feat: add retries to client credential requests

README.md

@@ -42,6 +42,7 @@ This is an autogenerated Java SDK for OpenFGA. It provides a wrapper around the
     - [Assertions](#assertions)
       - [Read Assertions](#read-assertions)
       - [Write Assertions](#write-assertions)
+  - [Retries](#retries)
   - [API Endpoints](#api-endpoints)
   - [Models](#models)
 - [Contributing](#contributing)
@@ -133,7 +134,7 @@ import java.net.http.HttpClient;
 public class Example {
     public static void main(String[] args) throws Exception {
         var config = new ClientConfiguration()
-                .apiUrl(System.getenv("FGA_API_URL")) // If not specified, will default to "https://localhost:8080"
+                .apiUrl(System.getenv("FGA_API_URL")) // If not specified, will default to "http://localhost:8080"
                 .storeId(System.getenv("FGA_STORE_ID")) // Not required when calling createStore() or listStores()
                 .authorizationModelId(System.getenv("FGA_AUTHORIZATION_MODEL_ID")); // Optional, can be overridden per request
 
@@ -156,7 +157,7 @@ import java.net.http.HttpClient;
 public class Example {
     public static void main(String[] args) throws Exception {
         var config = new ClientConfiguration()
-                .apiUrl(System.getenv("FGA_API_URL")) // If not specified, will default to "https://localhost:8080"
+                .apiUrl(System.getenv("FGA_API_URL")) // If not specified, will default to "http://localhost:8080"
                 .storeId(System.getenv("FGA_STORE_ID")) // Not required when calling createStore() or listStores()
                 .authorizationModelId(System.getenv("FGA_AUTHORIZATION_MODEL_ID")) // Optional, can be overridden per request
                 .credentials(new Credentials(
@@ -182,7 +183,7 @@ import java.net.http.HttpClient;
 public class Example {
     public static void main(String[] args) throws Exception {
         var config = new ClientConfiguration()
-                .apiUrl(System.getenv("FGA_API_URL")) // If not specified, will default to "https://localhost:8080"
+                .apiUrl(System.getenv("FGA_API_URL")) // If not specified, will default to "http://localhost:8080"
                 .storeId(System.getenv("FGA_STORE_ID")) // Not required when calling createStore() or listStores()
                 .authorizationModelId(System.getenv("FGA_AUTHORIZATION_MODEL_ID")) // Optional, can be overridden per request
                 .credentials(new Credentials(
@@ -212,7 +213,7 @@ import java.net.http.HttpClient;
 public class Example {
     public static void main(String[] args) throws Exception {
         var config = new ClientConfiguration()
-                .apiUrl(System.getenv("FGA_API_URL")) // If not specified, will default to "https://localhost:8080"
+                .apiUrl(System.getenv("FGA_API_URL")) // If not specified, will default to "http://localhost:8080"
                 .storeId(System.getenv("FGA_STORE_ID")) // Not required when calling createStore() or listStores()
                 .authorizationModelId(System.getenv("FGA_AUTHORIZATION_MODEL_ID")) // Optional, can be overridden per request
                 .credentials(new Credentials(
@@ -805,6 +806,33 @@ fgaClient.writeAssertions(assertions, options).get();
 ```
 
 
+### Retries
+
+If a network request fails with a 429 or 5xx error from the server, the SDK will automatically retry the request up to 15 times with a minimum wait time of 100 milliseconds between each attempt.
+
+To customize this behavior, call `maxRetries` and `minimumRetryDelay` on the `ClientConfiguration` builder. `maxRetries` determines the maximum number of retries (up to 15), while `minimumRetryDelay` sets the minimum wait time between retries in milliseconds.
+
+```java
+import com.fasterxml.jackson.databind.ObjectMapper;
+import dev.openfga.sdk.api.client.OpenFgaClient;
+import dev.openfga.sdk.api.configuration.ClientConfiguration;
+import java.net.http.HttpClient;
+
+public class Example {
+    public static void main(String[] args) throws Exception {
+        var config = new ClientConfiguration()
+                .apiUrl(System.getenv("FGA_API_URL")) // If not specified, will default to "http://localhost:8080"
+                .storeId(System.getenv("FGA_STORE_ID")) // Not required when calling createStore() or listStores()
+                .authorizationModelId(System.getenv("FGA_AUTHORIZATION_MODEL_ID")) // Optional, can be overridden per request
+                .maxRetries(3) // retry up to 3 times on API requests
+                .minimumRetryDelay(250); // wait a minimum of 250 milliseconds between requests
+
+        var fgaClient = new OpenFgaClient(config);
+        var response = fgaClient.readAuthorizationModels().get();
+    }
+}
+```
+
 ### API Endpoints
 
 | Method | HTTP request | Description |

build.gradle

@@ -72,6 +72,7 @@ testing {
                 implementation "org.junit.jupiter:junit-jupiter:$junit_version"
                 implementation "org.mockito:mockito-core:5.+"
                 runtimeOnly "org.junit.platform:junit-platform-launcher"
+                implementation "org.wiremock:wiremock:3.5.2"
 
                 // This test-only dependency is convenient but not widely used.
