fix: don't expect response to be json in endpointcreds provider

.changelog/018d3cef4def4b019c5ac7c60555b7e3.json

@@ -0,0 +1,8 @@
+{
+    "id": "018d3cef-4def-4b01-9c5a-c7c60555b7e3",
+    "type": "bugfix",
+    "description": "Don't expect error responses to have a JSON payload in the endpointcreds provider.",
+    "modules": [
+        "credentials"
+    ]
+}

credentials/endpointcreds/internal/client/client.go

@@ -62,7 +62,16 @@ func New(options Options, optFns ...func(*Options)) *Client {
 	}
 
 	if options.Retryer == nil {
-		options.Retryer = retry.NewStandard()
+		// Amazon-owned implementations of this endpoint are known to sometimes
+		// return plaintext responses (i.e. no Code) like normal, add a few
+		// additional status codes
+		options.Retryer = retry.NewStandard(func(o *retry.StandardOptions) {
+			o.Retryables = append(o.Retryables, retry.RetryableHTTPStatusCode{
+				Codes: map[int]struct{}{
+					http.StatusTooManyRequests: {},
+				},
+			})
+		})
 	}
 
 	for _, fn := range optFns {
@@ -122,9 +131,10 @@ type GetCredentialsOutput struct {
 
 // EndpointError is an error returned from the endpoint service
 type EndpointError struct {
-	Code    string            `json:"code"`
-	Message string            `json:"message"`
-	Fault   smithy.ErrorFault `json:"-"`
+	Code       string            `json:"code"`
+	Message    string            `json:"message"`
+	Fault      smithy.ErrorFault `json:"-"`
+	statusCode int               `json:"-"`
 }
 
 // Error is the error mesage string
@@ -146,3 +156,8 @@ func (e *EndpointError) ErrorMessage() string {
 func (e *EndpointError) ErrorFault() smithy.ErrorFault {
 	return e.Fault
 }
+
+// HTTPStatusCode implements retry.HTTPStatusCode.
+func (e *EndpointError) HTTPStatusCode() int {
+	return e.statusCode
+}

