database

Documentation

Overview

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*__ _____ __ ___ ___ __ _| |_ ___ *\ \ /\ / / _ \/ _` \ \ / / |/ _` | __/ _ \ * \ V V / __/ (_| |\ V /| | (_| | || __/ * \_/\_/ \___|\__,_| \_/ |_|\__,_|\__\___| * * Copyright © 2016 - 2019 Weaviate. All rights reserved. * LICENSE: https://github.com/creativesoftwarefdn/weaviate/blob/develop/LICENSE.md * DESIGN & CONCEPT: Bob van Luijt (@bobvanluijt) * CONTACT: hello@creativesoftwarefdn.org

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*__ _____ __ ___ ___ __ _| |_ ___ *\ \ /\ / / _ \/ _` \ \ / / |/ _` | __/ _ \ * \ V V / __/ (_| |\ V /| | (_| | || __/ * \_/\_/ \___|\__,_| \_/ |_|\__,_|\__\___| * * Copyright © 2016 - 2019 Weaviate. All rights reserved. * LICENSE: https://github.com/creativesoftwarefdn/weaviate/blob/develop/LICENSE.md * DESIGN & CONCEPT: Bob van Luijt (@bobvanluijt) * CONTACT: hello@creativesoftwarefdn.org

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*__ _____ __ ___ ___ __ _| |_ ___ *\ \ /\ / / _ \/ _` \ \ / / |/ _` | __/ _ \ * \ V V / __/ (_| |\ V /| | (_| | || __/ * \_/\_/ \___|\__,_| \_/ |_|\__,_|\__\___| * * Copyright © 2016 - 2019 Weaviate. All rights reserved. * LICENSE: https://github.com/creativesoftwarefdn/weaviate/blob/develop/LICENSE.md * DESIGN & CONCEPT: Bob van Luijt (@bobvanluijt) * CONTACT: hello@creativesoftwarefdn.org

Index

• type ConnectorLock
• type Database
  • func New(ctx context.Context, params *Params) (Database, error)
• type Params
• type RWLocker
• type SchemaLock
• type SchemaManager

Types

type ConnectorLock

type ConnectorLock interface {
	Connector() dbconnector.DatabaseConnector
	GetSchema() db_schema.Schema
	Unlock() error
}

type Database

type Database interface {
	graphqlapi.DatabaseResolverProvider

	ConnectorLock() (ConnectorLock, error)
	SchemaLock() (SchemaLock, error)
}

func New

func New(ctx context.Context, params *Params) (Database, error)

New Database with Params. See docs of "Params" for more details on the individual params.

type Params

type Params struct {
	// Messaging client, to be replaced with a more standardized logger like
	// logrus at some point. See gh-666.
	Messaging *messages.Messaging

	// The distributed RWLock is achieved using etcd. Instead of passing around a
	// reference to one RWMutex (which is impossible across multiple processes),
	// we pass around an etcd session that lives as long as this application as
	// well as a unique key. This key is used by the different processes
	// accessing etcd to know that they are requesting access to the same lock.
	LockerKey     string
	LockerSession *concurrency.Session

	// SchemaManager orchestrates schema changes. All those changes are applied
	// using a SchemaLock (which is the Write part on the RWMutex). This means
	// schema changes and "regular" changes, such as reading a class, updating a
	// class (while keeping the same schema) never happen at the same time as
	// updating the schema itself.
	SchemaManager SchemaManager

	// Connector allows us flexibility with the used databses. Users of the
	// "Database" type are agnostic of the underlying connector. This could be a
	// connector for a graph database, like Janusgraph or a NoSQL db or a SQL db.
	Connector dbconnector.DatabaseConnector

	// Contextionary used for NLP-processing
	Contextionary contextionary.Contextionary
}

type RWLocker

type RWLocker interface {
	Lock() error
	RLock() error

	Unlock() error
	RUnlock() error
}

type SchemaLock

type SchemaLock interface {
	ConnectorLock
	SchemaManager() SchemaManager
}

type SchemaManager

type SchemaManager interface {
	schema_migrator.Migrator
	connector_state.StateManager

	// Update the Thing or Action schema's meta data.
	UpdateMeta(ctx context.Context, kind kind.Kind, atContext strfmt.URI, maintainer strfmt.Email, name string) error

	// Return a reference to the database schema.
	// Note that this function can be both called from having a ConnectorLock as a SchemaLock.
	GetSchema() db_schema.Schema

	// Register callbacks that will be called when the schema has been updated. These callbacks
	// will be invoked before the migration methods return.
	// Take care to not cause a deadlock by modifying the schema directly again from a callback.
	// The are also run _once_ after the system has configured itself.
	RegisterSchemaUpdateCallback(func(updatedSchema db_schema.Schema))

	// Trigger the callbacks to be send out. Used during initialization.
	TriggerSchemaUpdateCallbacks()

	// Sets a contextionary to be used for future correctness checks of the schema.
	SetContextionary(context contextionary.Contextionary)
}