Add support for Mongo 6.0

[mserranom]

Description

Adds support for Mongo 6.0 in preparation for the next minor release. The main changes are:

• mongo shell has been replaced by mongosh. The toolkit now reads Mongo major version from overleaf.rc and sets a MONGOSH variable that is used in different places to invoke the Mongo shell.
• Replica set initialisation with rs.initiate() fails in Mongo 6.0 when the replica set is already initialised. It's now checking db.isMaster().primary beforehand, which should return an empty string if the replicaSet is not initialised.

Upgrade instructions have been updated: https://github.com/overleaf/overleaf/wiki/Updating-Mongo-version/_compare/4e81c4348e2f8a30e2676af13ca7271493f53e75...acc881bbfc8f257d8d1b016e0ecbdd6cbc12b0ce

Test

With MONGO_IMAGE=mongo:5.0 in overleaf.rc:

# Image inspection
"Image": "mongo:5.0",
 "Healthcheck": {
            "Test": [
                "CMD-SHELL",
                "echo 'db.stats().ok' | mongo localhost:27017/test --quiet"
            ],
            "Interval": 10000000000,
            "Timeout": 10000000000,
            "Retries": 5
},

$ bin/mongo
MongoDB shell version v5.0.18
connecting to: mongodb://127.0.0.1:27017/sharelatex?compressors=disabled&gssapiServiceName=mongodb

Updated MONGO_IMAGE=mongo:6.0 in overleaf.rc (previously set feature compatibility to 5.0):

# Image inspection
 "Image": "mongo:6.0",
 "Healthcheck": {
            "Test": [
                "CMD-SHELL",
                "echo 'db.stats().ok' | mongosh localhost:27017/test --quiet"
            ],
            "Interval": 10000000000,
            "Timeout": 10000000000,
            "Retries": 5
        },

$ bin/mongo
Current Mongosh Log ID: 667032abd41272b4ef8db5fa
Connecting to:          mongodb://127.0.0.1:27017/sharelatex?directConnection=true&serverSelectionTimeoutMS=2000&appName=mongosh+2.2.6
Using MongoDB:          6.0.15
Using Mongosh:          2.2.6

In both versions: tested login, project creation and compiles.

Contributor Agreement

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[mserranom]

GTM, not tested. There is a risk for these two to diverge now, e.g. the following is invalid but accepted by the Toolkit:

MONGO_VERSION=5.0.0
MONGO_IMAGE=my.registry.example.com/mongo:6.0.0

WDYT about adding MONGO_VERSION as tag to MONGO_IMAGE?

Been thinking about it:

• The tag might be custom (something like my-mongo:v6). We can't reliably extract the version number in those cases.
• If there's an alignment problem with MONGO_VERSION and MONGO_IMAGE they will quickly see a problem before the app is started, as mongosh won't work.

I lean towards leaving it as it is. I've tweaked a little bit to make it fail when MONGO_VERSION is not defined (as you suggested), and updated the error message to make it clear MONGO_IMAGE need to be a valid version (<major>.<minor>).

Maybe @mlevans0 can weigh in?

[mlevans0]

If I understand correctly, the MONGO_VERSION environment variable has been introduced to help identify which MongoDB shell to use (either mongo or mongosh). Other than that, its not used (still using MONGO_IMAGE in the compose file)?

The read_mongo_version function attempts to read MONGO_VERSION from config/overleaf.rc to set the correct MongoDB shell, but if MONGO_VERSION is not defined, it then tries to extract the version from MONGO_IMAGE instead and then issues a warning if it can't (in cases where it's a none-stock image).

Because of how this is handled, I think the MONGO_VERSION environment variable is unnecessary. Couldn't we parse the MONGO_IMAGE for the version number and show the warning if it's not a stock image (shortcutting the need for the variable)?

Adding MONGO_VERSION to the config/overleaf.rc file will be a manual step for existing deployments, and if missed, would result in it being undefined, and therefore falling back to the MONGO_IMAGE check anyway.

If we go with what's planned, and the MONGO_VERSION is only used for setting the MongoDB shell, this needs to be explicitly documented. It could cause some confusion when attempting upgrades - you only need to set MONGO_IMAGE and it must contain the version number - after MongoDB 6, you only need to set MONGO_IMAGE (with version number), MONGO_VERSION can be anything as long as its >= 6). It's also only really needed when going from 5 -> 6, after that there's no future requirement for it is there?