Update MultiplyBy2 test

hpc/test/MultiplyBy2/Makefile

@@ -0,0 +1,26 @@
+all: build-server build-lb run
+
+load-balancer-files = ../../LoadBalancer.cpp ../../LoadBalancer.hpp ../../../lib/httplib.h ../../../lib/json.hpp ../../../lib/umbridge.h
+
+build-server:
+	g++ -O3 -w -std=c++11 minimal-server.cpp -o server -lssl -lcrypto -pthread
+
+build-lb:
+	g++ -O3 -Wno-unused-result -std=c++17 $(load-balancer-files) -o ../../load-balancer -pthread
+
+run:
+	rm -f retry-port-job_id.txt
+	rm -f retry-respond-job_id.txt
+	mkdir -p logs
+	rm -f logs/*
+
+	if ! printenv PORT > /dev/null; then \
+		echo "PORT environment variable not set. Using default value 4242."; \
+		export PORT=4242; \
+	fi && \
+	export HQ_SUBMIT_DELAY_MS=100 && \
+	while nc -z localhost $$PORT; do \
+		read -p "Port $$PORT is already in use. Please enter a different port: " NEW_PORT; \
+		PORT=$${NEW_PORT:-$$PORT}; \
+	done; \
+	cd ../../ && ./load-balancer

hpc/test/MultiplyBy2/client.sh

@@ -0,0 +1,31 @@
+#!/bin/bash 
+
+# export TEST_DELAY=1e4
+
+if [ -z "$PORT" ]; then
+        PORT="4242"
+    fi
+
+echo "Using URL http://localhost:$PORT"
+
+echo "Sending requests..." 
+
+for i in {1..300} 
+do 
+   # Expected output: {"output":[[200.0]]} 
+   # Check if curl output equals expected output 
+   # If not, print error message 
+
+   if [ "$(curl -s http://localhost:$PORT/Evaluate -X POST -d '{"name": "forward", "input": [[100.0]]}')" == '{"output":[[200.0]]}' ]; then 
+       echo -n "y" 
+   else 
+       echo $(curl -s http://localhost:$PORT/Evaluate -X POST -d '{"name": "forward", "input": [[100.0]]}')
+       echo -n "n" 
+       #echo "Error: curl output does not equal expected output" 
+   fi & 
+
+done 
+
+echo "Requests sent. Waiting for responses..." 
+
+wait

hpc/test/MultiplyBy2/minimal-server.cpp

@@ -2,9 +2,36 @@
 #include <string>
 #include <chrono>
 #include <thread>
-
+#include <cstdlib>
+#include <cstring>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
 #include "../../../lib/umbridge.h"
 
+
+bool isPortInUse(int port) {
+    int sockfd = socket(AF_INET, SOCK_STREAM, 0);
+    if (sockfd < 0) {
+        std::cerr << "Failed to create socket." << std::endl;
+        return false;
+    }
+
+    struct sockaddr_in serverAddress;
+    memset(&serverAddress, 0, sizeof(serverAddress));
+    serverAddress.sin_family = AF_INET;
+    serverAddress.sin_addr.s_addr = htonl(INADDR_ANY);
+    serverAddress.sin_port = htons(port);
+
+    if (bind(sockfd, (struct sockaddr*)&serverAddress, sizeof(serverAddress)) < 0) {
+        close(sockfd);
+        return true;
+    }
+
+    close(sockfd);
+    return false;
+}
+
 class ExampleModel : public umbridge::Model
 {
 public:
@@ -79,6 +106,14 @@ int main(int argc, char *argv[])
     else
     {
         port = atoi(port_cstr);
+        std::cout << "Using port [ " << port_cstr << " ] as specified by environment variable PORT." << std::endl;
+        if (isPortInUse(port))
+        {
+            std::cerr << "Port " << port << " is already in use. Exiting." << std::endl;
+
+            exit(-1);
+        }
+
     }
 
     char const *delay_cstr = std::getenv("TEST_DELAY");