Added StickySessions feature for process dipatching (tjanczuk/iisnode/pull/384)

src/config/iisnode_dev_x64.xml

@@ -30,6 +30,7 @@ Details at http://learn.iis.net/page.aspx/241/configuration-extensibility/
     <attribute name="node_env" type="string" expanded="true" defaultValue="%node_env%"/>
     <attribute name="asyncCompletionThreadCount" type="uint" defaultValue="0"/>
     <attribute name="nodeProcessCountPerApplication" type="uint" defaultValue="1"/>
+    <attribute name="nodeProcessStickySessions" type="bool" defaultValue="false"/>
     <attribute name="nodeProcessCommandLine" type="string" expanded="true" defaultValue="node.exe"/>
     <attribute name="interceptor" type="string" expanded="true" defaultValue="&quot;%programfiles(x86)%\iisnode-dev\release\x64\interceptor.js&quot;" />
     <attribute name="maxConcurrentRequestsPerProcess" type="uint" allowInfitnite="true" defaultValue="1024"/>

src/config/iisnode_dev_x86_on_x64.xml

@@ -30,6 +30,7 @@ Details at http://learn.iis.net/page.aspx/241/configuration-extensibility/
     <attribute name="node_env" type="string" expanded="true" defaultValue="%node_env%"/>
     <attribute name="asyncCompletionThreadCount" type="uint" defaultValue="0"/>
     <attribute name="nodeProcessCountPerApplication" type="uint" defaultValue="1"/>
+    <attribute name="nodeProcessStickySessions" type="bool" defaultValue="false"/>
     <attribute name="nodeProcessCommandLine" type="string" expanded="true" defaultValue="node.exe"/>
     <attribute name="interceptor" type="string" expanded="true" defaultValue="&quot;%programfiles(x86)%\iisnode-dev\release\x86\interceptor.js&quot;" />
     <attribute name="maxConcurrentRequestsPerProcess" type="uint" allowInfitnite="true" defaultValue="1024"/>

src/config/iisnode_dev_x86_on_x86.xml

@@ -30,6 +30,7 @@ Details at http://learn.iis.net/page.aspx/241/configuration-extensibility/
     <attribute name="node_env" type="string" expanded="true" defaultValue="%node_env%"/>
     <attribute name="asyncCompletionThreadCount" type="uint" defaultValue="0"/>
     <attribute name="nodeProcessCountPerApplication" type="uint" defaultValue="1"/>
+    <attribute name="nodeProcessStickySessions" type="bool" defaultValue="false"/>
     <attribute name="nodeProcessCommandLine" type="string" expanded="true" defaultValue="node.exe"/>
     <attribute name="interceptor" type="string" expanded="true" defaultValue="&quot;%programfiles%\iisnode-dev\release\x86\interceptor.js&quot;" />
     <attribute name="maxConcurrentRequestsPerProcess" type="uint" allowInfitnite="true" defaultValue="1024"/>

src/config/iisnode_express_schema.xml

@@ -30,6 +30,7 @@ Details at http://learn.iis.net/page.aspx/241/configuration-extensibility/
     <attribute name="node_env" type="string" expanded="true" defaultValue="%node_env%"/>
     <attribute name="asyncCompletionThreadCount" type="uint" defaultValue="0"/>
     <attribute name="nodeProcessCountPerApplication" type="uint" defaultValue="1"/>
+    <attribute name="nodeProcessStickySessions" type="bool" defaultValue="false"/>
     <attribute name="nodeProcessCommandLine" type="string" expanded="true" defaultValue="node.exe"/>
     <attribute name="interceptor" type="string" expanded="true" defaultValue="&quot;%programfiles%\iisnode-express\interceptor.js&quot;" />
     <attribute name="maxConcurrentRequestsPerProcess" type="uint" allowInfitnite="true" defaultValue="1024"/>

src/config/iisnode_express_schema_x64.xml

@@ -30,6 +30,7 @@ Details at http://learn.iis.net/page.aspx/241/configuration-extensibility/
     <attribute name="node_env" type="string" expanded="true" defaultValue="%node_env%"/>
     <attribute name="asyncCompletionThreadCount" type="uint" defaultValue="0"/>
     <attribute name="nodeProcessCountPerApplication" type="uint" defaultValue="1"/>
+    <attribute name="nodeProcessStickySessions" type="bool" defaultValue="false"/>
     <attribute name="nodeProcessCommandLine" type="string" expanded="true" defaultValue="node.exe"/>
     <attribute name="interceptor" type="string" expanded="true" defaultValue="&quot;%programfiles(x86)%\iisnode-express\interceptor.js&quot;" />
     <attribute name="maxConcurrentRequestsPerProcess" type="uint" allowInfitnite="true" defaultValue="1024"/>

