updating finger table done with minor errors (will be resolved in the next commit)

dns.cpp

@@ -12,9 +12,12 @@ using grpc::ServerBuilder;
 using grpc::ServerCompletionQueue;
 using grpc::ServerContext;
 using grpc::Status;
+using grpc::Channel;
+using grpc::ClientContext;
 using keyvaluestore::KeyValueServices;
 using keyvaluestore::Info;
 using keyvaluestore::Null;
+using keyvaluestore::Addresses;
 
 ServerBuilder builder;
 KeyValueServices::AsyncService service;
@@ -23,12 +26,13 @@ std::unique_ptr<Server> server;
 enum RequestType {
     GETADDRESS,
     ADDADDRESS,
-    UPDATEFINGERTABLES
+    UPDATEFINGERTABLES,
+    GETSERVERS
 };
 
 class DNSData {
 public:
-    DNSData(KeyValueServices::AsyncService *service, ServerCompletionQueue *cq, RequestType reqType) : service(service), cq(cq), getAddressResponder(&context), addAddressResponder(&context), status(CREATE), reqType(reqType) {
+    DNSData(KeyValueServices::AsyncService *service, ServerCompletionQueue *cq, RequestType reqType) : service(service), cq(cq), getAddressResponder(&context), addAddressResponder(&context),updateFingerTablesResponder(&context),getServersResponder(&context), status(CREATE), reqType(reqType) {
         Proceed();
     }
 
@@ -39,6 +43,10 @@ public:
                 service->RequestGETADDRESS(&context, &null, &getAddressResponder, cq, cq, this);
             else if(reqType==ADDADDRESS)
                 service->RequestADDADDRESS(&context, &info, &addAddressResponder, cq, cq, this);
+            else if(reqType==UPDATEFINGERTABLES)
+                service->RequestUPDATEFINGERTABLES(&context,&null,&updateFingerTablesResponder,cq,cq,this);
+            else
+                service->RequestGETSERVERS(&context,&null,&getServersResponder,cq,cq,this);
         }
         else if (status == PROCESS) {
             new DNSData(service, cq, reqType);
@@ -72,7 +80,55 @@ public:
                 cout<<info.address()<<endl;
                 addAddressResponder.Finish(null,Status::OK,this);
             }
+            else if(reqType==UPDATEFINGERTABLES){
+                ifstream fin;
+                int index=0;
+                map<int,string> servers;
+                fin.open(SERVERS);
+                do {
+                    string temp;
+                    getline(fin,temp);
+                    if(temp.size()==0)
+                        break;
+                    servers[index++]=temp;
+                }while(fin);
+                fin.close();
+                string addressarr="";
+                for(int i=0;i<index;i++)
+                    addressarr+=servers[i]+";";
+                for(int i=0;i<index;i++) {
+                    string target_address(servers[i]);
+                    shared_ptr<Channel> channel=grpc::CreateChannel(target_address, grpc::InsecureChannelCredentials());
+                    unique_ptr<KeyValueServices::Stub> stub;
+                    stub=KeyValueServices::NewStub(channel);
+                    Null null;
+                    ClientContext cont;
+                    Addresses addr;
+                    addr.set_addresses(addressarr);
+                    addr.set_servers(index);
+                    stub->UPDATETABLE(&cont,addr,&null);
+                }
+                updateFingerTablesResponder.Finish(null,Status::OK,this);
+            }
             else {
+                ifstream fin;
+                int index=0;
+                map<int,string> servers;
+                fin.open(SERVERS);
+                do {
+                    string temp;
+                    getline(fin,temp);
+                    if(temp.size()==0)
+                        break;
+                    servers[index++]=temp;
+                }while(fin);
+                fin.close();
+                string addressarr="";
+                for(int i=0;i<index;i++)
+                    addressarr+=servers[i]+";";
+                addr1.set_addresses(addressarr);
+                addr1.set_servers(index);
+                getServersResponder.Finish(addr1,Status::OK,this);
             }
             status = FINISH;
         }
@@ -88,8 +144,11 @@ private:
     ServerContext context;
     Null null;
     Info info;
+    Addresses addr1;
     ServerAsyncResponseWriter<Info> getAddressResponder;
     ServerAsyncResponseWriter<Null> addAddressResponder;
+    ServerAsyncResponseWriter<Null> updateFingerTablesResponder;
+    ServerAsyncResponseWriter<Addresses> getServersResponder;
     enum CallStatus {
         CREATE,
         PROCESS,
@@ -110,6 +169,7 @@ int main(int argc,char **argv) {
     new DNSData(&service,comp_queue.get(),GETADDRESS);
     new DNSData(&service,comp_queue.get(),ADDADDRESS);
     new DNSData(&service,comp_queue.get(),UPDATEFINGERTABLES);
+    new DNSData(&service,comp_queue.get(),GETSERVERS);
     void *tag;
     bool ok;
     while(true) {