                 // Review project activity before updating the version here.

src/main/java/dev/openfga/sdk/api/auth/OAuth2Client.java

@@ -25,9 +25,9 @@ public class OAuth2Client {
     private static final String DEFAULT_API_TOKEN_ISSUER_PATH = "/oauth/token";
 
     private final ApiClient apiClient;
-    private final String apiTokenIssuer;
     private final AccessToken token = new AccessToken();
     private final CredentialsFlowRequest authRequest;
+    private final Configuration config;
 
     /**
      * Initializes a new instance of the {@link OAuth2Client} class
@@ -38,11 +38,14 @@ public OAuth2Client(Configuration configuration, ApiClient apiClient) throws Fga
         var clientCredentials = configuration.getCredentials().getClientCredentials();
 
         this.apiClient = apiClient;
-        this.apiTokenIssuer = buildApiTokenIssuer(clientCredentials.getApiTokenIssuer());
         this.authRequest =
                 new CredentialsFlowRequest(clientCredentials.getClientId(), clientCredentials.getClientSecret());
         this.authRequest.setAudience(clientCredentials.getApiAudience());
         this.authRequest.setScope(clientCredentials.getScopes());
+        this.config = new Configuration()
+                .apiUrl(buildApiTokenIssuer(clientCredentials.getApiTokenIssuer()))
+                .maxRetries(configuration.getMaxRetries())
+                .minimumRetryDelay(configuration.getMinimumRetryDelay());
     }
 
     /**
@@ -70,8 +73,6 @@ public CompletableFuture<String> getAccessToken() throws FgaInvalidParameterExce
     private CompletableFuture<CredentialsFlowResponse> exchangeToken()
             throws ApiException, FgaInvalidParameterException {
 
-        Configuration config = new Configuration().apiUrl(apiTokenIssuer);
-
         HttpRequest.Builder requestBuilder =
                 ApiClient.formRequestBuilder("POST", "", this.authRequest.buildFormRequestBody(), config);
         HttpRequest request = requestBuilder.build();

src/test/java/dev/openfga/sdk/api/auth/OAuth2ClientTest.java

@@ -12,25 +12,30 @@
 
 package dev.openfga.sdk.api.auth;
 
+import static com.github.tomakehurst.wiremock.client.WireMock.*;
 import static org.hamcrest.Matchers.allOf;
 import static org.hamcrest.core.StringContains.containsString;
 import static org.junit.jupiter.api.Assertions.*;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.when;
 
 import com.fasterxml.jackson.databind.ObjectMapper;
+import com.github.tomakehurst.wiremock.junit5.*;
+import com.github.tomakehurst.wiremock.stubbing.Scenario;
 import com.pgssoft.httpclient.HttpClientMock;
 import dev.openfga.sdk.api.client.ApiClient;
 import dev.openfga.sdk.api.configuration.*;
 import dev.openfga.sdk.errors.FgaInvalidParameterException;
 import java.net.URLEncoder;
 import java.nio.charset.StandardCharsets;
+import java.time.Duration;
 import java.util.stream.Stream;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.Arguments;
 import org.junit.jupiter.params.provider.MethodSource;
 
+@WireMockTest
 class OAuth2ClientTest {
     private static final String CLIENT_ID = "client";
     private static final String CLIENT_SECRET = "secret";
@@ -126,6 +131,49 @@ public void exchangeOAuth2Token(String apiTokenIssuer, String tokenEndpointUrl)
         assertEquals(ACCESS_TOKEN, result);
     }
 
+    @Test
+    public void exchangeOAuth2TokenWithRetriesSuccess(WireMockRuntimeInfo wm) throws Exception {
+        // Return 429 initially
+        stubFor(post(urlEqualTo("/oauth/token"))
+                .inScenario("retries")
+                .whenScenarioStateIs(Scenario.STARTED)
+                .willReturn(jsonResponse("rate_limited", 429))
+                .willSetStateTo("rate limited once"));
+
+        // Then return 500
+        stubFor(post(urlEqualTo("/oauth/token"))
+                .inScenario("retries")
+                .whenScenarioStateIs("rate limited once")
+                .willReturn(jsonResponse("rate_limited", 500))
+                .willSetStateTo("rate limited twice"));
+
+        // Finally return 200
+        stubFor(post(urlEqualTo("/oauth/token"))
