Skip to content
Kong Summit 2022: Where API Innovation Runs Wild  —Learn More →
Kong Logo | Kong Docs Logo
search
  • We're Hiring!
  • Docs
    • Kong Gateway
    • Konnect Cloud
    • Kong Mesh
    • Plugin Hub
    • decK
    • Kubernetes Ingress Controller
    • Insomnia
    • Kuma

    • Kong Konnect Platform

    • Docs contribution guidelines
  • Plugin Hub
  • Support
  • Community
  • Kong Academy
Request Demo
  • Kong Gateway
  • Konnect Cloud
  • Kong Mesh
  • Plugin Hub
  • decK
  • Kubernetes Ingress Controller
  • Insomnia
  • Kuma

  • Kong Konnect Platform

  • Docs contribution guidelines
  • 2.8.x (latest)
  • 2.7.x
  • 2.6.x
  • Older Enterprise versions (0.31-2.5)
  • Older OSS versions (0.13-2.5)
  • Archive (pre-0.13)
    • Overview of Kong Gateway
    • Version Support Policy
    • Changelog
    • Overview
    • Kubernetes
    • Helm
    • OpenShift with Helm
    • Docker
    • Amazon Linux
    • CentOS
    • macOS
    • Debian
    • RHEL
    • Ubuntu
    • Migrating from OSS to EE
    • Upgrade Kong Gateway
    • Upgrade Kong Gateway OSS
      • Configuring a Service
      • Configuring a gRPC Service
      • Enabling Plugins
      • Adding Consumers
      • Prepare to Administer
      • Expose your Services
      • Protect your Services
      • Improve Performance
      • Secure Services
      • Set Up Intelligent Load Balancing
      • Manage Administrative Teams
      • Publish, Locate, and Consume Services
    • Running Kong as a Non-Root User
    • Resource Sizing Guidelines
      • Deploy Kong Gateway in Hybrid Mode
    • Kubernetes Deployment Options
    • Control Kong Gateway through systemd
    • Performance Testing Framework
    • DNS Considerations
    • Default Ports
      • Access Your License
      • Deploy Your License
      • Monitor License Usage
      • Start Kong Gateway Securely
      • Keyring and Data Encryption
      • Kong Security Update Process
        • Getting Started
        • Advanced Usage
          • Environment Variables
          • AWS Secrets Manager
          • Hashicorp Vault
        • Reference Format
      • Authentication Reference
        • OpenID Connect with Curity
        • OpenID Connect with Azure AD
        • OpenID Connect with Google
        • OpenID Connect with Okta
        • OpenID Connect with Auth0
        • OpenID Connect with Cognito
        • OpenID Connect Plugin Reference
      • Allowing Multiple Authentication Methods
        • Create a Super Admin
        • Configure Networking
        • Configure Kong Manager to Send Email
        • Reset Passwords and RBAC Tokens
        • Configure Workspaces
        • Basic Auth
        • LDAP
        • OIDC
        • Sessions
        • Add a Role
        • Add a User
        • Add an Admin
      • Mapping LDAP Service Directory Groups to Kong Roles
    • Configure gRPC Plugins
    • GraphQL Quickstart
    • Logging Reference
    • Network and Firewall
    • Overview
    • Enable the Dev Portal
    • Structure and File Types
    • Portal API
    • Working with Templates
    • Using the Editor
        • Basic Auth
        • Key Auth
        • OIDC
        • Sessions
        • Adding Custom Registration Fields
      • SMTP
      • Workspaces
      • Manage Developers
      • Developer Roles and Content Permissions
        • Authorization Provider Strategy
        • Enable Application Registration
        • Enable Key Authentication for Application Registration
        • External OAuth2 Support
        • Set up Okta and Kong for external OAuth
        • Set Up Azure AD and Kong for External Authentication
        • Manage Applications
      • Easy Theme Editing
      • Migrating Templates Between Workspaces
      • Markdown Rendering Module
      • Customizing Portal Emails
      • Adding and Using JavaScript Assets
      • Single Page App in Dev Portal
      • Alternate OpenAPI Renderer
    • Helpers CLI
      • Metrics
      • Reports
      • Vitals with InfluxDB
      • Vitals with Prometheus
      • Estimate Vitals Storage in PostgreSQL
    • Prometheus plugin
    • Zipkin plugin
      • DB-less Mode
      • Declarative Configuration
      • Supported Content Types
      • Information Routes
      • Health Routes
      • Tags
      • Service Object
      • Route Object
      • Consumer Object
      • Plugin Object
      • Certificate Object
      • CA Certificate Object
      • SNI Object
      • Upstream Object
      • Target Object
      • Vaults Beta
        • Licenses Reference
        • Licenses Examples
        • Workspaces Reference
        • Workspace Examples
        • RBAC Reference
        • RBAC Examples
        • API Reference
        • Examples
      • Developers
        • API Reference
        • Examples
        • Event Hooks Reference
        • Examples
      • Audit Logging
      • Keyring and Data Encryption
      • Securing the Admin API
    • DB-less and Declarative Configuration
    • Configuration Reference
    • CLI Reference
    • Load Balancing Reference
    • Proxy Reference
    • Rate Limiting Library
    • Health Checks and Circuit Breakers Reference
    • Clustering Reference
      • kong.client
      • kong.client.tls
      • kong.cluster
      • kong.ctx
      • kong.ip
      • kong.log
      • kong.nginx
      • kong.node
      • kong.request
      • kong.response
      • kong.router
      • kong.service
      • kong.service.request
      • kong.service.response
      • kong.table
      • kong.vault
      • Introduction
      • File structure
      • Implementing custom logic
      • Plugin configuration
      • Accessing the datastore
      • Storing custom entities
      • Caching custom entities
      • Extending the Admin API
      • Writing tests
      • (un)Installing your plugin
    • Plugins in Other Languages

