1 files changed, 75 insertions, 0 deletions
diff --git a/rest-services/http-client/src/main/java/org/onap/dcaegen2/services/sdk/rest/services/adapters/http/retry/RetryLogic.java b/rest-services/http-client/src/main/java/org/onap/dcaegen2/services/sdk/rest/services/adapters/http/retry/RetryLogic.java
new file mode 100644
index 00000000..fd420843
--- /dev/null
+++ b/rest-services/http-client/src/main/java/org/onap/dcaegen2/services/sdk/rest/services/adapters/http/retry/RetryLogic.java
@@ -0,0 +1,75 @@
+/*
+ * ============LICENSE_START====================================
+ * DCAEGEN2-SERVICES-SDK
+ * =========================================================
+ * Copyright (C) 2021 Nokia. All rights reserved.
+ * =========================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=====================================
+ */
+
+package org.onap.dcaegen2.services.sdk.rest.services.adapters.http.retry;
+
+import org.onap.dcaegen2.services.sdk.rest.services.adapters.http.config.RetryConfig;
+import org.onap.dcaegen2.services.sdk.rest.services.adapters.http.exceptions.RetryableException;
+import org.onap.dcaegen2.services.sdk.rest.services.model.logging.RequestDiagnosticContext;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import reactor.core.publisher.Mono;
+import reactor.util.retry.Retry;
+
+import java.time.Duration;
+import java.util.Objects;
+
+public class RetryLogic {
+
+    private static final Logger LOGGER = LoggerFactory.getLogger(RetryLogic.class);
+
+    private final RetryConfig retryConfig;
+    private final RetryIntervalExtractor delayExtractor;
+
+    public RetryLogic(RetryConfig retryConfig, RetryIntervalExtractor delayExtractor) {
+        this.retryConfig = Objects.requireNonNull(retryConfig, "retryConfig must not be null");
+        this.delayExtractor = Objects.requireNonNull(delayExtractor, "delayExtractor must not be null");
+    }
+
+    public Retry retry(RequestDiagnosticContext requestDiagnosticContext) {
+        return Retry
+                .max(retryConfig.retryCount())
+                .doAfterRetryAsync(rc -> Mono.delay(calculateDelay(rc.failure())).then())
+                .doBeforeRetry(retrySignal -> requestDiagnosticContext.withSlf4jMdc(
+                        LOGGER.isTraceEnabled(), () -> LOGGER.trace("Retry: {}", retrySignal)))
+                .filter(ex -> isRetryable(retryConfig, ex))
+                .onRetryExhaustedThrow((retryBackoffSpec, retrySignal) -> retrySignal.failure());
+    }
+
+    public boolean shouldRetry(int code) {
+        return retryConfig.retryableHttpResponseCodes().contains(code);
+    }
+
+    private Duration calculateDelay(Throwable tx) {
+        Duration retryInterval = retryConfig.retryInterval();
+        if (tx instanceof RetryableException) {
+            RetryableException ex = (RetryableException) tx;
+            retryInterval = delayExtractor.extractDelay(ex.getResponse())
+                    .getOrElse(retryInterval);
+        }
+        return retryInterval;
+    }
+
+    private boolean isRetryable(RetryConfig retryConfig, Throwable ex) {
+        return retryConfig.retryableExceptions()
+                .toStream()
+                .exists(clazz -> clazz.isAssignableFrom(ex.getClass()));
+    }
+}