feat(protractor): add support for promises in configs

[samlecuyer]

Change driverProviders/hosted to resolve promise values
in configuration to allow async jobs in setup. Primarily,
this would be for a network call to acquire a selenium host
or to start a proxy server.

[theogravity]

Would love to have this feature in please as we'd love to be able to dynamically assign hosts and proxy servers into the config.

[samlecuyer]

Could someone take a look at this?

[juliemr]

I think this is a bad idea - if we extend onPrepare to be allowed to return a promise, this would try to wait for that too, for example. Let's be more specific about exactly what we're waiting on.

[juliemr]

To clarify - only waiting for seleniumAddress seems reasonable. Not sure why you would asynchronously pick a browser, or anything else.

[theogravity]

Dynamic proxy support (port assignment) would be for browsers for capabilities. Should we limit the change to only seleniumAddress, capabilities and multiCapabilities then?

[juliemr]

I'm being dense - what does port assignment have to do with the browser? Could you give an example of the config you'd like to be able to write?

[theogravity]

Sure:

...
baseConfig.multiCapabilities = [{
    browserName: 'firefox' ,
    version: 'latest' ,

    //To run the browser tests through a proxy server, use the proxy variable
    //Specify the proxyType as 'manual' to use proxy or 'direct' to skip proxy
    proxy: { //would be an async call to start a proxy(s) which would return the host/port; the proxies can have different rewrite rules, header rewrites that need to happen, etc that is specific for the tests
          proxyType: 'manual',
          httpProxy: 'localhost:10000', 
          sslProxy: 'localhost:10000'
    },
    shardTestFiles: true , // set if specs should be shard across the webdriver instances (of the same set of capabilities)
    maxInstances: 3 // # simultaneous webdriver instances
}];

We have a service that dynamically assigns a proxy host and port and would need to feed that into the capability object along with another service for getting a seleniumAddress to use.

[juliemr]

Ah that proxy. Thanks.

If this isn't being used for just seleniumAddress, I'm concerned about the confusion that it will only work with the hosted provider. It would be hard to debug why your capabilities promise doesn't resolve if you're testing on saucelabs, for example.

So, I propose only waiting for seleniumAddress here, and adding the ability for capabilities to be a promise in runner.js here - https://github.com/angular/protractor/blob/master/lib/runner.js#L221

[theogravity]

Sounds good - the proxy additions can wait, but seleniumAddress is a must-have. We'll update the PR next week as my colleague (Sam) is out for the week. Thanks!

[samlecuyer]

@juliemr I've made those adjustments according to your suggestions (and rebased the changes into a single commit)

[juliemr]

You need to do this before getting the driver, or else it fails. I'll fix it for you.

[juliemr]

Made the changes I mentioned and merged as 316961c

[samlecuyer]

👍

[hankduan]

@samlecuyer Can you explain why self.config_.capabilities needs to be a promise? It seems like all you need is for seleniumAddress to be a promise so that it can be resolved in the setupEnv.

[samlecuyer]

@hankduan self.config_.capabilities needs to be a promise because the proxy is a part of the browser capabilities and starting a proxy server is an async task. This is much more than just specifying a seleniumAddress.

[hankduan]

@samlecuyer Follow up. Is there a reason that you need the promises (capabilities and seleniumAddress) to resolve after setupEnv; it should work the same way for you if the promise is resolved way earlier right?

i.e. do you have to wait for some condition before those promises can be resolved?

[hankduan]

Please make note of change happening in #1629.
Specifically:

• capabilities can no longer be a promise. Use getMultiCapabilities if you need
  to return a promise.
• seleniumAddress can no longer be a promise. Likewise, use getMultiCapabilities.