src/config/iisnode_schema.xml

@@ -30,6 +30,7 @@ Details at http://learn.iis.net/page.aspx/241/configuration-extensibility/
     <attribute name="node_env" type="string" expanded="true" defaultValue="%node_env%"/>
     <attribute name="asyncCompletionThreadCount" type="uint" defaultValue="0"/>
     <attribute name="nodeProcessCountPerApplication" type="uint" defaultValue="1"/>
+    <attribute name="nodeProcessStickySessions" type="bool" defaultValue="false"/>
     <attribute name="nodeProcessCommandLine" type="string" expanded="true" defaultValue="node.exe"/>
     <attribute name="interceptor" type="string" expanded="true" defaultValue="&quot;%programfiles%\iisnode\interceptor.js&quot;" />
     <attribute name="maxConcurrentRequestsPerProcess" type="uint" allowInfitnite="true" defaultValue="1024"/>

src/config/iisnode_schema_x64.xml

@@ -30,6 +30,7 @@ Details at http://learn.iis.net/page.aspx/241/configuration-extensibility/
     <attribute name="node_env" type="string" expanded="true" defaultValue="%node_env%"/>
     <attribute name="asyncCompletionThreadCount" type="uint" defaultValue="0"/>
     <attribute name="nodeProcessCountPerApplication" type="uint" defaultValue="1"/>
+    <attribute name="nodeProcessStickySessions" type="bool" defaultValue="false"/>
     <attribute name="nodeProcessCommandLine" type="string" expanded="true" defaultValue="node.exe"/>
     <attribute name="interceptor" type="string" expanded="true" defaultValue="&quot;%programfiles%\iisnode\interceptor.js&quot;" />
     <attribute name="maxConcurrentRequestsPerProcess" type="uint" allowInfitnite="true" defaultValue="1024"/>

src/iisnode/cmoduleconfiguration.cpp

@@ -770,6 +770,10 @@ HRESULT CModuleConfiguration::ApplyConfigOverrideKeyValue(IHttpContext* context,
     {
         CheckError(GetDWORD(valueStart, &config->maxConcurrentRequestsPerProcess));
     }
+	else if (0 == strcmpi(keyStart, "nodeProcessStickySessions"))
+    {
+        CheckError(GetDWORD(valueStart, &config->nodeProcessStickySessions));
+    }
     else if (0 == strcmpi(keyStart, "maxNamedPipeConnectionRetry"))
     {
         CheckError(GetDWORD(valueStart, &config->maxNamedPipeConnectionRetry));
@@ -1216,6 +1220,7 @@ HRESULT CModuleConfiguration::GetConfig(IHttpContext* context, CModuleConfigurat
         CheckError(GetConfigSection(context, &section));		
         CheckError(GetDWORD(section, L"asyncCompletionThreadCount", &c->asyncCompletionThreadCount));
         CheckError(GetDWORD(section, L"nodeProcessCountPerApplication", &c->nodeProcessCountPerApplication));
+        CheckError(GetDWORD(section, L"nodeProcessStickySessions", &c->nodeProcessStickySessions));
         CheckError(GetDWORD(section, L"maxConcurrentRequestsPerProcess", &c->maxConcurrentRequestsPerProcess));
         CheckError(GetDWORD(section, L"maxNamedPipeConnectionRetry", &c->maxNamedPipeConnectionRetry));
         CheckError(GetDWORD(section, L"namedPipeConnectionRetryDelay", &c->namedPipeConnectionRetryDelay));
@@ -1318,6 +1323,11 @@ DWORD CModuleConfiguration::GetNodeProcessCountPerApplication(IHttpContext* ctx)
     GETCONFIG(nodeProcessCountPerApplication)
 }
 
