Add Mongodb Standalone, Sharded, Replica Set Metric Scraper

[schmikei]

Description:
Adds a new receiver mongodb. This receiver is intended to collect metrics from standalone, replica set, and sharded deployments of mongo.

I am open to potential renames as to differentiate further from the current mongodb as a service(atlas) receiver if we feel necessary or is too ambiguous.

Pre-requisites:

If authentication is enabled, a clusterMonitor user so that proper commands can be authenticated to collect metrics. There may be plans to extend authentication options but this appears to be the most common approach to authentication if necessary.

This is generally accomplished(at least for mongodb >3.0) via a command like

db.createUser({
  "user": "monitor-user",
  "pwd": "$MONITOR_USER_PASSWORD",
  "roles": [
    { role: "clusterMonitor", db: "admin" },
  ]
})

Configuration

Example:

receivers:
  mongodb:
    hosts: 
      - localhost:27017
    username: otel
    password: $MONGO_PASSWORD
    collection_interval: 10s

This is accomplished via the mongo-go-driver driver which supports back to mongo server versions >2.6.

Current proposed list of metrics:

Metric	Description	Type	Unit	Label(s)
cache.operations	The number of cache operations.	monotonic sum	1{.operations}	type (hits, misses)
collections	The number of collections.	non-monotomic sum	1	database
connections	The number of active server connections.	non-monotomic sum	1	database,connection_type
data.size	The size in bytes of the collection. Data compression does not affect this value.	non-monotomic sum	By	database
extents	The number of extents. (only available on mongo versions <=4.2)	non-monotomic sum	1	database
global_lock.hold	The time the global lock has been held.	monotonic sum	ms
index.countindexes	The number of indexes.	non-monotomic sum	1	database
index.size	The sum of the space allocated to all indexes in the database, including free index space.	non-monotonic sum		database
memory.usage	The amount of memory used.	non-monotonic sum	By	database, type (resident, virtual, mapped, mappedWithJournal)
objects	The number of objects.	non-monotomic sum	1	database
operations	The number of operations executed.	monotonic sum	1{.operations}	operation
storage.size	The total amount of storage in bytes allocated to this collection for document storage. If collection data is compressed it reflects the compressed size.	non-monotomic sum	By	database

Link to tracking Issue:

Testing:

Integration tests/unit tests

Tested manually against mongo 5.0, 4.4, and 4.0 expect to continue testing while this is reviewed up to earliest version that the mongo-driver supports 2.6

Documentation:

Documentation added specifies the metrics collected and configuration. This is autogenerated via the metadata.yml

[linux-foundation-easycla]

The committers are authorized under a signed CLA.

• ✅ Keith Schmitt (ca7b255, 6b8b292, 24d42a8)

[jpkrohling]

@schmikei, could you please go over #6926 confirm you have what's listed there?

[schmikei]

@jpkrohling Thanks! This was my first attempt at drafting up a contribution. That issue seems super helpful on how to proceed 🚀

Plan on breaking up this PR soonish to follow those guidelines more closely! Will still need to find a proper way to get a sponsor. Will look into it a bit more and come back.

[jpkrohling]

If you don't have a sponsor yet, let me know and I'll ping the approvers to see if anyone is interested.