Lock each list of memory persistence before using

[qazq]

In some cases, add/remove workflow at persistence store will throw an
exception. ("Collection was modified; enumeration operation may not execute.")

[danielgerlag]

Which persistence provider are you using?

…

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On May 22, 2017, at 9:00 PM, qazq ***@***.***> wrote: In some cases, add/remove workflow at persistence store will throw an exception. ("Collection was modified; enumeration operation may not execute.") You can view, comment on, or merge this pull request online at: #35 Commit Summary Lock each list of memory persistence before using File Changes M src/WorkflowCore/Services/MemoryPersistenceProvider.cs (131) Patch Links: https://github.com/danielgerlag/workflow-core/pull/35.patch https://github.com/danielgerlag/workflow-core/pull/35.diff — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub, or mute the thread.

[qazq]

MemoryPersistenceProvider

[qazq]

This is my testing code.

            var host = serviceProvider.GetService<IWorkflowHost>();
            host.RegisterWorkflow<HelloWorldWorkflow>();        
            host.Start();

            Thread.Sleep(100);
            for (int i = 0; i < 100; i++)
            {
                host.StartWorkflow("HelloWorld", 1, null);
                if (i % 10 == 0)
                {
                    Thread.Sleep(1000);
                }
            }

It has the chance to happen the exception.

[danielgerlag]

Thanks for the PR...
Would it work if we simply changed the List<> fields to ConcurrentBag<> fields, rather than adding the locks?

[qazq]

ConcurrentBag<> seems cannot remove a specific item, so I add the locks.