Extraction of configuration from packages

[tzdybal]

For library usage, individual packages cannot call flag to setup configuration options. All the command line parsing should be done in cmd/dgraph/main.

This change is related to #673.

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This change is 

[janardhan1993]

Reviewed 1 of 24 files at r1.
Review status: 1 of 24 files reviewed at latest revision, 2 unresolved discussions.

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cmd/dgraph/main.go, line 99 at r1 (raw file):

		"Number of pending mutation proposals. Useful for rate limiting.")
	flag.Float64Var(&worker.Config.Tracing, "trace", 0.0, "The ratio of queries to trace.")
	flag.StringVar(&worker.Config.GroupIds, "groups", "0,1", "RAFT groups handled by this server.")

100 chars

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worker/groups.go, line 43 at r1 (raw file):

var (
	pstore           *badger.KV
	workerServer     *grpc.Server

These variables are used/initialized in worker.go. Shouldn't these stay there ?

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Comments from Reviewable

[tzdybal]

Review status: 1 of 24 files reviewed at latest revision, 2 unresolved discussions.

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cmd/dgraph/main.go, line 99 at r1 (raw file):

Previously, janardhan1993 (Janardhan Reddy) wrote…

100 chars

Done.

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worker/groups.go, line 43 at r1 (raw file):

Previously, janardhan1993 (Janardhan Reddy) wrote…

These variables are used/initialized in worker.go. Shouldn't these stay there ?

Variables are used everywhere (for example pstore is accessed in 8 files). Entire var block moved to worker.go.

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Comments from Reviewable

[manishrjain]

Some comments. Otherwise, looks good. I'll defer to @janardhan1993 for the final approval.

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Reviewed 21 of 24 files at r1, 3 of 3 files at r2.
Review status: all files reviewed at latest revision, 9 unresolved discussions.

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cmd/dgraph/main.go, line 666 at r2 (raw file):

	// Posting will initialize index which requires schema. Hence, initialize
	// schema before calling posting.Init().
	schema.Init(dgraph.State.PStore)

Pstore (small s)

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cmd/dgraphloader/main.go, line 208 at r2 (raw file):

func main() {
	flag.Parse()
	x.Init()

Isn't x.Init() calling flag.Parse?

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dgraph/server.go, line 41 at r2 (raw file):

	ShutdownCh chan struct{} // channel to signal shutdown.

	PStore   *badger.KV

Pstore

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dgraph/server.go, line 42 at r2 (raw file):

	PStore   *badger.KV
	WALStore *badger.KV

WALstore

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dgraph/server.go, line 80 at r2 (raw file):

	opt.Dir = Config.PostingDir
	opt.ValueDir = Config.PostingDir
	opt.MapTablesTo = table.MemoryMap

Make this a flag, so user can decide how they want this. There're 3 options -- talk to @janardhan1993 .

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posting/config.go, line 20 at r2 (raw file):

type Options struct {
	MaxMemory      float64

Call it AllottedMemory (not allocated).

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posting/lists.go, line 211 at r2 (raw file):

			x.NumGoRoutines.Set(int64(runtime.NumGoroutine()))
			if setLruMemory && inUse > 0.75*(Config.MaxMemory) {
				go lcache.UpdateMaxSize()

This doesn't need to be a goroutine.

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Comments from Reviewable

[tzdybal]

Review status: 14 of 26 files reviewed at latest revision, 9 unresolved discussions.

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cmd/dgraph/main.go, line 666 at r2 (raw file):

Previously, manishrjain (Manish R Jain) wrote…

Pstore (small s)

Done.

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cmd/dgraphloader/main.go, line 208 at r2 (raw file):

Previously, manishrjain (Manish R Jain) wrote…

Isn't x.Init() calling flag.Parse?

Removed it from x.Init(), because we need to call x.Init() in library initialization, and we don't want the library to touch the flag library at all.

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dgraph/server.go, line 41 at r2 (raw file):

Previously, manishrjain (Manish R Jain) wrote…

Pstore

Done.

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dgraph/server.go, line 42 at r2 (raw file):

Previously, manishrjain (Manish R Jain) wrote…

WALstore

Done.

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dgraph/server.go, line 80 at r2 (raw file):

Previously, manishrjain (Manish R Jain) wrote…

Make this a flag, so user can decide how they want this. There're 3 options -- talk to @janardhan1993 .

OK, I'll talk to him.

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posting/config.go, line 20 at r2 (raw file):

Previously, manishrjain (Manish R Jain) wrote…

Call it AllottedMemory (not allocated).

Done.

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posting/lists.go, line 211 at r2 (raw file):

Previously, manishrjain (Manish R Jain) wrote…

This doesn't need to be a goroutine.

Nothing changed in here, but I'll change it to normal function invocation.

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Comments from Reviewable

[janardhan1993]

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Review status: 14 of 26 files reviewed at latest revision, 9 unresolved discussions.

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Comments from Reviewable

[tzdybal]

Merged to master.