[CELEBORN-407] Add conf setting to http request (#1337)

* [CELEBORN-407] Add conf setting to http request

service/src/main/scala/org/apache/celeborn/server/common/HttpService.scala

@@ -25,6 +25,16 @@ abstract class HttpService extends Service with Logging {
 
   private var httpServer: HttpServer = _
 
+  def getConf: String = {
+    val sb = new StringBuilder
+    val maxKeyLength = conf.getAll.toMap.keys.map(_.length).max
+    sb.append("==============Configurations==============\n")
+    conf.getAll.foreach { case (key, value) =>
+      sb.append(key.padTo(maxKeyLength + 10, " ") + value + "\n")
+    }
+    sb.toString()
+  }
+
   def getWorkerInfo: String
 
   def getLostWorkers: String

service/src/main/scala/org/apache/celeborn/server/common/http/HttpRequestHandler.scala

@@ -62,6 +62,8 @@ class HttpRequestHandler(
 
   def handleRequest(uri: String): String = {
     uri match {
+      case "/conf" =>
+        service.getConf
       case "/workerInfo" =>
         service.getWorkerInfo
       case "/lostWorkers" if service.serviceName == Service.MASTER =>