Allow to override default retry wait times for Client (#66)

* Added Client's retry wait times config methods
* Make sure Backoff always sleeps at least WaitTime
* Document retries usage

README.md

@@ -53,7 +53,7 @@ resty tested with Go `v1.2` and above.
     * FlexibleRedirectPolicy
     * DomainCheckRedirectPolicy
     * etc. [more info](redirect.go)
-  * Retry Mechanism [how to use](retry_test.go)
+  * Retry Mechanism [how to use](#retries)
     * Backoff Retry
     * Conditional Retry
   * SRV Record based request instead of Host URL [how to use](resty_test.go#L1412)
@@ -448,6 +448,50 @@ resp, err := c.R().
     Get("http://httpbin.org/get")
 ```
 
+#### Retries
+
+Resty uses [backoff](http://www.awsarchitectureblog.com/2015/03/backoff.html)
+to increase retry intervals after each attempt.
+
+Usage example:
+```go
+// Retries are configured per client
+resty.DefaultClient.
+    // Set retry count to non zero to enable retries
+    SetRetryCount(3).
+    // You can override initial retry wait time.
+    // Default is 100 milliseconds.
+    SetRetryWaitTime(5 * time.Second).
+    // MaxWaitTime can be overridden as well.
+    // Default is 2 seconds.
+    SetRetryMaxWaitTime(20 * time.Second)
+```
+
+Above setup will result in resty retrying requests returned non nil error up to
+3 times with delay increased after each attempt.
+
+You can optionally provide client with custom retry conditions:
+
+```go
+resty.DefaultClient.
+    AddRetryCondition(
+        // Condition function will be provided with *resty.Response as a
+        // parameter. It is expected to return (bool, error) pair. Resty will retry
+        // in case condition returns true or non nil error.
+        func(r *resty.Response) (bool, error) {
+            return r.StatusCode() == http.StatusTooManyRequests, nil
+        }
+    )
+```
+
+Above example will make resty retry requests ended with `429 Too Many Requests`
+status code.
+
+Multiple retry conditions can be added.
+
+It is also possible to use `resty.Backoff(...)` to get arbitrary retry scenarios
+implemented. [Reference](retry_test.go).
+
 #### Choose REST or HTTP mode
 ```go
 // REST mode. This is Default.

client.go

@@ -68,19 +68,21 @@ var (
 // Client type is used for HTTP/RESTful global values
 // for all request raised from the client
 type Client struct {
-	HostURL         string
-	QueryParam      url.Values
-	FormData        url.Values
-	Header          http.Header
-	UserInfo        *User
-	Token           string
-	Cookies         []*http.Cookie
-	Error           reflect.Type
-	Debug           bool
-	DisableWarn     bool
-	Log             *log.Logger
-	RetryCount      int
-	RetryConditions []RetryConditionFunc
+	HostURL          string
+	QueryParam       url.Values
+	FormData         url.Values
+	Header           http.Header
+	UserInfo         *User
+	Token            string
+	Cookies          []*http.Cookie
+	Error            reflect.Type
+	Debug            bool
+	DisableWarn      bool
+	Log              *log.Logger
+	RetryCount       int
+	RetryWaitTime    time.Duration
+	RetryMaxWaitTime time.Duration
+	RetryConditions  []RetryConditionFunc
 
 	httpClient       *http.Client
 	transport        *http.Transport
@@ -414,6 +416,22 @@ func (c *Client) SetRetryCount(count int) *Client {
 	return c
 }
 
+// SetRetryWaitTime method sets default wait time to sleep before retrying
+// request.
+// Default is 100 milliseconds.
+func (c *Client) SetRetryWaitTime(waitTime time.Duration) *Client {
+	c.RetryWaitTime = waitTime
+	return c
+}
+
+// SetRetryMaxWaitTime method sets max wait time to sleep before retrying
+// request.
+// Default is 2 seconds.
+func (c *Client) SetRetryMaxWaitTime(maxWaitTime time.Duration) *Client {
+	c.RetryMaxWaitTime = maxWaitTime
+	return c
+}
+
 // AddRetryCondition method adds a retry condition function to array of functions
 // that are checked to determine if the request is retried. The request will
 // retry if any of the functions return true and error is nil.

