Separate query-service functionality from http handler

[annanay25]

Signed-off-by: Annanay annanay.a@media.net

Which problem is this PR solving?

• Prereq for Support gRPC for query service #1307

Short description of the changes

• Separate common utils (span reader/writer, logger, tracer) of the query-service from the APIHandler definition. This will be used by the gRPC handler as well.

[codecov]

Codecov Report

Merging #1312 into master will not change coverage.
The diff coverage is 100%.

@@          Coverage Diff           @@
##           master   #1312   +/-   ##
======================================
  Coverage     100%    100%           
======================================
  Files         162     163    +1     
  Lines        7364    7374   +10     
======================================
+ Hits         7364    7374   +10

Impacted Files	Coverage Δ
cmd/query/app/handler_options.go	100% <ø> (ø)	⬆️
cmd/query/app/http_handler.go	100% <100%> (ø)
cmd/query/app/querysvc/query_service.go	100% <100%> (ø)

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[annanay25]

Thanks for the review, @yurishkuro

I've addressed comments and updated the PR. (A few failing tests will be fixed soon).

[yurishkuro]

this looks pretty good, no major comments

[annanay25]

A couple of things I came across as I'm fixing the test cases after refactoring.

1. Test cases like -
   

   jaeger/cmd/query/app/handler_deps_test.go

   Lines 309 to 314 in d40ea34

   	func TestGetDependenciesSuccess(t *testing.T) {
   	server, _, mock := initializeTestServer()
   	defer server.Close()
   	expectedDependencies := []model.DependencyLink{{Parent: "killer", Child: "queen", CallCount: 12}}
   	endTs := time.Unix(0, 1476374248550*millisToNanosMultiplier)
   	mock.On("GetDependencies", endTs, defaultDependencyLookbackDuration).Return(expectedDependencies, nil).Times(1)

... are going to change to -

func TestGetDependenciesSuccess(t *testing.T) {
	server, qs := initializeTestServer()
	defer server.Close()
	expectedDependencies := []model.DependencyLink{{Parent: "killer", Child: "queen", CallCount: 12}}
	endTs := time.Unix(0, 1476374248550*millisToNanosMultiplier)

And so we either need:

// Expose DependencyReader directly  
qs.DependencyReader.On("GetDependencies", endTs, defaultDependencyLookbackDuration).Return(expectedDependencies, nil).Times(1)

OR

// Expose dependencyReader through QueryService.getDepReader()
qs.getDepReader().On("GetDependencies", endTs, defaultDependencyLookbackDuration).Return(expectedDependencies, nil).Times(1)

.. (if we don't go with implementing a mock for QueryService)

2. Since we're moving away from functional arguments, we'll now need constructors for QueryServiceOptions with signatures like -

// QueryServiceOptions has optional members of QueryService
type QueryServiceOptions struct {
	archiveSpanReader spanstore.Reader
	archiveSpanWriter spanstore.Writer
	adjuster          adjuster.Adjuster
}

// NewQueryServiceWithReader creates a QueryServiceOption with an archive reader.
func NewQueryServiceWithReader(archiveSpanReader spanstore.Reader) QueryServiceOptions

// NewQueryServiceWithWriter creates a QueryServiceOption with an archive writer.
func NewQueryServiceWithWriter(archiveSpanWriter spanstore.Writer) QueryServiceOptions 

.
.

@yurishkuro could you please review?

[yurishkuro]

On the first question, initTestServer is the one that creates and returns the mocks for storage. It should continue doing that. The tests are testing the handler endpoints, they don't care if internally the init function constructs QueryService. It seems like I'm missing something that's confusing you.

On the second question, you need to make the fields of the options struct public, since they are part of the public API of the package.

[yurishkuro]

a couple minor nits, ready to merge otherwise

[annanay25]

@yurishkuro One test is failing because the querysvc directory doesn't have a test file. Not sure what to do here.

[yurishkuro]

One test is failing because the querysvc directory doesn't have a test file. Not sure what to do here.

ideally, we should add tests, it's a simple one to test with mocks.

[annanay25]

I've added an empty test for now because we have all the mock-tests in place for the reader/writer handlers anyway. Could you re-run travis on this @yurishkuro? The build seems to be failing with an unrelated error.

[yurishkuro]

@annanay25 there is a drop in code coverage, which shouldn't happen with plain refactoring. Could you find a way to bring coverage back?

[annanay25]

Looking into this.

[annanay25]

@yurishkuro Build is green :)

[annanay25]

@yurishkuro can we go ahead with this?

[yurishkuro]

this is identical to initializeTestServerWithOptions, please remove

[yurishkuro]

🎉 🎈

[annanay25]

Thanks Yuri! 😄