add event api integration for deploy health check

[tejal29]

Relates to #176

Fixes #3020
/cc @sujit-kamireddy
Description

In this PR, we add events for deployment status check phase which will help IDEs to get signal if a deployment is stabilized before they can start debugging an application.

User facing changes

Event Changes

Before

1. On example run skaffold dev --port-forward --status-check
   No deployment status check related events are seen.

tejaldesai@@nodejs-guestbook (master)$ curl localhost:50052/v1/event_log

{"result":{"timestamp":"2019-10-16T21:58:38.402979793Z","event":{"buildEvent":{"artifact":"gcr.io/tejal-test/node-guestbook-frontend","status":"Complete"}},"entry":"Build completed for artifact gcr.io/tejal-test/node-guestbook-frontend"}}
{"result":{"timestamp":"2019-10-16T21:58:38.796363557Z","event":{"deployEvent":{"status":"In Progress"}},"entry":"Deploy started"}}
{"result":{"timestamp":"2019-10-16T21:58:40.002287949Z","event":{"deployEvent":{"status":"Complete"}},"entry":"Deploy complete"}}
{"result":{"timestamp":"2019-10-16T21:58:40.203815130Z","event":{"portEvent":{"localPort":8080,"remotePort":8080,"namespace":"default","resourceType":"service","resourceName":"node-guestbook-backend"}},"entry":"Forwarding container  to local port 8080"}}

After
Deployment status check events are seen.

{"result":{"timestamp":"2019-10-16T22:04:27.036932835Z","event":{"buildEvent":{"artifact":"gcr.io/tejal-test/node-guestbook-frontend","status":"Complete"}},"entry":"Build completed for artifact gcr.io/tejal-test/node-guestbook-frontend"}}
{"result":{"timestamp":"2019-10-16T22:04:27.041619570Z","event":{"deployEvent":{"status":"In Progress"}},"entry":"Deploy started"}}
{"result":{"timestamp":"2019-10-16T22:04:28.839756885Z","event":{"deployEvent":{"status":"Complete"}},"entry":"Deploy complete"}}

{"result":{"timestamp":"2019-10-16T22:04:28.841071895Z","event":{"statusCheckEvent":{"status":"Started"}},"entry":"Status check started"}}

{"result":{"timestamp":"2019-10-16T22:04:29.554067745Z","event":{"resourceStatusCheckEvent":
{"resource":"default:deployment/node-guestbook-backend","status":"In Progress",
"message":"default:deployment/node-guestbook-backend Waiting for rollout to finish: 0 of 1 updated replicas are available...\n"}},
"entry":"Resource default:deployment/node-guestbook-backend status updated to In Progress"}}

{"result":{"timestamp":"2019-10-16T22:04:29.554119649Z","event":{"resourceStatusCheckEvent":
{"resource":"default:deployment/node-guestbook-frontend","status":"In Progress",
"message":"default:deployment/node-guestbook-frontend Waiting for rollout to finish: 0 of 1 updated replicas are available...\n"}},
"entry":"Resource default:deployment/node-guestbook-frontend status updated to In Progress"}}

{"result":{"timestamp":"2019-10-16T22:04:29.554152477Z","event":{"resourceStatusCheckEvent":
{"resource":"default:deployment/node-guestbook-mongodb","status":"In Progress",
"message":"default:deployment/node-guestbook-mongodb Waiting for rollout to finish: 0 of 1 updated replicas are available...\n"}},
"entry":"Resource default:deployment/node-guestbook-mongodb status updated to In Progress"}}

{"result":{"timestamp":"2019-10-16T22:04:30.652952944Z","event":{"resourceStatusCheckEvent":
{"resource":"default:deployment/node-guestbook-backend","status":"Succeeded",
"message":"Succeeded"}},
"entry":"Resource default:deployment/node-guestbook-backend status completed successfully"}}

{"result":{"timestamp":"2019-10-16T22:04:30.654777428Z","event":{"resourceStatusCheckEvent":
{"resource":"default:deployment/node-guestbook-frontend","status":"Succeeded",
"message":"Succeeded"}},
"entry":"Resource default:deployment/node-guestbook-frontend status completed successfully"}}

{"result":{"timestamp":"2019-10-16T22:04:31.860354818Z","event":{"resourceStatusCheckEvent":
{"resource":"default:deployment/node-guestbook-mongodb","status":"Succeeded",
"message":"Succeeded"}},
"entry":"Resource default:deployment/node-guestbook-mongodb status completed successfully"}}

{"result":{"timestamp":"2019-10-16T22:04:31.860376342Z","event":{"statusCheckEvent":
{"status":"Succeeded"}},"entry":"Status check succeeded"}}

{"result":{"timestamp":"2019-10-16T22:04:31.934776579Z",
"event":{"portEvent{"localPort":8080,"remotePort":8080,"namespace":"default",
"resourceType":"service","resourceName":"node-guestbook-backend"}},
"entry":"Forwarding container  to local port 8080"}}

Next PRs.

None

Submitter Checklist

These are the criteria that every PR should meet, please check them off as you
review them:

• Includes unit tests
• Mentions any output changes.
• Adds documentation as needed: user docs, YAML reference, CLI reference.
• Adds integration tests if needed.

See the contribution guide for more details.

Reviewer Notes

• The code flow looks good.
• Unit test added.
• User facing changes look good.

Release Notes

Describe any user facing changes here so maintainer can include it in the release notes, or delete this block.

Add skaffold deploy health check events for deployments, when 
- A deployment has a new status 
- A deployment failed
- A deployed is rolled out successfully.

[codecov]

Codecov Report

Merging #3072 into master will increase coverage by 0.01%.
The diff coverage is 87.5%.

Impacted Files	Coverage Δ
pkg/skaffold/deploy/status_check.go	55.75% <87.5%> (+1.97%)	⬆️

[nkubala]

code looks good. should this be documented somewhere in the code or is it just going to live in the API docs once those get merged?

[tejal29]

code looks good. should this be documented somewhere in the code or is it just going to live in the API docs once those get merged?

I think once status-check is turned on by default, i will document the feature and events.