OpenID Connect SDK (client and server) for Go

What Is It

This project is an easy-to-use client (RP) and server (OP) implementation for the OIDC (OpenID Connect) standard written for Go.

The RP is certified for the basic and config profile.

Whenever possible we tried to reuse / extend existing packages like OAuth2 for Go.

[!NOTE] We currently have limited availability for feature reviews: https://github.com/zitadel/oidc/discussions/785

Basic Overview

The most important packages of the library:

<pre> /pkg /client clients using the OP for retrieving, exchanging and verifying tokens /rp definition and implementation of an OIDC Relying Party (client) /rs definition and implementation of an OAuth Resource Server (API) /op definition and implementation of an OIDC OpenID Provider (server) /oidc definitions shared by clients and server /example /client/api example of an api / resource server implementation using token introspection /client/app web app / RP demonstrating authorization code flow using various authentication methods (code, PKCE, JWT profile) /client/github example of the extended OAuth2 library, providing an HTTP client with a reuse token source /client/service demonstration of JWT Profile Authorization Grant /server examples of an OpenID Provider implementations (including dynamic) with some very basic login UI </pre>

Semver

This package uses semver for releases. Major releases ship breaking changes. Starting with the v2 to v3 increment we provide an upgrade guide to ease migration to a newer version.

How To Use It

Check the /example folder where example code for different scenarios is located.

# start oidc op server
# oidc discovery http://localhost:9998/.well-known/openid-configuration
go run github.com/zitadel/oidc/v3/example/server
# start oidc web client (in a new terminal)
CLIENT_ID=web CLIENT_SECRET=secret ISSUER=http://localhost:9998/ SCOPES="openid profile" PORT=9999 go run github.com/zitadel/oidc/v3/example/client/app

open http://localhost:9999/login in your browser
you will be redirected to op server and the login UI
login with user test-user@localhost and password verysecure
the OP will redirect you to the client app, which displays the user info

for the dynamic issuer, just start it with:

go run github.com/zitadel/oidc/v3/example/server/dynamic

the oidc web client above will still work, but if you add oidc.local (pointing to 127.0.0.1) in your hosts file you can also start it with:

CLIENT_ID=web CLIENT_SECRET=secret ISSUER=http://oidc.local:9998/ SCOPES="openid profile" PORT=9999 go run github.com/zitadel/oidc/v3/example/client/app

Note: Usernames are suffixed with the hostname (test-user@localhost or test-user@oidc.local)

Build Tags

The library uses build tags to enable or disable features. The following build tags are available:

| Build Tag | Description | |-----------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | no_otel | Disables the OTel instrumentation, which is enabled by default. This is useful if you do not want to use OTel or if you want to use a different instrumentation library. |

Server configuration

Example server allows extra configuration using environment variables and could be used for end to end testing of your services.

| Name | Format | Description | | ------------ | -------------------------------- | ------------------------------------- | | PORT | Number between 1 and 65535 | OIDC listen port | | REDIRECT_URI | Comma-separated URIs | List of allowed redirect URIs | | USERS_FILE | Path to json in local filesystem | Users with their data and credentials |

Here is json equivalent for one of the default users

{
  "id2": {
    "ID": "id2",
    "Username": "test-user2",
    "Password": "verysecure",
    "FirstName": "Test",
    "LastName": "User2",
    "Email": "test-user2@zitadel.ch",
    "EmailVerified": true,
    "Phone": "",
    "PhoneVerified": false,
    "PreferredLanguage": "DE",
    "IsAdmin": false
  }
}

Features

| | Relying party | OpenID Provider | Specification | | -------------------- | ------------- | --------------- | -------------------------------------------- | | Code Flow | yes | yes | OpenID Connect Core 1.0, Section 3.1 | | Implicit Flow | no[^1] | yes | OpenID Connect Core 1.0, Section 3.2 | | Hybrid Flow | no | not yet | OpenID Connect Core 1.0, Section 3.3 | | Client Credentials | yes | yes | OpenID Connect Core 1.0, Section 9 | | Refresh Token | yes | yes | OpenID Connect Core 1.0, Section 12 | | Discovery | yes | yes | OpenID Connect Discovery 1.0 | | JWT Profile | yes | yes | RFC 7523 | | PKCE | yes | yes | RFC 7636 | | Token Exchange | yes | yes | RFC 8693 | | Device Authorization | yes | yes | RFC 8628 | | mTLS | not yet | not yet | RFC 8705 | | Back-Channel Logout | not yet | yes | OpenID Connect Back-Channel Logout 1.0 |

Contributors

Made with contrib.rocks.

Resources

For your convenience you can find the relevant guides linked below.

Supported Go Versions

For security reasons, we only support and recommend the use of one of the latest two Go versions (:white_check_mark:). Versions that also build are marked with :warning:.

| Version | Supported | | ------- | ------------------ | | <1.25 | :x: | | 1.25 | :white_check_mark: | | 1.26 | :white_check_mark: |

Why another library

As of 2020 there are not a lot of OIDC library's in Go which can handle server and client implementations. ZITADEL is strongly committed to the general field of IAM (Identity and Access Management) and as such, we need solid frameworks to implement services.

Oidc

Install / Use

README