default.go

@@ -24,18 +24,20 @@ func New() *Client {
 	cookieJar, _ := cookiejar.New(&cookiejar.Options{PublicSuffixList: publicsuffix.List})
 
 	c := &Client{
-		HostURL:    "",
-		QueryParam: url.Values{},
-		FormData:   url.Values{},
-		Header:     http.Header{},
-		UserInfo:   nil,
-		Token:      "",
-		Cookies:    make([]*http.Cookie, 0),
-		Debug:      false,
-		Log:        getLogger(os.Stderr),
-		RetryCount: 0,
-		httpClient: &http.Client{Jar: cookieJar},
-		transport:  &http.Transport{},
+		HostURL:          "",
+		QueryParam:       url.Values{},
+		FormData:         url.Values{},
+		Header:           http.Header{},
+		UserInfo:         nil,
+		Token:            "",
+		Cookies:          make([]*http.Cookie, 0),
+		Debug:            false,
+		Log:              getLogger(os.Stderr),
+		RetryCount:       0,
+		RetryWaitTime:    defaultWaitTime,
+		RetryMaxWaitTime: defaultMaxWaitTime,
+		httpClient:       &http.Client{Jar: cookieJar},
+		transport:        &http.Transport{},
 	}
 
 	c.httpClient.Transport = c.transport

request.go

@@ -411,23 +411,29 @@ func (r *Request) Execute(method, url string) (*Response, error) {
 
 	var resp *Response
 	attempt := 0
-	_ = Backoff(func() (*Response, error) {
-		attempt++
-
-		r.URL = r.selectAddr(addrs, url, attempt)
-
-		resp, err = r.client.execute(r)
-		if err != nil {
-			r.client.Log.Printf("ERROR [%v] Attempt [%v]", err, attempt)
-			if r.isContextCancelledIfAvailable() {
-				// stop Backoff from retrying request if request has been
-				// canceled by context
-				return resp, nil
+	_ = Backoff(
+		func() (*Response, error) {
+			attempt++
+
+			r.URL = r.selectAddr(addrs, url, attempt)
+
+			resp, err = r.client.execute(r)
+			if err != nil {
+				r.client.Log.Printf("ERROR [%v] Attempt [%v]", err, attempt)
+				if r.isContextCancelledIfAvailable() {
+					// stop Backoff from retrying request if request has been
+					// canceled by context
+					return resp, nil
+				}
 			}
-		}
 
-		return resp, err
-	}, Retries(r.client.RetryCount), RetryConditions(r.client.RetryConditions))
+			return resp, err
+		},
+		Retries(r.client.RetryCount),
+		WaitTime(r.client.RetryWaitTime),
+		MaxWaitTime(r.client.RetryMaxWaitTime),
+		RetryConditions(r.client.RetryConditions),
+	)
 
 	return resp, err
 }

resty_test.go

@@ -1163,10 +1163,10 @@ func getTestDataPath() string {
 	return pwd + "/test-data"
 }
 
-var attempt int32
-var sequence int32
-
 func createGetServer(t *testing.T) *httptest.Server {
+	var attempt int32
+	var sequence int32
+	var lastRequest time.Time
 	ts := createTestServer(func(w http.ResponseWriter, r *http.Request) {
 		t.Logf("Method: %v", r.Method)
 		t.Logf("Path: %v", r.URL.Path)
@@ -1184,6 +1184,19 @@ func createGetServer(t *testing.T) *httptest.Server {
 					time.Sleep(time.Second * 6)
 				}
 				_, _ = w.Write([]byte("TestClientRetry page"))
+			} else if r.URL.Path == "/set-retrywaittime-test" {
+				// Returns time.Duration since last request here
+				// or 0 for the very first request
+				if atomic.LoadInt32(&attempt) == 0 {
+					lastRequest = time.Now()
+					_, _ = fmt.Fprint(w, "0")
+				} else {
+					now := time.Now()
+					sinceLastRequest := now.Sub(lastRequest)
+					lastRequest = now
+					_, _ = fmt.Fprintf(w, "%d", uint64(sinceLastRequest))
+				}
+				atomic.AddInt32(&attempt, 1)
 			} else if r.URL.Path == "/set-timeout-test-with-sequence" {
 				seq := atomic.AddInt32(&sequence, 1)
 				time.Sleep(time.Second * 2)

retry.go

@@ -12,8 +12,8 @@ import (
 
 const (
 	defaultMaxRetries  = 3
-	defaultWaitTime    = 100  // base Milliseconds
-	defaultMaxWaitTime = 2000 // cap level Milliseconds
+	defaultWaitTime    = time.Duration(100) * time.Millisecond
+	defaultMaxWaitTime = time.Duration(2000) * time.Millisecond
 )
 
