new server adding code done (untested)

dns.cpp

@@ -22,7 +22,8 @@ std::unique_ptr<Server> server;
 
 enum RequestType {
     GETADDRESS,
-    ADDADDRESS
+    ADDADDRESS,
+    UPDATEFINGERTABLES
 };
 
 class DNSData {
@@ -36,7 +37,7 @@ public:
             status = PROCESS;
             if(reqType==GETADDRESS)
                 service->RequestGETADDRESS(&context, &null, &getAddressResponder, cq, cq, this);
-            else
+            else if(reqType==ADDADDRESS)
                 service->RequestADDADDRESS(&context, &info, &addAddressResponder, cq, cq, this);
         }
         else if (status == PROCESS) {
@@ -62,7 +63,7 @@ public:
                 }
                 getAddressResponder.Finish(info,Status::OK,this);
             }
-            else {
+            else if(reqType==ADDADDRESS){
                 ofstream fout;
                 fout.open(SERVERS,ios::app);
                 fout<<info.address()<<endl;
@@ -70,6 +71,8 @@ public:
                 null.set_nothing(0);
                 addAddressResponder.Finish(null,Status::OK,this);
             }
+            else {
+            }
             status = FINISH;
         }
         else {
@@ -124,6 +127,7 @@ int main(int argc,char **argv) {
     cout<<"DNS SERVER COMES UP SUCCESSFULLY"<<endl;
     new DNSData(&service,comp_queue.get(),GETADDRESS);
     new DNSData(&service,comp_queue.get(),ADDADDRESS);
+    new DNSData(&service,comp_queue.get(),UPDATEFINGERTABLES);
     void *tag;
     bool ok;
     while(true) {

keyvaluestore.proto

@@ -9,9 +9,13 @@ service KeyValueServices {
     rpc PUT(KeyValue) returns (ReqStatus) {}
     rpc DEL(Key) returns (ReqStatus) {}
     rpc NEW(Info) returns (SuccessorInfo) {}
-    rpc INFORM(Info) returns (KeyValues) {}
+    rpc INFORMSUCCESSOR(Info) returns (KeyValues) {}
+    rpc INFORMPREDECESSOR(Info) returns (Null) {}
     rpc GETADDRESS(Null) returns (Info) {}
     rpc ADDADDRESS(Info) returns (Null) {}
+    rpc UPDATEFINGERTABLES(Null) returns (Null) {}
+    rpc GETSUCCESSOR(Id) returns (Id) {}
+    rpc GETPREDECESSOR(Id) returns (Id) {}
 }
 
 message Key {
@@ -39,7 +43,8 @@ message Info {
 }
 
 message SuccessorInfo {
-    string address = 1;
+    string succaddress = 1;
+    string predaddress = 2;
 }
 
 message KeyValues {
@@ -50,3 +55,7 @@ message KeyValues {
 message Null {
     int32 nothing = 1;
 }
+
+message Id {
+    int64 id = 1;
+}
\ No newline at end of file

server.cpp

 #include <bits/stdc++.h>
 #include <pthread.h>
+#include <fstream>
 #include <grpcpp/grpcpp.h>
 #include "keyvaluestore.grpc.pb.h"
 #include "../Backend.h"
+#define NEIGHBOURS "neighbours.txt"
+#define FINGER_TABLE "fingertable.txt"
+#define DNS_SERVER "0.0.0.0:1234"
 
 using namespace std;
 
@@ -23,6 +27,7 @@ using keyvaluestore::Info;
 using keyvaluestore::SuccessorInfo;
 using keyvaluestore::KeyValues;
 using keyvaluestore::Null;
+using keyvaluestore::Id;
 
 pthread_mutex_t _masterLock;
 
@@ -34,7 +39,10 @@ enum RequestType {
 
 enum ServerRequest {
     NEW,
-    INFORM
+    INFORMSUCCESSOR,
+    INFORMPREDECESSOR,
+    GETSUCCESSOR,
+    GETPREDECESSOR
 };
 
 map<string, string> params;
@@ -71,7 +79,7 @@ void getConfig() {
 
 class ServerData {
 public:
-    ServerData(KeyValueServices::AsyncService *service, ServerCompletionQueue *cq, ServerRequest reqType) : service(service), cq(cq), newResponder(&context), informResponder(&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), status(CREATE), reqType(reqType) {
         Proceed();
     }
 
