Scala MongoDB aggregate group and match query

Question

I want a query that will take the latest version out of each document, and check if some given string (applicationId) is in the list allowedApplications.

documents example:

{
    "applicationId" : "y...",
    "allowedApplications": ["x..."],
    "name" : "some-name",
    "version" : 3
}
{
    "applicationId" : "y...",
    "allowedApplications": ["x..."],
    "name" : "some-name",
    "version" : 2
}
{
    "applicationId" : "x...",
    "allowedApplications": ["y..."],
    "name" : "some-other-name",
    "version" : 1
}

So the MongoDB query is:

db.getCollection('..').aggregate(
[
    { "$match": { "allowedApplications": "x..." }},
    {"$group": { "_id": "$name", "version": { "$max": "$version" }}}
]
   )

And the query will output the name and version (I'll perhaps add the allowedApplications later).

I'm trying now to write this in Scala's mongodb driver.

I tried a bunch of stuff, for example:

collection
            .aggregate(List(
                `match`(equal("allowedApplications", "x..")),
                group("$name", addToSet("version", addToSet("$max", "¢version")))
            )
            )

But couldn't get it to work.

Using Scala 2.13.1 and mongo-scala-driver 4.1.0. Any help would be appreciated.

Answer 1

Found the answer:

collection
            .aggregate(List(
                `match`(equal("allowedApplications", "x...")),
                group("$name", max("version", "$version"))
            )

The order isn't quite the same, but just use the function in the accumulator field.