Koa deprecated Support for generators

[henryoliver]

Hey guys!

I'm a paid user for the Google cloud platform and love it.

Could you guys please update the driver for koajs? I start to get the following warning:

Mon, 05 Feb 2018 11:47:29 GMT koa deprecated Support for generators will be removed in v3. See the documentation for examples of how to convert old middleware https://github.com/koajs/koa/blob/master/docs/migration.md at node_modules/@google-cloud/trace-agent/build/src/plugins/plugin-koa.js:99:24

You guys can follow the update instructions here, I think it will be pretty straightforward: https://github.com/koajs/koa/blob/master/docs/migration.md

Thank you for your awesome job in this library! Henry

[kjin]

The Trace Agent doesn't prepend generator functions for Koa 2. I think what's happening is that the warning message shows the top line of the stack trace when Koa#use is being called. Because the Trace Agent wraps this function, it altered the stack trace to add an extra frame to the top as you've observed.

I would expect that when turning off the Trace Agent (by removing the call to start), the warning message will show a line in your application where a generator is still being used.

Let us know if this solves the issue!

[henryoliver]

Hi @kjin thanks for your explanation, really appreciate that! But, could you be a little bit more detailed? How could I start the monitor in my Koa2 application without getting this warning? Any code example would be very helpful.

Below is how I currently call the monitor in my application:

// Stackdriver
const trace = require('@google-cloud/trace-agent').start({
    projectId: 'polen--project',
    serviceContext: {
        service: 'glasstone-travel-channel',
        version: '1.0.0'
    }
});

Getting the message: koa deprecated Support for generators will be removed in v3. See the documentation for examples of how to convert old middleware https://github.com/koajs/koa/blob/master/docs/migration.md node_modules/@google-cloud/trace-agent/build/src/plugins/plugin-koa.js:99:24

Thanks!

[kjin]

Sure, what I mean is that I suspect you will get a warning even if you comment out the code above. Here's a code example: https://gist.github.com/kjin/e1b9ddcf4360adbdef2e11b939d6a6f2

[henryoliver]

Can I use the agent without a generator function, since I'm using Koa2? Thanks

[kjin]

Yes, you can! The example shown was just for the sake of showing how the warning changes depending on whether the Trace Agent is started or not.

[kjin]

@henryoliver Were you able to verify whether the warning message comes from use of generators external to the Trace Agent?

[kjin]

@henryoliver Closing this for now. Please comment if this doesn't work for you.