credentials/endpointcreds/internal/client/client_test.go

@@ -18,21 +18,23 @@ import (
 
 func TestClient_GetCredentials(t *testing.T) {
 	cases := map[string]struct {
-		Token           string
-		RelativeURI     string
-		ResponseCode    int
-		ResponseBody    []byte
-		ExpectResult    *GetCredentialsOutput
-		ExpectErr       bool
-		ValidateRequest func(*testing.T, *http.Request)
-		ValidateError   func(*testing.T, error) bool
+		Token               string
+		RelativeURI         string
+		ResponseCode        int
+		ResponseBody        []byte
+		ResponseContentType string
+		ExpectResult        *GetCredentialsOutput
+		ExpectErr           bool
+		ValidateRequest     func(*testing.T, *http.Request)
+		ValidateError       func(*testing.T, error) bool
 	}{
 		"success static": {
 			ResponseCode: 200,
 			ResponseBody: []byte(` {
    "AccessKeyId" : "FooKey",
    "SecretAccessKey" : "FooSecret"
  }`),
+			ResponseContentType: "application/json",
 			ExpectResult: &GetCredentialsOutput{
 				AccessKeyID:     "FooKey",
 				SecretAccessKey: "FooSecret",
@@ -45,6 +47,7 @@ func TestClient_GetCredentials(t *testing.T) {
    "AccessKeyId" : "FooKey",
    "SecretAccessKey" : "FooSecret"
  }`),
+			ResponseContentType: "application/json",
 			ExpectResult: &GetCredentialsOutput{
 				AccessKeyID:     "FooKey",
 				SecretAccessKey: "FooSecret",
@@ -59,6 +62,7 @@ func TestClient_GetCredentials(t *testing.T) {
   "Token": "FooToken",
   "Expiration": "2016-02-25T06:03:31Z"
 }`),
+			ResponseContentType: "application/json",
 			ExpectResult: &GetCredentialsOutput{
 				AccessKeyID:     "FooKey",
 				SecretAccessKey: "FooSecret",
@@ -76,6 +80,7 @@ func TestClient_GetCredentials(t *testing.T) {
    "AccessKeyId" : "FooKey",
    "SecretAccessKey" : "FooSecret"
  }`),
+			ResponseContentType: "application/json",
 			ValidateRequest: func(t *testing.T, r *http.Request) {
 				t.Helper()
 				if e, a := "/path/to/thing", r.URL.Path; e != a {
@@ -96,7 +101,8 @@ func TestClient_GetCredentials(t *testing.T) {
   "code": "Unauthorized",
   "message": "not authorized for endpoint"
 }`),
-			ExpectErr: true,
+			ResponseContentType: "application/json",
+			ExpectErr:           true,
 			ValidateError: func(t *testing.T, err error) (ok bool) {
 				t.Helper()
 				var apiError smithy.APIError
@@ -126,7 +132,8 @@ func TestClient_GetCredentials(t *testing.T) {
   "code": "InternalError",
   "message": "an error occurred"
 }`),
-			ExpectErr: true,
+			ResponseContentType: "application/json",
+			ExpectErr:           true,
 			ValidateError: func(t *testing.T, err error) (ok bool) {
 				t.Helper()
 				var apiError smithy.APIError
@@ -151,13 +158,28 @@ func TestClient_GetCredentials(t *testing.T) {
 			},
 		},
 		"non-json error response": {
-			ResponseCode: 500,
-			ResponseBody: []byte(`<html><body>unexpected message format</body></html>`),
-			ExpectErr:    true,
+			ResponseCode:        500,
+			ResponseBody:        []byte(`<html><body>unexpected message format</body></html>`),
+			ResponseContentType: "text/html",
+			ExpectErr:           true,
 			ValidateError: func(t *testing.T, err error) (ok bool) {
 				t.Helper()
-				if e, a := "failed to decode error message", err.Error(); !strings.Contains(a, e) {
-					t.Errorf("expect %v, got %v", e, a)
+				var apiError smithy.APIError
+				if errors.As(err, &apiError) {
+					if e, a := "", apiError.ErrorCode(); e != a {
+						t.Errorf("expect %v, got %v", e, a)
+						ok = false
+					}
+					if e, a := "<html><body>unexpected message format</body></html>", apiError.ErrorMessage(); e != a {
+						t.Errorf("expect %v, got %v", e, a)
+						ok = false
+					}
+					if e, a := smithy.FaultServer, apiError.ErrorFault(); e != a {
+						t.Errorf("expect %v, got %v", e, a)
+						ok = false
+					}
+				} else {
+					t.Errorf("expect %T error type, got %T: %v", apiError, err, err)
 					ok = false
 				}
 				return ok
@@ -177,6 +199,7 @@ func TestClient_GetCredentials(t *testing.T) {
 
 				actualReq.Body = ioutil.NopCloser(bytes.NewReader(buf.Bytes()))
 
+				w.Header().Set("Content-Type", tt.ResponseContentType)
 				w.WriteHeader(tt.ResponseCode)
 				w.Write(tt.ResponseBody)
 			}))

credentials/endpointcreds/internal/client/middleware.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
+	"io"
 	"net/url"
 
 	"github.com/aws/smithy-go"
@@ -104,17 +105,44 @@ func (d *deserializeOpGetCredential) HandleDeserialize(ctx context.Context, in s
 }
 
 func deserializeError(response *smithyhttp.Response) error {
-	var errShape *EndpointError
-	err := json.NewDecoder(response.Body).Decode(&errShape)
+	// we could be talking to anything, json isn't guaranteed
+	// see https://github.com/aws/aws-sdk-go-v2/issues/2316
+	if response.Header.Get("Content-Type") == "application/json" {
+		return deserializeJSONError(response)
+	}
+
+	msg, err := io.ReadAll(response.Body)
 	if err != nil {
-		return &smithy.DeserializationError{Err: fmt.Errorf("failed to decode error message, %w", err)}
+		return &smithy.DeserializationError{
+			Err: fmt.Errorf("read response, %w", err),
+		}
+	}
+
+	return &EndpointError{
+		// no sensible value for Code
+		Message:    string(msg),
+		Fault:      stof(response.StatusCode),
+		statusCode: response.StatusCode,
 	}
+}
 
