feat: add retry mechanism

docs/index.md

@@ -37,6 +37,7 @@ description: |-
 - **read_method** (String, Optional) Defaults to `GET`. The HTTP method used to READ objects of this type on the API server.
 - **test_path** (String, Optional) If set, the provider will issue a read_method request to this path after instantiation requiring a 200 OK response before proceeding. This is useful if your API provides a no-op endpoint that can signal if this provider is configured correctly. Response data will be ignored.
 - **timeout** (Number, Optional) When set, will cause requests taking longer than this time (in seconds) to be aborted.
+- **retry** (Number, Optional) When set, will cause requests to be retried on network error.
 - **update_method** (String, Optional) Defaults to `PUT`. The HTTP method used to UPDATE objects of this type on the API server.
 - **use_cookies** (Boolean, Optional) Enable cookie jar to persist session.
 - **username** (String, Optional) When set, will use this username for BASIC auth to the API.

restapi/api_client.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"context"
 	"crypto/tls"
+	"crypto/x509"
 	"errors"
 	"fmt"
 	"io/ioutil"
@@ -12,6 +13,7 @@ import (
 	"net/http"
 	"net/http/cookiejar"
 	"net/url"
+	"regexp"
 	"strings"
 	"time"
 
@@ -26,6 +28,7 @@ type apiClientOpt struct {
 	password            string
 	headers             map[string]string
 	timeout             int
+	retry               int
 	idAttribute         string
 	createMethod        string
 	readMethod          string
@@ -75,8 +78,13 @@ type APIClient struct {
 	rateLimiter         *rate.Limiter
 	debug               bool
 	oauthConfig         *clientcredentials.Config
+	retry               int
 }
 
+var redirectsErrorRe = regexp.MustCompile(`stopped after \d+ redirects\z`)
+var schemeErrorRe = regexp.MustCompile(`unsupported protocol scheme`)
+var notTrustedErrorRe = regexp.MustCompile(`certificate is not trusted`)
+
 //NewAPIClient makes a new api client for RESTful calls
 func NewAPIClient(opt *apiClientOpt) (*APIClient, error) {
 	if opt.debug {
@@ -173,6 +181,7 @@ func NewAPIClient(opt *apiClientOpt) (*APIClient, error) {
 		createReturnsObject: opt.createReturnsObject,
 		xssiPrefix:          opt.xssiPrefix,
 		debug:               opt.debug,
+		retry:               opt.retry,
 	}
 
 	if opt.oauthClientID != "" && opt.oauthClientSecret != "" && opt.oauthTokenURL != "" {
@@ -218,6 +227,8 @@ func (client *APIClient) sendRequest(method string, path string, data string) (s
 	fullURI := client.uri + path
 	var req *http.Request
 	var err error
+    var resp http.Response
+
 
 	if client.debug {
 		log.Printf("api_client.go: method='%s', path='%s', full uri (derived)='%s', data='%s'\n", method, path, fullURI, data)
@@ -290,7 +301,37 @@ func (client *APIClient) sendRequest(method string, path string, data string) (s
 		_ = client.rateLimiter.Wait(context.Background())
 	}
 
-	resp, err := client.httpClient.Do(req)
+    for attempt := 0; attempt < client.retry; attempt++ {
+	    resp, err := client.httpClient.Do(req)
+	    if err != nil { // No HTTP response, transport error
+	        if v, ok := err.(*url.Error); ok {
+                if redirectsErrorRe.MatchString(v.Error()) {
+                    break
+                }
+                if schemeErrorRe.MatchString(v.Error()) {
+                    break
+                }
+                if notTrustedErrorRe.MatchString(v.Error()) {
+                    break
+                }
+                if _, ok := v.Err.(x509.UnknownAuthorityError); ok {
+                    break
+                }
+	        }
+	        // if none of the above conditions matched, the error is likely recoverable.
+            // continue
+	    } else { // HTTP response available
+               	if resp.StatusCode == http.StatusTooManyRequests {
+                    continue
+                }
+                if resp.StatusCode == 0 || (resp.StatusCode >= 500 && resp.StatusCode != http.StatusNotImplemented) {
+                   continue
+                }
+               // if none of the above conditions matched, the error is likely unrecoverable.
+               // break
+	    }
+	    time.Sleep(5)
+	}
 
 	if err != nil {
 		//log.Printf("api_client.go: Error detected: %s\n", err)

restapi/api_client_test.go

@@ -25,6 +25,7 @@ func TestAPIClient(t *testing.T) {
 		password:            "",
 		headers:             make(map[string]string),
 		timeout:             2,
+		retry:               0,
 		idAttribute:         "id",
 		copyKeys:            make([]string, 0),
 		writeReturnsObject:  false,

restapi/api_object_test.go

@@ -87,6 +87,7 @@ var client, err = NewAPIClient(&apiClientOpt{
 	password:            "",
 	headers:             make(map[string]string),
 	timeout:             5,
+	retry:               0,
 	idAttribute:         "Id",
 	copyKeys:            []string{"Thing"},
 	writeReturnsObject:  true,

restapi/datasource_api_object_test.go

@@ -30,6 +30,7 @@ func TestAccRestapiobject_Basic(t *testing.T) {
 		password:            "",
 		headers:             make(map[string]string),
 		timeout:             2,
+		retry:               0,
 		idAttribute:         "id",
 		copyKeys:            make([]string, 0),
 		writeReturnsObject:  false,

restapi/import_api_object_test.go

@@ -22,6 +22,7 @@ func TestAccRestApiObject_importBasic(t *testing.T) {
 		password:            "",
 		headers:             make(map[string]string),
 		timeout:             2,
+		retry:               0,
 		idAttribute:         "id",
 		copyKeys:            make([]string, 0),
 		writeReturnsObject:  false,

restapi/provider.go

@@ -54,6 +54,12 @@ func Provider() *schema.Provider {
 				DefaultFunc: schema.EnvDefaultFunc("REST_API_TIMEOUT", 0),
 				Description: "When set, will cause requests taking longer than this time (in seconds) to be aborted.",
 			},
+            "retry": {
+				Type:        schema.TypeInt,
+				Optional:    true,
+				DefaultFunc: schema.EnvDefaultFunc("REST_API_RETRY", 0),
+				Description: "When set, will cause requests to be retried on network error.",
+			},
 			"id_attribute": {
 				Type:        schema.TypeString,
 				Optional:    true,
@@ -232,6 +238,7 @@ func configureProvider(d *schema.ResourceData) (interface{}, error) {
 		headers:             headers,
 		useCookies:          d.Get("use_cookies").(bool),
 		timeout:             d.Get("timeout").(int),
+		retry:               d.Get("retry").(int),
 		idAttribute:         d.Get("id_attribute").(string),
 		copyKeys:            copyKeys,
 		writeReturnsObject:  d.Get("write_returns_object").(bool),

restapi/resource_api_object_test.go

@@ -36,6 +36,7 @@ func TestAccRestApiObject_Basic(t *testing.T) {
 		password:            "",
 		headers:             make(map[string]string),
 		timeout:             2,
+		retry:               0,
 		idAttribute:         "id",
 		copyKeys:            make([]string, 0),
 		writeReturnsObject:  false,