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Introduction

Google Cloud Datastore is a NoSQL document database built for automatic scaling, high performance, and ease of application development offered by Google on the Google Cloud Platform. Cloud Datastore is built upon Google's Bigtable and Megastore technology.

Use case(s)

  • Users would like to batch build a data pipeline to read complete table from Google Cloud Datastore instance.
  • Users would like to batch build a data pipeline to perform inserts / upserts into Google Cloud Datastore tables in batch 
  • Users should get relevant information from the tool tip while configuring the Google Cloud Datastore source and Google Cloud Datastore sink
    • The tool tip should describe accurately what each field is used for
  • Users should get field level lineage for the source and sink that is being used
  • Reference documentation be available from the source and sink plugins

User Storie(s)

  • Source code in data integrations org
  • Integration test code 
  • Relevant documentation in the source repo and reference documentation section in plugin

Plugin Type

  •  Batch Source
  •  Batch Sink 
  •  Real-time Source
  •  Real-time Sink
  •  Action
  •  Post-Run Action
  •  Aggregate
  •  Join
  •  Spark Model
  •  Spark Compute

Configurables

This section defines properties that are configurable for this plugin. 

Design

Properties

Source

User Facing NameTypeDescriptionConstraints
Project IDString

Google Cloud Project ID, which uniquely identifies a project. It can be found on the Dashboard in the Google Cloud Platform Console.

Required.
JSON key file pathString

The credential JSON key file path. Path on the local file system of the service account key used for authorization. Can be set to 'auto-detect' when running on a Dataproc cluster. When running on other clusters, the file must be present on every node in the cluster.

https://cloud.google.com/storage/docs/authentication#generating-a-private-key

Required.
NamespaceString

A namespace partitions entities into a subset of Datastore.

https://cloud.google.com/datastore/docs/concepts/multitenancy

Optional. If not provided, [default] namespace will be used.

Kind

String

The kind of an entity categorizes it for the purpose of Datastore queries. Equivalent to relational database table notion.

https://cloud.google.com/datastore/docs/concepts/entities#kinds_and_identifiers

Required.
Has AncestorStringAncestor identifies the common root entity in which the entities are grouped.
Must be written in Key Literal format: key(kind_1, identifier_1, kind_2, identifier_2, [...]). Example: key(kind_1, 'stringId', kind_2, 100)

https://cloud.google.com/datastore/docs/concepts/structuring_for_strong_consistency

Optional.
FiltersString

List of filter property names and values pairs by which equality filter will be applied.
This is a semi-colon separated list of key-value pairs, where each pair is separated by a pipe sign `|`.


Filter properties must be present in the schema. Allowed property types are STRING, LONG, DOUBLE, BOOLEAN and TIMESTAMP. Property value indicated as `null` string will be treated as `is null` clause. TIMESTAMP string should be in the RFC 3339 format without the timezone offset (always ends in Z). Expected pattern: yyyy-MM-dd'T'HH:mm:ssX, example: 2011-10-02T13:12:55Z

Optional.
Number of SplitsInteger

Desired number of splits to split a query into multiple shards during execution.
Will be created up to desired number of splits, however less splits can be created if desired number is unavailable.

Required. Min value: 1. Max value: 2147483647.
Key TypeString

Key is unique identifier assigned to the entity when it is created.
Property defines if key will be included in the output, commonly is needed to perform upserts to the Cloud Datastore. Can be one of three options:

None - key will not be included.

Key literal - key will be included in Datastore key literal format including complete path with ancestors.

URL-safe key - key will be included in the encoded form that can be used as part of a URL.

Note, if Key literal or URL-safe key is selected, default key name (__key__) or its alias must be present in the schema with non-nullable STRING type.

https://cloud.google.com/datastore/docs/concepts/entities#kinds_and_identifiers

Required. None by default.
Key AliasString

Allows to set user-friendly name for the key column which default name is __key__. Only applicable, if Key Type is set to Key literal or URL-safe key. If Key Type is set to None, property must be empty.

Optional.
SchemaJSON schema

Schema of the data to read, can be imported or fetched by clicking the Get Schema button.

Required.

Sink

User Facing NameTypeDescriptionConstraints

Design / Implementation Tips

  • Tip #1
  • Tip #2

Design

Approach(s)

Properties
Project IDString

Google Cloud Project ID, which uniquely identifies a project. It can be found on the Dashboard in the Google Cloud Platform Console.

Required.
JSON key file pathString

The credential JSON key file path. Path on the local file system of the service account key used for authorization. Can be set to 'auto-detect' when running on a Dataproc cluster. When running on other clusters, the file must be present on every node in the cluster.

https://cloud.google.com/storage/docs/authentication#generating-a-private-key

Required.
NamespaceString

A namespace partitions entities into a subset of Datastore.

https://cloud.google.com/datastore/docs/concepts/multitenancy

Optional. If not provided, [default] namespace will be used.

