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/*
* Copyright 2024 The BtrPlace Authors. All rights reserved.
* Use of this source code is governed by a LGPL-style
* license that can be found in the LICENSE.txt file.
*/
package org.btrplace.scheduler.choco;
import org.btrplace.model.*;
import org.btrplace.plan.ReconfigurationPlan;
import org.btrplace.scheduler.SchedulerException;
import org.btrplace.scheduler.SchedulerModelingException;
import org.btrplace.scheduler.choco.duration.DurationEvaluators;
import org.btrplace.scheduler.choco.transition.NodeTransition;
import org.btrplace.scheduler.choco.transition.VMTransition;
import org.btrplace.scheduler.choco.view.ChocoView;
import org.chocosolver.solver.ResolutionPolicy;
import org.chocosolver.solver.Solution;
import org.chocosolver.solver.Solver;
import org.chocosolver.solver.variables.IntVar;
import org.slf4j.Logger;
import java.util.Collection;
import java.util.List;
import java.util.Set;
/**
* Interface for the Reconfiguration Problem.
*
* VM and node identifiers are translated to a position in an array.
*
* @author Fabien Hermenier
*/
public interface ReconfigurationProblem {
/**
* Get the current location of a running or a sleeping VM.
*
* @param vmIdx the index of the VM
* @return the node index if exists, -1 if the VM is unknown
*/
int getCurrentVMLocation(int vmIdx);
/**
* Get all the nodes in the model. Indexed by their identifier.
*
* @return an immutable list of Nodes.
*/
List getNodes();
/**
* Get all the VMs in the model. Indexed by their identifier.
*
* @return an immutable list of VMs
*/
List getVMs();
/**
* Get the initial Model.
*
* @return a model
*/
Model getSourceModel();
/**
* Get the VMs that will be in the running state at the
* end of the reconfiguration process.
*
* @return a set, may be empty
*/
Set getFutureRunningVMs();
/**
* Get the VMs that will be in the ready state at the
* end of the reconfiguration process.
*
* @return a set, may be empty
*/
Set getFutureReadyVMs();
/**
* Get the VMs that will be in the sleeping state at the
* end of the reconfiguration process.
*
* @return a set, may be empty
*/
Set getFutureSleepingVMs();
/**
* Get the VMs that will be killed at the
* end of the reconfiguration process.
*
* @return a set, may be empty
*/
Set getFutureKilledVMs();
/**
* Get the next state for a given VM.
*
* @param v the VM
* @return the state if the VM is known, {@code null} otherwise
*/
VMState getFutureState(VM v);
/**
* Get the current VM state.
* @param v the VM
* @return its states if the VM is known. {@code null} otherwise
*/
VMState getSourceState(VM v);
/**
* Get the current node state.
* @param n the node
* @return its states if the node is known. {@code null} otherwise
*/
NodeState getSourceState(Node n);
/**
* Get the starting moment of the reconfiguration.
*
* @return a variable equals to 0
*/
IntVar getStart();
/**
* Get the end moment of the reconfiguration
*
* @return a variable, should be equals to the last end moment of actions
*/
IntVar getEnd();
/**
* Get the index of a VM
*
* @param vm the VM
* @return its index or -1 in case of failure
*/
int getVM(VM vm);
/**
* Get the VM with a specified index.
*
* @param idx the index of the VM
* @return the VM or null in case of failure
*/
VM getVM(int idx);
/**
* Get the index of a node.
*
* @param n the node
* @return its index or -1 in case of failure
*/
int getNode(Node n);
/**
* Get the node with a specified index.
*
* @param idx the index of the node
* @return the node or null in case of failure
*/
Node getNode(int idx);
/**
* Get the VMs transition.
*
* @return an immutable list of transitions.
*/
List getVMActions();
/**
* Get the transition associated to a given VM.
*
* @param id the VM identifier
* @return the associated transition if exists, {@code null} otherwise
*/
VMTransition getVMAction(VM id);
/**
* Get the transitions associated to a set of VMs.