@@ -80,18 +88,221 @@ public:
             status = PROCESS;
             if (reqType == NEW)
                 service->RequestNEW(&context, &info, &newResponder, cq, cq, this);
-            else
-                service->RequestINFORM(&context, &info, &informResponder, cq, cq, this);
-        } else if (status == PROCESS) {
+            else if(reqType==INFORMSUCCESSOR)
+                service->RequestINFORMSUCCESSOR(&context, &info, &informSuccessorResponder, cq, cq, this);
+            else if(reqType==INFORMPREDECESSOR)
+                service->RequestINFORMPREDECESSOR(&context,&info,&informPredecessorResponder,cq,cq,this);
+            else if(reqType==GETSUCCESSOR)
+                service->RequestGETSUCCESSOR(&context,&idvar1,&getSuccessorResponder,cq,cq,this);
+            else if(reqType==GETPREDECESSOR)
+                service->RequestGETPREDECESSOR(&context,&idvar1,&getPredecessorResponder,cq,cq,this);
+        }
+        else if (status == PROCESS) {
             new ServerData(service, cq, reqType);
             if (reqType == NEW) {
                 //calculate id of node, return it's successor
+                string address=info.address();
+                int id=stoi(address.substr(address.find(':')+1));
+                int fingers[16];
+                ifstream fin;
+                fin.open(FINGER_TABLE);
+                for(int i=0;i<16;i++) {
+                    string temp;
+                    getline(fin,temp);
+                    fingers[i]=stoi(temp);
+                }
+                fin.close();
+                int node=-1;
+                int next=-1;
+                for(int i=0;i<16;i++) {
+                    if(i>0&&fingers[i]>fingers[i-1]) {
+                        node=fingers[i-1];
+                        next=fingers[i];
+                        break;
+                    }
+                    if(fingers[i]>id||i==16) {
+                        if(i==16&&fingers[i]>id) {
+                            node=fingers[i-1];
+                            next=fingers[i];
                         }
+                        else if(i==16)
+                            node=fingers[i];
                         else {
+                            node=fingers[i-1];
+                            next=fingers[i];
+                        }
+                        break;
+                    }
+                }
+                if(next!=-1) {
+                    string target_address("0.0.0.0:"+to_string(next));
+                    shared_ptr<Channel> channel=grpc::CreateChannel(target_address, grpc::InsecureChannelCredentials());
+                    unique_ptr<KeyValueServices::Stub> stub;
+                    stub=KeyValueServices::NewStub(channel);
+                    ClientContext context;
+                    Id x;
+                    x.set_id(next);
+                    Id y;
+                    stub->GETPREDECESSOR(&context,x,&y);
+                    if(y.id()<id) {
+                        successorInfo.set_succaddress("0.0.0.0:"+to_string(x.id()));
+                        successorInfo.set_predaddress("0.0.0.0:"+to_string(y.id()));
+                    }
+                    else {
+                        string tar_address("0.0.0.0:"+to_string(node));
+                        channel=grpc::CreateChannel(tar_address, grpc::InsecureChannelCredentials());
+                        stub=KeyValueServices::NewStub(channel);
+                        ClientContext context1;
+                        x.set_id(id);
+                        stub->GETSUCCESSOR(&context1,x,&y);
+                        Id z;
+                        string t_address("0.0.0.0:"+to_string(y.id()));
+                        channel=grpc::CreateChannel(t_address, grpc::InsecureChannelCredentials());
+                        stub=KeyValueServices::NewStub(channel);
+                        ClientContext context2;
+                        stub->GETPREDECESSOR(&context2,y,&z);
+                        successorInfo.set_succaddress("0.0.0.0:"+to_string(y.id()));
+                        successorInfo.set_predaddress("0.0.0.0:"+to_string(z.id()));
+                    }
+                }
+                else {
+                    if(node==id) {
+                        successorInfo.set_succaddress("0.0.0.0:"+to_string(id));
+                        successorInfo.set_predaddress("0.0.0.0:"+to_string(id));
+                    }
+                    string tar_address("0.0.0.0:"+to_string(node));
+                    shared_ptr<Channel> channel=grpc::CreateChannel(tar_address, grpc::InsecureChannelCredentials());
+                    unique_ptr<KeyValueServices::Stub> stub=KeyValueServices::NewStub(channel);
+                    ClientContext context1;
+                    Id x,y,z;
+                    x.set_id(id);
+                    stub->GETSUCCESSOR(&context1,x,&y);
+                    string t_address("0.0.0.0:"+to_string(y.id()));
+                    channel=grpc::CreateChannel(t_address, grpc::InsecureChannelCredentials());
+                    stub=KeyValueServices::NewStub(channel);
+                    ClientContext context2;
+                    stub->GETPREDECESSOR(&context2,y,&z);
+                    successorInfo.set_succaddress("0.0.0.0:"+to_string(y.id()));
+                    successorInfo.set_predaddress("0.0.0.0:"+to_string(z.id()));
+                }
+                newResponder.Finish(successorInfo,Status::OK,this);
+            }
+            else if(reqType==INFORMSUCCESSOR){
                 //return half of the keyvalue pairs to the requesting node
+                string address=info.address();
+                int id=stoi(address.substr(address.find(':')+1));
+                ifstream fin;
+                fin.open(NEIGHBOURS);
+                string successor,predecessor;
+                getline(fin,successor);
+                getline(fin,predecessor);