Kind

String

The kind of an entity categorizes it for the purpose of Datastore queries. Equivalent to relational database table notion.

https://cloud.google.com/datastore/docs/concepts/entities#kinds_and_identifiers

Required.
Key TypeString

Key is unique identifier assigned to the entity when it is created. Property defines what type of key will be added to the entity, commonly is needed to perform upserts to the Cloud Datastore. Can be one of four options:

Auto-generated key - key will be generated by Datastore as Numeric ID.

Custom name - key will be provided by user. Supported types: non-nullable STRING, INT or LONG.

Key literal - key will be provided in Datastore key literal format including complete path with ancestors. Supported type: non-nullable STRING in key literal format: key(<kind>, <identifier>, <kind>, <identifier>, [...]). Example: key(kind_name, 'stringId')

URL-safe key - key will be provided in the encoded form that can be used as part of a URL. Supported type: non-nullable STRING in URL-safe key format.

Note, if Custom name, Key literal or URL-safe key is selected, default key name (__key__) or its alias must be present in the schema.

https://cloud.google.com/datastore/docs/concepts/entities#kinds_and_identifiers

Required. Auto-generated key by default.
Key AliasString

Allows to set user-friendly name for the key column which default name is __key__.
Only applicable, if Key Type is set to Custom name, Key literal or URL-safe key. If Key Type is set to Auto-generated key, property must be empty.

Optional.
AncestorStringAncestor identifies the common root entity in which the entities are grouped.
Must be written in Key Literal format: key(kind_1, identifier_1, kind_2, identifier_2, [...]). Example: key(kind_1, 'stringId', kind_2, 100)

https://cloud.google.com/datastore/docs/concepts/structuring_for_strong_consistency

Optional.
Index StrategyString

Index strategy defines which fields defined in schema will be indexed in Cloud Datastore. Can be one of three options:

All - all fields will be indexed

None - none of fields will be indexed

Custom - indexed fields will be provided in Indexed Properties

Required. All by default.
Indexed PropertiesString

List of property names to be marked as indexed separated by comma.

https://cloud.google.com/datastore/docs/concepts/indexes

Optional. Must be provided if Index Strategy is set to Custom, otherwise must be empty.
Batch sizeInteger

Maximum number of entities that can be passed in one batch to a Commit operation.

https://cloud.google.com/datastore/docs/concepts/limits

Required. Default value 25. Min value 1. Max value 500.

Implementation Tips

Implementation will be done using Google Cloud Datastore Data API since it provides mechanisms to allow query splitting during data reads.

https://cloud.google.com/datastore/docs/reference/data/rpc/

https://github.com/GoogleCloudPlatform/google-cloud-datastore

Examples

Initial Dataset

Kind: TaskType

KeyLabel
name='DEV'Development

Kind: Task

KeyParentPriority
id=1Key(TaskType, 'DEV')1
id=2
1

Source examples

Read data filtered by ancestor and property, including Key

KindTask
Has AncestorKey(TaskType, 'DEV')
FiltersPriority1
Key TypeKey literal
Key AliasTaskKey

Output Schema

TaskKeyString
PriorityLong

Output Dataset

TaskKeyPriority
key(Task, 1)1

Read data filtered by property, without including Key

KindTask
Has Ancestor

FiltersPriority1
Key TypeNone
Key Alias

Output Schema

PriorityLong

Output Dataset

Priority
1
1

Sink examples

Insert new row with Ancestor and Custom name

Input Dataset

TaskIdPriority
32

Sink properties

KindTask
AncestorKey(TaskType, 'DEV')
Key TypeCustom name
Key AliasTaskId

Input Schema

TaskKeyLong
PriorityLong

Resulting Dataset (new row was inserted)

KeyParentPriority
id=1Key(TaskType, 'DEV')1
id=2
1
id=3Key(TaskType, 'DEV')2

Insert new row without Ancestor and with Auto-generated key

Input Dataset

Priority
2

Sink properties

KindTask
Ancestor
Key TypeAuto-generated key
Key Alias

Resulting Dataset (new row was inserted)

KeyParentPriority
id=1Key(TaskType, 'DEV')1
id=2
1
id=11010104985 2

Security

Limitation(s)

Future Work

  • Some future work – HYDRATOR-99999
  • Another future work – HYDRATOR-99999

Test Case(s)

  • Test case #1
  • Test case #2

Sample Pipeline

Please attach one or more sample pipeline(s) and associated data. 

Pipeline #1

Pipeline #2





Table of Contents

Table of Contents
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Checklist

  •  User stories documented 
  •  User stories reviewed 
  •  Design documented 
  •  Design reviewed 
  •  Feature merged 
  •  Examples and guides 
  •  Integration tests 
  •  Documentation for feature 
  •  Short video demonstrating the feature