Further enhancement to OtlpMetricsSender

Introduces an immutable Request object and builder.

Author: shakuzen

docs/src/test/java/io/micrometer/docs/metrics/OtlpMeterRegistryCustomizationTest.java

@@ -23,8 +23,6 @@
 import io.micrometer.registry.otlp.OtlpMetricsSender;
 import org.junit.jupiter.api.Test;
 
-import java.util.Map;
-
 class OtlpMeterRegistryCustomizationTest {
 
     @Test
@@ -49,7 +47,7 @@ void customizeOtlpSender() {
     private static class OtlpGrpcMetricsSender implements OtlpMetricsSender {
 
         @Override
-        public void send(String address, byte[] metricsData, Map<String, String> headers) {
+        public void send(Request request) {
         }
 
     }

implementations/micrometer-registry-otlp/src/main/java/io/micrometer/registry/otlp/MetricsSender.java

@@ -15,21 +15,15 @@
  */
 package io.micrometer.registry.otlp;
 
-import io.micrometer.common.util.internal.logging.InternalLogger;
-import io.micrometer.common.util.internal.logging.InternalLoggerFactory;
 import io.micrometer.core.ipc.http.HttpSender;
 
-import java.util.Map;
-
 /**
  * An implementation of {@link OtlpMetricsSender} that uses an {@link HttpSender}.
  *
  * @since 1.15.0
  */
 public class OtlpHttpMetricsSender implements OtlpMetricsSender {
 
-    private static final InternalLogger logger = InternalLoggerFactory.getInstance(OtlpHttpMetricsSender.class);
-
     private final HttpSender httpSender;
 
     private final String userAgentHeader;
@@ -41,19 +35,23 @@ public OtlpHttpMetricsSender(HttpSender httpSender) {
 
     /**
      * Send a batch of OTLP Protobuf format metrics to an OTLP HTTP receiver.
-     * @param address address of the OTLP HTTP receiver to which metrics will be sent
-     * @param metricsData OTLP protobuf encoded batch of metrics
-     * @param headers metadata to send as headers with the metrics data
-     * @throws Throwable when there is an exception in sending the metrics; the caller
+     * @param request metrics request to publish
+     * @throws Exception when there is an exception in sending the metrics; the caller
      * should handle this in some way such as logging the exception
      */
     @Override
-    public void send(String address, byte[] metricsData, Map<String, String> headers) throws Throwable {
-        HttpSender.Request.Builder httpRequest = this.httpSender.post(address)
+    public void send(Request request) throws Exception {
+        HttpSender.Request.Builder httpRequest = this.httpSender.post(request.getAddress())
             .withHeader("User-Agent", userAgentHeader)
-            .withContent("application/x-protobuf", metricsData);
-        headers.forEach(httpRequest::withHeader);
-        HttpSender.Response response = httpRequest.send();
+            .withContent("application/x-protobuf", request.getMetricsData());
+        request.getHeaders().forEach(httpRequest::withHeader);
+        HttpSender.Response response;
+        try {
+            response = httpRequest.send();
+        }
+        catch (Throwable e) {
+            throw new Exception(e);
+        }
         if (!response.isSuccessful()) {
             throw new OtlpHttpMetricsSendUnsuccessfulException(String
                 .format("Server responded with HTTP status code %d and body %s", response.code(), response.body()));
@@ -71,7 +69,7 @@ private String getUserAgentHeader() {
 
     private static class OtlpHttpMetricsSendUnsuccessfulException extends RuntimeException {
 
-        public OtlpHttpMetricsSendUnsuccessfulException(String message) {
+        private OtlpHttpMetricsSendUnsuccessfulException(String message) {
             super(message);
         }
 

implementations/micrometer-registry-otlp/src/main/java/io/micrometer/registry/otlp/OtlpHttpMetricsSender.java

@@ -181,9 +181,9 @@ protected void publish() {
                         .build())
                     .build();
 