+DWORD CModuleConfiguration::GetProcessStickySessions(IHttpContext* ctx)
+{
+    GETCONFIG(nodeProcessStickySessions)
+}
+
 LPWSTR CModuleConfiguration::GetNodeProcessCommandLine(IHttpContext* ctx)
 {
     GETCONFIG(nodeProcessCommandLine)

src/iisnode/cmoduleconfiguration.h

@@ -9,6 +9,7 @@ class CModuleConfiguration : public IHttpStoredContext
 
     DWORD asyncCompletionThreadCount;
     DWORD nodeProcessCountPerApplication;
+    DWORD nodeProcessStickySessions;
     LPWSTR nodeProcessCommandLine;
     LPWSTR interceptor;
     DWORD maxConcurrentRequestsPerProcess;
@@ -94,6 +95,7 @@ class CModuleConfiguration : public IHttpStoredContext
     static DWORD GetIdlePageOutTimePeriod(IHttpContext* ctx);
     static DWORD GetAsyncCompletionThreadCount(IHttpContext* ctx); 
     static DWORD GetNodeProcessCountPerApplication(IHttpContext* ctx);
+    static DWORD GetProcessStickySessions(IHttpContext* ctx);
     static LPWSTR GetNodeProcessCommandLine(IHttpContext* ctx); 
     static LPWSTR GetInterceptor(IHttpContext* ctx); 
     static DWORD GetMaxConcurrentRequestsPerProcess(IHttpContext* ctx);

src/iisnode/cnodeprocessmanager.cpp

@@ -7,10 +7,12 @@ CNodeProcessManager::CNodeProcessManager(CNodeApplication* application, IHttpCon
     if (this->GetApplication()->IsDebugMode())
     {
         this->processCount = 1;
+        this->stickySessions = false;
     }
     else
     {
         this->processCount = CModuleConfiguration::GetNodeProcessCountPerApplication(context);
+        this->stickySessions = CModuleConfiguration::GetProcessStickySessions(context);
     }
 
     // cache event provider since the application can be disposed prior to CNodeProcessManager
@@ -92,7 +94,7 @@ HRESULT CNodeProcessManager::AddProcess(int ordinal, IHttpContext* context)
     HRESULT hr;
 
     ErrorIf(NULL != this->processes[ordinal], ERROR_INVALID_PARAMETER);
-    ErrorIf(NULL == (this->processes[ordinal] = new CNodeProcess(this, context)), ERROR_NOT_ENOUGH_MEMORY);	
+    ErrorIf(NULL == (this->processes[ordinal] = new CNodeProcess(this, context)), ERROR_NOT_ENOUGH_MEMORY);    
     CheckError(this->processes[ordinal]->Initialize(context));
 
     return S_OK;
@@ -107,10 +109,41 @@ HRESULT CNodeProcessManager::AddProcess(int ordinal, IHttpContext* context)
     return hr;
 }
 
+int CNodeProcessManager::ExtractStickySessionsProcess( PCSTR pszCookie )
+{
+    const char* pszKey = "iisnode.p";
+    const char* pszDivider = "=";
+    const char* pszNext = ";";
+    char acProcess[10]; // characters needed for MAXDWORD64
+    memset(acProcess, 0, sizeof(acProcess));
+
+    const char* pStart = strstr(pszCookie, pszKey);
+    const char* pEnd = NULL;
+
+    if(pStart)
+    {
+        pStart = strstr(pStart, pszDivider); 
+        pEnd = strstr(pStart, pszNext);
+        if(!pEnd) 
+        {
+            pEnd = pStart;
+            while (*pEnd) /* Works because end-of-string and FALSE are identical. */
+            {
+                pEnd++;
+            }
+        }
+        memcpy(acProcess, pStart, pEnd - pStart); // copy result
+        return atoi(acProcess);
+    }
+
+    return -1;
+}
+
 HRESULT CNodeProcessManager::Dispatch(CNodeHttpStoredContext* request)
 {
     HRESULT hr;
     unsigned int tmpProcess, processToUse;
+    int processInCookie = -1;
 
     CheckNull(request);
 
@@ -122,19 +155,48 @@ HRESULT CNodeProcessManager::Dispatch(CNodeHttpStoredContext* request)
 
         if (!this->isClosing)
         {
-            // employ a round robin routing logic to get a "ticket" to use a process with a specific ordinal number
+            if(this->stickySessions) // sticky sessions
+            {
+                IHttpRequest *httpRequest;
+                PCSTR pszCookieHeader = NULL;
+
+                httpRequest = request->GetHttpContext()->GetRequest();
+
+                pszCookieHeader = httpRequest->GetHeader(HttpHeaderCookie);
+                if(pszCookieHeader != NULL) // There might be a sticky session
+                {
+                    processInCookie = ExtractStickySessionsProcess(pszCookieHeader);
+                }
+            }
 
