DE-1329 Fix race conditions with capturedCurlOutput fields (#333)

exports.go

@@ -83,7 +83,9 @@ func (mg *MailgunImpl) GetExportLink(ctx context.Context, id string) (string, er
 
 	if Debug {
 		if CaptureCurlOutput {
+			r.mu.Lock()
 			r.capturedCurlOutput = r.curlString(req, nil)
+			r.mu.Unlock()
 		} else {
 			fmt.Println(r.curlString(req, nil))
 		}

httphelpers.go

@@ -14,19 +14,22 @@ import (
 	"path"
 	"regexp"
 	"strings"
+	"sync"
 
 	"github.com/mailgun/errors"
 )
 
 var validURL = regexp.MustCompile(`/v[1-5].*`)
 
 type httpRequest struct {
-	URL                string
-	Parameters         map[string][]string
-	Headers            map[string]string
-	BasicAuthUser      string
-	BasicAuthPassword  string
-	Client             *http.Client
+	URL               string
+	Parameters        map[string][]string
+	Headers           map[string]string
+	BasicAuthUser     string
+	BasicAuthPassword string
+	Client            *http.Client
+
+	mu                 sync.RWMutex
 	capturedCurlOutput string
 }
 
@@ -294,7 +297,9 @@ func (r *httpRequest) makeRequest(ctx context.Context, method string, payload pa
 
 	if Debug {
 		if CaptureCurlOutput {
+			r.mu.Lock()
 			r.capturedCurlOutput = r.curlString(req, payload)
+			r.mu.Unlock()
 		} else {
 			fmt.Println(r.curlString(req, payload))
 		}

mailgun.go

@@ -82,6 +82,7 @@ import (
 	"io"
 	"net/http"
 	"os"
+	"sync"
 	"time"
 )
 
@@ -267,12 +268,14 @@ type Mailgun interface {
 // MailgunImpl bundles data needed by a large number of methods in order to interact with the Mailgun API.
 // Colloquially, we refer to instances of this structure as "clients."
 type MailgunImpl struct {
-	apiBase            string
-	domain             string
-	apiKey             string
-	client             *http.Client
-	baseURL            string
-	overrideHeaders    map[string]string
+	apiBase         string
+	domain          string
+	apiKey          string
+	client          *http.Client
+	baseURL         string
+	overrideHeaders map[string]string
+
+	mu                 sync.RWMutex
 	capturedCurlOutput string
 }
 
@@ -370,6 +373,9 @@ func (mg *MailgunImpl) AddOverrideHeader(k string, v string) {
 // mailgun.CaptureCurlOutput must be set to true
 // This is mostly useful for testing the Mailgun API hosted at a different endpoint.
 func (mg *MailgunImpl) GetCurlOutput() string {
+	mg.mu.RLock()
+	defer mg.mu.RUnlock()
+
 	return mg.capturedCurlOutput
 }
 

messages.go

@@ -713,7 +713,11 @@ func (mg *MailgunImpl) Send(ctx context.Context, message *Message) (mes string,
 		id = response.Id
 	}
 
+	r.mu.RLock()
+	defer r.mu.RUnlock()
 	if r.capturedCurlOutput != "" {
+		mg.mu.Lock()
+		defer mg.mu.Unlock()
 		mg.capturedCurlOutput = r.capturedCurlOutput
 	}