Update host metrics receiver to use scraper controller

[james-bebbington]

Update host metrics receiver to use scraper controller removing around 400 lines of code. There is some "scraper factory" code left over that might be able to be moved into the receiverhelper (or scraper) library. Will think about that for next phase.

Resolves #918

---

Sample Output:

Note in these examples we see quite a lot of errors scraping process data due to not running the Collector in "Administrative mode" on Windows:

Traces (from http://localhost:55679/debug/tracez?zspanname=scraper%2fprocess%2fMetricsScraped&ztype=2&zsubtype=0):

Metrics (from http://localhost:8888/metrics):

[codecov]

Codecov Report

Merging #1949 into master will increase coverage by 0.09%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #1949      +/-   ##
==========================================
+ Coverage   91.92%   92.01%   +0.09%     
==========================================
  Files         282      278       -4     
  Lines       16797    16746      -51     
==========================================
- Hits        15440    15409      -31     
+ Misses        933      921      -12     
+ Partials      424      416       -8     

Impacted Files	Coverage Δ
...rnal/scraper/processesscraper/processes_scraper.go	77.77% <ø> (-2.23%)	⬇️
receiver/hostmetricsreceiver/internal/utils.go	100.00% <ø> (ø)
receiver/hostmetricsreceiver/factory.go	86.66% <100.00%> (+11.66%)	⬆️
...eceiver/internal/scraper/cpuscraper/cpu_scraper.go	100.00% <100.00%> (ø)
...icsreceiver/internal/scraper/cpuscraper/factory.go	100.00% <100.00%> (ø)
...nternal/scraper/diskscraper/disk_scraper_others.go	100.00% <100.00%> (ø)
...csreceiver/internal/scraper/diskscraper/factory.go	100.00% <100.00%> (ø)
...iver/internal/scraper/filesystemscraper/factory.go	88.88% <100.00%> (+3.17%)	⬆️
...al/scraper/filesystemscraper/filesystem_scraper.go	100.00% <100.00%> (ø)
...csreceiver/internal/scraper/loadscraper/factory.go	100.00% <100.00%> (ø)
... and 13 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 07d7a1f...98a76e5. Read the comment docs.

[asuresh4]

@james-bebbington do you think it makes sense to split this PR? Asking since there are changes in componenterror and obsreport apart from updates to host metrics receiver.

[james-bebbington]

@james-bebbington do you think it makes sense to split this PR? Asking since there are changes in componenterror and obsreport apart from updates to host metrics receiver.

Yes definitely.

This PR actually depends on #1961 (the first commit of this PR with changes to componenterror, obsreport, etc is in #1961). If you want you can just review the second commit of this PR, but otherwise I would recommend reviewing #1961 first and waiting for that to be merged before reviewing this.

[github-actions]

This PR was marked stale due to lack of activity. It will be closed in 7 days.

[james-bebbington]

This is now unblocked and ready for review again

[jrcamp]

Didn't think of this during the previous review but seeing it now a less verbose version might be

var errs consumererror.ScrapeErrors
errs.Add(fmt.Errorf("error reading process name for pid %v: %w", pid, err), 1))
errs.Add(...)
return errs.Combine()

Or something. Just an idea.

[james-bebbington]

It is a bit ugly yea.

Another option might be to just make a fmt-like constructor for PartialScrapeError so we can do something like

errs = append(errs, consumererror.NewScrapeError(1, "error reading process name for pid %v: %w", pid, err))

WDYT?

In any case I will probably do in a follow up PR as this one is very large already

[jrcamp]

Another option might be to just make a fmt-like constructor for PartialScrapeError so we can do something like

Yeah I think that'd be good. I was worried go vet might not catch fmt string errors but looks like it does from a quick test:

package main

import (
	"fmt"
)

func f(s string, args... interface{}) string {
   return fmt.Sprintf(s, args...)
  
}

func main() {
//	fmt.Printf("Hello, playground %s %s", "foo", 5)
	f("hello, playground %s %s", "foo", 3)
}

[jrcamp]

But I still think it'd be nice to have a struct to accumulate errors into instead of having to do all the appends. Could give it an Addf for formatted strings as well.

[james-bebbington]

Yea that seems like a good idea. Note we would also want a way to include regular unexpected errors that don't necessarily make sense to be represented as a scrape error.

Moved this discussion to an issue: #2046

[tigrannajaryan]

OK to merge this?

[jrcamp]

OK to merge this?

@tigrannajaryan yes