MongoClient partecipate to transaction

[luca-bassoricci]

I'm currently using mongodb support (plain one, no Panache): is there any way to let MongoClient partecipate to current transaction?
I wrote a @Decorator around MongoClient but it is removed during build; made it @unremovable doesn't resolve the problem because the decorator in never called.

Any idea?
Regards Luca

[quarkus-bot[bot]]

/cc @loicmathieu (mongodb)

[loicmathieu]

Hi,
Two solutions here:

• You wrote your own transaction support and use the MongoDB client directly. It's not that simple but it can be done. I don't know what is an @Decorator so I don't know why it is not called, a reproducer project may help.
• You use MongoDB with Panache as it comes with transaction support and you can still use the underlying MongoDB collection so you can still do whatever you want.

I strongly suggest the second option but I may be biased as I wrote the extension ;)

[luca-bassoricci]

Thanks for your quick response.
About decorator, this reproducer contains a simple decorator around a MongoClient and a test; this test fails because decorator is never called (it is removed during build).

• Transaction support will require too much time and this solution has been discarded
• MongoDB with Panache give me Panache::mongoCollection() but this method doesn't partecipate to active transaction; it's necessary a call to Panache::getSession() and/or manage transaction manually and I prefer to stick with @Transactional support.

Currently I'm using quarkus-morphia.
When I tried to decorate the synthetic Morphia's Datastore created from extension because I want to add transactional support and I faced the same problem I had decorating the MongoClient.
Could be a problem related to synthentic beans?

[loicmathieu]

You can open an issue for the decorator being removed, this may be because MongoClient is a synthetic bean or not, this is a question for a CDI guru ;)

In MongoDB, to participate in a transaction you must pass the ClientSession on each call to the driver.
This is why MongoDB with Panache is convenient, we do this for you ;)

So if you don't want to use MongoDB with Panache, you have to do the hard work by yourself.

[luca-bassoricci]

You can open an issue for the decorator being removed, this may be because MongoClient is a synthetic bean or not, this is a question for a CDI guru ;)

I'll do.

In MongoDB, to participate in a transaction you must pass the ClientSession on each call to the driver.
This is why MongoDB with Panache is convenient, we do this for you ;)

I have a small question about this use case using panache:

@Transactional
public void doStuff()
{
  MyMongoEntity.mongoCollection().aggregate(...);
  MyMongoEntity.mongoCollection().findOneAndDelete(...);
}

in this case Panache doesn't pass to MongoCollection::aggregate() any client session: should it do it?

In

quarkus/extensions/panache/mongodb-panache-common/runtime/src/main/java/io/quarkus/mongodb/panache/common/binder/CommonQueryBinder.java

Line 66 in b36adcb

return "'" + value.toString().replace("\\", "\\\\").replace("'", "\\'") + "'";

instead value should be encoded using the registered Codec instead of value.toString()?

[loicmathieu]

in this case Panache doesn't pass to MongoCollection::aggregate() any client session: should it do it?

If you use directly the MongoCollection, you're on your own so you must pass the ClientSession on each method call on the collection.

instead value should be encoded using the registered Codec instead of value.toString()?

Maybe, if you have a use case with a reproducer you can open an issue so we can discuss this.