Store group to predicate mapping as part of the backup manifest.

[martinmr]

This change is 

[manishrjain]

Reviewable status: 0 of 9 files reviewed, 8 unresolved discussions (waiting on @golangcibot, @manishrjain, and @martinmr)

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dgraph/cmd/alpha/admin_backup.go, line 113 at r1 (raw file):

	}

	predState, err := worker.PredicateState()

s/predState/state? Unless state was already used above.

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dgraph/cmd/zero/zero.go, line 717 at r1 (raw file):

// PredicateState returns the group to predicate mapping.
func (s *Server) PredicateState(ctx context.Context, req *pb.Empty) (*pb.MembershipState, error) {

Can use s.membershipState(), which is already available, and then remove whatever you don't need instead of copying what you do need (copying what you do need isn't future-proof, taking it all and removing what you don't is).

Also, no need to have this func in the first place. See my comments below.

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dgraph/cmd/zero/zero.go, line 720 at r1 (raw file):

	s.RLock()
	defer s.RUnlock()
	memState := &pb.MembershipState{

state :=

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protos/pb.proto, line 435 at r1 (raw file):

	rpc CommitOrAbort (api.TxnContext) returns (api.TxnContext) {}
	rpc TryAbort (TxnTimestamps)       returns (OracleDelta) {}
  rpc PredicateState(Empty)          returns (MembershipState) {}

Don't need this API. Connect gives you the latest membership state. You can ask for info only without causing any changes at Zero.

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protos/pb.proto, line 445 at r1 (raw file):

	rpc Sort (SortMessage)                  returns (SortResult) {}
	rpc Schema (SchemaRequest)              returns (SchemaResult) {}
	rpc Backup (BackupRequest)              returns (Empty) {}

How about returning a Status object like Export does?

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worker/groups.go, line 947 at r1 (raw file):

	zc := pb.NewZeroClient(pl.Get())

	out, err := zc.PredicateState(context.Background(), &pb.Empty{})

use Connect endpoint to get the latest membership state.

Technically, the state is already available in groups via the membership stream that's happening. But, I reckon you don't want to use that because it could be behind? Can you confirm that's the reasoning? And add a comment explaining this reasoning.

[manishrjain]

Reviewed 9 of 9 files at r1.
Reviewable status: all files reviewed, 8 unresolved discussions (waiting on @golangcibot and @martinmr)

[martinmr]

Reviewable status: all files reviewed, 8 unresolved discussions (waiting on @golangcibot and @manishrjain)

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dgraph/cmd/alpha/admin_backup.go, line 113 at r1 (raw file):

Previously, manishrjain (Manish R Jain) wrote…

s/predState/state? Unless state was already used above.

Done.

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dgraph/cmd/zero/zero.go, line 717 at r1 (raw file):

Previously, manishrjain (Manish R Jain) wrote…

Can use s.membershipState(), which is already available, and then remove whatever you don't need instead of copying what you do need (copying what you do need isn't future-proof, taking it all and removing what you don't is).

Also, no need to have this func in the first place. See my comments below.

Done. Removed this method.

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dgraph/cmd/zero/zero.go, line 720 at r1 (raw file):

Previously, manishrjain (Manish R Jain) wrote…

state :=

Done. Removed this method.

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protos/pb.proto, line 435 at r1 (raw file):

Previously, manishrjain (Manish R Jain) wrote…

Don't need this API. Connect gives you the latest membership state. You can ask for info only without causing any changes at Zero.

Done.

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protos/pb.proto, line 445 at r1 (raw file):

Previously, manishrjain (Manish R Jain) wrote…

How about returning a Status object like Export does?

Done.

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worker/groups.go, line 947 at r1 (raw file):

Previously, manishrjain (Manish R Jain) wrote…

use Connect endpoint to get the latest membership state.

Technically, the state is already available in groups via the membership stream that's happening. But, I reckon you don't want to use that because it could be behind? Can you confirm that's the reasoning? And add a comment explaining this reasoning.

Yes, that's why I was requesting the membership status instead of using the one already in the worker. I have added a comment.

I found UpdateMembershipState, which is already using Connect under the hood to only get the state without updating zero. I have deleted all the PredicateState methods and instead just get the membership status right after the update. This simplified the code quite a bit.

addressed comments

[manishrjain]

Do the proto.Clone for membership state. And in another PR, add a ChooseKey func to only choose the right preds picked up by the membership state during backup.

Reviewed 7 of 8 files at r2, 1 of 1 files at r3.
Reviewable status: all files reviewed, 5 unresolved discussions (waiting on @golangcibot and @martinmr)

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worker/groups.go, line 241 at r3 (raw file):

	g.RLock()
	defer g.RUnlock()
	return g.state

Do the cloning like it is happening in zero.go:membershipState().

[martinmr]

Reviewable status: 8 of 9 files reviewed, 5 unresolved discussions (waiting on @golangcibot and @manishrjain)

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dgraph/cmd/alpha/admin_backup.go, line 113 at r2 (raw file):

Previously, golangcibot (Bot from GolangCI) wrote…

File is not gofmt-ed with -s (from gofmt)

Done.

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dgraph/cmd/alpha/admin_backup.go, line 119 at r2 (raw file):

Previously, golangcibot (Bot from GolangCI) wrote…

nilness: impossible condition: nil != nil (from govet)

Done.

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worker/groups.go, line 241 at r3 (raw file):

Previously, manishrjain (Manish R Jain) wrote…

Do the cloning like it is happening in zero.go:membershipState().

Done.