myjson

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MyJSON is an embedded relational document store built on top of pluggable key value storage

go get -u github.com/autom8ter/myjson

Use Case
Features:
Getting Started
Tikv Setup Guide (full scale)
Contributing

Use Case

Build powerful applications on top of simple key value storage.

Features:

Architecture

Feature	Description	Implemented
Single Node (in-memory)	Run the embedded database with no persistance on a single node	[x]
Single Node (on-disk)	Run the embedded database with persistance on a single node	[x]
Distributed (distributed kv-store)	Run the embedded database with horizontal scalability using tikv distributed key value storage	[x]

Database

Feature	Description	Implemented
JSON Documents	Records are stored as JSON documents	[x]
Collections	Records are stored in Collections which can hold any number of JSON documents	[x]
Collection Schema	Collections define a JSON Schema which enforces the schema of JSON documents in a collection	[x]
Transactions	Cross Collection transactions can be used to persist/rollback changes to the database	[x]
Change Streams	Built in Change-Data-Capture collection can be queried & streamed for triggering realtime events	[x]
Scripting	Javascript scripts can be executed with full access to database functionality	[x]
Triggers	Javascript triggers can be configured at the collection level to add custom business logic based on when events occur	[x]
Migrations	Built in support for atomic database migrations written in javascript	[x]
Relationships	Built in support for relationships with foreign keys - Joins and cascade deletes are also supported	[x]
Secondary Indexes	Multi-field secondary indexes may be used to boost query performance (eq/gt/lt/gte/lte)	[x]
Unique Fields	Unique fields can be configured which ensure the uniqueness of a field value in a collection	[x]
Complex Queries	Complex queries can be executed with support for select/where/join/having/orderby/groupby/limit/page clauses	[x]
Aggregate Queries	Complex aggregate queries can be executed for analytical purposes	[x]
Time Travel	Find the value of a document at a specific timestamp	[x]
Revert	Revert the value of a document to it's value at a specific timestamp	[x]

Storage Providers

Provider	Description	Implemented
Badger	persistant, embedded LSM database written in Go	[x]
Tikv	persistant, distributed LSM database written in Rust	[x]
RocksDB	persistant, embedded LSM database written in C++

Getting Started

go get -u github.com/autom8ter/myjson

Before getting started, take a look at the examples and Godoc

Collection Schemas

Collection schemas are custom JSON Schema documents that declaratively configure a collection of documents. The schema defines the structure of the JSON documents in the collection and the constraints that should be enforced on the documents. The schema is used to validate the documents in the collection and to enforce the constraints on the documents. The schema is also used to define secondary indexes, foreign keys, authorization, and triggers.

Custom Root Level Properties

MyJSON supports a number of custom root level properties that can be used to configure the schema of a collection.

x-collection

x-collection configures the unique name of the collection. The name of the collection must be unique across all collections in the database. x-collection is a required property.

x-authorization

x-authorization is a set of javascript authorization rules to enforce against actions taken against the database. x-authorization is an optional property.

x-triggers

x-triggers are a set of javascript triggers that execute when certain actions are taken against the database. x-triggers is an optional property.

x-read-only

x-readonly indicates that the collection is updated internally and may only be read. x-readonly is an optional property.

x-prevent-deletes

x-prevent-deletes indicates that documents in the collection may not be deleted. x-prevent-deletes is an optional property.

x-immutable

x-immutable indicates that documents in the collection may not be updated or deleted.

Custom Field Level Properties

MyJSON supports a number of custom field level properties that can be used to configure the schema of a collection.

x-primary

x-primary configures the documents primary key (exactly 1 field must specify x-primary). The value of the field must be unique across all documents in the collection.

x-foreign

x-foreign configures a foreign key relationship. The value of the field must be the primary key of another document in the database. Foreign keys are enforced by the database at runtime and boost query join performance.

x-unique

x-unique configures a unique field for the document. The value of the field must be unique across all documents in the collection. a unique field is enforced by the database and is not configurable. For example, if a document has a field called _secondary_id with x-unique set to true, then the value of the field must be unique across all documents in the collection. Unique indexes also boost query performance.

x-index

x-index configures a secondary index. The value of the field is indexed and can be used to boost query performance. For example, if a document has a field called _secondary_id with x-index set to true, then the value of the field will be indexed and can be used to boost query performance.

x-immutable

x-immutable indicates that the field is immutable and all edits will be replaced with it's original value. For example, if a document has a field called _secondary_id with x-immutable set to true, then the value of the field will be set to it's permanent, immutable value on creattion. If the document is updated, the value of the field will not be changed. Immutable properties override the x-compute and default properties.

x-compute

x-compute is a javascript expression that is evaluated when the document is created or updated. The expression is evaluated in the context of the document and the result is stored in the field. The expression is evaluated before the document is validated against the schema. The expression may be used to compute a value for a field based on the values of other fields in the document. Computed properties override the default property.

