compute: implement autoscaler

[stephenplusplus]

For #1073

Fixes #1152

Implements Autoscaler support.

To Dos

• Docs
• Tests
  • System
    • Figure out how to create an instance group before the tests run
  • Unit
    • autoscaler.js
    • index.js
    • zone.js

Creating an autoscaler...

// Easy way
var config = {
  coolDown: 30,
  cpu: 80,
  loadBalance: 40,
  maxReplicas: 5,
  minReplicas: 0,
  target: 'instance-group-name'
};

// Hard (but supported) way
var config = {
  autoscalingPolicy: {
    coolDownPeriodSec: 30,
    cpuUtilization: {
      utilizationTarget: 0.8
    },
    loadBalancingUtilization: {
      utilizationTarget: 0.4
    },
    maxNumReplicas: 5,
    minNumReplicas: 0
  },
  target: 'https://content.googleapis.com/compute/v1/projects/{PROJECT_ID}/zones/{ZONE_ID}/instanceGroupMangers/instance-group-name'
};

var zone = compute.zone('us-central1-a');
zone.createAutoscaler('autoscaler-namer', config, function(err, operation, autoscaler, apiResponse) {
  // ...
});

[stephenplusplus]

Fixed those things!

[callmehiphop]

Locally I'm getting an error when testing the docs on v0.12.7.

Uncaught TypeError: The callback's first argument must be a status code

When running against v5.6.0 npm run test seems to be timing out on something. I think this might relate to gRPC, but TBH I didn't look into it very much.

Other than those errors and a few documentation nitpicks, this LGTM!

[stephenplusplus]

My gosh, gRPC is haunting us. I'll try to get that error on 0.12.7.

[stephenplusplus]

If you strictly run node_modules/mocha/bin/mocha test/docs.js, you get the Uncaught TypeError?

[callmehiphop]

If you strictly run node_modules/mocha/bin/mocha test/docs.js, you get the Uncaught TypeError?

Nope!

[callmehiphop]

Although it is still hanging on something

[stephenplusplus]

Please check all that apply:

v0.12.7

• npm test hangs
• node_modules/mocha/bin/mocha test/docs.js hangs
• npm test returns Uncaught TypeError: The callback's first argument must be a status code
• node_modules/mocha/bin/mocha test/docs.js returns Uncaught TypeError: The callback's first argument must be a status code

v5.6.0

• npm test hangs
• node_modules/mocha/bin/mocha test/docs.js hangs
• npm test returns Uncaught TypeError: The callback's first argument must be a status code
• node_modules/mocha/bin/mocha test/docs.js returns Uncaught TypeError: The callback's first argument must be a status code

As you probably guessed, none of the above happens for me locally. There's obviously something going on, but I don't really know where to start to find it.

[stephenplusplus]

Just for reference, found the origin of the status code error: https://github.com/grpc/grpc/blob/72724bce84b4bc027ce8dd3f7508b9216788434b/src/node/ext/call_credentials.cc#L176

[stephenplusplus]

If you run the same tests prior to this commit, will you get the same errors?

[stephenplusplus]

I pushed a commit to see if anything improves. Travis is never happy, so I'm not expecting it to win him over. But maybe it'll help what you're getting locally. If it does, I'll send a different PR with that change.

[callmehiphop]

If you run the same tests prior to this commit, will you get the same errors?

I don't, I'm somehow magically all green when I run against master.

[stephenplusplus]

It makes no sense, man!!

[callmehiphop]

I just pulled your latest commit! It helped, lol.

[stephenplusplus]

That's awesome. The only thing I can't line up is why this PR revealed the problem. Oh well, as long as it works for us all, that's all that matters. I'll just add a test for it and we can merge it in with this PR. We talked about it most here anyway, so finding it later, this PR would help.

I'm thinking it solves #1140 and #1152 - wdyt?

[callmehiphop]

SGTM.. I'm a little lost on what's going on, but maybe we should open a new issue for investigating gRPC stuff since it has been giving us weird/random errors.

[stephenplusplus]

Yeah, we can leave #1140 open as a place to log issues that might relate to gRPC.

I think this is ready for a merge!