Add custom retry decider for fail http requests

client.go

@@ -289,6 +289,11 @@ type Client struct {
 	// By default will not waiting, return ErrNoFreeConns immediately
 	MaxConnWaitTimeout time.Duration
 
+	// RetryIf controls whether a retry should be attempted after an error.
+	//
+	// By default will use isIdempotent function
+	RetryIf RetryIfFunc
+
 	mLock sync.Mutex
 	m     map[string]*HostClient
 	ms    map[string]*HostClient
@@ -493,6 +498,7 @@ func (c *Client) Do(req *Request, resp *Response) error {
 			DisableHeaderNamesNormalizing: c.DisableHeaderNamesNormalizing,
 			DisablePathNormalizing:        c.DisablePathNormalizing,
 			MaxConnWaitTimeout:            c.MaxConnWaitTimeout,
+			RetryIf:                       c.RetryIf,
 		}
 		m[string(host)] = hc
 		if len(m) == 1 {
@@ -560,6 +566,11 @@ const DefaultMaxIdemponentCallAttempts = 5
 //   - foobar.com:8080
 type DialFunc func(addr string) (net.Conn, error)
 
+// RetryIfFunc signature of retry if function
+//
+// Request argument passed to RetryIfFunc, if there are any request errors.
+type RetryIfFunc func(request *Request) bool
+
 // HostClient balances http requests among hosts listed in Addr.
 //
 // HostClient may be used for balancing load among multiple upstream hosts.
@@ -698,6 +709,11 @@ type HostClient struct {
 	// By default will not waiting, return ErrNoFreeConns immediately
 	MaxConnWaitTimeout time.Duration
 
+	// RetryIf controls whether a retry should be attempted after an error.
+	//
+	// By default will use isIdempotent function
+	RetryIf RetryIfFunc
+
 	clientName  atomic.Value
 	lastUseTime uint32
 
@@ -1183,6 +1199,10 @@ func (c *HostClient) Do(req *Request, resp *Response) error {
 	if maxAttempts <= 0 {
 		maxAttempts = DefaultMaxIdemponentCallAttempts
 	}
+	isRequestRetryable := isIdempotent
+	if c.RetryIf != nil {
+		isRequestRetryable = c.RetryIf
+	}
 	attempts := 0
 	hasBodyStream := req.IsBodyStream()
 
@@ -1196,7 +1216,7 @@ func (c *HostClient) Do(req *Request, resp *Response) error {
 		if hasBodyStream {
 			break
 		}
-		if !isIdempotent(req) {
+		if !isRequestRetryable(req) {
 			// Retry non-idempotent requests if the server closes
 			// the connection before sending the response.
 			//

client_test.go

@@ -1648,6 +1648,58 @@ func TestClientIdempotentRequest(t *testing.T) {
 	}
 }
 
+func TestClientRetryRequestWithCustomDecider(t *testing.T) {
+	t.Parallel()
+
+	dialsCount := 0
+	c := &Client{
+		Dial: func(addr string) (net.Conn, error) {
+			dialsCount++
+			switch dialsCount {
+			case 1:
+				return &singleReadConn{
+					s: "invalid response",
+				}, nil
+			case 2:
+				return &writeErrorConn{}, nil
+			case 3:
+				return &readErrorConn{}, nil
+			case 4:
+				return &singleReadConn{
+					s: "HTTP/1.1 345 OK\r\nContent-Type: foobar\r\nContent-Length: 7\r\n\r\n0123456",
+				}, nil
+			default:
+				t.Fatalf("unexpected number of dials: %d", dialsCount)
+			}
+			panic("unreachable")
+		},
+		RetryIf: func(req *Request) bool {
+			return req.URI().String() == "http://foobar/a/b"
+		},
+	}
+
+	var args Args
+
+	// Post must succeed for http://foobar/a/b uri.
+	statusCode, body, err := c.Post(nil, "http://foobar/a/b", &args)
+	if err != nil {
+		t.Fatalf("unexpected error: %s", err)
+	}
+	if statusCode != 345 {
+		t.Fatalf("unexpected status code: %d. Expecting 345", statusCode)
+	}
+	if string(body) != "0123456" {
+		t.Fatalf("unexpected body: %q. Expecting %q", body, "0123456")
+	}
+
+	// POST must fail for http://foobar/a/b/c uri.
+	dialsCount = 0
+	_, _, err = c.Post(nil, "http://foobar/a/b/c", &args)
+	if err == nil {
+		t.Fatalf("expecting error")
+	}
+}
+
 type writeErrorConn struct {
 	net.Conn
 }