Example Schema

account.yaml

type: object
x-collection: account
required:
  - _id
  - name
properties:
  _id:
    type: string
    description: The account's id.
    x-primary: true
  name:
    type: string
    description: The accounts's name.
x-authorization:
  rules:
    ## allow super users to do anything
    - effect: allow
      ## match on any action
      action:
      - "*"
      ## context metadata must have role super_user set to true
      match: |
        contains(meta.Get('roles'), 'super_user')

      ## dont allow read-only users to create/update/delete/set accounts
    - effect: deny
      ## match on document mutations
      action:
        - create
        - update
        - delete
        - set
        ## context metadata must have a read_only role set to true
      match: |
        contains(meta.Get('roles'), 'read_only')

      ## only allow users to update their own account
    - effect: allow
        ## match on document mutations
      action:
        - create
        - update
        - delete
        - set
        ## the account's _id must match the user's account_id
      match: |
        doc.Get('_id') == meta.Get('account_id')

      ## only allow users to query their own account
    - effect: allow
        ## match on document queries (includes ForEach and other Query based methods)
      action:
        - query
        ## user must have a group matching the account's _id
      match: |
        query.where?.length > 0 && query.where[0].field == '_id' && query.where[0].op == 'eq' && contains(meta.Get('groups'), query.where[0].value)

user.yaml

type: object
# x-collection specifies the name of the collection the object will be stored in
x-collection: user
# required specifies the required attributes
required:
  - _id
  - name
  - age
  - contact
  - gender
  - account_id
properties:
  _id:
    type: string
    description: The user's id.
    # x-primary indicates that the property is the primary key for the object - only one primary key may be specified
    x-primary: true
  name:
    type: string
    description: The user's name.
  contact:
    type: object
    properties:
      email:
        type: string
        description: The user's email.
        `x-unique`: true
  age:
    description: Age in years which must be equal to or greater than zero.
    type: integer
    minimum: 0
  account_id:
    type: string
    # x-foreign indicates that the property is a foreign key - foreign keys are automatically indexed
    x-foreign:
      collection: account
      field: _id
      cascade: true
    # `x-index` specifies a secondary index which can have 1-many fields
    `x-index`:
      account_email_idx:
        additional_fields:
          - contact.email
  language:
    type: string
    description: The user's first language.
    `x-index`:
      language_idx: { }
  gender:
    type: string
    description: The user's gender.
    enum:
      - male
      - female
  timestamp:
    type: string
  annotations:
    type: object

# x-triggers are javascript functions that execute based on certain events
x-triggers:
  # name of the trigger
  set_timestamp:
    # order determines the order in which the functions are executed - lower ordered triggers are executed first
    order: 1
    # events configures the trigger to execute on certain events
    events:
      - on_create
      - on_update
      - on_set
    # script is the javascript to execute
    script: |
      doc.Set('timestamp', new Date().toISOString())

task.yaml

type: object
x-collection: task
required:
  - _id
  - user
  - content
properties:
  _id:
    type: string
    description: The user's id.
    x-primary: true
  user:
    type: string
    description: The id of the user who owns the task
    x-foreign:
      collection: user
      field: _id
      cascade: true
  content:
    type: string
    description: The content of the task

Authorization

TODO

Opening a database instance

Single Node in Memory (badger)

db, err := myjson.Open(context.Background(), "badger", map[string]any{
	"storage_path": "",
})

Single Node w/ Persistance (badger)

db, err := myjson.Open(context.Background(), "badger", map[string]any{
	"storage_path": "./tmp",
})

Multi Node w/ Persistance (tikv)

db, err := myjson.Open(context.Background(), "tikv", map[string]any{
    "pd_addr":    []string{"http://pd0:2379"},
    "redis_addr": "localhost:6379",
    "redis_user": "admin", //change me
    "redis_password": "123232", //change me
})