+                fin.close();
+                predecessor=info.address();
+                ofstream fout;
+                fout.open(NEIGHBOURS);
+                fout<<successor<<endl;
+                fout<<predecessor<<endl;
+                fout.close();
+                null.set_nothing(0);
+                informSuccessorResponder.Finish(keyValues,Status::OK,this);
+            }
+            else if(reqType==GETSUCCESSOR) {
+                int idtofind=idvar1.id();
+                int fingers[16];
+                ifstream fin;
+                fin.open(FINGER_TABLE);
+                for(int i=0;i<16;i++) {
+                    string temp;
+                    getline(fin,temp);
+                    fingers[i]=stoi(temp);
+                }
+                fin.close();
+                int node=-1;
+                int next=-1;
+                for(int i=0;i<16;i++) {
+                    if(i>0&&fingers[i]>fingers[i-1]) {
+                        node=fingers[i-1];
+                        next=fingers[i];
+                        break;
+                    }
+                    if(fingers[i]>idtofind||i==16) {
+                        if(i==16&&fingers[i]>idtofind) {
+                            node=fingers[i-1];
+                            next=fingers[i];
+                        }
+                        else if(i==16)
+                            node=fingers[i];
+                        else {
+                            node=fingers[i-1];
+                            next=fingers[i];
+                        }
+                        break;
+                    }
+                }
+                if(next!=-1) {
+                    string target_address("0.0.0.0:"+to_string(next));
+                    shared_ptr<Channel> channel=grpc::CreateChannel(target_address, grpc::InsecureChannelCredentials());
+                    unique_ptr<KeyValueServices::Stub> stub;
+                    stub=KeyValueServices::NewStub(channel);
+                    ClientContext context;
+                    Id x;
+                    x.set_id(next);
+                    Id y;
+                    stub->GETPREDECESSOR(&context,x,&y);
+                    if(y.id()<idtofind) {
+                        idvar2.set_id(y.id());
+                    }
+                    else {
+                        string tar_address("0.0.0.0:"+to_string(node));
+                        channel=grpc::CreateChannel(tar_address, grpc::InsecureChannelCredentials());
+                        stub=KeyValueServices::NewStub(channel);
+                        ClientContext context1;
+                        x.set_id(idtofind);
+                        stub->GETSUCCESSOR(&context1,x,&y);
+                        idvar2.set_id(y.id());
+                    }
+                }
+                else {
+                    string tar_address("0.0.0.0:"+to_string(node));
+                    shared_ptr<Channel> channel=grpc::CreateChannel(tar_address, grpc::InsecureChannelCredentials());
+                    unique_ptr<KeyValueServices::Stub> stub=KeyValueServices::NewStub(channel);
+                    ClientContext context1;
+                    Id x,y;
+                    x.set_id(idtofind);
+                    stub->GETSUCCESSOR(&context1,x,&y);
+                    idvar2.set_id(y.id());
+                }
+                getSuccessorResponder.Finish(idvar2,Status::OK,this);
+            }
+            else if(reqType==GETPREDECESSOR) {
+                ifstream fin;
+                fin.open(NEIGHBOURS);
+                string successor,predecessor;
+                getline(fin,successor);
+                getline(fin,predecessor);
+                fin.close();
+                idvar2.set_id(stoi(predecessor.substr(predecessor.find(':')+1)));
+                getPredecessorResponder.Finish(idvar2,Status::OK,this);
+            }
+            else {
+                ifstream fin;
+                fin.open(NEIGHBOURS);
+                string successor,predecessor;
+                getline(fin,successor);
+                getline(fin,predecessor);
+                fin.close();
+                successor=info.address();
+                ofstream fout;
+                fout.open(NEIGHBOURS);
+                fout<<successor<<endl;
+                fout<<predecessor<<endl;
+                fout.close();
+                null.set_nothing(0);
+                informPredecessorResponder.Finish(null,Status::OK,this);
             }
             status = FINISH;
-        } else {
+        }
+        else {
             GPR_ASSERT(status == FINISH);
             delete this;
         }
@@ -103,9 +314,15 @@ private:
     ServerContext context;
     Info info;
     SuccessorInfo successorInfo;
+    Null null;
     KeyValues keyValues;
+    Id idvar1;
+    Id idvar2;
     ServerAsyncResponseWriter<SuccessorInfo> newResponder;
-    ServerAsyncResponseWriter<KeyValues> informResponder;
+    ServerAsyncResponseWriter<KeyValues> informSuccessorResponder;
+    ServerAsyncResponseWriter<Null> informPredecessorResponder;
+    ServerAsyncResponseWriter<Id> getSuccessorResponder;
+    ServerAsyncResponseWriter<Id> getPredecessorResponder;
     enum CallStatus {
         CREATE,
         PROCESS,
@@ -217,7 +434,10 @@ void *handleServerRequests(void *thread_id) {
         pthread_cond_wait(&startRpcs,&myLock);
     pthread_mutex_unlock(&myLock);
     new ServerData(&service,comp_queue.get(),NEW);
-    new ServerData(&service,comp_queue.get(),INFORM);
+    new ServerData(&service,comp_queue.get(),INFORMSUCCESSOR);
+    new ServerData(&service,comp_queue.get(),INFORMPREDECESSOR);
+    new ServerData(&service,comp_queue.get(),GETSUCCESSOR);
+    new ServerData(&service,comp_queue.get(),GETPREDECESSOR);
     void *tag;
     bool ok;
     while(true) {
@@ -266,8 +486,20 @@ void signalHandler(int signum) {
     exit(0);
 }
 