-	if response.StatusCode >= 500 {
-		errShape.Fault = smithy.FaultServer
-	} else {
-		errShape.Fault = smithy.FaultClient
+func deserializeJSONError(response *smithyhttp.Response) error {
+	var errShape *EndpointError
+	if err := json.NewDecoder(response.Body).Decode(&errShape); err != nil {
+		return &smithy.DeserializationError{
+			Err: fmt.Errorf("failed to decode error message, %w", err),
+		}
 	}
 
+	errShape.Fault = stof(response.StatusCode)
+	errShape.statusCode = response.StatusCode
 	return errShape
 }
+
+// maps HTTP status code to smithy ErrorFault
+func stof(code int) smithy.ErrorFault {
+	if code >= 500 {
+		return smithy.FaultServer
+	}
+	return smithy.FaultClient
+}

credentials/endpointcreds/provider_test.go

@@ -5,6 +5,7 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"io"
 	"io/ioutil"
 	"net/http"
 	"strings"
@@ -201,6 +202,9 @@ func TestFailedRetrieveCredentials(t *testing.T) {
   "code": "Error",
   "message": "Message"
 }`))),
+				Header: http.Header{
+					"Content-Type": {"application/json"},
+				},
 			}, nil
 		})
 	})
@@ -238,3 +242,72 @@ func TestFailedRetrieveCredentials(t *testing.T) {
 		t.Errorf("expect empty creds not to be expired")
 	}
 }
+
+type mockClientN struct {
+	responses []*http.Response
+	index     int
+}
+
+func (c *mockClientN) Do(r *http.Request) (*http.Response, error) {
+	resp := c.responses[c.index]
+	c.index++
+	return resp, nil
+}
+
+func TestRetryHTTPStatusCode(t *testing.T) {
+	expTime := time.Now().UTC().Add(1 * time.Hour).Format("2006-01-02T15:04:05Z")
+	credsResp := fmt.Sprintf(`{"AccessKeyID":"AKID","SecretAccessKey":"SECRET","Token":"TOKEN","Expiration":"%s"}`, expTime)
+
+	p := endpointcreds.New("http://127.0.0.1", func(o *endpointcreds.Options) {
+		o.HTTPClient = &mockClientN{
+			responses: []*http.Response{
+				{
+					StatusCode: 429,
+					Body:       io.NopCloser(strings.NewReader("You have made too many requests.")),
+					Header: http.Header{
+						"Content-Type": {"text/plain"},
+					},
+				},
+				{
+					StatusCode: 500,
+					Body:       io.NopCloser(strings.NewReader("Internal server error.")),
+					Header: http.Header{
+						"Content-Type": {"text/plain"},
+					},
+				},
+				{
+					StatusCode: 200,
+					Body:       ioutil.NopCloser(strings.NewReader(credsResp)),
+					Header: http.Header{
+						"Content-Type": {"application/json"},
+					},
+				},
+			},
+		}
+	})
+
+	creds, err := p.Retrieve(context.Background())
+	if err != nil {
+		t.Fatalf("expect no error, got %v", err)
+	}
+
+	if e, a := "AKID", creds.AccessKeyID; e != a {
+		t.Errorf("expect %v, got %v", e, a)
+	}
+	if e, a := "SECRET", creds.SecretAccessKey; e != a {
+		t.Errorf("expect %v, got %v", e, a)
+	}
+	if e, a := "TOKEN", creds.SessionToken; e != a {
+		t.Errorf("expect %v, got %v", e, a)
+	}
+	if creds.Expired() {
+		t.Errorf("expect not expired")
+	}
+
+	sdk.NowTime = func() time.Time {
+		return time.Now().Add(2 * time.Hour)
+	}
+	if !creds.Expired() {
+		t.Errorf("expect to be expired")
+	}
+}