go-nat | NAT port mapping library for Go | Serialization library

It likely already starts a server per test. You cannot run things concurrently without a goroutine. The error doesn't really make any sense - anything in Go must be able to run in a goroutine, and in fact everything does run in a goroutine (even main), so it's unclear what they're really trying to say here (I would definitely recommend opening a bug report about it as that error message is terrible). In the meantime, you can keep go test from running concurrently with -parallel 1 (as indicated in go help testflag), which might help.

it's me from the slides!! :) I remember that session, it was fun.

Yeah that doesn't work any more, they killed this magnificent feature like 6 months after we implemented it and we were out with it in Beta at the time. We had to change the way we work..

It's a shame since till this day, in Mongo, "connection" (network stuff, SSL, cluster identification) and authentication are 2 separate actions. Think about when you run mongo shell, you provide the host, port, replica set if any, and your in, connected! But not authenticated. You can then authenticate to user1, do stuff, and then authenticate to user2 and do stuff only user2 can do. And this is done on the same connection! without going thru the overhead creating the channel again, SSL handshake and so on...

Back then, the driver let us have a connection pool of "blank" connections that we could authenticate at will to the current tenant in context of that current execution thread.

Then they deprecated this capability, I think it was with Mongo 2.4. Now they only supported connections that are authenticated at creation. We asked enterprise support, they didn't say why, but to me it looked like they found this way is not secured, "old" authentication may leak, linger on that "not so blank" reusable connection.

We made a change in our multi-tenancy infra implementation, from a large pool of blank connections to many (small) pools of authenticated connections, a pool per tenant. These pools per tenant can be extremely small, like 3 or 5 connections. This solution scaled nicely to several hundreds of tenants, but to meet thousands of tenants we had to make all kinds of optimizations to create pools as needed, close them after idle time, lazy creation for non-active or dormant tenants, etc. This allowed us to scale even more... We're still looking into solutions and optimizations.

You could always go back to a global pool of authenticated connections to a Mongo user that have access to multiple databases. Yes, you can switch database on that same authenticated connection. You just can't switch authentication.. This is an example of pure Mongo Java driver, we used Spring which provide similar functionality:

go get internally calls the "reference" client-side tool of the particular VCS used to host the package to be fetched. In other words, go get by itself does not know how to interact with VCS servers.

So yes, in order to go get a package which is hosted by Git, you need the working Git installation providing a callable git binary.

As to your second problem, it does not appear to have anything related to Go, so I suggest you to do a bit of research and then ask a separate question tagged alpine if that fails.

I figure it out, just set the mirror, and ignore some package, like this

The infinite for loops are likely starving the garbage collector: https://github.com/golang/go/issues/15442#issuecomment-214965471

I was able to reproduce the issue by just running the publisher. To resolve, I recommend using a sync.WaitGroup. Here's how I updated the code linked to in the comments to get it to complete:

Subscribe create an asynchronous listener for events on that channel. As your main function exits straight after the call to subscribe there program will edit before the asynchronous process has finished. There is also synchronised subscribe function:

https://godoc.org/github.com/nats-io/go-nats#Conn.SubscribeSync

Or you can add a wait into your main method so that it doesn't exit straight away.

Gnatsd reply to Request in async manner, but it doesn't start goroutine for each request, just pure async. And because you simulate processing load using time.Sleep, which pauses calling goroutine, it looks like sync processing. If you modify your example to use goroutines, everything works well.

So I was able to solve this using examples on the internet (shown above) along with going through the existing code for the Barcode Scan Service. The issue I was experiencing with the above code was that the present view controller could not be found. However, looking at the bit bucket source for Barcode Scan, I was able to get the root view with the following code:

In the underlying collection, updated field is stored as a string and in your application you are querying it as a date, which won't yield anything but when you query it in mongo shell using a string it correctly returns the document.

Seeing that updated field is a string, try querying it as one i.e. changing the query variable to