/* -------------------------------------------------------------------------- */
/* Copyright 2002-2014, OpenNebula Project (OpenNebula.org), C12G Labs */
/* */
/* Licensed under the Apache License, Version 2.0 (the "License"); you may */
/* not use this file except in compliance with the License. You may obtain */
/* a copy of the License at */
/* */
/* http://www.apache.org/licenses/LICENSE-2.0 */
/* */
/* Unless required by applicable law or agreed to in writing, software */
/* distributed under the License is distributed on an "AS IS" BASIS, */
/* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. */
/* See the License for the specific language governing permissions and */
/* limitations under the License. */
/* -------------------------------------------------------------------------- */ #ifndef MAD_H_
#define MAD_H_ #include <pthread.h>
#include <sys/types.h> #include <map>
#include <string>
#include <sstream> #include <unistd.h> #include "Log.h" using namespace std; /**
* Base class to build specific middleware access drivers (MAD).
* This class provides generic MAD functionality.
*/
class Mad
{
protected:
/**
* The constructor initialize the class members but DOES NOT start the
* driver. A subsequent call to the start() method is needed.
* @param userid user running this MAD
* @param attrs configuration attributes for the driver
* @param sudo the driver is started through sudo if true
*/
Mad(
int userid,
const map<string,string> &attrs,
bool sudo):
uid(userid),
attributes(attrs),
sudo_execution(sudo),
pid(-1)
{}; /**
* The destructor of the class finalizes the driver process, and all its
* associated resources (i.e. pipes)
*/
virtual ~Mad(); /**
* Send a command to the driver
* @param os an output string stream with the message, it must be
* terminated with the end of line character.
*/
void write(
ostringstream& os) const
{
string str;
const char * cstr; str = os.str();
cstr = str.c_str(); ::write(nebula_mad_pipe, cstr, str.size());
}; /**
* Send a DRIVER_CANCEL command to the driver
* @param oid identifies the action (that associated with oid)
*/
void driver_cancel (const int oid) const
{
ostringstream os; os << "DRIVER_CANCEL " << oid << endl; write(os);
}; /**
* Sets the log message type as specify by the driver.
* @param first character of the type string
* @return the message type
*/
Log::MessageType log_type(const char r) const
{
Log::MessageType lt; switch (r)
{
case 'E':
lt = Log::ERROR;
break;
case 'I':
lt = Log::INFO;
break;
case 'D':
lt = Log::DEBUG;
break;
default:
lt = Log::INFO;
} return lt;
} private:
friend class MadManager; /**
* Communication pipe file descriptor. Represents the MAD to nebula
* communication stream (nebula<-mad)
*/
int mad_nebula_pipe; /**
* Communication pipe file descriptor. Represents the nebula to MAD
* communication stream (nebula->mad)
*/
int nebula_mad_pipe; /**
* User running this MAD as defined in the upool DB
*/
int uid; /**
* Mad configuration attributes (e.g. executable, attributes...). Attribute
* names MUST be lowecase.
*/
map<string,string> attributes; /**
* True if the mad is to be executed through sudo, with the identity of the
* Mad owner (uid).
*/
bool sudo_execution; /**
* Process ID of the running MAD.
*/
pid_t pid; /**
* Starts the MAD. This function creates a new process, sets up the
* communication pipes and sends the initialization command to the driver.
* @return 0 on success
*/
int start(); /**
* Reloads the driver: sends the finalize command, "waits" for the
* driver process and closes the communication pipes. Then the driver is
* started again by calling the start() function
* @return 0 on success
*/
int reload(); /**
* Implements the driver specific protocol, this function should trigger
* actions on the associated manager.
* @param message the string read from the driver
*/
virtual void protocol(const string& message) const = 0; /**
* This function is called whenever the driver crashes. This function
* should perform the actions needed to recover the VMs.
*/
virtual void recover() = 0;
}; #endif /*MAD_H_*/
上面这个类是OpenNebula 中间件訪问驱动的接口.