keyvaluestore.proto

@@ -16,6 +16,8 @@ service KeyValueServices {
     rpc UPDATEFINGERTABLES(Null) returns (Null) {}
     rpc GETSUCCESSOR(Id) returns (Id) {}
     rpc GETPREDECESSOR(Id) returns (Id) {}
+    rpc UPDATETABLE(Addresses) returns (Null) {}
+    rpc GETSERVERS(Null) returns (Addresses) {}
 }
 
 message Key {
@@ -58,4 +60,9 @@ message Null {
 
 message Id {
     int64 id = 1;
+}
+
+message Addresses {
+    string addresses = 1;
+    int64 servers = 2;
 }
\ No newline at end of file

server.cpp

@@ -28,6 +28,7 @@ using keyvaluestore::SuccessorInfo;
 using keyvaluestore::KeyValues;
 using keyvaluestore::Null;
 using keyvaluestore::Id;
+using keyvaluestore::Addresses;
 
 pthread_mutex_t _masterLock;
 
@@ -42,7 +43,8 @@ enum ServerRequest {
     INFORMSUCCESSOR,
     INFORMPREDECESSOR,
     GETSUCCESSOR,
-    GETPREDECESSOR
+    GETPREDECESSOR,
+    UPDATETABLE
 };
 
 map<string, string> params;
@@ -79,7 +81,7 @@ void getConfig() {
 
 class ServerData {
 public:
-    ServerData(KeyValueServices::AsyncService *service, ServerCompletionQueue *cq, ServerRequest reqType) : service(service), cq(cq), newResponder(&context), informSuccessorResponder(&context),informPredecessorResponder(&context),getSuccessorResponder(&context),getPredecessorResponder(&context), status(CREATE), reqType(reqType) {
+    ServerData(KeyValueServices::AsyncService *service, ServerCompletionQueue *cq, ServerRequest reqType) : service(service), cq(cq), newResponder(&context), informSuccessorResponder(&context),informPredecessorResponder(&context),getSuccessorResponder(&context),getPredecessorResponder(&context),updateTableResponder(&context), status(CREATE), reqType(reqType) {
         Proceed();
     }
 
