Create an AlarmBackend interface to fix unexported-return

[aladesawe]

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[k8s-ci-robot]

Hi @aladesawe. Thanks for your PR.

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[aladesawe]

Pulled from PR

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 68.88%. Comparing base (92673d1) to head (1f5aab7).
Report is 165 commits behind head on main.

Additional details and impacted files

Files with missing lines	Coverage Δ
server/storage/schema/alarm.go	86.66% <100.00%> (ø)

... and 59 files with indirect coverage changes

@@            Coverage Diff             @@
##             main   #19342      +/-   ##
==========================================
+ Coverage   68.79%   68.88%   +0.09%     
==========================================
  Files         420      420              
  Lines       35629    35716      +87     
==========================================
+ Hits        24510    24604      +94     
+ Misses       9700     9685      -15     
- Partials     1419     1427       +8     

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[ahrtr]

It's duplicated to

etcd/server/etcdserver/api/v3alarm/alarms.go

Lines 32 to 38 in f1d09c0

	type AlarmBackend interface {
	CreateAlarmBucket()
	MustPutAlarm(member *pb.AlarmMember)
	MustDeleteAlarm(alarm *pb.AlarmMember)
	GetAllAlarms() ([]*pb.AlarmMember, error)
	ForceCommit()
	}

The simplest solution is to move the interface into storage/alarm. cc @serathius

[aladesawe]

good catch

[aladesawe]

@ahrtr I did a quick search; the only exported interface in the schema sub-folder is WALVersion, which will eventually be moved out. Is this by design, and should we instead be importing the definition in api into storage/schema/alarm.go?