Merge pull request #8 from sekikatsu36/feature/update-apache-httpclinet-to-handle-error

update apache-httpclinet module to handle error

Author: sekikatsu36

.idea/gradle.xml

@@ -6,7 +6,7 @@
 
 ## Release notes - 1.0.4 (2020-08-07)
 
-## Added
+### Added
 
 - OkHttp integration
 

CHANGELOG.md

@@ -3,21 +3,31 @@
 ## How to setup
 
 Add `M3TracingHttpInterceptor` as request/response interceptor of HttpClient.
+In addition, to close a span whenever failed to send a request, set M3TracingHttpRequestRetryHandler as HttpRequestRetryHandler.
 
 ### httpclient 4.2-
 
-```java:
+```java
+private static final M3TracingHttpRequestRetryHandler retryHander = new M3TracingHttpRequestRetryHandler(new DefaultHttpRequestRetryHandler());
+```
+
+```java
 // CAUTION: Must setup as BOTH interceptor otherwise it may cause memory leak.
 httpclient.addRequestInterceptor(M3TracingHttpInterceptor.INSTANCE);
 httpclient.addResponseInterceptor(M3TracingHttpInterceptor.INSTANCE);
+httpclient.setHttpRequestRetryHandler(retryHander);
 ```
 
 ### httpclient 4.3+
 
+```java
+private static final M3TracingHttpRequestRetryHandler retryHander = new M3TracingHttpRequestRetryHandler(new DefaultHttpRequestRetryHandler());
+```
+
 ```java
 CloseableHttpClient httpClient = HttpClientBuilder.create()
     .addInterceptorFirst((HttpRequestInterceptor) M3TracingHttpInterceptor.INSTANCE)
     .addInterceptorLast((HttpResponseInterceptor) M3TracingHttpInterceptor.INSTANCE)
+    .setRetryHandler(retryHander)
     .build();
 ```
-                }

jvm/apache-httpclient/README.md

@@ -28,6 +28,21 @@ open class M3TracingHttpInterceptor(
 
     constructor() : this(M3TracerFactory.get())
 
+    internal fun closeSpan(callback: (span: TraceSpan) -> Unit) {
+        val span = currentSpan.get()
+        if(span == null) {
+            logger.debug("Current span is not found. Unable to close and send span.")
+            return
+        }
+
+        doQuietly {
+            callback(span)
+        }
+        span.close()
+        currentSpan.set(null) // Prevent ClassLoader leak
+    }
+
+
     override fun process(request: HttpRequest, context: HttpContext) {
         val requestInfo = ApacheHttpRequestInfo(request, context)
         val span = tracer.processOutgoingHttpRequest(requestInfo)
@@ -41,14 +56,9 @@ open class M3TracingHttpInterceptor(
     }
 
     override fun process(response: HttpResponse, context: HttpContext) {
-        val span = currentSpan.get() ?: return
-        currentSpan.set(null) // Prevent ClassLoader leak
-
-        // Must continue to span.close() statement to prevent memory leak
-        doQuietly {
-            span["status"] = response.statusLine.statusCode
+        closeSpan {
+            it["status"] = response.statusLine.statusCode
         }
-        span.close()
     }
 
     /**

jvm/apache-httpclient/src/main/kotlin/com/m3/tracing/apache/httpclient/M3TracingHttpInterceptor.kt

@@ -0,0 +1,24 @@
+package com.m3.tracing.apache.httpclient
+
+import org.apache.http.client.HttpRequestRetryHandler
+import org.apache.http.protocol.HttpContext
+import org.slf4j.LoggerFactory
+import java.io.IOException
+
+open class M3TracingHttpRequestRetryHandler(private val baseHandler: HttpRequestRetryHandler) : HttpRequestRetryHandler {
+    companion object {
+        private val logger = LoggerFactory.getLogger(M3TracingHttpRequestRetryHandler::class.java)
+    }
+
+    override fun retryRequest(exception: IOException?, executionCount: Int, context: HttpContext?): Boolean {
+        val result = baseHandler.retryRequest(exception, executionCount, context)
+
+        // When not retrying, try to close current span
+        if(!result) {
+            M3TracingHttpInterceptor.INSTANCE.closeSpan {
+                it["error"] = exception?.message
+            }
+        }
+        return result
+    }
+}

jvm/apache-httpclient/src/main/kotlin/com/m3/tracing/apache/httpclient/M3TracingHttpRequestRetryHandler.kt

@@ -12,7 +12,7 @@ plugins {
 
 allprojects {
     group = "com.m3.tracing"
-    version = "1.0.4"
+    version = "1.0.5-SNAPSHOT"
 
     repositories {
         jcenter()