Add labels support

[jbutz]

This is a Feature Proposal

Description

Google Cloud Engine Functions support labels to allow the grouping of functions and other resources. These are supported by Google's API, and could already be used with the version included in this plugin.

Google requires that the labels be key-value pairs. I suggest a new labels property be added to the function definition and that the new property accepts an object. An example with a single label is below.

...
functions:
  first:
    handler: http
    labels:
      application: Serverless Example
    events:
      - http: path
...

I also suggest allowing global labels to be defined in a labels property on the provider property, as in the example below.

service: my-gcloud-service

provider:
  name: google
  labels:
    application: Serverless Example
...

These two objects should be merged to allow overriding values and to decrease repetition.

service: my-gcloud-service

provider:
  name: google
  labels:
    application: Serverless Example
    team: Experienced Devs

plugins:
  - serverless-google-cloudfunctions

functions:
  helloWorld:
    handler: helloWorld
    labels:
      team: Interns
    events:
      - http: path
  fooBar:
    handler: fooBar
    events:
      - http: path

Given the above configuration both the helloWorld and fooBar functions would have an application label with Serverless Example as the value. Both would also have a team label. The value for the fooBar function would be Experienced Devs and the value for the helloWorld function would be Interns.

I was able to rough this feature in very quickly. I'd like to fully implement it and the tests.

[jbutz]

I took the liberty of building this since it was such a small change without any discussion

[adnasa]

I think this is reference documentation for this

[adnasa]

Given the above configuration both the helloWorld and fooBar functions would have an application label

Question, is this because they are both deployed from the same configuration?
I don't see how application is applied on helloWorld and fooBar since they already have their labels configured

[jbutz]

Question, is this because they are both deployed from the same configuration?

@adnasa I'm not sure exactly what you mean by that, but I'll try and give a bit better explanation. The way I suggest it work is the labels applied to the function are the union/merger of the provider-labels and function-label objects, with the function-label properties taking precedence.

Here is more of a code example for that last configuration:

let helloWorldLabels = Object.assign({}, {
        application: 'Serverless Example',
        team: 'Experienced Devs'
    }, {
        team: 'Interns'
    });
// { application: 'Serverless Example', team: 'Interns' }

let fooBarLabels = Object.assign({}, {
        application: 'Serverless Example',
        team: 'Experienced Devs'
    }, {
        // Empty object
    });
// { application: 'Serverless Example', team: 'Experienced Devs' }

As I said in a previous comment I already went ahead and implemented this, here is a link to the line of code that does this.

[adnasa]

aah allright. makes sense. thanks for clarifying that ! :)