Function extractConfigValue

programs/docker-init/docker-init.cpp:241–254

Extract a single value from a ClickHouse config key via `clickhouse extract-from-config`. Returns an empty string if the key is absent (--try flag suppresses errors).

/// Extract a single value from a ClickHouse config key via `clickhouse extract-from-config`.
/// Returns an empty string if the key is absent (--try flag suppresses errors).
std::string extractConfigValue(const std::string & config_file, const std::string & key, bool use_users = false)
{
    std::vector<std::string> args = {
        g_clickhouse_binary, "extract-from-config",
        "--config-file", config_file,
        "--key", key,
        "--try",
    };
    if (use_users)
        args.emplace_back("--users");

    auto [code, lines] = captureCommand(args);
    return (code == 0 && !lines.empty()) ? lines[0] : std::string{};
}

/// Extract multiple values from a ClickHouse config key (wildcard patterns return multiple lines).
std::vector<std::string> extractConfigValues(const std::string & config_file, const std::string & key)