 // Option is to create convenient retry options like wait time, max retries, etc.
@@ -25,8 +25,8 @@ type RetryConditionFunc func(*Response) (bool, error)
 // Options to hold go-resty retry values
 type Options struct {
 	maxRetries      int
-	waitTime        int
-	maxWaitTime     int
+	waitTime        time.Duration
+	maxWaitTime     time.Duration
 	retryConditions []RetryConditionFunc
 }
 
@@ -38,14 +38,14 @@ func Retries(value int) Option {
 }
 
 // WaitTime sets the default wait time to sleep between requests
-func WaitTime(value int) Option {
+func WaitTime(value time.Duration) Option {
 	return func(o *Options) {
 		o.waitTime = value
 	}
 }
 
 // MaxWaitTime sets the max wait time to sleep between requests
-func MaxWaitTime(value int) Option {
+func MaxWaitTime(value time.Duration) Option {
 	return func(o *Options) {
 		o.maxWaitTime = value
 	}
@@ -100,9 +100,11 @@ func Backoff(operation func() (*Response, error), options ...Option) error {
 		// See the following article...
 		// http://www.awsarchitectureblog.com/2015/03/backoff.html
 		temp := math.Min(capLevel, base*math.Exp2(float64(attempt)))
-		sleepTime := int(temp/2) + rand.Intn(int(temp/2))
+		sleepDuration := time.Duration(int(temp/2) + rand.Intn(int(temp/2)))
 
-		sleepDuration := time.Duration(sleepTime) * time.Millisecond
+		if sleepDuration < opts.waitTime {
+			sleepDuration = opts.waitTime
+		}
 		time.Sleep(sleepDuration)
 	}
 

retry_test.go

@@ -180,6 +180,50 @@ func TestClientRetryGet(t *testing.T) {
 	assertEqual(t, true, strings.HasPrefix(err.Error(), "Get "+ts.URL+"/set-retrycount-test"))
 }
 
+func TestClientRetryWait(t *testing.T) {
+	ts := createGetServer(t)
+	defer ts.Close()
+
+	attempt := 0
+
+	retryCount := 5
+	retryIntervals := make([]uint64, retryCount)
+
+	// Set retry wait times that do not intersect with default ones
+	retryWaitTime := time.Duration(3) * time.Second
+	retryMaxWaitTime := time.Duration(9) * time.Second
+
+	c := dc()
+	c.SetHTTPMode().
+		SetRetryCount(retryCount).
+		SetRetryWaitTime(retryWaitTime).
+		SetRetryMaxWaitTime(retryMaxWaitTime).
+		AddRetryCondition(
+			func(r *Response) (bool, error) {
+				timeSlept, _ := strconv.ParseUint(string(r.Body()), 10, 64)
+				retryIntervals[attempt] = timeSlept
+				attempt++
+				return true, nil
+			},
+		)
+	c.R().Get(ts.URL + "/set-retrywaittime-test")
+
+	// 5 attempts were made
+	assertEqual(t, attempt, 5)
+
+	// Initial attempt has 0 time slept since last request
+	assertEqual(t, retryIntervals[0], uint64(0))
+
+	for i := 1; i < len(retryIntervals); i++ {
+		slept := time.Duration(retryIntervals[i])
+		// Ensure that client has slept some duration between
+		// waitTime and maxWaitTime for consequent requests
+		if slept < retryWaitTime || slept > retryMaxWaitTime {
+			t.Errorf("Client has slept %f seconds before retry %d", slept.Seconds(), i)
+		}
+	}
+}
+
 func TestClientRetryPost(t *testing.T) {
 	ts := createPostServer(t)
 	defer ts.Close()