Configuring a database instance

Collection schemas can be configured at runtime or at startup. Collection schemas are declarative - any changes to indexing or validation happen within the database when Configure is called

var (
    //go:embed account.yaml
    accountSchema string
    //go:embed user.yaml
    userSchema string
    //go:embed task.yaml
    taskSchema string
)

if err := db.Configure(ctx, "", []string{accountSchema, userSchema, taskSchema}); err != nil {
    panic(err)
})

Working with JSON documents

Creating a JSON document

document, err := myjson.NewDocumentFrom(map[string]any{
    "name": "acme.com",
})

doc := myjson.NewDocument()
doc.Set("name", "acme.com")

Setting JSON values

doc := myjson.NewDocument()
doc.Set("name", "acme.com")

SJSON syntax is supported: https://github.com/tidwall/sjson#path-syntax

doc := myjson.NewDocument()
doc.Set("contact.email", "info@acme.com")

Getting JSON values

doc := myjson.NewDocument()
doc.Set("name", "acme.com")

GJSON syntax is supported: https://github.com/tidwall/sjson#path-syntax

value := doc.Get("contact.email")

additional GJSON modifiers are available:

@camelCase - convert a json string field to camel case doc.Get("project|@camelCase")
@snakeCase - convert a json string field to snake case doc.Get("project|@snakeCase")
@kebabCase - convert a json string field to kebab case doc.Get("project|@kebabCase")
@replaceAll - replace a substring within a json string field with another string
@unix - get the unix timestamp of the json time field doc.Get("timestamp|@unix")
@unixMilli - get the unix millisecond timestamp of the json time field doc.Get("timestamp|@unixMilli")
@unixNano - get the unix nanosecond timestamp of the json time field doc.Get("timestamp|@unixNano")
@dateTrunc - truncate a date to day, month, or year ex: doc.GetString("timestamp|@dateTrunc:month"), doc.GetString("timestamp|@dateTrunc:year"), doc.GetString("timestamp|@dateTrunc:day")

Transactions

Most database functionality is made available via the Tx interface which has read/write methods across 1-many collections.

Writable

if err := db.Tx(ctx, kv.TxOpts{IsReadOnly: false}, func(ctx context.Context, tx myjson.Tx) error {
	// do stuff ...tx.Set(...)
	// return error to rollback
	// return no error to commit
}

Read Only

if err := db.Tx(ctx, kv.TxOpts{IsReadOnly: true}, func(ctx context.Context, tx myjson.Tx) error {
	// ...tx.Get(...)
}

Adding documents to a collection

if err := db.Tx(ctx, kv.TxOpts{}, func(ctx context.Context, tx myjson.Tx) error {
    doc := myjson.NewDocument()
    doc.Set("name", "acme.com")
	id, err := tx.Create(ctx, "account", document)
	if err != nil {
		return err
    }
}

Queries

results, err := tx.Query(ctx, "user", myjson.Q().
    Select(myjson.Select{Field: "*"}).
	OrderBy(myjson.OrderBy{Field: "age", Direction: myjson.OrderByDirectionDesc}).
    Query())

Joins

1-many joins are

results, err := db.Query(ctx, "user", myjson.Q().
    Select(
        myjson.Select{Field: "acc._id", As: "account_id"},
        myjson.Select{Field: "acc.name", As: "account_name"},
		myjson.Select{Field: "_id", As: "user_id"},
    ).
    Join(myjson.Join{
        Collection: "account",
        On: []myjson.Where{
            {
				Field: "_id",
				Op:    myjson.WhereOpEq,
                Value: "$account_id", //self reference the account_id on the user document
            },
    },
        As: "acc",
    }).
Query())

Iterating through documents in a collection

_, err := tx.ForEach(ctx, "user", myjson.ForEachOpts{}, func(d *myjson.Document) (bool, error) {
    fmt.Println(d)
    return true, nil
})

Reading documents in a collection

doc, err := tx.Get(ctx, "user", "$id")

Change Streams

Stream Changes in a given collection

CDC persistance must be enabled for change streams to work. See the database Options for more info.

ctx, cancel := context.WithCancel(context.Background())
defer cancel()
err := db.ChangeStream(ctx, "user", func(cdc myjson.CDC) (bool, error) {
    fmt.Println(cdc)
    return true, nil
})

