HPC: Ensure load balancer finds hq when located in same directory

[linusseelinger]

Currently needs PATH variable to be extended by location of hq

[Crambor]

Would it be fine to implement a function that checks for the existence of this binary in PATH and expands for execution?

proof of concept below (excluding any checks for whether this binary is executable):

#include <cstdlib>
#include <iostream>
#include <string>
#include <filesystem>
#include <vector>

std::string findBinary() {
    std::vector<std::string> pathsToCheck;

    // Check in PATH
    if (const char* env_p = std::getenv("PATH")) {
        std::string pathEnv = env_p;
        std::string delimiter = ":";
        size_t pos = 0;
        while ((pos = pathEnv.find(delimiter)) != std::string::npos) {
            pathsToCheck.push_back(pathEnv.substr(0, pos));
            pathEnv.erase(0, pos + delimiter.length());
        }
        pathsToCheck.push_back(pathEnv);
    }

    // Also check current directory
    pathsToCheck.push_back(".");

    for (const auto& path : pathsToCheck) {
        std::filesystem::path fullPath = path + "/hq";
        if (std::filesystem::exists(fullPath) && std::filesystem::is_regular_file(fullPath)) {
            return fullPath;
        }
    }

    throw std::runtime_error("Error: 'hq' binary not found in PATH or current directory.");
}

int main() {
    std::string hqBinaryPath;
    try {
        hqBinaryPath = findBinary();
        std::cout << "Found hq binary at: " << hqBinaryPath << std::endl;
    } catch (const std::runtime_error& e) {
        std::cerr << e.what() << std::endl;
        return EXIT_FAILURE;
    }
    return EXIT_SUCCESS;
}

[linusseelinger]

I wonder if a hq installation outside the load balancer directory is realistic, so maybe we should just directly call ./hq ?
Playing devil's advocate, I just tried creating a directory with a colon in its name, turns out that is valid and would break the parser

[linusseelinger]

Quickly fixed by recent commit. Additionally checking for hq binary as in #67 would be nicer though