/// <summary>
/// Reads the checkpoint information from the file for partition id
/// </summary>
/// <param name="partitionId">The partition id the checkpoint data is for</param>
/// <returns>A checkpoint instance populated from the file</returns>
private async Task <CheckpointEntry> ReadCheckpointFromFileAsync(string partitionId)
{
CheckpointEntry result = null;
using (_logger.BeginScope("Read Checkpoint"))
{
_checkpointReadCounter.Increment();
_logger.LogDebug("Reading checkpoint partition {partitionId}", partitionId);
var fileName = GetFileName(partitionId);
if (File.Exists(fileName))
{
_logger.LogDebug("File {fileName} exists", fileName);
try
{
var json = await File.ReadAllTextAsync(fileName, ContainerLifecycle.CancellationToken).ConfigureAwait(false);
if (string.IsNullOrWhiteSpace(json))
{
_logger.LogInformation("File {fileName} was empty", fileName);
}
else
{
_logger.LogInformation("File {fileName} had the following content: {content}", fileName, json);
try
{
result = CheckpointEntry.FromJson(json);
}
catch (Exception e)
{
_logger.LogError(e, "Error deserializing checkpoint contents");
_checkpointErrorCounter.Increment();
}
}
}
catch (Exception e)
{
_logger.LogError(e, "Error reading checkpoint file {fileName}", fileName);
_checkpointErrorCounter.Increment();
}
}
else
{
_logger.LogInformation("File {fileName} does not exists", fileName);
}
}
return(result);
}
/// <inheritdoc />
public async Task <Checkpoint> CreateCheckpointIfNotExistsAsync(string partitionId)
{
CheckpointEntry checkpoint;
using (_logger.BeginScope("Create checkpoint"))
{
_checkpointUpdateCounter.Increment();
_logger.LogDebug("Checkpoint partition {partitionId}", partitionId);
checkpoint = await ReadCheckpointFromFileAsync(partitionId).ConfigureAwait(false);
if (checkpoint == null)
{
_logger.LogInformation("Checkpoint not found for partition {partitionId}, creating", partitionId);
var fileName = GetFileName(partitionId);
var newCheckpoint = new CheckpointEntry {
PartitionId = partitionId, Owner = _eventProcessorName
};
var json = newCheckpoint.ToJson();
_logger.LogTrace("Checkpoint json: ", json);
try
{
await File.WriteAllTextAsync(fileName, json, ContainerLifecycle.CancellationToken).ConfigureAwait(false);
_logger.LogDebug("Checkpoint complete for file {fileName}", fileName);
checkpoint = newCheckpoint;
}
catch (Exception e)
{
_logger?.LogError(e, "Error writing checkpoint file {fileName}", fileName);
_checkpointErrorCounter.Increment();
}
}
else
{
_logger?.LogTrace("Checkpoint found for partition {partitionId}", partitionId);
}
}
return(checkpoint);
}