src/system/Sysrepo.cpp

/*
 * Copyright (C) 2021 CESNET, https://photonics.cesnet.cz/
 *
 * Written by Tomáš Pecka <tomas.pecka@fit.cvut.cz>
 *
 */

#include <boost/algorithm/string/predicate.hpp>
#include <fstream>
#include "Sysrepo.h"
#include "utils/io.h"
#include "utils/log.h"

using namespace std::literals;

namespace {

const auto IETF_SYSTEM_MODULE_NAME = "ietf-system"s;
const auto IETF_SYSTEM_STATE_MODULE_PREFIX = "/"s + IETF_SYSTEM_MODULE_NAME + ":system-state/"s;

/** @brief Returns key=value pairs from (e.g. /etc/os-release) as a std::map */
std::map<std::string, std::string> parseKeyValueFile(const std::filesystem::path& path)
{
    std::map<std::string, std::string> res;
    std::ifstream ifs(path);
    if (!ifs.is_open())
        throw std::invalid_argument("File '" + std::string(path) + "' not found.");

    std::string line;
    while (std::getline(ifs, line)) {
        // man os-release: Lines beginning with "#" shall be ignored as comments. Blank lines are permitted and ignored.
        if (line.empty() || boost::algorithm::starts_with(line, "#")) {
            continue;
        }

        size_t equalSignPos = line.find_first_of('=');
        if (equalSignPos != std::string::npos) {
            std::string key = line.substr(0, equalSignPos);
            std::string val = line.substr(equalSignPos + 1);

            // remove quotes from value
            if (val.length() >= 2 && val.front() == '"' && val.front() == val.back()) {
                val = val.substr(1, val.length() - 2);
            }

            res[key] = val;
        } else { // when there is no = sign, treat the value as empty string
            res[line] = "";
        }
    }

    return res;
}

}

namespace velia::system {

/** @brief Reads some OS-identification data from osRelease file and publishes them via ietf-system model */
Sysrepo::Sysrepo(std::shared_ptr<::sysrepo::Session> srSession, const std::filesystem::path& osRelease)
    : m_srSession(std::move(srSession))
    , m_log(spdlog::get("system"))
{
    std::map<std::string, std::string> osReleaseContents = parseKeyValueFile(osRelease);

    std::map<std::string, std::string> opsSystemStateData {
        {IETF_SYSTEM_STATE_MODULE_PREFIX + "platform/os-name", osReleaseContents.at("NAME")},
        {IETF_SYSTEM_STATE_MODULE_PREFIX + "platform/os-release", osReleaseContents.at("VERSION")},
        {IETF_SYSTEM_STATE_MODULE_PREFIX + "platform/os-version", osReleaseContents.at("VERSION")},
    };

    sr_datastore_t oldDatastore = m_srSession->session_get_ds();
    m_srSession->session_switch_ds(SR_DS_OPERATIONAL);

    for (const auto& [k, v] : opsSystemStateData) {
        m_log->debug("Pushing to sysrepo: {} = {}", k, v);
        m_srSession->set_item_str(k.c_str(), v.c_str());
    }

    m_srSession->apply_changes();
    m_srSession->session_switch_ds(oldDatastore);
}
}