Store and query types.

[martinmr]

This change adds the ability to store the types and query them similarly
to how the schema is currently being parsed.

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This change is 

[manishrjain]

Test this thoroughly, so you're not breaking anything.

I don't yet understand how would snapshot copies work -- do test them out manually -- when a snapshot is copied, all previous data is deleted, so the type system would need to be copied as well. @danielmai can help you with those.

Reviewed 10 of 16 files at r1, 5 of 6 files at r2.
Reviewable status: all files reviewed, 6 unresolved discussions (waiting on @martinmr)

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gql/parser.go, line 889 at r2 (raw file):

// parseSchemaPredsOrTypes parses till rightround is found
func parseSchemaPredsOrTypes(it *lex.ItemIterator, s *pb.SchemaRequest) error {
	// pred (or type) should be followed by colon

remove the brackets.

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query/common_test.go, line 197 at r1 (raw file):

const testSchema = `
type Person {
	name: string

Can we support capital S String?

name: String

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query/common_test.go, line 200 at r2 (raw file):

	pet: Animal
}

Add a test here picking from a real GraphQL example from their docs, if possible. We should be able to parse their schema, w.r.t. the type system.

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query/query.go, line 2722 at r2 (raw file):

			return er, x.Wrapf(&InternalError{err: err}, "error while fetching schema")
		}
		if er.Types, err = worker.GetTypes(ctx, req.GqlQuery.Schema); err != nil {

Should it be req.GqlQuery.Schema? Or, Types or something?

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schema/schema.go, line 96 at r2 (raw file):

	glog.Infof("Deleting type definition for type: [%s]", typeName)
	delete(s.types, typeName)

I'd delete from memory after successfully deleting it from disk.

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x/keys.go, line 265 at r2 (raw file):

}

// SchemaPrefix returns the prefix for Schema keys.

The comment is incorrect.

[martinmr]

Reviewable status: 6 of 16 files reviewed, 6 unresolved discussions (waiting on @manishrjain)

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gql/parser.go, line 889 at r2 (raw file):

Previously, manishrjain (Manish R Jain) wrote…

remove the brackets.

Done.

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query/common_test.go, line 197 at r1 (raw file):

Previously, manishrjain (Manish R Jain) wrote…

Can we support capital S String?

name: String

Done. Primitive types are not case sensitive so this is already supported. I added a explicit test for this.

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query/common_test.go, line 200 at r2 (raw file):

Previously, manishrjain (Manish R Jain) wrote…

Add a test here picking from a real GraphQL example from their docs, if possible. We should be able to parse their schema, w.r.t. the type system.

There's a lot more parsing tests in schema/parse_test.go that tests a lot more stuff (non-nullable types, lists, etc.). I kept the types simple here since the tests are mostly about being able to retrieve the types.

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query/query.go, line 2722 at r2 (raw file):

Previously, manishrjain (Manish R Jain) wrote…

Should it be req.GqlQuery.Schema? Or, Types or something?

This is fine. The reason it's that types are queried in a schema block.

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schema/schema.go, line 96 at r2 (raw file):

Previously, manishrjain (Manish R Jain) wrote…

I'd delete from memory after successfully deleting it from disk.

Done.

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x/keys.go, line 265 at r2 (raw file):

Previously, manishrjain (Manish R Jain) wrote…

The comment is incorrect.

Done.

[martinmr]

Did more testing. Snapshots work as expected (was able to stop replicas and the entire cluster and still get the types back)