/// <summary>
/// Take responsibility for a set of new queues that were assigned to me via a new range.
/// We first create one pulling agent for every new queue and store them in our internal data structure, then try to initialize the agents.
/// ERROR HANDLING:
/// The responsibility to handle initialization and shutdown failures is inside the Agents code.
/// The manager will call Initialize once and log an error. It will not call initialize again and will assume initialization has succeeded.
/// Same applies to shutdown.
/// </summary>
/// <param name="myQueues"></param>
/// <param name="failOnInit"></param>
/// <returns></returns>
private async Task AddNewQueues(IEnumerable <QueueId> myQueues, bool failOnInit)
{
// Create agents for queues in range that we don't yet have.
// First create them and store in local queuesToAgentsMap.
// Only after that Initialize them all.
var agents = new List <PersistentStreamPullingAgent>();
foreach (var queueId in myQueues.Where(queueId => !queuesToAgentsMap.ContainsKey(queueId)))
{
try
{
var agentId = GrainId.NewSystemTargetGrainIdByTypeCode(Constants.PULLING_AGENT_SYSTEM_TARGET_TYPE_CODE);
var agent = new PersistentStreamPullingAgent(agentId, streamProviderName, providerRuntime, queueId, queueGetPeriod, initQueueTimeout);
providerRuntime.RegisterSystemTarget(agent);
queuesToAgentsMap.Add(queueId, agent);
agents.Add(agent);
}
catch (Exception exc)
{
logger.Error((int)ErrorCode.PersistentStreamPullingManager_07, String.Format("Exception while creating PersistentStreamPullingAgent."), exc);
// What should we do? This error is not recoverable and considered a bug. But we don't want to bring the silo down.
// If this is when silo is starting and agent is initializing, fail the silo startup. Otherwise, just swallow to limit impact on other receivers.
if (failOnInit)
{
throw;
}
}
}
try
{
var initTasks = new List <Task>();
foreach (var agent in agents)
{
// Init the agent only after it was registered locally.
var agentGrainRef = PersistentStreamPullingAgentFactory.Cast(agent.AsReference());
// Need to call it as a grain reference.
var task = OrleansTaskExtentions.SafeExecute(() => agentGrainRef.Initialize(((IQueueAdapter)queueAdapter).AsImmutable()));
task = task.LogException(logger, ErrorCode.PersistentStreamPullingManager_08, String.Format("PersistentStreamPullingAgent {0} failed to Initialize.", agent.QueueId));
initTasks.Add(task);
}
await Task.WhenAll(initTasks);
}
catch (Exception)
{
// Just ignore this exception and proceed as if Initialize has succeeded.
// We already logged individual exceptions for individual calls to Initialize. No need to log again.
}
logger.Info((int)ErrorCode.PersistentStreamPullingManager_09, "Took {0} new queues under my responsibility: {1}", agents.Count,
Utils.EnumerableToString(agents, agent => agent.QueueId.ToStringWithHashCode()));
}
private async Task RemoveQueues(IEnumerable <QueueId> myQueues)
{
// Stop the agents that for queues that are not in my range anymore.
List <QueueId> queuesToRemove = queuesToAgentsMap.Keys.Where(queueId => !myQueues.Contains(queueId)).ToList();
var agents = new List <PersistentStreamPullingAgent>(queuesToRemove.Count);
logger.Info((int)ErrorCode.PersistentStreamPullingManager_10, "Removing {0} agents from my responsibility: {1}", queuesToRemove.Count, Utils.EnumerableToString(queuesToRemove, q => q.ToStringWithHashCode()));
var removeTasks = new List <Task>();
foreach (var queueId in queuesToRemove)
{
PersistentStreamPullingAgent agent;
if (!queuesToAgentsMap.TryGetValue(queueId, out agent))
{
continue;
}
agents.Add(agent);
queuesToAgentsMap.Remove(queueId);
var agentGrainRef = PersistentStreamPullingAgentFactory.Cast(agent.AsReference());
var task = OrleansTaskExtentions.SafeExecute(agentGrainRef.Shutdown);
task = task.LogException(logger, ErrorCode.PersistentStreamPullingManager_11,
String.Format("PersistentStreamPullingAgent {0} failed to Shutdown.", agent.QueueId));
removeTasks.Add(task);
}
try
{
await Task.WhenAll(removeTasks);
}
catch (Exception)
{
// Just ignore this exception and proceed as if Initialize has succeeded.
// We already logged individual exceptions for individual calls to Shutdown. No need to log again.
}
foreach (var agent in agents)
{
try
{
providerRuntime.UnRegisterSystemTarget(agent);
}
catch (Exception exc)
{
logger.Info((int)ErrorCode.PersistentStreamPullingManager_12,
"Exception while UnRegisterSystemTarget of PersistentStreamPullingAgent {0}. Ignoring. Exc.Message = {1}.", agent.GrainId, exc.Message);
}
}
}
