Implement M3TracingHttpInterceptor

jvm/apache-httpclient/README.md

@@ -0,0 +1,11 @@
+# Apache HttpClient integration
+
+## How to setup
+
+Add `M3TracingHttpInterceptor` as request/response interceptor of HttpClient.
+
+```java
+// CAUTION: Must setup as BOTH interceptor otherwise it may cause memory leak.
+httpclient.addRequestInterceptor(M3TracingHttpInterceptor.INSTANCE);
+httpclient.addResponseInterceptor(M3TracingHttpInterceptor.INSTANCE);
+```

jvm/apache-httpclient/build.gradle.kts

@@ -0,0 +1,9 @@
+plugins {
+    kotlin("jvm")
+}
+
+dependencies {
+    api(project(":core"))
+
+    implementation("org.apache.httpcomponents:httpclient:${project.extra["apacheHttpClientVersion"]}")
+}

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

@@ -0,0 +1,73 @@
+package com.m3.tracing.apache.httpclient
+
+import com.m3.tracing.M3Tracer
+import com.m3.tracing.M3TracerFactory
+import com.m3.tracing.TraceSpan
+import org.apache.http.HttpRequest
+import org.apache.http.HttpRequestInterceptor
+import org.apache.http.HttpResponse
+import org.apache.http.HttpResponseInterceptor
+import org.apache.http.client.methods.HttpUriRequest
+import org.apache.http.protocol.HttpContext
+import org.slf4j.LoggerFactory
+
+/**
+ * Interceptor for Apache HTTP Client.
+ *
+ */
+open class M3TracingHttpInterceptor(
+        protected val tracer: M3Tracer
+) : HttpRequestInterceptor, HttpResponseInterceptor {
+    companion object {
+        @JvmStatic
+        public val INSTANCE = M3TracingHttpInterceptor()
+
+        private val currentSpan = ThreadLocal<TraceSpan>()
+        private val logger = LoggerFactory.getLogger(M3TracingHttpInterceptor::class.java)
+    }
+
+    constructor(): this(M3TracerFactory.get())
+
+    override fun process(request: HttpRequest, context: HttpContext) {
+        val span = tracer.startSpan(createSpanName(request))
+        currentSpan.set(span) // Set to ThreadLocal ASAP to prevent leak
+
+        doQuietly {
+            span["method"] = request.requestLine.method
+            span["uri"] = request.requestLine.uri
+        }
+    }
+
+    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
+        }
+        span.close()
+    }
+
+
+    private fun createSpanName(request: HttpRequest): String {
+        // Intentionally excluded queryString because it might contain dynamic string
+        // Dynamic span name makes runningSpan table so huge
+        return if (request is HttpUriRequest) {
+            "HTTP ${request.method} ${request.uri.host}"
+        } else {
+            "HTTP ${request.requestLine.method}"
+        }
+    }
+
+    /**
+     * `On Error Resume Next` in 21st century.
+     */
+    protected fun doQuietly(action: () -> Unit) {
+        try {
+            action()
+        } catch (e: Throwable) {
+            logger.error("Failed to update Span.", e)
+        }
+    }
+}

jvm/apache-httpclient/src/test/resources/logging.properties

@@ -0,0 +1,2 @@
+handlers = org.slf4j.bridge.SLF4JBridgeHandler
+.level=INFO

jvm/build.gradle.kts

@@ -27,9 +27,15 @@ subprojects {
     apply(plugin = "maven-publish")
 
     val opencensusVersion by extra { "0.20.0" }
+
+    //Intentionally support Servlet API 3.0
+    //Intentionally support Servlet API 3.0
     val servletApiVersion by extra { "3.0.1" }
+
+    // Following versions are based on spring-boot
+    val springBootVersion by extra { "2.1.4.RELEASE" }
     val springWebVersion by extra { "5.1.6.RELEASE" }
-    val springBootVersion by extra { "2.1.4.RELEASE" } // spring-boot 2.1.4 -> spring-web 5.1.6
+    val apacheHttpClientVersion by extra { "4.5.8" }
 
     dependencies {
         compile(kotlin("stdlib-jdk8"))

jvm/jdbc-p6spy/src/main/kotlin/com/m3/tracing/jdbc/p6spy/M3TracingJdbcEventListener.kt

@@ -24,6 +24,8 @@ open class M3TracingJdbcEventListener: SimpleJdbcEventListener() {
 
     override fun onAfterAnyExecute(statementInformation: StatementInformation, timeElapsedNanos: Long, e: SQLException?) {
         val span = currentSpan.get() ?: return
+        currentSpan.set(null) // Prevent ClassLoader leak
+
         doQuietly { // Must proceed to close() statement to prevent leak
             span["time_elapsed_nanos"] = timeElapsedNanos
             if (e != null) {
@@ -37,7 +39,7 @@ open class M3TracingJdbcEventListener: SimpleJdbcEventListener() {
     /**
      * `On Error Resume Next` in 21st century.
      */
-    protected inline fun doQuietly(action: () -> Unit) {
+    protected fun doQuietly(action: () -> Unit) {
         try {
             action()
         } catch (e: Throwable) {

jvm/settings.gradle.kts

@@ -1,4 +1,5 @@
 include(
+        "apache-httpclient",
         "core",
         "jdbc-p6spy",
         "opencensus",