Merge branch 'giving-resolution-multiple-tries' into 'develop'

feat(fqdn): giving some time for FQDN resolution

See merge request oai/cn5g/oai-cn5g-amf!151

build/scripts/build_helper

@@ -131,13 +131,12 @@ check_supported_distribution() {
         "ubuntu20.04") return 0 ;;
         "ubuntu22.04") return 0 ;;
         "rhel8")       return 0 ;;
-        "rhel8.2")       return 0 ;;
-        "rhel8.3")       return 0 ;;
-        "rhel8.4")       return 0 ;;
-        "rhel8.5")       return 0 ;;
-        "rhel8.6")       return 0 ;;
-        "rhel8.7")       return 0 ;;
-        #"centos7")     return 0 ;;
+        "rhel8.2")     return 0 ;;
+        "rhel8.3")     return 0 ;;
+        "rhel8.4")     return 0 ;;
+        "rhel8.5")     return 0 ;;
+        "rhel8.6")     return 0 ;;
+        "rhel8.7")     return 0 ;;
     esac
     return 1
 }
@@ -297,7 +296,10 @@ check_enable_epel_repos() {
       echo "EPEL repos already present. Good."
     else
       echo "EPEL repos not present. Installing them."
-      $SUDO $INSTALLER install $OPTION https://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm
+      wget --tries=4 --retry-connrefused --wait=8 \
+        https://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm
+      $SUDO $INSTALLER install $OPTION epel-release-latest-7.noarch.rpm
+      rm -f epel-release-latest-7.noarch.rpm
     fi
   fi
 }

docker/Dockerfile.amf.rhel8

@@ -51,6 +51,7 @@ RUN rm -f /etc/rhsm-host && \
         boost-devel \
         openssl-devel \
         openssl \
+        wget \
         libasan && \
     echo "/usr/local/lib" > /etc/ld.so.conf.d/local-lib.conf && \
     echo "/usr/local/lib64" >> /etc/ld.so.conf.d/local-lib.conf

src/utils/fqdn.cpp

@@ -20,43 +20,54 @@
  */
 
 #include "fqdn.hpp"
-
+#include "logger.hpp"
 #include <boost/asio.hpp>
 #include <iostream>
+#include <chrono>
+#include <thread>
 
-#include "logger.hpp"
+#define MAX_NB_RESOLVE_TRIES 4
+#define TIME_BETWEEN_TRIES 2
 
 bool fqdn::resolve(
     const std::string& host_name, std::string& address, uint32_t& port,
     uint8_t& addr_type, const std::string& protocol) {
-  try {
-    Logger::amf_app().debug("Resolving DNS:- %s", host_name.c_str());
-    boost::asio::io_context io_context = {};
+  int tries = 0;
+  Logger::amf_app().debug("Resolving a DNS (name %s)", host_name.c_str());
+  while (tries < MAX_NB_RESOLVE_TRIES) {
+    try {
+      boost::asio::io_context io_context = {};
+      Logger::amf_app().debug("Resolving DNS Try #%u", tries);
 
-    boost::asio::ip::tcp::resolver resolver{io_context};
-    boost::asio::ip::tcp::resolver::results_type endpoints =
-        resolver.resolve(host_name, protocol);
+      boost::asio::ip::tcp::resolver resolver{io_context};
+      boost::asio::ip::tcp::resolver::results_type endpoints =
+          resolver.resolve(host_name, protocol);
 
-    addr_type = 0;  // IPv4 by default
-    for (auto it = endpoints.cbegin(); it != endpoints.cend(); it++) {
-      // get the first Endpoint
-      boost::asio::ip::tcp::endpoint endpoint = *it;
-      address                                 = endpoint.address().to_string();
-      port                                    = endpoint.port();
-      Logger::amf_app().debug(
-          "Resolve a DNS (name %s, protocol %s): Ip Addr %s, port %u",
-          host_name.c_str(), protocol.c_str(), address.c_str(), port);
-      if (endpoint.address().is_v4())
-        addr_type = 0;
-      else
-        addr_type = 1;
-      return true;
+      addr_type = 0;  // IPv4 by default
+      for (auto it = endpoints.cbegin(); it != endpoints.cend(); it++) {
+        // get the first Endpoint
+        boost::asio::ip::tcp::endpoint endpoint = *it;
+        address = endpoint.address().to_string();
+        port    = endpoint.port();
+        Logger::amf_app().debug(
+            "Resolved a DNS (name %s, protocol %s): Ip Addr %s, port %u",
+            host_name.c_str(), protocol.c_str(), address.c_str(), port);
+        if (endpoint.address().is_v4())
+          addr_type = 0;
+        else
+          addr_type = 1;
+        return true;
+      }
+    } catch (std::exception& e) {
+      tries++;
+      if (tries == MAX_NB_RESOLVE_TRIES) {
+        throw std::runtime_error(
+            "Cannot resolve a DNS name " + std::string(e.what()) + " after " +
+            std::to_string(tries) + " tries");
+        return false;
+      }
+      std::this_thread::sleep_for(std::chrono::seconds(TIME_BETWEEN_TRIES));
     }
-  } catch (std::exception& e) {
-    // TODO: Remove this line so that AMF can re-try several times
-    throw std::runtime_error(
-        "Cannot resolve a DNS name " + std::string(e.what()));
-    return false;
   }
 
   return false;