gh-4873: configurable Document.toJson() serialization for logging

[rfelgent]

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[rfelgent]

Hi @mp911de ,

after looking into the code, I would like to discuss options with you.

1. introduce XXXDelegate class for logging serialization (with refactoring of MongoTemplate/ReactiveMongoTemplate)
2. add SerializationUtils#serializeToJsonSafely(@Nullable Document document, JsonWriterSettings settings) {} (with refactoring of MongoTemplate/ReactiveMongoTemplate)
3. introduce a Log-EntityCallback to log Document before persisting it to data base (no refactoring of MongoTemplate/ReactiveMongoTemplate). This will not work for "query()" logs, will it ? Is it a valid requirement ?
4. shouldn't the mongodb-driver itself provide this logging functionality (json and bson) ?

If we want to put hands on it, my preference is option 3) otherwise option 4). What dou you think ?

Furthermore, is there another way to discuss ideas and implementation details with you apart form comments in pull requests ?

[mp911de]

There's some logging inside the MongoDB driver through the org.mongodb.driver.protocol logger.

2018-01-18 16:51:07|[main]|[NA]|DEBUG|org.mongodb.driver.protocol.insert|Inserting 1 documents into namespace stackoverflow.sample on connection [connectionId{localValue:2, serverValue:39}] to server localhost:27017  
2018-01-18 16:51:07|[main]|[NA]|DEBUG|org.mongodb.driver.protocol.insert|Insert completed  
2018-01-18 16:51:07|[main]|[NA]|DEBUG|org.mongodb.driver.protocol.command|Sending command {find : BsonString{value='sample'}} to database stackoverflow on connection [connectionId{localValue:2, serverValue:39}] to server localhost:27017  
2018-01-18 16:51:07|[main]|[NA]|DEBUG|org.mongodb.driver.protocol.command|Command execution completed  
2018-01-18 16:51:07|[main]|[NA]|DEBUG|org.mongodb.driver.protocol.command|Sending command {findandmodify : BsonString{value='sample'}} to database stackoverflow on connection [connectionId{localValue:2, serverValue:39}] to server localhost:27017  

I think having a logger delegate seems a good starting point. It doesn't introduce any changes to type inheritance and having another serializeToJsonSafely(…) overload would fit in nicely.