Domino

Features

• Fully typesafe fluent syntax DSL
• Full Condition and Filter Expression functionality
• Static schema definition
• Streaming results for Query, Scan and BatchGet operations

Examples

Creating a Table

import(
  "github.com/aws/aws-sdk-go/service/dynamodb"
  "github.com/aws/aws-sdk-go/aws/session"
)

sess := session.New(config)
dynamo := dynamodb.New(sess)

//Define your table schema statically
type UserTable struct {
  DynamoTable
  emailField    domino.String
  passwordField domino.String

  registrationDate domino.Numeric
  loginCount       domino.Numeric
  lastLoginDate    domino.Numeric
  vists            domino.NumericSet
  preferences      domino.MapField
  nameField        domino.String
  lastNameField    domino.String
  locales          domino.List
  degrees          domino.NumericSet

  registrationDateIndex domino.LocalSecondaryIndex
  nameGlobalIndex       domino.GlobalSecondaryIndex
}

// Define domain object
type User struct {
  Email       string            `dynamodbav:"email"`
  Password    string            `dynamodbav:"password"`
  Visits      []int64           `dynamodbav:"visits,numberset,omitempty"`
  Degrees     []float64         `dynamodbav:"degrees,numberset,omitempty"`
  Locales     []string          `dynamodbav:"locales,omitempty"`
  LoginCount  int               `dynamodbav:"loginCount"`
  RegDate     int64             `dynamodbav:"registrationDate"`
  Preferences map[string]string `dynamodbav:"preferences,omitempty"`
}

//Initialize the table
func NewUserTable() MyTable {
  pk := domino.StringField("email")
  rk := domino.StringField("password")
  firstName := domino.StringField("firstName")
  lastName := domino.StringField("lastName")
  reg := domino.NumericField("registrationDate")
  return MyTable{
    DynamoTable{
      Name:         "mytable",
      PartitionKey: pk,
      RangeKey:     rk,
    },
    pk,  //email
    rk,  //password
    reg, //registration
    domino.NumericField("loginCount"),
    domino.NumericField("lastLoginDate"),
    domino.NumericSetField("visits"),
    domino.MapField("preferences"),
    firstName,
    lastName,
    StringSetField("locales"),
    NumericSetField("degrees"),
    domino.LocalSecondaryIndex{"registrationDate-index", reg},
    domino.GlobalSecondaryIndex{"name-index", firstName, lastName},
  }
}

table := NewUserTable()

Use a fluent style DSL to interact with your table. All DynamoDB data operations are supported

Put Item

q := table.
  PutItem(
    User{"[email protected]","password"},
  ).
  SetConditionExpression(
    table.PartitionKey.NotExists()
  )

result := dynamo.PutItem(q).ReturnAllOld().ExecuteWith(dynamo)
user := &User{}
err := result.Result(user) //Inflate the user object representing the old value.

Get Item

q := table.
  GetItem(
    KeyValue{"[email protected]", "password"},
  ).
  SetConsistentRead(true)

user := &User{}
err = dynamo.GetItem(q, &User{}).ExecuteWith(dynamo).Result(user) //Pass in domain object template object

Update Item

q := table.
  UpdateItem(
    KeyValue{"[email protected]", "password"}
  ).
  SetUpdateExpression(
    table.loginCount.Increment(1),
    table.lastLoginDate.SetField(time.Now().UnixNano(), false),
    table.registrationDate.SetField(time.Now().UnixNano(), true),
    table.vists.RemoveElemIndex(0),
    table.preferences.RemoveKey("update_email"),
  )
err = dynamo.UpdateItem(q).ExecuteWith(dynamo).Error()

Batch Get Item

q := table.
  BatchGetItem(
    KeyValue{"[email protected]", "password"},
    KeyValue{"[email protected]", "password"},
  ).
  SetConsistentRead(true)

  users := []*User{} //Set of return items
  q.ExecuteWith(db).Results(func() interface{} {
    user := User{}
    users = append(users, &user)
    return &user
  })

Fully typesafe condition expression and filter expression support.

expr := Or(
    table.lastNameField.Contains("gattu"),
    Not(table.registrationDate.Contains(12345)),
    And(
      table.visits.Size(lte, 25),
      table.nameField.Size(gte, 25),
    ),
    table.lastLoginDate.LessThanOrEq(time.Now().UnixNano()),
  )
q = table.
  Query(
    table.nameField.Equals("naveen"),
    table.lastNameField.Equals("gattu"),
  ).
  SetFilterExpression(expr)

Atomic Set and List operations

table.
  UpdateItem(
    KeyValue{"[email protected]", "password"}
  ).
  SetUpdateExpression(
    table.visits.AddInteger(time.Now().UnixNano()),
    table.locales.Append("us"),
  )

Streaming Results - Allows for lazy data fetching and consuming

p := table.passwordField.BeginsWith("password")
q := table.
Query(
    table.emailField.Equals("[email protected]"),
    &p,
  ).
  SetLimit(100).
  SetScanForward(true)

channel := make(chan *User)
errChan := q.ExecuteWith(ctx, db).StreamWithChannel(channel)
users := []*User{}

for {
  select {
  case u, ok := <-channel:
    if ok {
      users = append(users, u)
    }
  case err = <-errChan:

  }
}

p := table.passwordField.BeginsWith("password")
q := table.Scan().SetLimit(100).

channel := make(chan *User)
errChan := q.ExecuteWith(db).StreamWithChannel(channel)

for {
  select {
  case u, ok := <-channel:
    if ok {
      fmt.Println(u)
    }
  case err = <-errChan:
  }
}