[devel] ClientID Agency Transaction (#8652)

* Changed clientId to format <serverid>:<uuid>.
* Changed behavior if id is not known.

arangod/Agency/AgencyComm.cpp

@@ -249,6 +249,17 @@ bool AgencyWriteTransaction::validate(AgencyCommResult const& result) const {
           result.slice().get("results").isArray());
 }
 
+std::string AgencyWriteTransaction::randomClientId() {
+  std::string uuid = to_string(boost::uuids::random_generator()()), id;
+
+  auto ss = ServerState::instance();
+  if (ss != nullptr && !ss->getId().empty()) {
+    return ss->getId() + ":" + uuid;
+  }
+  return uuid;
+}
+
+
 // -----------------------------------------------------------------------------
 // --SECTION-- AgencyTransientTransaction
 // -----------------------------------------------------------------------------

arangod/Agency/AgencyComm.h

@@ -357,23 +357,26 @@ class AgencyTransaction {
 
 struct AgencyWriteTransaction : public AgencyTransaction {
  public:
+
+  static std::string randomClientId();
+
   explicit AgencyWriteTransaction(AgencyOperation const& operation)
-      : clientId(to_string(boost::uuids::random_generator()())) {
+      : clientId(randomClientId()) {
     operations.push_back(operation);
   }
 
   explicit AgencyWriteTransaction(std::vector<AgencyOperation> const& _opers)
-      : operations(_opers), clientId(to_string(boost::uuids::random_generator()())) {}
+      : operations(_opers), clientId(randomClientId()) {}
 
   AgencyWriteTransaction(AgencyOperation const& operation, AgencyPrecondition const& precondition)
-      : clientId(to_string(boost::uuids::random_generator()())) {
+      : clientId(randomClientId()) {
     operations.push_back(operation);
     preconditions.push_back(precondition);
   }
 
   AgencyWriteTransaction(std::vector<AgencyOperation> const& opers,
                          AgencyPrecondition const& precondition)
-      : clientId(to_string(boost::uuids::random_generator()())) {
+      : clientId(randomClientId()) {
     std::copy(opers.begin(), opers.end(),
               std::back_inserter(operations));
     preconditions.push_back(precondition);
@@ -381,7 +384,7 @@ struct AgencyWriteTransaction : public AgencyTransaction {
 
   AgencyWriteTransaction(AgencyOperation const& operation,
                          std::vector<AgencyPrecondition> const& precs)
-      : clientId(to_string(boost::uuids::random_generator()())) {
+      : clientId(randomClientId()) {
     operations.push_back(operation);
     std::copy(precs.begin(), precs.end(),
               std::back_inserter(preconditions));
@@ -389,14 +392,14 @@ struct AgencyWriteTransaction : public AgencyTransaction {
 
   AgencyWriteTransaction(std::vector<AgencyOperation> const& opers,
                          std::vector<AgencyPrecondition> const& precs)
-      : clientId(to_string(boost::uuids::random_generator()())) {
+      : clientId(randomClientId()) {
     std::copy(opers.begin(), opers.end(),
               std::back_inserter(operations));
     std::copy(precs.begin(), precs.end(),
               std::back_inserter(preconditions));
   }
 
-  AgencyWriteTransaction() = default;
+  AgencyWriteTransaction() : clientId(randomClientId()) {};
 
   void toVelocyPack(arangodb::velocypack::Builder& builder) const override final;
 

arangod/Cluster/ServerState.cpp

@@ -368,7 +368,7 @@ bool ServerState::integrateIntoCluster(ServerState::RoleEnum role,
     id = getPersistedId();
     LOG_TOPIC("db3ce", DEBUG, Logger::CLUSTER) << "Restarting with persisted UUID " << id;
   }
-  _id = id;
+  setId(id);
   _myEndpoint = myEndpoint;
   _advertisedEndpoint = advEndpoint;
   TRI_ASSERT(!_myEndpoint.empty());
@@ -690,7 +690,7 @@ void ServerState::setRole(ServerState::RoleEnum role) {
 ////////////////////////////////////////////////////////////////////////////////
 
 std::string ServerState::getId() const {
-  READ_LOCKER(readLocker, _lock);
+  std::lock_guard<std::mutex> guard(_idLock);
   return _id;
 }
 
@@ -703,7 +703,7 @@ void ServerState::setId(std::string const& id) {
     return;
   }
 
-  WRITE_LOCKER(writeLocker, _lock);
+  std::lock_guard<std::mutex> guard(_idLock);
   _id = id;
 }
 

arangod/Cluster/ServerState.h

@@ -24,6 +24,8 @@
 #ifndef ARANGOD_CLUSTER_SERVER_STATE_H
 #define ARANGOD_CLUSTER_SERVER_STATE_H 1
 
+#include <mutex>
+
 #include "Basics/Common.h"
 #include "Basics/ReadWriteSpinLock.h"
 #include "VocBase/voc-types.h"
@@ -283,8 +285,10 @@ class ServerState {
   /// @brief r/w lock for state
   mutable arangodb::basics::ReadWriteSpinLock _lock;
 
-  /// @brief the server's id, can be set just once
+  /// @brief the server's id, can be set just once, use getId and setId, do not access directly
   std::string _id;
+  /// @brief lock for writing and reading server id
+  mutable std::mutex _idLock;
 
   /// @brief the server's short id, can be set just once
   std::atomic<uint32_t> _shortId;