/// <summary>
/// Attempts to acquire a lease based on the provided lease policy.
/// </summary>
/// <param name="leasePolicy">The configuration details for the lease.</param>
/// <param name="leaseId">The id of the currently acquired lease.</param>
/// <returns>A task for the async operation.</returns>
public async Task <string> AcquireAsync(ILeasePolicy leasePolicy, string leaseId)
{
this.LeasePolicy = leasePolicy;
await this.InitialiseAsync();
if (!this.blob.Exists())
{
await Retriable.RetryAsync(async() =>
{
using (var ms = new MemoryStream())
{
await this.blob.UploadFromStreamAsync(ms);
}
});
}
try
{
return(await Retriable.RetryAsync(
() => this.blob.AcquireLeaseAsync(leasePolicy.Duration, leaseId),
new CancellationToken(),
new Count(10),
new DoNotRetryOnConflictPolicy()));
}
catch (StorageException exception)
{
if (exception.RequestInformation.HttpStatusCode == 409)
{
throw new LeaseAcquisitionUnsuccessfulException(this.LeasePolicy, exception);
}
throw;
}
}
/// <summary>
/// Attempts to extend the lease based on the lease policy provided to initially acquire it.
/// </summary>
/// <param name="leaseId">The id of the lease to attempt to extend.</param>
/// <remarks>A valid lease and lease policy must exist for this operation to execute. An InvalidOperationException will be thrown otherwise.</remarks>
/// <returns>A task for the async operation.</returns>
public async Task ExtendAsync(string leaseId)
{
await this.InitialiseAsync();
await Retriable.RetryAsync(() => this.blob.RenewLeaseAsync(new AccessCondition {
LeaseId = leaseId
}));
}
public async Task ThenAfterSecondsAtMostThereShouldBeAWorkflowInstanceWithTheIdInTheWorkflowInstanceStore(string instanceId, int maximumWaitTime)
{
var tokenSource = new CancellationTokenSource();
tokenSource.CancelAfter(TimeSpan.FromSeconds(maximumWaitTime));
await Retriable.RetryAsync(
() => this.GetWorkflowInstance(instanceId, false),
tokenSource.Token,
new Linear(TimeSpan.FromSeconds(1), int.MaxValue),
new AnyExceptionPolicy(),
false).ConfigureAwait(false);
}
private async Task InitialiseAsync()
{
if (!this.isInitialised)
{
var storageAccount = CloudStorageAccount.Parse(Configuration.GetSettingFor(this.connectionStringProvider.ConnectionStringKey));
var client = storageAccount.CreateCloudBlobClient();
var container = client.GetContainerReference("endjin-leasing-leases");
await Retriable.RetryAsync(container.CreateIfNotExistsAsync);
this.blob = container.GetBlockBlobReference(this.LeasePolicy.Name.ToLowerInvariant());
this.isInitialised = true;
}
}
private async Task PublishWithRetryAsync <T>(string source, string subject, T cloudEvent, WorkflowEventSubscription destination)
{
try
{
await Retriable.RetryAsync(() => this.PublishAsync(source, subject, cloudEvent, destination)).ConfigureAwait(false);
}
catch (Exception ex)
{
// In this "v1" solution to event publishing, we don't want exceptions to propagate outside the
// publisher because we don't want failure in event publishing to break anything.
this.logger.LogError(
ex,
"Unexpected exception when trying to a CloudEvent with source '{source}', '{subject}' and destinationUrl '{destinationUrl}' with authentication resource '{msiAuthenticationResource}'.",
source,
subject,
destination?.ExternalUrl,
destination?.MsiAuthenticationResource);
}
}