fix: remove readPreferenceTags for database&collection lookups if the cluster is sharded and readPreferenceTags was set COMPASS-9111

[lerouxb]

There's a bug https://jira.mongodb.org/browse/PRODTRIAGE-3102 where readPreferenceTags does not work with config servers. This means that if compass connects to a sharded cluster and then the user specifies something like readPreferenceTags=nodeType:ANALYTICS as part of the connection string, Compass won't be able to list the databases&collections which should appear in the sidebar.

The workaround here is to remove the tags for those commands IF we're connected to a sharded cluster AND readPreferenceTags is present.

To test this it is almost enough to just connect to any sharded cluster without any special node tags and then specify readPreferenceTags, but in that case no command will work because there aren't nodes for that cluster. If a node exists with the read preference tag then it would only be the database/collection lookups that don't work.

To test this manually, I used mongodb-runner:

(number of shards is probably irrelevant)

npx mongodb-runner start -t sharded --shards=2 --version=8.0.5

which prints the connection string, but then in order to configure sharding you have to connect to a shard manually (I found a port to connect to by just doing ps aux | grep mongos)

In my case something like mongosh "127.0.0.1:58109"

Then in mongosh:

conf = rs.conf();
conf.members[0].tags = { "nodeType": "ANALYTICS"};
rs.reconfig(conf);

Then connect to the URL you got from mongodb runner, but with some parameters added. In my case:

mongodb://127.0.0.1:21676/?retryWrites=true&readPreference=secondary&w=majority&readPreferenceTags=nodeType:ANALYTICS

Then on compass main you'll see that loading the databases/collections in the sidebar hangs until it times out.

With this branch you'll see that the collections load as expected.

[addaleax]

LGTM, only suggestion might be to add a comment referencing the COMPASS ticket just so if somebody in the future wonders why we do this, they have a way of reading the related conversations, but that's definitely optional

[lerouxb]

I added a comment near the code that references the ticket and I also added a test that uses an actual sharded database. It isn't exactly the same as the situation in the ticket since there are no secondaries and no nodes with the ANALYTICS tag in that setup, but it does recreate the situation where those database operations would timeout because it does not know about any nodes that match the tags.

[lerouxb]

Oh and if anyone ever wants to run the sharded docker image on an apple silicon mac:

~/test-envs % git diff
diff --git a/docker/sharded/docker-compose.yaml b/docker/sharded/docker-compose.yaml
index d5f50a7..d4e5041 100644
--- a/docker/sharded/docker-compose.yaml
+++ b/docker/sharded/docker-compose.yaml
@@ -1,9 +1,8 @@
-version: '2'
-
 services:
   mongodb-sharded:
+    platform: linux/amd64
     # TODO: https://jira.mongodb.org/browse/COMPASS-7265
-    image: 'docker.io/bitnami/mongodb-sharded:6.0.10'
+    image: 'docker.io/bitnami/mongodb-sharded:8.0.5'
     environment:
       - MONGODB_ADVERTISED_HOSTNAME=mongodb-sharded
       - MONGODB_SHARDING_MODE=mongos
@@ -11,12 +10,14 @@ services:
       - MONGODB_CFG_REPLICA_SET_NAME=cfgreplicaset
       - MONGODB_REPLICA_SET_KEY=replicasetkey123
       - MONGODB_ROOT_PASSWORD=password123
+      - EXPERIMENTAL_DOCKER_DESKTOP_FORCE_QEMU=1
     ports:
       - '28004:27017'

   mongodb-shard0:
+    platform: linux/amd64
     # TODO: https://jira.mongodb.org/browse/COMPASS-7265
-    image: 'docker.io/bitnami/mongodb-sharded:6.0.10'
+    image: 'docker.io/bitnami/mongodb-sharded:8.0.5'
     environment:
       - MONGODB_ADVERTISED_HOSTNAME=mongodb-shard0
       - MONGODB_SHARDING_MODE=shardsvr
@@ -25,10 +26,12 @@ services:
       - MONGODB_REPLICA_SET_MODE=primary
       - MONGODB_REPLICA_SET_KEY=replicasetkey123
       - MONGODB_REPLICA_SET_NAME=shard0
+      - EXPERIMENTAL_DOCKER_DESKTOP_FORCE_QEMU=1

   mongodb-cfg:
+    platform: linux/amd64
     # TODO: https://jira.mongodb.org/browse/COMPASS-7265
-    image: 'docker.io/bitnami/mongodb-sharded:6.0.10'
+    image: 'docker.io/bitnami/mongodb-sharded:8.0.5'
     environment:
       - MONGODB_ADVERTISED_HOSTNAME=mongodb-cfg
       - MONGODB_SHARDING_MODE=configsvr
@@ -36,3 +39,4 @@ services:
       - MONGODB_REPLICA_SET_MODE=primary
       - MONGODB_REPLICA_SET_KEY=replicasetkey123
       - MONGODB_REPLICA_SET_NAME=cfgreplicaset
+      - EXPERIMENTAL_DOCKER_DESKTOP_FORCE_QEMU=1

via bitnami/containers#40947 (comment)