Specification: Ballerina OAuth2 Library

Owners: @ldclakmal @shafreenAnfar
Reviewers: @shafreenAnfar
Created: 2021/10/01
Updated: 2022/02/17
Edition: Swan Lake

Introduction

This is the specification for the OAuth2 standard library of Ballerina language, which is used for authorization of listeners and clients (HTTP, gRPC, GraphQL, WebSocket, WebSub, etc.).

The OAuth2 library specification has evolved and may continue to evolve in the future. The released versions of the specification can be found under the relevant GitHub tag.

If you have any feedback or suggestions about the library, start a discussion via a GitHub issue or in the Slack channel. Based on the outcome of the discussion, the specification and implementation can be updated. Community feedback is always welcome. Any accepted proposal, which affects the specification is stored under /docs/proposals. Proposals under discussion can be found with the label type/proposal in GitHub.

The conforming implementation of the specification is released and included in the distribution. Any deviation from the specification is considered a bug.

Contents

  1. Overview
  2. OAuth2
  3. Listener Auth
  4. Client Auth
  5. Samples

1. Overview

This specification elaborates on OAuth2 authorization for all the Ballerina listeners and clients. The HTTP, gRPC, GraphQL, WebSocket, WebSub protocol-based listeners and clients are secured according to this specification.

This has a number of design principles:

  • Listener auth: This refers to the authentication and authorization of the listener as defined in Ballerina 2021R1 Section 5.7.4. The inbound requests/messages independent of the transport protocol are authenticated and authorized according to the configured authentication protocol and related configurations.
  • Client auth: This refers to the authentication of the client as defined in Ballerina 2021R1 Section 7.9. The outbound requests/messages independent of the transport protocol are enriched according to the configured authentication protocol and related configurations.
  • Auth provider: This is the entity that is responsible for providing all the auth protocol-related implementations.
  • Auth handler: This is the entity that is responsible for handling the security of the API based on the transport protocol and with the use of provider APIs. This API gets the credentials and required configurations as user inputs and returns the authentication protocol-related information. Internally, these APIs call the provider APIs of the relevant authentication protocol.
  • Declarative approach: This is also known as the configuration-driven approach, which is used for simple use cases, where users have to provide a set of configurations and do not need to be worried more about how authentication and authorization works.
  • Imperative approach: This is also known as the code-driven approach, which is used for advanced use cases, where users need to be worried more about how authentication and authorization work and need to have further customizations.

2. OAuth2

OAuth2 protocol defines the credential as an access token which is defined in RFC6749 Section 1.4.

3. Listener Auth

This refers to the authentication and authorization of the listener as defined in Ballerina 2021R1 Section 5.7.4. The inbound requests/messages independent of the transport protocol are authenticated and authorized according to the configured authentication protocol and related configurations.

3.1. OAuth2 Provider

The OAuth2 Provider has an API to authorize the OAuth2 credential. The IntrospectionConfig record is used to provide the configuration related to the introspection server which is being called at the time of credential validation. This returns the IntrospectionResponse which consists of all the available information of the introspection server response.

3.2. OAuth2 Handler

NOTE: Since the auth handlers are tightly bound with the transport protocol, for the explanation of the concept, all the samples are created for HTTP transport protocol hereinafter.

The OAuth2 Handler has an API to authorize the HTTP request, headers of the HTTP request, or the credential as defined in RFC6750 Section 2.1. This API is also used to authorize the user against the expected scope or scopes. The OAuth2IntrospectionConfig record is used to provide the configuration related to the introspection server which is being called at the time of credential validation along with the scopeKey which defines the claim used for scopes. This returns the IntrospectionResponse which consists of all the available information of the introspection server response or Unauthorized in case of authentication failure or Forbidden in case of authorization failure.

3.3. Declarative Approach

This is also known as the configuration-driven approach, which is used for simple use cases, where users have to provide a set of configurations and do not need to be worried more about how authentication and authorization works. The user does not have full control over the configuration-driven approach.

The service and/or resource configurations are used to define the authentication and authorization configurations. Users can configure the configurations needed for different authentication schemes and configurations needed for authorizations of each authentication scheme. Also, the configurations can be provided at both the service and resource levels. The priority will be given from bottom to top. Then, the auth handler creation and request authentication/authorization is handled internally without user intervention. The requests that succeeded both authentication and/or authorization phases according to the configurations will be passed to the business logic layer.

3.4. Imperative Approach

This is also known as the code-driven approach, which is used for advanced use cases, where users need to be worried more about how authentication and authorization work and need to have further customizations. The user has full control of the code-driven approach. The handler creation and authentication/authorization calls are made by the user at the business logic layer.

4. Client Auth

This refers to the authentication of the client as defined in Ballerina 2021R1 Section 7.9. The outbound requests/messages independent of the transport protocol are enriched according to the configured authentication protocol and related configurations.

4.1. OAuth2 Provider

The OAuth2 Provider has an API to generate the OAuth2 credential. The ClientCredentialsGrantConfig, PasswordGrantConfig, RefreshTokenGrantConfig, or JwtBearerGrantConfig records are used to provide the configuration related to the OAuth2 grant type used for access token generation. This returns the generated access token.

4.2. OAuth2 Handler

NOTE: Since the auth handlers are tightly bound with the transport protocol, for the explanation of the concept, all the samples are created for HTTP transport protocol hereinafter.

4.2.1. Bearer Token

The Bearer Token Auth Handler has an API to enrich the HTTP request as defined in RFC6750 Section 2.1. The BearerTokenConfig record is used to provide the configuration related to the access token. This returns the enriched Request with headers or Error in case of failure.

4.2.2. Grant Types

The OAuth2 Handler has an API to enrich the HTTP request as defined in RFC6750 Section 2.1. The OAuth2ClientCredentialsGrantConfig, OAuth2PasswordGrantConfig, OAuth2RefreshTokenGrantConfig, or OAuth2JwtBearerGrantConfig records are used to provide the configuration related to the OAuth2 grant type used for access token generation. This returns the enriched Request with headers or Error in case of failure.

4.3. Declarative Approach

This is also known as a configuration-driven approach, which is used for simple use cases, where users have to provide a set of configurations and do not need to be worried more about how authentication works. The user does not have full control over the configuration-driven approach.

The client configurations are used to define the authentication configurations. Users can configure the configurations needed for different authentication schemes. Then, the auth handler creation and request enrichment is handled internally without user intervention.

4.4. Imperative Approach

This is also known as the code-driven approach, which is used for advanced use cases, where users need to be worried more about how authentication works and need to have further customizations. The user has full control of the code-driven approach. The handler creation and request enrichment calls are made by the user at the business logic layer.

5. Samples

5.1. Listener Auth

5.1.1. Declarative Approach (HTTP Listener)

5.1.2. Imperative Approach (HTTP Listener)

5.2. Client Auth

5.2.1. Declarative Approach (HTTP Client)

5.2.1.1. Bearer Token
5.2.1.2. Grant Types

5.2.2. Imperative Approach (HTTP Client)

5.2.2.1. Bearer Token
5.2.2.2. Grant Types