@@ -96,6 +98,8 @@ public:
                 service->RequestGETSUCCESSOR(&context,&idvar1,&getSuccessorResponder,cq,cq,this);
             else if(reqType==GETPREDECESSOR)
                 service->RequestGETPREDECESSOR(&context,&idvar1,&getPredecessorResponder,cq,cq,this);
+            else
+                service->RequestUPDATETABLE(&context,&addressarr,&updateTableResponder,cq,cq,this);
         }
         else if (status == PROCESS) {
             new ServerData(service, cq, reqType);
@@ -108,27 +112,31 @@ public:
                 ifstream fin;
                 //cout<<"Getting my finger table"<<endl;
                 fin.open(FINGER_TABLE);
+                int nums=0;
                 for(int i=0;i<16;i++) {
                     string temp;
                     getline(fin,temp);
+                    if(temp=="null")
+                        break;
+                    nums++;
                     fingers[i]=stoi(temp);
                 }
                 fin.close();
                 int node=-1;
                 int next=-1;
                 //cout<<"Looking for the possible successor and predecessor"<<endl;
-                for(int i=0;i<16;i++) {
+                for(int i=0;i<nums;i++) {
                     if(i>0&&fingers[i]<fingers[i-1]) {
                         node=fingers[i-1];
                         next=fingers[i];
                         break;
                     }
-                    if(fingers[i]>id||i==15) {
-                        if(i==15&&fingers[i]>id) {
+                    if(fingers[i]>id||i==nums-1) {
+                        if(i==nums-1&&fingers[i]>id) {
                             node=fingers[i-1];
                             next=fingers[i];
                         }
-                        else if(i==15)
+                        else if(i==nums-1)
                             node=fingers[i];
                         else {
                             node=fingers[i-1];
@@ -256,26 +264,29 @@ public:
                 ifstream fin;
                 //cout<<"Getting the finger table"<<endl;
                 fin.open(FINGER_TABLE);
+                int nums=0;
                 for(int i=0;i<16;i++) {
                     string temp;
                     getline(fin,temp);
+                    if(temp=="null")
+                        break;
                     fingers[i]=stoi(temp);
                 }
                 fin.close();
                 int node=-1;
                 int next=-1;
-                for(int i=0;i<16;i++) {
+                for(int i=0;i<nums;i++) {
                     if(i>0&&fingers[i]>fingers[i-1]) {
                         node=fingers[i-1];
                         next=fingers[i];
                         break;
                     }
-                    if(fingers[i]>idtofind||i==15) {
-                        if(i==15&&fingers[i]>idtofind) {
+                    if(fingers[i]>idtofind||i==nums-1) {
+                        if(i==nums-1&&fingers[i]>idtofind) {
                             node=fingers[i-1];
                             next=fingers[i];
                         }
-                        else if(i==15)
+                        else if(i==nums-1)
                             node=fingers[i];
                         else {
                             node=fingers[i-1];
@@ -339,7 +350,7 @@ public:
                 //cout<<"Sent my predecessor"<<endl;
                 getPredecessorResponder.Finish(idvar2,Status::OK,this);
             }
-            else {
+            else if(reqType==INFORMPREDECESSOR) {
                 //cout<<"Okay, i got the information that my successor has changed"<<endl;
                 //cout<<"My new successor: "<<info.address()<<endl;
                 ifstream fin;
@@ -358,6 +369,46 @@ public:
                 //cout<<"Okay, i made the necessary changes"<<endl;
                 informPredecessorResponder.Finish(null,Status::OK,this);
             }
+            else {
+                string addresses=addressarr.addresses();
+                int num=addressarr.servers();
+                int ids[num];
+                string addr[num];
+                for(int i=0;i<num;i++) {
+                    addr[i]=addresses.substr(0,addresses.find(';'));
+                    ids[i]=stoi(addr[i].substr(addr[i].find(':')+1));