*
* @param id the VMs
* @return an immutable list of transitions.
*/
List getVMActions(Collection id);
/**
* Get all the nodes transition.
* @return an immutable list of transitions.
*/
List getNodeActions();
/**
* Get the transition associated to a given node.
*
* @param id the node identifier
* @return the associated transition if exists, {@code null} otherwise
*/
NodeTransition getNodeAction(Node id);
/**
* Get the evaluator to estimate the duration of the actions.
* @return the current evaluator.
*/
DurationEvaluators getDurationEvaluators();
/**
* Solve the RP and return a solution if exists.
*
* @param timeLimit the timeout in second. Must be superior to 0 to be considered
* @param optimize {@code true} to make the solver try to improve the first computed solution.
* @return a plan if the solving process succeeded, {@code null} if the solver was not able to compute
* a solution.
* @throws SchedulerException if an error occurred
*/
ReconfigurationPlan solve(int timeLimit, boolean optimize) throws SchedulerException;
/**
* Build a plan for a solution.
* @param s the solution
* @param src the source model
* @return the resulting plan
* @throws SchedulerException if a error occurred
*/
ReconfigurationPlan buildReconfigurationPlan(Solution s, Model src) throws SchedulerException;
/**
* Return all the solutions that have been computed from a previous {@link #solve(int, boolean)} call.
* @return a list of plan that may be empty
* @throws SchedulerException if an error occurred
*/
List getComputedSolutions() throws SchedulerException;
/**
* Get the Solver used to model this problem.
*
* @return the Solver
*/
Solver getSolver();
/**
* Get the CSP model to solve
*
* @return the model
*/
org.chocosolver.solver.Model getModel();
/**
* Create a variable that indicate the placement of an element on a node.
*
* @param n the variable label as a possible concatenation of objects
* @return a variable
*/
IntVar makeHostVariable(Object... n);
/**
* Create a variable that indicate the placement of an element on a node.
* @return a variable
*/
IntVar makeHostVariable();
/**
* Create a variable that indicate the placement of an element on a node.
*
* @param candidates the candidate nodes.
* @param n the variable label as a possible concatenation of objects
* @return a variable
*/
IntVar makeHostVariable(List candidates, Object... n);
/**
* Create a variable that indicate the current placement of a VM.
* The variable is then already instantiated
*
* @param vmId the VM identifier
* @param n the variable label
* @return the created variable
* @throws org.btrplace.scheduler.SchedulerException if an error occurred while creating the variable
*/
IntVar makeCurrentHost(VM vmId, Object... n) throws SchedulerException;
/**
* Create a variable that indicate the current placement of a VM.
* The variable is then already instantiated
*
* @param vmId the VM identifier
* @return the created variable
* @throws org.btrplace.scheduler.SchedulerException if an error occurred while creating the variable
*/
IntVar makeCurrentHost(VM vmId) throws SchedulerException;
/**
* Create a variable that indicate a given node.
* The variable is then already instantiated
*
* @param nId the node identifier
* @param n the variable label
* @return the created variable
* @throws org.btrplace.scheduler.SchedulerException if an error occurred while creating the variable
*/
IntVar makeCurrentNode(Node nId, Object... n) throws SchedulerException;
/**
* Create a variable that indicate a given node.
* The variable is then already instantiated
*
* @param nId the node identifier
* @return the created variable
* @throws org.btrplace.scheduler.SchedulerException if an error occurred while creating the variable
*/
IntVar makeCurrentNode(Node nId) throws SchedulerException;
/**
* Create a variable denoting a duration.
*
* @param n the variable label. The toString() representation of the objects will be used
* @return the created variable.
*/
IntVar makeUnboundedDuration(Object... n);
/**
* Create a variable denoting a duration.
*
* @return the created variable.
*/
IntVar makeUnboundedDuration();
/**
* Create a variable that indicate a moment.