github-edit-pageEdit this page

report-issueReport an issue

enterprise-switcher-iconSwitch to OSS

On this page
  • kong.db
  • The DAO Lua API
Kong Gateway
2.8.x (latest)
  • Home
  • Kong Gateway
  • Plugin development

Plugin Development - Accessing the Datastore

Kong interacts with the model layer through classes we refer to as “DAOs”. This chapter will detail the available API to interact with the datastore.

Kong supports two primary datastores: Cassandra and PostgreSQL .

Deprecation warning: Cassandra as a backend database for Kong Gateway is deprecated. This means the feature will eventually be removed.
Our target for Cassandra removal is the Kong Gateway 4.0 release. Starting with the Kong Gateway 3.0 release, some new features might not be supported with Cassandra.

kong.db

All entities in Kong are represented by:

  • A schema that describes which table the entity relates to in the datastore, constraints on its fields such as foreign keys, non-null constraints etc. This schema is a table described in the plugin configuration chapter.
  • An instance of the DAO class mapping to the database currently in use. This class’ methods consume the schema and expose methods to insert, update, select and delete entities of that type.

The core entities in Kong are: Services, Routes, Consumers and Plugins. All of them are accessible as Data Access Objects (DAOs), through the kong.db global singleton:

-- Core DAOs
local services  = kong.db.services
local routes    = kong.db.routes
local consumers = kong.db.consumers
local plugins   = kong.db.plugins

Both core entities from Kong and custom entities from plugins are available through kong.db.*.

The DAO Lua API

The DAO class is responsible for the operations executed on a given table in the datastore, generally mapping to an entity in Kong. All the underlying supported databases (currently Cassandra and Postgres) comply to the same interface, thus making the DAO compatible with all of them.

For example, inserting a Service and a Plugin is as easy as:

local inserted_service, err = kong.db.services:insert({
  name = "mockbin",
  url  = "http://mockbin.org",
})

local inserted_plugin, err = kong.db.plugins:insert({
  name    = "key-auth",
  service = inserted_service,
})

For a real-life example of the DAO being used in a plugin, see the Key-Auth plugin source code.


Next: Storing Custom Entities ›

Thank you for your feedback.
Was this page useful?
  • Kong
    THE CLOUD CONNECTIVITY COMPANY

    Kong powers reliable digital connections across APIs, hybrid and multi-cloud environments.

    • Company
    • Customers
    • Events
    • Investors
    • Careers Hiring!
    • Partners
    • Press
    • Contact
  • Products
    • Kong Konnect
    • Kong Gateway
    • Kong Mesh
    • Get Started
    • Pricing
  • Resources
    • eBooks
    • Webinars
    • Briefs
    • Blog
    • API Gateway
    • Microservices
  • Open Source
    • Install Kong Gateway
    • Kong Community
    • Kubernetes Ingress
    • Kuma
    • Insomnia
  • Solutions
    • Decentralize
    • Secure & Govern
    • Create a Dev Platform
    • API Gateway
    • Kubernetes
    • Service Mesh
Star
  • Terms•Privacy
© Kong Inc. 2022