Adding error reason to message, when JWT token signing failed.

appstoreconnect/appstoreconnect.go

@@ -102,7 +102,7 @@ func (c *Client) NewRequest(method, endpoint string, body interface{}) (*http.Re
 	endpoint = apiVersion + "/" + endpoint
 	u, err := c.BaseURL.Parse(endpoint)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("parsing endpoint failed, %v", err)
 	}
 
 	var buf io.ReadWriter
@@ -111,13 +111,13 @@ func (c *Client) NewRequest(method, endpoint string, body interface{}) (*http.Re
 		enc := json.NewEncoder(buf)
 		enc.SetEscapeHTML(false)
 		if err := enc.Encode(body); err != nil {
-			return nil, err
+			return nil, fmt.Errorf("encoding body failed, %v", err)
 		}
 	}
 
 	req, err := http.NewRequest(method, u.String(), buf)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("preparing request failed, %v", err)
 	}
 
 	if body != nil {
@@ -127,7 +127,7 @@ func (c *Client) NewRequest(method, endpoint string, body interface{}) (*http.Re
 	if _, ok := c.client.(*http.Client); ok {
 		signedToken, err := c.ensureSignedToken()
 		if err != nil {
-			return nil, err
+			return nil, fmt.Errorf("ensuring JWT token failed, %v", err)
 		}
 		req.Header.Set("Authorization", "Bearer "+signedToken)
 	}

appstoreconnect/jwt.go

@@ -5,6 +5,7 @@ import (
 	"crypto/x509"
 	"encoding/pem"
 	"errors"
+	"fmt"
 	"time"
 
 	jwt "github.com/dgrijalva/jwt-go"
@@ -18,7 +19,7 @@ func signToken(token *jwt.Token, privateKeyContent []byte) (string, error) {
 	}
 	key, err := x509.ParsePKCS8PrivateKey(block.Bytes)
 	if err != nil {
-		return "", err
+		return "", fmt.Errorf("failed to sign JWT token, private key format is invalid: %v", err)
 	}
 
 	privateKey, ok := key.(*ecdsa.PrivateKey)