Aggregation

query := myjson.Query{
	Select: []myjson.Select{
		{
            Field: "account_id",
		},
		{
            Field:     "age",
            Aggregate: myjson.AggregateFunctionSum,
            As:        "age_sum",
		},
	},
	GroupBy: []string{"account_id"},
}
results, err := db.Query(ctx, "user", query)

Triggers

add a triggers block to your JSON schema ex: update timestamp on set/update/create with a javascript expression

triggers:
  set_timestamp:
    order: 1
    events:
      - on_create
      - on_update
      - on_set
    script: |
      doc.Set('timestamp', new Date().toISOString())

javascript variables are injected at runtime:

doc - the JSON document that is being changed
db - the global database instance(all methods are available)
ctx - the context when the trigger was called
metadata - the context metadata when the script is called
tx - the current transaction instance

Scripts

Scripts are javascript expressions/functions that can be called in Go - this may be used when embedded/dynamic functionality is required.

getAccountScript:

function setAccount(ctx, db, params) {
    db.tx(ctx, {isReadOnly: false}, (ctx, tx) => {
        tx.set(ctx, "account", params.doc)
    })
}

execute with custom paramaters:

id := ksuid.New().String()
doc, err := myjson.NewDocumentFrom(map[string]any{
    "_id":  id,
    "name": gofakeit.Company(),
})
_, err = db.RunScript(ctx, "setAccount", getAccountScript, map[string]any{
    "doc": doc,
})

javascript variables are injected at runtime:

db - the global database instance(all methods are available lowercased)
ctx - the context when the script is called
metadata - the context metadata when the script is called
newDocument - function to intialize a new JSON document
newDocumentFrom - function to initialize a new JSON document from a javascript object

Tikv Setup Guide (full scale)

WIP - see tikv foldeer w/ Makefile for running tikv locally

Contributing

Install Dependencies

go mod download

Checkout Branch

git checkout -b ${issueNumber}

Run Tests

go test -race -covermode=atomic -coverprofile=coverage.out -v .

Run Benchmarks

go test -bench=. -benchmem -run=^#

Lint Repository

golangci-lint run

Check Coverage

go tool cover -func=coverage.out

Name		Name	Last commit message	Last commit date
Latest commit History 31 Commits
.github/workflows		.github/workflows
benchmarks		benchmarks
errors		errors
kv		kv
testutil		testutil
util		util
.gitignore		.gitignore
.golangci.yaml		.golangci.yaml
LICENSE		LICENSE
README.md		README.md
api.go		api.go
authorization.go		authorization.go
authorization_test.go		authorization_test.go
builder.go		builder.go
builder_test.go		builder_test.go
cdc.yaml		cdc.yaml
coverage.out		coverage.out
dag.go		dag.go
dag_test.go		dag_test.go
db.go		db.go
db_test.go		db_test.go
db_util.go		db_util.go
document.go		document.go
document_test.go		document_test.go
example_test.go		example_test.go
go.mod		go.mod
go.sum		go.sum
indexing.go		indexing.go
indexing_test.go		indexing_test.go
javascript.go		javascript.go
javascript_test.go		javascript_test.go
metadata.go		metadata.go
metadata_test.go		metadata_test.go
metakeys.go		metakeys.go
model.go		model.go
model_test.go		model_test.go
optimizer.go		optimizer.go
optimizer_test.go		optimizer_test.go
opts.go		opts.go
schema.go		schema.go
schema_test.go		schema_test.go
tx.go		tx.go
tx_test.go		tx_test.go
tx_util.go		tx_util.go
util.go		util.go
util_test.go		util_test.go

License

autom8ter/myjson

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myjson

Use Case

Features:

Architecture

Database

Storage Providers

Getting Started

Collection Schemas

Custom Root Level Properties

x-collection

x-authorization

x-triggers

x-read-only

x-prevent-deletes

x-immutable

Custom Field Level Properties

x-primary

x-foreign

x-unique

x-index

x-immutable

x-compute

Example Schema

Authorization

Opening a database instance

Single Node in Memory (badger)

Single Node w/ Persistance (badger)

Multi Node w/ Persistance (tikv)

Configuring a database instance

Working with JSON documents

Creating a JSON document

Setting JSON values

Getting JSON values

Transactions

Writable

Read Only

Adding documents to a collection

Queries

Joins

Iterating through documents in a collection

Reading documents in a collection

Change Streams

Stream Changes in a given collection

Aggregation

Triggers

Scripts

Tikv Setup Guide (full scale)

Contributing

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