/**
* Starts an instance (prerequisite: DEPLOYED_STOPPED).
*
* @param instance the instance
* @param plugin the associated plug-in
* @throws IOException if something went wrong
*/
void start(Instance instance, PluginInterface plugin) throws IOException {
String instancePath = InstanceHelpers.computeInstancePath(instance);
if (instance.getStatus() != InstanceStatus.DEPLOYED_STOPPED
&& instance.getStatus() != InstanceStatus.WAITING_FOR_ANCESTOR) {
this.logger.fine(
instancePath
+ " cannot be started. Prerequisite status: DEPLOYED_STOPPED or WAITING_FOR_ANCESTOR (but was "
+ instance.getStatus()
+ ").");
} else if (instance.getParent() != null
&& instance.getParent().getStatus() != InstanceStatus.DEPLOYED_STARTED) {
// An element cannot start if its parent is not started.
// However, if the parent is unresolved (or waiting for its parent to start),
// then we can mark this instance as ready to start with its parent.
this.logger.fine(
instancePath
+ " cannot be started because its parent is not started. Parent status: "
+ instance.getParent().getStatus()
+ ".");
if (instance.getParent().getStatus() == InstanceStatus.UNRESOLVED
|| instance.getParent().getStatus() == InstanceStatus.WAITING_FOR_ANCESTOR) {
instance.setStatus(InstanceStatus.WAITING_FOR_ANCESTOR);
this.logger.fine(instancePath + " will start as soon as its parent starts.");
}
} else {
// Otherwise, start it
try {
if (ImportHelpers.hasAllRequiredImports(instance, this.logger)) {
instance.data.put(FORCE, "whatever");
updateStateFromImports(instance, plugin, null, null);
} else {
this.logger.fine(
"Instance "
+ InstanceHelpers.computeInstancePath(instance)
+ " cannot be started, dependencies are missing. Requesting exports from other agents.");
instance.setStatus(InstanceStatus.UNRESOLVED);
this.messagingClient.sendMessageToTheDm(
new MsgNotifInstanceChanged(this.appName, instance));
this.messagingClient.requestExportsFromOtherAgents(instance);
}
} catch (PluginException e) {
this.logger.severe(
"An error occured while starting " + InstanceHelpers.computeInstancePath(instance));
Utils.logException(this.logger, e);
instance.setStatus(InstanceStatus.DEPLOYED_STOPPED);
this.messagingClient.sendMessageToTheDm(
new MsgNotifInstanceChanged(this.appName, instance));
}
}
}
/**
* Updates the status of an instance based on the imports.
*
* @param impactedInstance the instance whose imports may have changed
* @param plugin the plug-in to use to apply a concrete modification
* @param statusChanged The changed status of the instance that changed (e.g. that provided new
* imports)
* @param importChanged The individual imports that changed
*/
public void updateStateFromImports(
Instance impactedInstance,
PluginInterface plugin,
Import importChanged,
InstanceStatus statusChanged)
throws IOException, PluginException {
// Do we have all the imports we need?
boolean haveAllImports = ImportHelpers.hasAllRequiredImports(impactedInstance, this.logger);
// Update the life cycle of this instance if necessary
// Maybe we have something to start
if (haveAllImports) {
if (impactedInstance.getStatus() == InstanceStatus.UNRESOLVED
|| impactedInstance.data.remove(FORCE) != null) {
InstanceStatus oldState = impactedInstance.getStatus();
impactedInstance.setStatus(InstanceStatus.STARTING);
try {
this.messagingClient.sendMessageToTheDm(
new MsgNotifInstanceChanged(this.appName, impactedInstance));
plugin.start(impactedInstance);
impactedInstance.setStatus(InstanceStatus.DEPLOYED_STARTED);
this.messagingClient.sendMessageToTheDm(
new MsgNotifInstanceChanged(this.appName, impactedInstance));
this.messagingClient.publishExports(impactedInstance);
this.messagingClient.listenToRequestsFromOtherAgents(
ListenerCommand.START, impactedInstance);
} catch (Exception e) {
this.logger.severe(
"An error occured while starting "
+ InstanceHelpers.computeInstancePath(impactedInstance));
Utils.logException(this.logger, e);
impactedInstance.setStatus(oldState);
this.messagingClient.sendMessageToTheDm(
new MsgNotifInstanceChanged(this.appName, impactedInstance));
}
} else if (impactedInstance.getStatus() == InstanceStatus.DEPLOYED_STARTED) {
plugin.update(impactedInstance, importChanged, statusChanged);
} else {
this.logger.fine(
InstanceHelpers.computeInstancePath(impactedInstance)
+ " checked import changes but has nothing to update (1).");
}
}
// Or maybe we have something to stop
else {
if (impactedInstance.getStatus() == InstanceStatus.DEPLOYED_STARTED) {
stopInstance(impactedInstance, plugin, true);
} else {
this.logger.fine(
InstanceHelpers.computeInstancePath(impactedInstance)
+ " checked import changes but has nothing to update (2).");
}
}
}