*
* @param ub the variable upper bound
* @param lb the variable lower bound
* @param n the variable label. The toString() representation of the objects will be used
* @return the created variable with a upper-bound necessarily lesser than {@code getEnd().getUB()}
* @throws org.btrplace.scheduler.SchedulerException if the bounds are not valid
*/
IntVar makeDuration(int ub, int lb, Object... n) throws SchedulerException;
/**
* Create a variable that indicates a moment.
*
* @param ub the variable upper bound
* @param lb the variable lower bound
* @return the created variable with a upper-bound necessarily lesser than {@code getEnd().getUB()}
* @throws org.btrplace.scheduler.SchedulerException if the bounds are not valid
*/
IntVar makeDuration(int ub, int lb) throws SchedulerException;
/**
* Get the view associated to a given identifier.
*
* @param id the view identifier
* @return the view if exists, {@code null} otherwise
*/
ChocoView getView(String id);
/**
* Get the view associated to a given identifier.
*
* @param id the view identifier
* @return the view
* @throws SchedulerModelingException if the view is missing.
*/
default ChocoView getRequiredView(String id) throws SchedulerModelingException {
ChocoView v = getView(id);
if (v == null) {
throw SchedulerModelingException.missingView(getSourceModel(), id);
}
return v;
}
/**
* Get all the declared view keys.
*
* @return a collection of keys, may be empty
*/
Collection getViews();
/**
* Add a view.
* There must not be a view with a same identifier already in.
*
* @param v the view to add
* @return {@code true} iff the view has been added.
*/
boolean addView(ChocoView v);
/**
* Get the amount of VMs hosted on each node.
*
* @return an immutable list of variables counting the number of VMs on each node
*/
List getNbRunningVMs();
/**
* Make a label for a variable iff the labelling is enabled
*
* @param lbl the label to make
* @return the label that will be used in practice
*/
String makeVarLabel(Object... lbl);
/**
* Make a label for a variable iff the labelling is enabled
*
* @param lbl the label to make
* @return the label that will be used in practice
*/
String makeVarLabel(Object lbl);
/**
* Check if variables are expected to be labelled.
*
* @return {@code true} iff variables must be labelled.
*/
boolean labelVariables();
/**
* Make a constant.
* This methods allows to cache constant if variable labelling is disabled.
*
* @param v the constant
* @param lbl the label to make
* @return the variable
*/
IntVar fixed(int v, Object... lbl);
/**
* Make a constant.
* @param v the constant
* @param lbl the label.
* @return the variable.
*/
IntVar fixed(int v, Object lbl);
/**
* Get the VMs managed by the solver.
* This set contains all the VMs that will have their state changed
* plus the set of manageable running VMs that was passed to the constructor.
*
* @return a set of VMs identifier
*/
Set getManageableVMs();
/**
* Get the VMs that are supposed to be misplaced.
* This is the conjunction of all the VMs reported by views and constraints
* implementing {@link MisplacedVMsEstimator}.
*
* @return a set, possibly empty.
*/
Set getMisplacedVMs();
/**
* Get the logger.
*
* @return well, the logger
*/
Logger getLogger();
/**
* Create a clone of a given VM.
* The clone will take the place of the VM by the end of the reconfiguration process.
*
* @param vm the identifier of the VM to substitute
* @return the identifier of the new VM. {@code null} if the process failed
*/
VM cloneVM(VM vm);
/**
* Set the optimisation variable.
*
* @param b {@code true} to minimise the value. {@code false} to maximise it
* @param v the variable to optimise
*/
void setObjective(boolean b, IntVar v);
/**
* Get the optimisation variable
*
* @return a variable that is {@code null} if {@code #getResolutionPolicy() == ResolutionPolicy#SATISFACTION}
*/
IntVar getObjective();
/**
* Get the current resolution policy.
*
* @return the current resolution policy
*/
ResolutionPolicy getResolutionPolicy();
/**
* Stop the solver.
*/
void stop();
}