+void updateAllFingerTables() {
+    string target_address(DNS_SERVER);
+    shared_ptr<Channel> channel=grpc::CreateChannel(target_address, grpc::InsecureChannelCredentials());
+    unique_ptr<KeyValueServices::Stub> stub;
+    stub=KeyValueServices::NewStub(channel);
+    Null null1;
+    null1.set_nothing(0);
+    Null null2;
+    ClientContext context;
+    Status status=stub->UPDATEFINGERTABLES(&context,null1,&null2);
+}
+
 void register_server_DNS(string my_address) {
-    string target_address("0.0.0.0:1234");
+    string target_address(DNS_SERVER);
     shared_ptr<Channel> channel=grpc::CreateChannel(target_address, grpc::InsecureChannelCredentials());
     unique_ptr<KeyValueServices::Stub> stub;
     stub=KeyValueServices::NewStub(channel);
@@ -282,8 +514,18 @@ void register_server_DNS(string my_address) {
         info.set_address(my_address);
         ClientContext new_context;
         stub->ADDADDRESS(&new_context,info,&null);
-        if(old_server=="null")
+        ofstream fout;
+        fout.open(FINGER_TABLE);
+        for(int i=0;i<16;i++)
+            fout<<my_address.substr(my_address.find(':')+1)<<endl;
+        fout.close();
+        if(old_server=="null") {
+            fout.open(NEIGHBOURS);
+            fout<<"-1"<<endl;
+            fout<<"-1"<<endl;
+            fout.close();
             return;
+        }
         channel=grpc::CreateChannel(old_server,grpc::InsecureChannelCredentials());
         stub=KeyValueServices::NewStub(channel);
         info.set_address(my_address);
@@ -291,13 +533,25 @@ void register_server_DNS(string my_address) {
         ClientContext context1;
         status=stub->NEW(&context1,info,&successorInfo);
         if(status.ok()) {
-            string successor=successorInfo.address();
+            string successor=successorInfo.succaddress();
+            string predecessor=successorInfo.predaddress();
+            ofstream fout;
+            fout.open(NEIGHBOURS);
+            fout<<successor<<endl;
+            fout<<predecessor<<endl;
+            fout.close();
             channel=grpc::CreateChannel(successor,grpc::InsecureChannelCredentials());
             stub=KeyValueServices::NewStub(channel);
             info.set_address(my_address);
             KeyValues keyValues;
             ClientContext context2;
-            status=stub->INFORM(&context2,info,&keyValues);
+            status=stub->INFORMSUCCESSOR(&context2,info,&keyValues);
+            channel=grpc::CreateChannel(predecessor,grpc::InsecureChannelCredentials());
+            stub=KeyValueServices::NewStub(channel);
+            info.set_address(my_address);
+            ClientContext context3;
+            status=stub->INFORMPREDECESSOR(&context3,info,&null);
+            updateAllFingerTables();
         }
     }
 }