Recover or crash on initial mongo connection failure

[pward123]

I'm getting the error below when the mongodb is down when meteor first starts. Any chance we can get a fix like http://bites.goodeggs.com/post/35878004826/reconnecting-to-mongodb-when-mongoose-connect-fails-at/ ?

Exception in callback of async function: Error: failed to connect to [127.0.0.1:27017]
    at null.<anonymous> (/Users/pward/.meteor/packages/mongo/.1.0.8.1kr7rhx++os+web.browser+web.cordova/npm/node_modules/mongodb/lib/mongodb/connection/server.js:536:74)
    at emit (events.js:106:17)
    at null.<anonymous> (/Users/pward/.meteor/packages/mongo/.1.0.8.1kr7rhx++os+web.browser+web.cordova/npm/node_modules/mongodb/lib/mongodb/connection/connection_pool.js:150:15)
    at emit (events.js:98:17)
    at Socket.<anonymous> (/Users/pward/.meteor/packages/mongo/.1.0.8.1kr7rhx++os+web.browser+web.cordova/npm/node_modules/mongodb/lib/mongodb/connection/connection.js:516:10)
    at Socket.emit (events.js:95:17)
    at net.js:440:14
    at process._tickCallback (node.js:419:13)

[glasser]

Can you provide the full context here? https://github.com/meteor/meteor/wiki/Contributing-to-Meteor#reporting-a-bug-in-meteor

Meteor apps that use the mongo package generally expect to be able to connect to Mongo at startup and crash the server otherwise (and should be run in a standard environment that knows how to deal with crashing processes). If your server is NOT crashing, that would be be concerning. Otherwise, it is working as intended.

[pward123]

My app is currently running in a docker container and uses systemd to keep the container running. The server is NOT crashing. Here are the steps you can use to reproduce.

git clone https://github.com/meteor/simple-todos
cd simple-todos
meteor update
MONGO_URL=mongodb://bad_address:27017/todo meteor

The above will cause the error message in my original post to be displayed but the app remains running. It's just non-responsive. If you look at MUP, arunoda hacks around this problem by pinging the mongo instance until it's running and then starting the app.

This is actually indicative of a bigger problem (at least where my app is concerned). I can't find the module right now, but I traced it down to a common async callback handler that traps exceptions and just console logs the message then goes on about its business. I'd really like to see an environment switch that will force the app to crash on any unhanded exception inside a callback.

[pward123]

The mongo connect call is wrapped with bindEnvironment
https://github.com/meteor/meteor/blob/devel/packages/mongo/mongo_driver.js#L151

bindEnvironment ignores errors by calling Meteor._debug
https://github.com/meteor/meteor/blob/devel/packages/meteor/dynamics_nodejs.js#L92

[glasser]

Hmm, looks like I broke this in 0.8.1 with 24a0006c1452bdba

[BlackYoup]

Hi, I'm getting this error too using an external mongoDB database.
Any news on this ?

[glasser]

This should be fixed on devel.