public async Task StartShard(IAsyncProjectionShard shard, CancellationToken cancellationToken)
{
if (!_hasStarted)
{
StartNode();
}
// Don't duplicate the shard
if (_agents.ContainsKey(shard.Name.Identity))
{
return;
}
await TryAction(null, async() =>
{
try
{
var agent = new ProjectionAgent(_store, shard, _logger, cancellationToken);
var position = await agent.Start(this);
Tracker.Publish(new ShardState(shard.Name, position)
{
Action = ShardAction.Started
});
_agents[shard.Name.Identity] = agent;
}
catch (Exception e)
{
_logger.LogError(e, "Error when trying to start projection shard '{ShardName}'", shard.Name.Identity);
throw new ShardStartException(shard.Name, e);
}
}, cancellationToken);
}
public ProjectionAgent(DocumentStore store, IAsyncProjectionShard projectionShard, ILogger logger, CancellationToken cancellation)
{
if (cancellation == CancellationToken.None)
{
_cancellationSource = new CancellationTokenSource();
_cancellation = _cancellationSource.Token;
}
_store = store;
_projectionShard = projectionShard;
_logger = logger;
_cancellation = cancellation;
_controller =
new ProjectionController(projectionShard.Name, this, projectionShard.Options);
}
public async Task StartShard(IAsyncProjectionShard shard)
{
if (!_hasStarted)
{
StartNode();
}
// TODO -- log the start, or error if it fails
var agent = new ProjectionAgent(_store, shard, _logger);
var position = await agent.Start(Tracker);
Tracker.Publish(new ShardState(shard.ProjectionOrShardName, position)
{
Action = ShardAction.Started
});
_agents[shard.ProjectionOrShardName] = agent;
}
// ReSharper disable once ContextualLoggerProblem
public ProjectionAgent(DocumentStore store, IAsyncProjectionShard projectionShard, ILogger <IProjection> logger)
{
_store = store;
_projectionShard = projectionShard;
_logger = logger;
var singleFile = new ExecutionDataflowBlockOptions
{
EnsureOrdered = true,
MaxDegreeOfParallelism = 1,
CancellationToken = _cancellationSource.Token
};
_commandBlock = new ActionBlock <Command>(processCommand, singleFile);
_controller =
new ProjectionController(projectionShard.ProjectionOrShardName, this, projectionShard.Options);
_loader = new TransformBlock <EventRange, EventRange>(loadEvents, singleFile);
}
internal bool TryFindAsyncShard(string projectionOrShardName, out IAsyncProjectionShard shard)
{
return(_asyncShards.Value.TryGetValue(projectionOrShardName, out shard));
}
public ShardState(IAsyncProjectionShard shard, ShardAction action) : this(shard.ProjectionOrShardName, 0)
{
Action = action;
}
public ShardState(IAsyncProjectionShard shard, long sequenceNumber) : this(shard.ProjectionOrShardName, sequenceNumber)
{
}
