Add setting graphql server endpoint via environment variable.

gql.go

@@ -9,12 +9,16 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
+	"os"
 
+	"github.com/lukaszraczylo/zero"
 	"github.com/tidwall/gjson"
 	"github.com/valyala/fasthttp"
 )
 
 // Endpoint of your GraphQL server to query
+// this variable can be overwritten by setting env variable, for example:
+// GRAPHQL_ENDPOINT=http://hasura.local/v1/graphql
 var GraphQLUrl = "http://127.0.0.1:9090/v1/graphql"
 
 type requestBase struct {
@@ -22,6 +26,12 @@ type requestBase struct {
 	Variables interface{} `json:"variables"`
 }
 
+func init() {
+	if !zero.IsZero(os.Getenv("GRAPHQL_ENDPOINT")) {
+		GraphQLUrl = os.Getenv("GRAPHQL_ENDPOINT")
+	}
+}
+
 // queryBuilder takes query data (string) and variables (interface) as a parameter and assembles
 // graphQL query. It also compacts the JSON result. Function returns query as []byte and error if anything went wrong.
 func queryBuilder(data string, variables interface{}) ([]byte, error) {