[CAMEL-16024] [camel-mongodb] ChangeStreams Consumer cannot handle string based _id

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Later
• Affects Version/s: 3.7.0
• Fix Version/s: 3.x
• Component/s: camel-mongodb
• Estimated Complexity: Unknown
• Assignee: Ramu
• Reporter: Dario Nuevo
• Created: 12/Jan/21 10:55
• Updated: 02/Sep/22 17:33
• Resolved: 02/Sep/22 17:33

Description

We're having quite a basic use case: Our documents in MongoDB have string based IDs (field _id) - as opposed to having ObjectId() instances. It seems, the current release of camel-mongodb cannot handle that.

Having defined a route based on ChangeStreams like that:

from("mongodb:mongoConnection?database=db&consumerType=changeStreams&collection=coll")
  .routeId("changestream")
   .process("changeStreamProcessor")
   .to("stream:out");

When an event arrives on an object with a string based _id; I get this Exception:

Exception in thread "Camel (camel-1) thread #1 - mongodb://mongoConnection" org.bson.BsonInvalidOperationException: Value expected to be of type OBJECT_ID is of unexpected type STRING
	at org.bson.BsonValue.throwIfInvalidType(BsonValue.java:419)
	at org.bson.BsonValue.asObjectId(BsonValue.java:150)
	at org.bson.BsonDocument.getObjectId(BsonDocument.java:271)
	at org.apache.camel.component.mongodb.MongoDbChangeStreamsThread.doRun(MongoDbChangeStreamsThread.java:75)
	at org.apache.camel.component.mongodb.MongoAbstractConsumerThread.run(MongoAbstractConsumerThread.java:68)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
	at java.base/java.lang.Thread.run(Thread.java:830)

So we basically have a problem here: https://github.com/apache/camel/blob/camel-3.7.0/components/camel-mongodb/src/main/java/org/apache/camel/component/mongodb/MongoDbChangeStreamsThread.java#L75

So now the fix would be easy - check the type with instanceof ObjectId and act accordingly - and i could also contribute that - but I'm not clear if that can succeed.

As I see it, the _id is later set on the header as MongoDbConstants.MONGO_ID - which then also would be a string. IMHO that's totally fine, everybody knows what type their _id's have.

How to resolve this? IMHO it's quite a normal use case to have non-ObjectId-IDs..

Thanks for any input