feat(MCOL-6082): Multiple readers of dbroots using OamCache logic

This patch introduces centralized logic of selecting what dbroot is
accessible in PrimProc on what node. The logic is in OamCache for time
being and can be moved later.

oam/oamcpp/oamcache.cpp

@@ -39,7 +39,6 @@ using namespace boost;
 namespace oam
 {
 
-
 struct CacheReloaded
 {
   CacheReloaded()
@@ -56,11 +55,20 @@ OamCache* OamCache::makeOamCache()
   return &cache.oamcache;
 }
 
+static bool isWESConfigured(config::Config* config, int moduleID)
+{
+  char buff[200];
+  snprintf(buff, sizeof(buff), "pm%u_WriteEngineServer", moduleID);
+  string fServer(buff);
+  // Check if WES IP address record exists in the config (if not, this is a read-only node)
+  std::string otherEndDnOrIPStr = config->getConfig(fServer, "IPAddr");
+  return !(otherEndDnOrIPStr.empty() || otherEndDnOrIPStr == "unassigned");
+}
 void OamCache::checkReload()
 {
   Oam oam;
   config::Config* config = config::Config::makeConfig();
-  int temp;
+  set<int> temp;
 
   if (config->getCurrentMTime() == mtime)
     return;
@@ -73,7 +81,7 @@ void OamCache::checkReload()
   idbassert(txt != "");
   numDBRoots = config->fromText(txt);
 
-  dbRootPMMap.reset(new map<int, int>());
+  dbRootPMMap.reset(new map<int, set<int>>());
 
   // cerr << "reloading oamcache\n";
   for (uint32_t i = 0; i < dbroots.size(); i++)
@@ -88,39 +96,32 @@ void OamCache::checkReload()
   oam.getSystemConfig("pm", moduletypeconfig);
   int moduleID = 0;
 
+  rwPMs.clear();
   for (unsigned i = 0; i < moduletypeconfig.ModuleCount; i++)
   {
     moduleID = atoi((moduletypeconfig.ModuleNetworkList[i])
                         .DeviceName.substr(MAX_MODULE_TYPE_SIZE, MAX_MODULE_ID_SIZE)
                         .c_str());
     uniquePids.insert(moduleID);
+    if (isWESConfigured(config, moduleID))
+    {
+      rwPMs.insert(moduleID);
+    }
   }
 
   std::set<int>::const_iterator it = uniquePids.begin();
   moduleIds.clear();
   uint32_t i = 0;
-  map<int, int> pmToConnectionMap;
+  pmConnectionMap.clear();
 
   // Restore for Windows when we support multiple PMs
   while (it != uniquePids.end())
   {
-    pmToConnectionMap[*it] = i++;
+    pmConnectionMap[*it] = i++;
     moduleIds.push_back(*it);
     it++;
   }
 
-  dbRootConnectionMap.reset(new map<int, int>());
-
-  for (i = 0; i < dbroots.size(); i++)
-  {
-    map<int, int>::iterator pmIter = pmToConnectionMap.find((*dbRootPMMap)[dbroots[i]]);
-
-    if (pmIter != pmToConnectionMap.end())
-    {
-      (*dbRootConnectionMap)[dbroots[i]] = (*pmIter).second;
-    }
-  }
-
   pmDbrootsMap.reset(new OamCache::PMDbrootsMap_t::element_type());
   systemStorageInfo_t t;
   t = oam.getStorageConfig();
@@ -142,21 +143,18 @@ void OamCache::checkReload()
   tm = oam.getModuleInfo();
   OAMParentModuleName = boost::get<3>(tm);
   systemName = config->getConfig("SystemConfig", "SystemName");
-}
+  dbRootConnectionMap.clear();
 
-OamCache::dbRootPMMap_t OamCache::getDBRootToPMMap()
-{
-  return dbRootPMMap;
-}
+  for (i = 0; i < dbroots.size(); i++)
+  {
+    auto pmIter = pmConnectionMap.find(getOwnerPM(dbroots[i]));
 
-OamCache::dbRootPMMap_t OamCache::getDBRootToConnectionMap()
-{
-  return dbRootConnectionMap;
-}
+    if (pmIter != pmConnectionMap.end())
+    {
+      dbRootConnectionMap[dbroots[i]] = (*pmIter).second;
+    }
+  }
 
-OamCache::PMDbrootsMap_t OamCache::getPMToDbrootsMap()
-{
-  return pmDbrootsMap;
 }
 
 uint32_t OamCache::getDBRootCount()
@@ -237,4 +235,77 @@ string OamCache::getModuleName()
   return moduleName;
 }
 
+bool OamCache::isAccessibleBy(int dbRoot, int pmId)
+{
+  return (*dbRootPMMap)[dbRoot].contains(pmId);
+}
+
+bool OamCache::isOffline(int dbRoot)
+{
+  return dbRootConnectionMap.find(dbRoot) == dbRootConnectionMap.end();
+}
+
+int OamCache::getClosestPM(int dbroot) // who can access dbroot's records for read requests - either owner or us.
+{
+  if ((*dbRootPMMap)[dbroot].contains(mLocalPMId))
+  {
+    return mLocalPMId;
+  }
+  for(auto j : (*dbRootPMMap)[dbroot])
+  {
+    int pm = j;
+    if (rwPMs.contains(pm))
+    {
+      return pm;
+    }
+  }
+  idbassert_s(0, "dbroot " << dbroot << " has empty set of PM's");
+}
+
+int OamCache::getClosestConnection(int dbroot) // connection index to owner's PM or ours PM - who can access dbRoot.
+{
+  return pmConnectionMap[getClosestPM(dbroot)];
+}
+
+int OamCache::getOwnerConnection(int dbroot) // connection index to owner's PM.
+{
+  return pmConnectionMap[getOwnerPM(dbroot)];
+}
+
+int OamCache::getOwnerPM(int dbroot) // Owner's PM index.
+{
+  for(auto j : (*dbRootPMMap)[dbroot])
+  {
+    int pm = j;
+    if (rwPMs.contains(pm))
+    {
+      return pm;
+    }
+  }
+  idbassert_s(0, "cannot find owner for dbroot " << dbroot);
+}
+
+std::vector<int> OamCache::getPMDBRoots(int PM) // what DBRoots are owned by given PM.
+{
+  std::vector<int> result;
+  for (const auto& dbroot : (*dbRootPMMap))
+  {
+    if (dbroot.second.find(PM) != dbroot.second.end())
+    {
+      result.push_back(dbroot.first);
+    }
+  }
+  return result;
+}
+
+std::vector<int> OamCache::getAllDBRoots() // get all DBRoots.
+{
+  std::vector<int> result;
+  for (const auto& dbroot : (*dbRootPMMap))
+  {
+    result.push_back(dbroot.first);
+  }
+  return result;
+}
+
 } /* namespace oam */