-            if (1 == this->processCount)
+            if( processInCookie < 0) // employ a round robin routing logic to get a "ticket" to use a process with a specific ordinal number
             {
-                processToUse = 0;
+                if (1 == this->processCount)
+                {
+                    processToUse = 0;
+                }
+                else
+                {
+                    do 
+                    {
+                        tmpProcess = this->currentProcess;
+                        processToUse = (tmpProcess + 1) % this->processCount;
+                    } while (tmpProcess != InterlockedCompareExchange(&this->currentProcess, processToUse, tmpProcess));
+                }
             }
             else
             {
-                do 
-                {
-                    tmpProcess = this->currentProcess;
-                    processToUse = (tmpProcess + 1) % this->processCount;
-                } while (tmpProcess != InterlockedCompareExchange(&this->currentProcess, processToUse, tmpProcess));
+                processToUse = (unsigned int)processInCookie % this->processCount; // ensure the cookie did not carry a value outside of the possible processes
+            }
+
+            if(this->stickySessions && (processInCookie < 0))
+            {
+                // Set cookie for sticky session with selected process
+                char buffer [255];
+                int l = sprintf (buffer, "iisnode.p=%d", processToUse);
+                IHttpResponse *httpResponse;
+                httpResponse = request->GetHttpContext()->GetResponse();
+                CheckError(httpResponse->SetHeader(HttpHeaderSetCookie, buffer, l, FALSE));
             }
 
             // try dispatch to that process
@@ -287,7 +349,7 @@ HRESULT CNodeProcessManager::Recycle()
 
     ENTER_SRW_EXCLUSIVE(this->srwlock)
 
-    this->isClosing = TRUE;	
+    this->isClosing = TRUE;    
 
     // perform actual recycling on a diffrent thread to free up the file watcher thread
 
@@ -358,7 +420,7 @@ unsigned int CNodeProcessManager::GracefulShutdown(void* arg)
     {
         CloseHandle(drainHandles[i]);
     }
-    delete[] drainHandles;	
+    delete[] drainHandles;    
     drainHandles = NULL;
 
     if (args->disposeApplication)
@@ -451,4 +513,9 @@ DWORD CNodeProcessManager::GetActiveRequestCount()
 DWORD CNodeProcessManager::GetProcessCount()
 {
     return this->processCount;
+}
+
+DWORD CNodeProcessManager::GetProcessStickySessions()
+{
+    return this->stickySessions;
 }

src/iisnode/cnodeprocessmanager.h

@@ -22,6 +22,7 @@ class CNodeProcessManager
 	CNodeApplication* application;
 	CNodeProcess** processes;
 	DWORD processCount;
+	BOOL stickySessions;
 	unsigned int currentProcess;
 	SRWLOCK srwlock;
 	DWORD gracefulShutdownTimeout;
@@ -51,6 +52,8 @@ class CNodeProcessManager
 	long DecRef();
 	DWORD GetActiveRequestCount();
 	DWORD GetProcessCount();
+	DWORD GetProcessStickySessions();
+	int ExtractStickySessionsProcess( PCSTR pszCookie );
 };
 
 #endif

src/iisnode/cprotocolbridge.cpp

@@ -717,13 +717,14 @@ void CProtocolBridge::SendHttpRequestHeaders(CNodeHttpStoredContext* context)
     memcpy(&activityId, context->GetActivityId(), sizeof GUID);
 
     // request the named pipe to be kept alive by the server after the response is sent
-    // to enable named pipe connection pooling
+    // to enable named pipe connection pooling.
+    // but leave upgrade request untouched
 
     request = context->GetHttpContext()->GetRequest();
 
     pszConnectionHeader = request->GetHeader(HttpHeaderConnection);
     if( pszConnectionHeader == NULL || 
-        (pszConnectionHeader != NULL && stricmp(pszConnectionHeader, "upgrade") != 0))
+        (pszConnectionHeader != NULL && strstr(pszConnectionHeader, "Upgrade") == 0))
     {
         CheckError(request->SetHeader(HttpHeaderConnection, "keep-alive", 10, TRUE));
     }