src/config.cpp

// SPDX-License-Identifier: Apache-2.0
// Copyright (C) 2020 YADRO

#include "config.hpp"

#include <algorithm>
#include <climits>
#include <cstring>
#include <stdexcept>
#include <string>

/**
 * @brief Set boolean value from environment variable.
 *
 * @param[in] name name of environment variable
 * @param[out] value value to set
 *
 * @throw std::invalid_argument in case of errors
 */
static void safeSet(const char* name, bool& value)
{
    const char* envVal = std::getenv(name);
    if (envVal)
    {
        if (strcmp(envVal, "true") == 0)
        {
            value = true;
        }
        else if (strcmp(envVal, "false") == 0)
        {
            value = false;
        }
        else
        {
            std::string err = "Invalid value of environment variable ";
            err += name;
            err += ": '";
            err += envVal;
            err += "', expected 'true' or 'false'";
            throw std::invalid_argument(err);
        }
    }
}

/**
 * @brief Set unsigned numeric value from environment variable.
 *
 * @param[in] name name of environment variable
 * @param[out] value value to set
 *
 * @throw std::invalid_argument in case of errors
 */
static void safeSet(const char* name, size_t& value)
{
    const char* envVal = std::getenv(name);
    if (envVal)
    {
        const size_t num = strtoul(envVal, nullptr, 0);
        if (std::all_of(envVal, envVal + strlen(envVal), isdigit) &&
            num != ULONG_MAX)
        {
            value = num;
        }
        else
        {
            std::string err = "Invalid argument: ";
            err += envVal;
            err += ", expected unsigned numeric value";
            throw std::invalid_argument(err);
        }
    }
}

/**
 * @brief Set string value from environment variable.
 *
 * @param[in] name name of environment variable
 * @param[out] value value to set
 */
static void safeSet(const char* name, const char*& value)
{
    const char* envVal = std::getenv(name);
    if (envVal)
    {
        value = envVal;
    }
}

Config::Config()
{
    safeSet("SOCKET_ID", socketId);
    safeSet("BUF_MAXSIZE", bufMaxSize);
    safeSet("BUF_MAXTIME", bufMaxTime);
    safeSet("FLUSH_FULL", bufFlushFull);
    safeSet("HOST_STATE", hostState);
    safeSet("OUT_DIR", outDir);
    safeSet("MAX_FILES", maxFiles);

    // Validate parameters
    if (bufFlushFull && !bufMaxSize && !bufMaxTime)
    {
        throw std::invalid_argument(
            "Flush policy is set to save the buffer as it fills, but buffer's "
            "limits are not defined");
    }
}