Impossible to fetch jobs when using conventions on discriminator

[uselessChiP]

Hi,
I have an external library that sets this kind of convention:

classMap.SetDiscriminator(classMap.ClassType.FullName);

in Hangfire.Mongo, MongoWriteOnlyTransaction -> CreateExpiredJob, jobDto.ToBsonDocument() is called and that makes it so that the types for the job are serialized using the fully qualified name:

{ ... "_t": [ "Hangfire.Mongo.Dto.BaseJobDto", "Hangfire.Mongo.Dto.ExpiringJobDto", "Hangfire.Mongo.Dto.JobDto" ], ... }

The problem is that most of the other code in MongoWriteOnlyTransaction writes "_t" as follows:

["_t"] = new BsonArray {nameof(BaseJobDto), nameof(ExpiringJobDto), nameof(KeyJobDto), nameof(CounterDto)},

making the stored data have different kind of values:

Other than that, the BsonDiscriminator is also set as the nameof of the class:

[BsonDiscriminator(nameof(SetDto))]

In this configuration my project isn't working because I guess that OfType is using the discriminator convention that I've mentioned in the beginning and so it doesn't find any set.

I think that the writer class should be updated to serialize all the discriminators based on the conventions.

[gottscj]

@uselessChiP,

Thank you for submitting this. I will look into a solution.

[gottscj]

@uselessChiP,

Kindly try adding this configuration to your codebase:

ConventionRegistry.Register(
               "Hangfire Mongo Conventions",
               new ConventionPack
            {
                new DelegateClassMapConvention("Set Hangfire Mongo Discriminator", cm => 
                cm.SetDiscriminator(cm.ClassType.Name))
            },
               t => t.FullName.StartsWith("Hangfire.Mongo.Dto"));

[uselessChiP]

Just to give you some feedback.
Your configuration worked but I had to change the DelegateClassMapConvention to a DelegatePostProcessingConvention, since the first convention is registered in post processing (so later than the class maps) and second I had to make sure that this convention was registered somewhere that is called after the initialization of the library containing the FullName discriminator convention.

So it seems to work but it feels like a workaround at the moment.

[gottscj]

@uselessChiP,

Thank you for your feedback. Would initialization be easier if this was embedded in the Hangfire Mongo bootstrapper code? The challenge is that to comply to the "WriteOnlyTransaction" API defined in the Hangfire.Core lib I have to work directly on BsonDocuments. Hangfire.Mongo also needs the "HierarchicalDiscriminatorConvention" as other parts of the code.

I will look into making this library more resilient against other serializer conventions

[gottscj]

@uselessChiP,

Our conversation triggered a minor re-write. Im now manually serializing the DTO's which should make it immune to any convention there might be used.

Thanks for your input

[gottscj]

@uselessChiP,

Please let me know if your issue has been resolved. Then I'll close this issue.

Thanks!

[gottscj]

closing due to inactivity