Implement IptablesHelper to ease blocking / unblocking a port

CHANGELOG.md

 # Changelog
 
+## Unreleased
+
+### New features
+- Possibility to choose between three different journal fsync policies through
+``RAFT-SET-FSYNC-POLICY`` command.
+- Implementation of ``CLIENT GETNAME``, and automatic tagging of intercluster
+connections.
+
+### Improvements
+- Automatic fsync of the raft journal once per second.
+- Better resilience in case of sudden machine powercuts.
+
 ## 0.4.0 (2019-12-06)
 
 ### Bug fixes

qclient @ b14f94b6

-Subproject commit 0da6445cf5c0c7793b82f703d27d53be72442b2b
+Subproject commit b14f94b6506cee945e3ccdad98251610af385ee1

test/sudo/poweroff.cc

@@ -30,6 +30,12 @@ using namespace quarkdb;
 class Poweroff : public TestCluster3NodesFixture {};
 
 TEST_F(Poweroff, WithDataLoss) {
+  IptablesHelper iptables;
+
+  ASSERT_TRUE(iptables.singleAcceptPackets(nodes()[0].port));
+  ASSERT_TRUE(iptables.singleAcceptPackets(nodes()[1].port));
+  ASSERT_TRUE(iptables.singleAcceptPackets(nodes()[2].port));
+
   spinup(0); spinup(1); spinup(2);
   RETRY_ASSERT_TRUE(checkStateConsensus(0, 1, 2));
 
@@ -47,13 +53,13 @@ TEST_F(Poweroff, WithDataLoss) {
   int follower = (leaderID + 1) % 3;
   int followerPort = nodes()[follower].port;
 
-  ASSERT_EQ(system(SSTR("iptables -I OUTPUT -p tcp --dest 127.0.0.1 --dport " << followerPort << " -j DROP").c_str()), 0);
+  ASSERT_TRUE(iptables.singleDropPackets(followerPort));
   spindown(follower);
 
   ASSERT_TRUE(journal(follower)->simulateDataLoss(3));
   ASSERT_EQ(journal(follower)->getLogSize(), journal(leaderID)->getLogSize() - 3);
 
-  ASSERT_EQ(system(SSTR("iptables -I OUTPUT -p tcp --dest 127.0.0.1 --dport " << followerPort << " -j ACCEPT").c_str()), 0);
+  ASSERT_TRUE(iptables.singleAcceptPackets(followerPort));
   spinup(follower);
 
   // ensure the leader restores the missing entries

test/sudo/qclient.cc

@@ -21,12 +21,17 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.*
  ************************************************************************/
 
+#include "../test-utils.hh"
 #include <qclient/QClient.hh>
 #include <gtest/gtest.h>
 #include <chrono>
 
+using namespace quarkdb;
+
 TEST(QClient, HostDroppingIncomingPacketsConstructor) {
-  ASSERT_EQ(system("iptables -I OUTPUT -p tcp --dest 127.0.0.1 --dport 56789 -j DROP"), 0);
+  IptablesHelper iptables;
+
+  ASSERT_TRUE(iptables.singleDropPackets(56789));
 
   qclient::Options opts;
   std::unique_ptr<qclient::QClient> qcl;
@@ -50,11 +55,12 @@ TEST(QClient, HostDroppingIncomingPacketsConstructor) {
   std::cout << "Destructor took " << destructorDuration.count() << " ms" << std::endl;
   ASSERT_LE(destructorDuration, std::chrono::milliseconds(50));
 
-  ASSERT_EQ(system("iptables -I OUTPUT -p tcp --dest 127.0.0.1 --dport 56789 -j ACCEPT"), 0);
+  ASSERT_TRUE(iptables.singleAcceptPackets(56789));
 }
 
 TEST(QClient, HostDroppingIncomingPacketsFutureTimeout) {
-  ASSERT_EQ(system("iptables -I OUTPUT -p tcp --dest 127.0.0.1 --dport 56789 -j DROP"), 0);
+  IptablesHelper iptables;
+  ASSERT_TRUE(iptables.singleDropPackets(56789));
 
   qclient::Options opts;
   opts.tcpTimeout = std::chrono::seconds(3);
@@ -72,6 +78,6 @@ TEST(QClient, HostDroppingIncomingPacketsFutureTimeout) {
   ASSERT_GE(dur, std::chrono::seconds(3));
   ASSERT_LE(dur, std::chrono::seconds(4));
 
-  ASSERT_EQ(system("iptables -I OUTPUT -p tcp --dest 127.0.0.1 --dport 56789 -j ACCEPT"), 0);
+  ASSERT_TRUE(iptables.singleAcceptPackets(56789));
 }
 

test/test-utils.cc

@@ -398,4 +398,13 @@ void TestNode::spindown() {
   shard()->spindown();
 }
 
+bool IptablesHelper::singleDropPackets(int port) {
+  return system(SSTR("iptables -I OUTPUT -p tcp --dest 127.0.0.1 --dport " << port << " -j DROP").c_str()) == 0;
+}
+
+bool IptablesHelper::singleAcceptPackets(int port) {
+  return system(SSTR("iptables -I OUTPUT -p tcp --dest 127.0.0.1 --dport " << port << " -j ACCEPT").c_str()) == 0;
+}
+
+
 }

test/test-utils.hh

@@ -519,6 +519,12 @@ public:
   }
 };
 
+class IptablesHelper {
+public:
+  bool singleDropPackets(int port);
+  bool singleAcceptPackets(int port);
+
+};
 
 
 }