTX (WIP)

* linter: fix issues

* ftx/exchanges: fix bug where error was being returned when setting pair management variables to an already enabled state

* bitmex: fix bug where a dangly supported asset in config danglied up the place.

* linter: fix more linter issues

* linter: fix my terrible spelling.

* currency: fix test

* exchanges: fix tests

* logger: fix test

* exchanges: fix tests

* glorious: nits

* vm: revert rm variable and instigate test

exchanges/gemini/gemini.go

@@ -41,13 +41,6 @@ const (
 	geminiWithdraw           = "withdraw/"
 	geminiHeartbeat          = "heartbeat"
 	geminiVolume             = "notionalvolume"
-
-	// Too many requests returns this
-	geminiRateError = "429"
-
-	// Assigned API key roles on creation
-	geminiRoleTrader      = "trader"
-	geminiRoleFundManager = "fundmanager"
 )
 
 // Gemini is the overarching type across the Gemini package, create multiple
@@ -392,7 +385,12 @@ func (g *Gemini) SendAuthenticatedHTTPRequest(ep exchange.URL, method, path stri
 		}
 
 		PayloadBase64 := crypto.Base64Encode(PayloadJSON)
-		hmac := crypto.GetHMAC(crypto.HashSHA512_384, []byte(PayloadBase64), []byte(g.API.Credentials.Secret))
+		hmac, err := crypto.GetHMAC(crypto.HashSHA512_384,
+			[]byte(PayloadBase64),
+			[]byte(g.API.Credentials.Secret))
+		if err != nil {
+			return nil, err
+		}
 
 		headers := make(map[string]string)
 		headers["Content-Length"] = "0"

exchanges/gemini/gemini_test.go

@@ -241,8 +241,10 @@ func setFeeBuilder() *exchange.FeeBuilder {
 func TestGetFeeByTypeOfflineTradeFee(t *testing.T) {
 	t.Parallel()
 	var feeBuilder = setFeeBuilder()
-	g.GetFeeByType(feeBuilder)
-
+	_, err := g.GetFeeByType(feeBuilder)
+	if err != nil {
+		t.Fatal(err)
+	}
 	if !areTestAPIKeysSet() {
 		if feeBuilder.FeeType != exchange.OfflineTradeFee {
 			t.Errorf("Expected %v, received %v",

exchanges/gemini/gemini_websocket.go

@@ -193,7 +193,13 @@ func (g *Gemini) WsAuth(dialer *websocket.Dialer) error {
 	}
 	endpoint := wsEndpoint + geminiWsOrderEvents
 	PayloadBase64 := crypto.Base64Encode(PayloadJSON)
-	hmac := crypto.GetHMAC(crypto.HashSHA512_384, []byte(PayloadBase64), []byte(g.API.Credentials.Secret))
+	hmac, err := crypto.GetHMAC(crypto.HashSHA512_384,
+		[]byte(PayloadBase64),
+		[]byte(g.API.Credentials.Secret))
+	if err != nil {
+		return err
+	}
+
 	headers := http.Header{}
 	headers.Add("Content-Length", "0")
 	headers.Add("Content-Type", "text/plain")