dynamodb

Documentation

Overview

Package dynamodb contains an implementation of the `gokv.Store` interface for Amazon DynamoDB.

Index

• Variables
• type Client
  • func NewClient(options Options) (Client, error)
  • func (c Client) Close() error
  • func (c Client) Delete(k string) error
  • func (c Client) Get(k string, v interface{}) (found bool, err error)
  • func (c Client) Set(k string, v interface{}) error
• type Options

Variables

var DefaultOptions = Options{
	TableName:            "gokv",
	ReadCapacityUnits:    5,
	WriteCapacityUnits:   5,
	WaitForTableCreation: aws.Bool(true),
	Codec:                encoding.JSON,
}

DefaultOptions is an Options object with default values. Region: "" (use shared config file or environment variable), TableName: "gokv", AWSaccessKeyID: "" (use shared credentials file or environment variable), AWSsecretAccessKey: "" (use shared credentials file or environment variable), CustomEndpoint: "", Codec: encoding.JSON

Types

type Client

type Client struct {
	// contains filtered or unexported fields
}

Client is a gokv.Store implementation for DynamoDB.

func NewClient

func NewClient(options Options) (Client, error)

NewClient creates a new DynamoDB client.

Credentials can be set in the options, but it's recommended to either use the shared credentials file (Linux: "~/.aws/credentials", Windows: "%UserProfile%\.aws\credentials") or environment variables (AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY). See https://github.com/awsdocs/aws-go-developer-guide/blob/0ae5712d120d43867cf81de875cb7505f62f2d71/doc_source/configuring-sdk.rst#specifying-credentials.

func (Client) Close

func (c Client) Close() error

Close closes the client. In the DynamoDB implementation this doesn't have any effect.

func (Client) Delete

func (c Client) Delete(k string) error

Delete deletes the stored value for the given key. Deleting a non-existing key-value pair does NOT lead to an error. The key must not be "".

func (Client) Get

func (c Client) Get(k string, v interface{}) (found bool, err error)

Get retrieves the stored value for the given key. You need to pass a pointer to the value, so in case of a struct the automatic unmarshalling can populate the fields of the object that v points to with the values of the retrieved object's values. If no value is found it returns (false, nil). The key must not be "" and the pointer must not be nil.

func (Client) Set

func (c Client) Set(k string, v interface{}) error

Set stores the given value for the given key. Values are automatically marshalled to JSON or gob (depending on the configuration). The key must not be "" and the value must not be nil.

type Options

type Options struct {
	// Region of the DynamoDB service you want to use.
	// Valid values: https://docs.aws.amazon.com/general/latest/gr/rande.html#ddb_region.
	// E.g. "us-west-2".
	// Optional (read from shared config file or environment variable if not set).
	// Environment variable: "AWS_REGION".
	Region string
	// Name of the DynamoDB table.
	// Optional ("gokv" by default).
	TableName string
	// ReadCapacityUnits of the table.
	// Only required when the table doesn't exist yet and is created by gokv.
	// Optional (5 by default, which is the same default value as when creating a table in the web console)
	// 25 RCUs are included in the free tier (across all tables).
	// For example calculations, see https://github.com/awsdocs/amazon-dynamodb-developer-guide/blob/c420420a59040c5b3dd44a6e59f7c9e55fc922ef/doc_source/HowItWorks.ProvisionedThroughput.
	// For limits, see https://github.com/awsdocs/amazon-dynamodb-developer-guide/blob/c420420a59040c5b3dd44a6e59f7c9e55fc922ef/doc_source/Limits.md#capacity-units-and-provisioned-throughput.md#provisioned-throughput.
	ReadCapacityUnits int64
	// ReadCapacityUnits of the table.
	// Only required when the table doesn't exist yet and is created by gokv.
	// Optional (5 by default, which is the same default value as when creating a table in the web console)
	// 25 RCUs are included in the free tier (across all tables).
	// For example calculations, see https://github.com/awsdocs/amazon-dynamodb-developer-guide/blob/c420420a59040c5b3dd44a6e59f7c9e55fc922ef/doc_source/HowItWorks.ProvisionedThroughput.
	// For limits, see https://github.com/awsdocs/amazon-dynamodb-developer-guide/blob/c420420a59040c5b3dd44a6e59f7c9e55fc922ef/doc_source/Limits.md#capacity-units-and-provisioned-throughput.md#provisioned-throughput.
	WriteCapacityUnits int64
	// If the table doesn't exist yet, gokv creates it.
	// If WaitForTableCreation is true, gokv will block until the table is created, with a timeout of 15 seconds.
	// If the table still doesn't exist after 15 seconds, an error is returned.
	// If WaitForTableCreation is false, gokv returns the client immediately.
	// In the latter case you need to make sure that you don't read from or write to the table before it's created,
	// because otherwise you will get ResourceNotFoundException errors.
	// Optional (true by default).
	WaitForTableCreation *bool
	// AWS access key ID (part of the credentials).
	// Optional (read from shared credentials file or environment variable if not set).
	// Environment variable: "AWS_ACCESS_KEY_ID".
	AWSaccessKeyID string
	// AWS secret access key (part of the credentials).
	// Optional (read from shared credentials file or environment variable if not set).
	// Environment variable: "AWS_SECRET_ACCESS_KEY".
	AWSsecretAccessKey string
	// CustomEndpoint allows you to set a custom DynamoDB service endpoint.
	// This is especially useful if you're running a "DynamoDB local" Docker container for local testing.
	// Typical value for the Docker container: "http://localhost:8000".
	// See https://hub.docker.com/r/amazon/dynamodb-local/.
	// Optional ("" by default)
	CustomEndpoint string
	// Encoding format.
	// Optional (encoding.JSON by default).
	Codec encoding.Codec
}

Options are the options for the DynamoDB client.