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//
// Copyright 2017 Ettus Research, a National Instruments Company
//
// SPDX-License-Identifier: GPL-3.0-or-later
//
#ifndef INCLUDED_UTILS_RPC_HPP
#define INCLUDED_UTILS_RPC_HPP
#include <rpc/client.h>
#include <rpc/rpc_error.h>
#include <uhd/utils/log.hpp>
#include <uhd/exception.hpp>
#include <boost/format.hpp>
namespace uhd {
/*! Abstraction for RPC client
*
* Purpose of this class is to wrap the underlying RPC implementation.
* This class holds a connection to an RPC server (the connection is severed on
* destruction).
*/
class rpc_client
{
public:
using sptr = std::shared_ptr<rpc_client>;
static sptr make(
const std::string &addr,
const uint16_t port,
const std::string &get_last_error_cmd=""
) {
return std::make_shared<rpc_client>(addr, port, get_last_error_cmd);
}
/*!
* \param addr An IP address to connect to
* \param port Port to connect to
* \param get_last_error_cmd A command that queries an error string from
* the RPC server. If set, the RPC client will
* try and use this command to fetch information
* about what went wrong on the client side.
*/
rpc_client(
const std::string &addr,
const uint16_t port,
std::string const &get_last_error_cmd=""
) : _client(addr, port)
, _get_last_error_cmd(get_last_error_cmd)
{
// nop
}
/*! Perform an RPC request.
*
* Thread safe (locked). This function blocks until it receives a valid
* response from the server.
*
* \param func_name The function name that is called via RPC
* \param args All these arguments are passed to the RPC call
*
* \throws uhd::runtime_error in case of failure
*/
template <typename return_type, typename... Args>
return_type request(std::string const& func_name, Args&&... args)
{
std::lock_guard<std::mutex> lock(_mutex);
try {
return _client.call(func_name, std::forward<Args>(args)...)
.template as<return_type>();
} catch (const ::rpc::rpc_error &ex) {
const std::string error = _get_last_error_safe();
if (not error.empty()) {
UHD_LOG_ERROR("RPC", error);
}
throw uhd::runtime_error(str(
boost::format("Error during RPC call to `%s'. Error message: %s")
% func_name % (error.empty() ? ex.what() : error)
));
} catch (const std::bad_cast& ex) {
throw uhd::runtime_error(str(
boost::format("Error during RPC call to `%s'. Error message: %s")
% func_name % ex.what()
));
}
};
/*! Perform an RPC notification.
*
* Thread safe (locked). This function does not require a response from the
* server, although the underlying implementation may provide one.
*
* \param func_name The function name that is called via RPC
* \param args All these arguments are passed to the RPC call
*
* \throws uhd::runtime_error in case of failure
*/
template <typename... Args>
void notify(std::string const& func_name, Args&&... args)
{
std::lock_guard<std::mutex> lock(_mutex);
try {
_client.call(func_name, std::forward<Args>(args)...);
} catch (const ::rpc::rpc_error &ex) {
const std::string error = _get_last_error_safe();
if (not error.empty()) {
UHD_LOG_ERROR("RPC", error);
}
throw uhd::runtime_error(str(
boost::format("Error during RPC call to `%s'. Error message: %s")
% func_name % (error.empty() ? ex.what() : error)
));
} catch (const std::bad_cast& ex) {
throw uhd::runtime_error(str(
boost::format("Error during RPC call to `%s'. Error message: %s")
% func_name % ex.what()
));
}
};
/*! Like request(), also provides a token.
*
* This is a convenience wrapper to directly call a function that requires
* a token without having to have a copy of the token.
*/
template <typename return_type, typename... Args>
return_type request_with_token(std::string const& func_name, Args&&... args)
{
return request<return_type>(func_name, _token, std::forward<Args>(args)...);
};
/*! Like notify(), also provides a token.
*
* This is a convenience wrapper to directly call a function that requires
* a token without having to have a copy of the token.
*/
template <typename... Args>
void notify_with_token(std::string const& func_name, Args&&... args)
{
notify(func_name, _token, std::forward<Args>(args)...);
};
/*! Sets the token value. This is used by the `_with_token` methods.
*/
void set_token(const std::string &token)
{
_token = token;
}
void set_timeout(size_t timeout_ms)
{
_client.set_timeout(timeout_ms);
}
private:
/*! Pull the last error out of the RPC server. Not thread-safe, meant to
* be called from notify() or request().
*
* This function will do its best not to get in anyone's way. If it can't
* get an error string, it'll return an empty string.
*/
std::string _get_last_error_safe()
{
if (_get_last_error_cmd.empty()) {
return "";
}
try {
return _client.call(_get_last_error_cmd).as<std::string>();
} catch (const ::rpc::rpc_error &ex) {
// nop
} catch (const std::bad_cast& ex) {
// nop
} catch (...) {
// nop
}
return "";
}
//! Reference the actual RPC client
::rpc::client _client;
//! If set, this is the command that will retrieve an error
const std::string _get_last_error_cmd;
std::string _token;
std::mutex _mutex;
};
} /* namespace uhd */
#endif /* INCLUDED_UTILS_RPC_HPP */
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