+                .inScenario("retries")
+                .whenScenarioStateIs("rate limited twice")
+                .willReturn(ok(String.format("{\"access_token\":\"%s\"}", ACCESS_TOKEN))));
+
+        OAuth2Client auth0 = newOAuth2Client(wm.getHttpBaseUrl(), false);
+
+        String result = auth0.getAccessToken().get();
+
+        assertEquals(ACCESS_TOKEN, result);
+        verify(3, postRequestedFor(urlEqualTo("/oauth/token")));
+    }
+
+    @Test
+    public void exchangeOAuth2TokenWithRetriesFailure(WireMockRuntimeInfo wm) throws Exception {
+        stubFor(post(urlEqualTo("/oauth/token")).willReturn(jsonResponse("error", 429)));
+
+        OAuth2Client auth0 = newOAuth2Client(wm.getHttpBaseUrl(), false);
+
+        var exception = assertThrows(java.util.concurrent.ExecutionException.class, () -> auth0.getAccessToken()
+                .get());
+
+        assertEquals("dev.openfga.sdk.errors.FgaApiRateLimitExceededError: exchangeToken", exception.getMessage());
+        verify(3, postRequestedFor(urlEqualTo("/oauth/token")));
+    }
+
     @Test
     public void apiTokenIssuer_invalidScheme() {
         // When
@@ -164,7 +212,8 @@ private OAuth2Client newAuth0Client(String apiTokenIssuer) throws FgaInvalidPara
                         .clientId(CLIENT_ID)
                         .clientSecret(CLIENT_SECRET)
                         .apiAudience(AUDIENCE)
-                        .apiTokenIssuer(apiTokenIssuer)));
+                        .apiTokenIssuer(apiTokenIssuer)),
+                true);
     }
 
     private OAuth2Client newOAuth2Client(String apiTokenIssuer) throws FgaInvalidParameterException {
@@ -174,21 +223,45 @@ private OAuth2Client newOAuth2Client(String apiTokenIssuer) throws FgaInvalidPar
                         .clientId(CLIENT_ID)
                         .clientSecret(CLIENT_SECRET)
                         .scopes(SCOPES)
-                        .apiTokenIssuer(apiTokenIssuer)));
+                        .apiTokenIssuer(apiTokenIssuer)),
+                true);
+    }
+
+    private OAuth2Client newOAuth2Client(String apiTokenIssuer, Boolean useMockHttpClient)
+            throws FgaInvalidParameterException {
+        return newClientCredentialsClient(
+                apiTokenIssuer,
+                new Credentials(new ClientCredentials()
+                        .clientId(CLIENT_ID)
+                        .clientSecret(CLIENT_SECRET)
+                        .scopes(SCOPES)
+                        .apiTokenIssuer(apiTokenIssuer)),
+                useMockHttpClient);
     }
 
-    private OAuth2Client newClientCredentialsClient(String apiTokenIssuer, Credentials credentials)
+    private OAuth2Client newClientCredentialsClient(
+            String apiTokenIssuer, Credentials credentials, Boolean useMockHttpClient)
             throws FgaInvalidParameterException {
         System.setProperty("HttpRequestAttempt.debug-logging", "enable");
 
-        mockHttpClient = new HttpClientMock();
-        mockHttpClient.debugOn();
+        var configuration = new Configuration()
+                .apiUrl("")
+                .credentials(credentials)
+                .maxRetries(2)
+                .minimumRetryDelay(Duration.ofMillis(10));
 
-        var configuration = new Configuration().apiUrl("").credentials(credentials);
+        // If requested, enable the HttpClientMock and set that as the HttpClient to use in ApiClient
+        ApiClient apiClient;
+        if (useMockHttpClient) {
+            mockHttpClient = new HttpClientMock();
+            mockHttpClient.debugOn();
 
-        var apiClient = mock(ApiClient.class);
-        when(apiClient.getHttpClient()).thenReturn(mockHttpClient);
-        when(apiClient.getObjectMapper()).thenReturn(mapper);
+            apiClient = mock(ApiClient.class);
+            when(apiClient.getHttpClient()).thenReturn(mockHttpClient);
+            when(apiClient.getObjectMapper()).thenReturn(mapper);
+        } else {
+            apiClient = new ApiClient();
+        }
 
         return new OAuth2Client(configuration, apiClient);
     }