Fixed a bug in the result file URL generator

Using worker's "vnid" (virtual netvork identifier) instead of
the worker's host name for the XROOT protocol option. Using FQND
of the worker's host name for the HTTP protocol option. The changes
allow running the application in the Kubernetes environment.

src/wbase/Task.cc

@@ -37,7 +37,6 @@
 
 // Third-party headers
 #include <boost/algorithm/string/replace.hpp>
-#include "boost/asio.hpp"
 #include "boost/filesystem.hpp"
 
 // LSST headers
@@ -51,6 +50,7 @@
 #include "proto/TaskMsgDigest.h"
 #include "proto/worker.pb.h"
 #include "util/Bug.h"
+#include "util/common.h"
 #include "util/HoldTrack.h"
 #include "util/IterableFormatter.h"
 #include "util/TimeUtils.h"
@@ -69,18 +69,6 @@ namespace {
 
 LOG_LOGGER _log = LOG_GET("lsst.qserv.wbase.Task");
 
-string get_hostname() {
-    // Get the short name of the current host.
-    boost::system::error_code ec;
-    string const hostname = boost::asio::ip::host_name(ec);
-    if (ec.value() != 0) {
-        throw runtime_error("Task::" + string(__func__) +
-                            " boost::asio::ip::host_name failed: " + ec.category().name() + string(":") +
-                            to_string(ec.value()) + "[" + ec.message() + "]");
-    }
-    return hostname;
-}
-
 string buildResultFilePath(shared_ptr<lsst::qserv::proto::TaskMsg> const& taskMsg,
                            string const& resultsDirname) {
     if (resultsDirname.empty()) return resultsDirname;
@@ -155,14 +143,14 @@ Task::Task(TaskMsgPtr const& t, int fragmentNumber, std::shared_ptr<UserQueryInf
     auto const resultDeliveryProtocol = workerConfig->resultDeliveryProtocol();
     if (resultDeliveryProtocol != wconfig::WorkerConfig::ResultDeliveryProtocol::SSI) {
         _resultFilePath = ::buildResultFilePath(t, workerConfig->resultsDirname());
+        auto const fqdn = util::get_current_host_fqdn();
         if (resultDeliveryProtocol == wconfig::WorkerConfig::ResultDeliveryProtocol::XROOT) {
-            // NOTE: one extra '/' after the <server>[:<port>] spec is required to make
+            // NOTE: one extra '/' after the <host>[:<port>] spec is required to make
             // a "valid" XROOTD url.
-            _resultFileXrootUrl = "xroot://" + ::get_hostname() + ":" +
-                                  to_string(workerConfig->resultsXrootdPort()) + "/" + _resultFilePath;
+            _resultFileXrootUrl = "xroot://" + fqdn + ":" + to_string(workerConfig->resultsXrootdPort()) +
+                                  "/" + _resultFilePath;
         } else if (resultDeliveryProtocol == wconfig::WorkerConfig::ResultDeliveryProtocol::HTTP) {
-            _resultFileHttpUrl =
-                    "http://" + ::get_hostname() + ":" + to_string(resultsHttpPort) + _resultFilePath;
+            _resultFileHttpUrl = "http://" + fqdn + ":" + to_string(resultsHttpPort) + _resultFilePath;
         } else {
             throw std::runtime_error("wbase::Task::Task: unsupported results delivery protocol: " +
                                      wconfig::WorkerConfig::protocol2str(resultDeliveryProtocol));