+                    addresses=addresses.substr(addresses.find(';')+1);
+                }
+                ofstream fout;
+                fout.open(FINGER_TABLE);
+                int my_id=stoi(params.find("LISTENING_PORT")->second);
+                int prev_entry=my_id;
+                int i=0;
+                for(i=0;i<16;i++) {
+                    int next_entry=(my_id+(1<<i))%(1<<16);
+                    if(prev_entry<my_id&&next_entry>=my_id)
+                        break;
+                    for(int j=0;j<num;j++) {
+                        if(ids[j]==my_id)
+                            continue;
+                        if(ids[j]>=next_entry) {
+                            fout<<ids[j]<<endl;
+                            continue;
+                        }
+                        if(j==num-1)
+                            fout<<"null"<<endl;
+                    }
+                    prev_entry=next_entry;
+                }
+                while(i<16) {
+                    fout<<"null"<<endl;
+                    i++;
+                }
+                fout.close();
+                Null n;
+                n.set_nothing(0);
+                updateTableResponder.Finish(n,Status::OK,this);
+            }
             status = FINISH;
         }
         else {
@@ -376,11 +427,13 @@ private:
     KeyValues keyValues;
     Id idvar1;
     Id idvar2;
+    Addresses addressarr;
     ServerAsyncResponseWriter<SuccessorInfo> newResponder;
     ServerAsyncResponseWriter<KeyValues> informSuccessorResponder;
     ServerAsyncResponseWriter<Null> informPredecessorResponder;
     ServerAsyncResponseWriter<Id> getSuccessorResponder;
     ServerAsyncResponseWriter<Id> getPredecessorResponder;
+    ServerAsyncResponseWriter<Null> updateTableResponder;
     enum CallStatus {
         CREATE,
         PROCESS,
@@ -496,6 +549,7 @@ void *handleServerRequests(void *thread_id) {
     new ServerData(&service,comp_queue.get(),INFORMPREDECESSOR);
     new ServerData(&service,comp_queue.get(),GETSUCCESSOR);
     new ServerData(&service,comp_queue.get(),GETPREDECESSOR);
+    new ServerData(&service,comp_queue.get(),UPDATETABLE);
     void *tag;
     bool ok;
     while(true) {
@@ -553,7 +607,45 @@ void updateAllFingerTables() {
     null1.set_nothing(0);
     Null null2;
     ClientContext context;
-    Status status=stub->UPDATEFINGERTABLES(&context,null1,&null2);
+    Addresses addr;
+    stub->GETSERVERS(&context,null1,&addr);
+    string addresses=addr.addresses();
+    int num=addr.servers();
+    string ad[num];
+    int ids[num];
+    for(int i=0;i<num;i++) {
+        ad[i]=addresses.substr(0,addresses.find(';'));
+        ids[i]=stoi(ad[i].substr(ad[i].find(':')+1));
+        addresses=addresses.substr(addresses.find(';')+1);
+    }
+    ofstream fout;
+    fout.open(FINGER_TABLE);
+    int my_id=stoi(params.find("LISTENING_PORT")->second);
+    int prev_entry=my_id;
+    int i=0;
+    for(i=0;i<16;i++) {
+        int next_entry=(my_id+(1<<i))%(1<<16);
+        if(prev_entry<my_id&&next_entry>=my_id)
+            break;
+        for(int j=0;j<num;j++) {
+            if(ids[j]==my_id)
+                continue;
+            if(ids[j]>=next_entry) {
+                fout<<ids[j]<<endl;
+                continue;
+            }
+            if(j==num-1)
+                fout<<"null"<<endl;
+        }
+        prev_entry=next_entry;
+    }
+    while(i<16) {
+        fout<<"null"<<endl;
+        i++;
+    }
+    fout.close();
+    ClientContext context2;
+    stub->UPDATEFINGERTABLES(&context2,null1,&null2);
 }
 
 void register_server_DNS(string my_address) {
@@ -580,7 +672,7 @@ void register_server_DNS(string my_address) {
         //cout<<"Generating initial finger table"<<endl;
         fout.open(FINGER_TABLE);
         for(int i=0;i<16;i++)
-            fout<<my_address.substr(my_address.find(':')+1)<<endl;
+            fout<<"null"<<endl;
         fout.close();
         //cout<<"Initial finger table generated"<<endl;
         if(old_server=="null") {
@@ -625,7 +717,7 @@ void register_server_DNS(string my_address) {
             //cout<<"Informing predecessor about my presence"<<endl;
             status=stub->INFORMPREDECESSOR(&context3,info,&null);
             //cout<<"Informed predecessor"<<endl;
-            //updateAllFingerTables();
+            updateAllFingerTables();
         }
     }
 }