[Infra] Change host count KPI query

[jennypavlova]

Closes #188757

Summary

This PR adds an endpoint to get the hosts (monitored by the system integration) count. Currently, it supports only hosts but it can be extended to other asset types (if/when needed). So the endpoint ( POST /api/infra/{assetType}/count ) supports only 'host' as {assetType}.

⚠️ This PR adds only the endpoint - it is not used yet! To avoid having different host counts and results shown on the UI this PR is not updating the hook responsible for the request because currently the hosts shown in the table are not filtered by the system integration (showing the filtered result of this endpoint can lead to inconsistencies between the count and the results shown in the table) Once #188756 and #188752 are done we can use this endpoint.

Testing

It can't be tested in the UI so we can test it:

Using curl:

curl --location -u elastic:changeme 'http://0.0.0.0:5601/ftw/api/infra/host/count' \
--header 'kbn-xsrf: xxxx' \
--header 'Content-Type: application/json' \
--data '{
   "query": {
      "bool": {
         "must": [],
         "filter": [],
         "should": [],
         "must_not": []
      }
   },
   "from": "2024-07-23T11:34:11.640Z",
   "to": "2024-07-23T11:49:11.640Z",
   "sourceId": "default"
}'

In case of testing with oblt replace the elastic:changeme with your user and password

[obltmachine]

🤖 GitHub comments

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[elasticmachine]

Pinging @elastic/obs-ux-infra_services-team (Team:obs-ux-infra_services)

[crespocarlos]

Thanks for this change Jenny. I had a quick look but haven't had the chance to test it yet.

[crespocarlos]

We could use termQuery helper functions. Also, how about creating constants for the field names?

Suggested change

	{
	term: {
	'event.module': 'system',
	},
	},
	{
	term: {
	'metricset.module': 'system',
	},
	},
	...termQuery(EVENT_MODULE, 'system')
	...termQuery(METRICSET_MODULE, 'system'),

[crespocarlos]

We could use the rangeQuery helper function here.

Suggested change

	...rangeQuery,
	...rangeQuery(new Date(from).getTime(), new Date(to).getTime())

[crespocarlos]

I wonder if we this could be a GET request.

[jennypavlova]

I need to pass the query, filters, time range, etc. so we can even expand more the body if it is a POST. I am not sure how much will those params extend in the future so I was thinking that having the consistency with the other endpoints with similar functions can help here. But I don't have a strong opinion on that. Do you think it's better to have query params instead of the request body and convert to GET?

[crespocarlos]

GET operation is preferable in this case, since nothing is being created. Infra uses POST for historical reasons, but most of them should be GET instead. The complicated part is on how to pass the filters in the query params.

[jennypavlova]

As discussed I created an issue to investigate the option to use GET instead of POST in our APIs #189170 There are some benefits and concerns described there and it would be nice also to keep them consistent and have GET requests where possible ( I totally agree that it will be better but we still need to check if the url limitations affect us) So this change won't be part of this PR

[crespocarlos]

Perhaps these could be in the constants in common instead. It will allow the client to also access them.

[jennypavlova]

Good point, thanks ✅

[crespocarlos]

LGMT! Thanks for this change.

[kibana-ci]

💚 Build Succeeded

• Buildkite Build
• Commit: befee95
• Kibana Serverless Image: docker.elastic.co/kibana-ci/kibana-serverless:pr-188950-befee9548c6f
• Observability Deployment

Metrics [docs]

Module Count

Fewer modules leads to a faster build time

id	before	after	diff
infra	1576	1577	+1

Async chunks

Total size of all lazy-loaded chunks that will be downloaded as the user navigates the app

id	before	after	diff
infra	1.5MB	1.5MB	+540.0B

History

• 💛 Build #223508 was flaky 9063842
• 💔 Build #223456 failed 9c8e4af

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@elasticmachine merge upstream

cc @jennypavlova