[Opennebula] Middleware interview driver

/*--------------------------------------------------------------------------*//* 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.                                                                            Obtain *//* a copy of the License at *//*                                 *//* http://www.apache.org/licenses/LICENSE-2.0 *//* *//* unless required by APPL           Icable law or agreed into writing, software *//* distributed under the License is distributed on a "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 Acce SS 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 Sud o 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 * t     Erminated 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 (which 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::D ebug;            Break        Default:lt = Log::info;    } return lt;    }private:friend class Madmanager; /** * Communication pipe file descriptor.    Represents the MAD to nebula * Communication Stream (NEBULA&LT;-MAD) */int mad_nebula_pipe; /** * Communication pipe file descriptor.    Represents the nebula to MAD * Communication Stream (NEBULA-&GT;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 DR     Iver.    * @return 0 on Success */int start (); /** * Reloads the Driver:sends the Finalize command, "waits" for the * driver process and closes the Communicat Ion pipes. Then the driver was * 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_*/

The above class is the Opennebula middleware access-driven interface.

[Opennebula] Middleware interview driver