private async Task <Result <Role> > UpdateRoleAsync(OperationContext context, bool release)
{
return(await context.PerformOperationAsync <Result <Role> >(
Tracer,
async() =>
{
// This mutex ensure that Release of master role during shutdown and Heartbeat role acquisition are synchronized.
// Ensuring that a heartbeat during shutdown doesn't trigger the released master role to be acquired again.
using (await _roleMutex.AcquireAsync())
{
if (ShutdownStarted)
{
// Don't acquire a role during shutdown
return Role.Worker;
}
var configuredRole = _configuration.Checkpoint?.Role;
if (configuredRole != null)
{
return configuredRole.Value;
}
var localMachineName = LocalMachineLocation.ToString();
var masterAcquisitonResult = await _masterLeaseKey.UseReplicatedHashAsync(context, _configuration.RetryWindow, RedisOperation.UpdateRole, (batch, key) => batch.AcquireMasterRoleAsync(
masterRoleRegistryKey: key,
machineName: localMachineName,
currentTime: _clock.UtcNow,
leaseExpiryTime: _configuration.Checkpoint.MasterLeaseExpiryTime,
// 1 master only is allowed. This should be changed if more than one master becomes a possible configuration
slotCount: 1,
release: release
)).ThrowIfFailureAsync();
if (release)
{
Tracer.Debug(context, $"'{localMachineName}' released master role.");
return Role.Worker;
}
if (masterAcquisitonResult != null)
{
var priorMachineName = masterAcquisitonResult.Value.PriorMasterMachineName;
if (priorMachineName != localMachineName || masterAcquisitonResult.Value.PriorMachineStatus != SlotStatus.Acquired)
{
Tracer.Debug(context, $"'{localMachineName}' acquired master role from '{priorMachineName}', Status: '{masterAcquisitonResult?.PriorMachineStatus}', LastHeartbeat: '{masterAcquisitonResult?.PriorMasterLastHeartbeat}'");
}
return Role.Master;
}
else
{
return Role.Worker;
}
}
},
Counters[GlobalStoreCounters.UpdateRole]));
}
public Task <BoolResult> RegisterCheckpointAsync(OperationContext context, string checkpointId, EventSequencePoint sequencePoint)
{
return(context.PerformOperationAsync(
Tracer,
async() =>
{
Contract.Assert(sequencePoint.SequenceNumber != null);
var checkpoint = new RedisCheckpointInfo(checkpointId, sequencePoint.SequenceNumber.Value, _clock.UtcNow, LocalMachineLocation.ToString());
Tracer.Debug(context, $"Saving checkpoint '{checkpoint}' into the central store.");
var slotNumber = await _checkpointsKey.UseReplicatedHashAsync(
context,
_configuration.RetryWindow,
RedisOperation.UploadCheckpoint,
(batch, key) => batch.AddCheckpointAsync(key, checkpoint, MaxCheckpointSlotCount)).ThrowIfFailureAsync();
Tracer.Debug(context, $"Saved checkpoint into slot '{slotNumber}'.");
return BoolResult.Success;
},
Counters[GlobalStoreCounters.RegisterCheckpoint]));
}
public Task <BoolResult> RegisterCheckpointAsync(OperationContext context, string checkpointId, EventSequencePoint sequencePoint)
{
return(context.PerformOperationAsync(
Tracer,
() =>
{
Contract.Assert(sequencePoint.SequenceNumber != null);
var checkpoint = new RedisCheckpointInfo(checkpointId, sequencePoint.SequenceNumber.Value, _clock.UtcNow, LocalMachineLocation.ToString());
Tracer.Debug(context, $"Saving checkpoint '{checkpoint}' into the central store.");
return ExecuteRedisAsync(context, async redisDb =>
{
var slotNumber = await redisDb.ExecuteBatchAsync(context, batch =>
{
return batch.AddCheckpointAsync(_checkpointsKey, checkpoint, MaxCheckpointSlotCount);
}, RedisOperation.UploadCheckpoint);
Tracer.Debug(context, $"Saved checkpoint into slot '{slotNumber}' on {GetDbName(redisDb)}.");
return BoolResult.Success;
});
},
Counters[GlobalStoreCounters.RegisterCheckpoint]));
}