Fixing multi resource lifecycle hooks

[Memeriaj]

Description

Fixing lifecycle hooks for Multi-Site deploys as found by this issue. Essentially the lifecycle hooks only deal with the top level object and were never changed to deal with an array of configs. I tried to make this generic so that it'll be usable by other mutli resource deploys (which I don't think exist but RTDB could and we could technically do it for individual functions).

Scenarios Tested

Verified both single Site deploy and Multi-Site deploys. Also made sure that it worked if predeploy or postdeploy was an array or a single string.

Sample Commands

Everything used firebase deploy --only hosting but single Site deploy had a firebase.json of:

{
  "hosting": {
    "public": "public",
    "predeploy": ["echo 'single predeploy 1'", "echo 'single predeploy 2'"],
    "postdeploy": "echo 'single postdeploy 1' && echo 'single postdeploy 2'",

...

  }
}

Multi-Site deploy had a firebase.json of:

{
  "hosting": [{
    "target": "first",
    "predeploy": ["echo 'multi first predeploy 1'", "echo 'multi first predeploy 2'"],
    "postdeploy": ["echo 'multi first postdeploy 1'", "echo 'multi first postdeploy 2'"],

...

  },
  {
    "target": "second",
    "predeploy": ["echo 'multi second predeploy 1'", "echo 'multi second predeploy 2'"],
    "postdeploy": "echo 'multi second postdeploy 1' && echo 'multi second postdeploy 2'",
    "public": "public"
  }]
}

[coveralls]

Coverage remained the same at 60.427% when pulling 0cd8308 on am-multi-predeploy into 05857c8 on master.

[coveralls]

Coverage remained the same at 60.427% when pulling 4308c8a on am-multi-predeploy into adb77a5 on master.

[bkendall]

Can some unit tests be written for this functionality? Looks to me as if you could create some fake options with some echo statements that would succeed. Or maybe it could return a representation of the commands run that would be able to be verified? I'll leave it to you, but I think some tests here might be worth while.

[mbleigh]

I understand @bkendall's encouragement to add tests, but I won't block on them here...I'd like to get this released and scaffolding deploy tests will take a non-trivial amount of time I imagine. If you somehow find time, lovely 😄

[bkendall]

LGTM from me - comment from Michael to look at still...

[Memeriaj]

Gave some tests a quick shot, both unit tests for just the lifecycle file and an integration test. I suspect creating meaningful tests are going to be quite a bit of work, and making them understandable and not brittle is going to require a fair amount of refactoring of how deploys are handled.