Unable to use unix-socket connections

[craether-nbb]

Describe the bug
MongoDB is able to use unix sockets, next to regular IPs. But when trying to use this socket (following the documentation) for the PMM MongoDB Exporter (running at the same container), it fails to handle the socket URI.
PMM itself seems to have no issue with defining a socket, just the MongoDB exporter.
It's throwing 3 exceptions when trying to use sockets. (See Logs section)

To Reproduce
Steps to reproduce the behavior:

• Launch a MongoDB and configure the required pmm user
• Configure the PMM agent
• Add the mongodb_export using the following command: pmm-admin add mongodb --socket="/tmp/mongodb-27017.sock" --username="pmm" --password="pmm" --query-source="profiler" --replication-set="rs0" --server-insecure-tls --skip-connection-check

Attached you'll find an example stack of a MongoDB and PMM configured to use sockets, throwing the exceptions.
pmm_socket_issue.zip

Expected behavior
As documented at MongoDB itself and the PMM MongoDB Exporter help (CLI), it should be possible to use sockets instead of IPs to connect the exporter with the MongoDB.

Logs

1. First "invalid URL escape"

   time="2026-03-04T11:56:48.782+00:00" level=error msg="time=2026-03-04T11:56:48.782Z level=ERROR source=server.go:181 msg=\"Unable to parse provided address as url\" address=\"mongodb://***:***@%2Ftmp%2Fmongodb-27017.sock/?connectTimeoutMS=1000&directConnection=true&serverSelectionTimeoutMS=1000\" error=\"parse \\\"mongodb://***:***@%2Ftmp%2Fmongodb-27017.sock/?connectTimeoutMS=1000&directConnection=true&serverSelectionTimeoutMS=1000\\\": invalid URL escape \\\"%2F\\\"\"" agentID=bfcd3f7f-2a9e-4dcc-9d93-d8a937a2bfe3 component=agent-process type=mongodb_exporter
   

   In this case the url.Parse() seems to be unable to handle the encoded socket URL.
   Source of the exception is server.go:181

2. Second "invalid URL escape"

   time="2026-03-04T11:57:23.384+00:00" level=warning msg="Failed to get instance ID for action: failed to parse DSN: parse \"mongodb://pmm:pmm@%2Ftmp%2Fmongodb-27017.sock/?connectTimeoutMS=1000&directConnection=true&serverSelectionTimeoutMS=1000\": invalid URL escape \"%2F\"" component=runner
   

3. "Broken pipe"

   {"t":{"$date":"2026-03-04T11:57:23.407+00:00"},"s":"I",  "c":"EXECUTOR", "id":22989,   "ctx":"conn38","msg":"Error sending response to client. Ending connection from remote","attr":{"error":{"code":9001,"codeName":"SocketException","errmsg":"futurize :: caused by :: Broken pipe"},"remote":"anonymous unix socket:27017","connectionId":38}}
   

   One of these exceptions during the initial startup is ok and occures no matter of using a unix socket or the localhost IP, but all the other occurences are related to using a unix socket.

Environment

• Hostsystem: MacOS 26.3 on a M1 MacBook Pro
• Docker 4.62.0
• MongoDB 8.0
• PMM admin version: 3.6.0

Additional context

• Enabling the UnixDomainSocket at MongoDB: https://www.mongodb.com/docs/manual/reference/configuration-options/#mongodb-setting-net.unixDomainSocket.enabled
• Using a UnixDomainSocket in a connection string: https://www.mongodb.com/docs/manual/reference/connection-string/?deployment-type=self&interface-atlas-only=None&topology=replica-set&connection-string-format=srv#unix-domain-socket
• Using a socket when adding the mongodb_exporter to PMM:

pmm-admin add mongodb --help

Usage: pmm-admin add mongodb [<name> [<address>]] [flags]

Add MongoDB to monitoring

[...]

Flags:
[...]
    --socket=STRING                                Path to socket
[...]