-                metricsSender.send(config.url(), request.toByteArray(), config.headers());
+                metricsSender.newRequest(request.toByteArray()).address(config.url()).headers(config.headers()).send();
             }
-            catch (Throwable e) {
+            catch (Exception e) {
                 logger.warn(String.format("Failed to publish metrics to OTLP receiver (context: %s)",
                         getConfigurationContext()), e);
             }

implementations/micrometer-registry-otlp/src/main/java/io/micrometer/registry/otlp/OtlpMeterRegistry.java

@@ -15,6 +15,10 @@
  */
 package io.micrometer.registry.otlp;
 
+import io.micrometer.common.lang.Nullable;
+
+import java.nio.charset.StandardCharsets;
+import java.util.Collections;
 import java.util.Map;
 
 /**
@@ -23,17 +27,112 @@
  *
  * @since 1.15.0
  */
-public interface OtlpMetricsSender extends MetricsSender {
+public interface OtlpMetricsSender {
 
     /**
      * Send a batch of OTLP Protobuf format metrics to an OTLP receiver.
-     * @param address address of the OTLP receiver to which metrics will be sent
-     * @param metricsData OTLP protobuf encoded batch of metrics
-     * @param headers metadata to send as headers with the metrics data
-     * @throws Throwable when there is an exception in sending the metrics; the caller
+     * @param request metrics request to publish
+     * @throws Exception when there is an exception in sending the metrics; the caller
      * should handle this in some way such as logging the exception
      */
-    @Override
-    void send(String address, byte[] metricsData, Map<String, String> headers) throws Throwable;
+    void send(Request request) throws Exception;
+
+    /**
+     * Start building a request to use with this sender.
+     * @param metricsData metrics data that will be sent
+     * @return builder
+     * @see Request.Builder#send
+     */
+    default Request.Builder newRequest(byte[] metricsData) {
+        return new Request.Builder(metricsData, this);
+    }
+
+    /**
+     * Immutable representation of a payload of metrics to use with a
+     * {@link OtlpMetricsSender}.
+     *
+     * @since 1.15.0
+     */
+    class Request {
+
+        @Nullable
+        private final String address;
+
+        private final Map<String, String> headers;
+
+        private final byte[] metricsData;
+
+        /**
+         * Represents a payload of metrics to be sent.
+         * @param address where to send the metrics
+         * @param metricsData encoded batch of metrics
+         * @param headers metadata to send as headers with the metrics data
+         */
+        private Request(@Nullable String address, Map<String, String> headers, byte[] metricsData) {
+            this.address = address;
+            this.headers = headers;
+            this.metricsData = metricsData;
+        }
+
+        @Nullable
+        public String getAddress() {
+            return address;
+        }
+
+        public byte[] getMetricsData() {
+            return metricsData;
+        }
+
+        public Map<String, String> getHeaders() {
+            return headers;
+        }
+
+        @Override
+        public String toString() {
+            return "OtlpMetricsSender.Request for address: " + address + ", headers: " + headers + ", metricsData: "
+                    + new String(metricsData, StandardCharsets.UTF_8);
+        }
+
+        public static class Builder {
+
+            private final byte[] metricsData;
+
+            private final OtlpMetricsSender sender;
+
+            @Nullable
+            private String address;
+
+            private Map<String, String> headers = Collections.emptyMap();
+
+            private Builder(byte[] metricsData, OtlpMetricsSender sender) {
+                this.metricsData = metricsData;
+                this.sender = sender;
+            }
+
+            public Builder address(String address) {
+                this.address = address;
+                return this;
+            }
+
+            public Builder headers(Map<String, String> headers) {
+                this.headers = headers;
+                return this;
+            }
+
+            public Request build() {
+                return new Request(address, headers, metricsData);
+            }
+
+            /**
+             * Build this request and send it to the associated sender.
+             * @throws Exception when sending the request fails, an exception is thrown
+             */
+            public void send() throws Exception {
+                sender.send(build());
+            }
+
+        }
+
+    }
 
 }