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openid-connect
Apache APISIX
API Gateway
OpenID Connect
OIDC
OpenID Connect allows the client to obtain user information from the identity providers, such as Keycloak, Ory Hydra, Okta, Auth0, etc. API Gateway APISIX supports to integrate with the above identity providers to protect your APIs.

Description

OpenID Connect (OIDC) is an authentication protocol based on the OAuth 2.0. It allows the client to obtain user information from the identity provider (IdP), e.g., Keycloak, Ory Hydra, Okta, Auth0, etc. API Gateway Apache APISIX supports to integrate with the above identity providers to protect your APIs.

Attributes

Name Type Required Default Valid values Description
client_id string True OAuth client ID.
client_secret string True OAuth client secret.
discovery string True Discovery endpoint URL of the identity server.
scope string False "openid" OIDC scope that corresponds to information that should be returned about the authenticated user, also known as claims. The default value is openid, the required scope for OIDC to return a sub claim that uniquely identifies the authenticated user. Additional scopes can be appended and delimited by spaces, such as openid email profile.
required_scopes string[] False Array of strings. Used in conjunction with the introspection endpoint (when bearer_only is true). If present, the plugin will check if the token contains all required scopes. If not, 403 will be returned with an error message
realm string False "apisix" Realm used for authentication.
bearer_only boolean False false When set to true, APISIX will only check if the authorization header in the request matches a bearer token.
logout_path string False "/logout" Path for logging out.
post_logout_redirect_uri string False URL to redirect to after logging out. If the OIDC discovery endpoint does not provide an end_session_endpoint, the plugin internally redirects using the redirect_after_logout_uri. Otherwise, it redirects using the post_logout_redirect_uri.
redirect_uri string False URI to which the identity provider redirects back to. If not configured, APISIX will append the .apisix/redirect suffix to determine the default redirect_uri. Note that the provider should be properly configured to allow such redirect_uri values.
timeout integer False 3 [1,...] Request timeout time in seconds.
ssl_verify boolean False false When set to true, verifies the identity provider's SSL certificates.
introspection_endpoint string False URL of the token verification endpoint of the identity server.
introspection_endpoint_auth_method string False "client_secret_basic" Authentication method name for token introspection.
token_endpoint_auth_method string False Authentication method name for token endpoint. The default will get the first supported method specified by the OP.
public_key string False Public key to verify the token.
use_jwks boolean False false When set to true, uses the JWKS endpoint of the identity server to verify the token.
use_pkce boolean False false when set to true, the "Proof Key for Code Exchange" as defined in RFC 7636 will be used.
token_signing_alg_values_expected string False Algorithm used for signing the authentication token.
set_access_token_header boolean False true When set to true, sets the access token in a request header. By default, the X-Access-Token header is used.
access_token_in_authorization_header boolean False false When set to true and set_access_token_header is also true, sets the access token in the Authorization header.
set_id_token_header boolean False true When set to true and the ID token is available, sets the ID token in the X-ID-Token request header.
set_userinfo_header boolean False true When set to true and the UserInfo object is available, sets it in the X-Userinfo request header.
set_refresh_token_header boolean False false When set to true and a refresh token object is available, sets it in the X-Refresh-Token request header.
session object False When bearer_only is set to false, openid-connect will use Authorization Code flow to authenticate on the IDP, so you need to set the session-related configuration.
session.secret string True Automatic generation 16 or more characters The key used for session encrypt and HMAC operation.
session.cookie object False
session.cookie.lifetime integer False 3600 Cookie lifetime in seconds.
unauth_action string False "auth" ["auth","deny","pass"] Specify the response type on unauthenticated requests. "auth" redirects to identity provider, "deny" results in a 401 response, "pass" will allow the request without authentication.
proxy_opts object False HTTP proxy that the OpenID provider is behind.
proxy_opts.http_proxy string False http://proxy-server:port HTTP proxy server address.
proxy_opts.https_proxy string False http://proxy-server:port HTTPS proxy server address.
proxy_opts.http_proxy_authorization string False Basic [base64 username:password] Default Proxy-Authorization header value to be used with http_proxy. Can be overridden with custom Proxy-Authorization request header.
proxy_opts.https_proxy_authorization string False Basic [base64 username:password] Default Proxy-Authorization header value to be used with https_proxy. Cannot be overridden with custom Proxy-Authorization request header since with with HTTPS the authorization is completed when connecting.
proxy_opts.no_proxy string False Comma separated list of hosts that should not be proxied.
authorization_params object False Additional parameters to send in the request to the authorization endpoint.
client_rsa_private_key string False Client RSA private key used to sign JWT.
client_rsa_private_key_id string False Client RSA private key ID used to compute a signed JWT.
client_jwt_assertion_expires_in integer False 60 Life duration of the signed JWT in seconds.
renew_access_token_on_expiry boolean False true If true, attempt to silently renew the access token when it expires or if a refresh token is available. If the token fails to renew, redirect user for re-authentication.
access_token_expires_in integer False Lifetime of the access token in seconds if no expires_in attribute is present in the token endpoint response.
refresh_session_interval integer False Time interval to refresh user ID token without requiring re-authentication. When not set, it will not check the expiration time of the session issued to the client by the gateway. If set to 900, it means refreshing the user's id_token (or session in the browser) after 900 seconds without requiring re-authentication.
iat_slack integer False 120 Tolerance of clock skew in seconds with the iat claim in an ID token.
accept_none_alg boolean False false Set to true if the OpenID provider does not sign its ID token, such as when the signature algorithm is set to none.
accept_unsupported_alg boolean False true If true, ignore ID token signature to accept unsupported signature algorithm.
access_token_expires_leeway integer False 0 Expiration leeway in seconds for access token renewal. When set to a value greater than 0, token renewal will take place the set amount of time before token expiration. This avoids errors in case the access token just expires when arriving to the resource server.
force_reauthorize boolean False false If true, execute the authorization flow even when a token has been cached.
use_nonce boolean False false If true, enable nonce parameter in authorization request.
revoke_tokens_on_logout boolean False false If true, notify the authorization server a previously obtained refresh or access token is no longer needed at the revocation endpoint.
jwk_expires_in integer False 86400 Expiration time for JWK cache in seconds.
jwt_verification_cache_ignore boolean False false If true, force re-verification for a bearer token and ignore any existing cached verification results.
cache_segment string False Optional name of a cache segment, used to separate and differentiate caches used by token introspection or JWT verification.
introspection_interval integer False 0 TTL of the cached and introspected access token in seconds.
introspection_expiry_claim string False Name of the expiry claim, which controls the TTL of the cached and introspected access token. The default value is 0, which means this option is not used and the plugin defaults to use the TTL passed by expiry claim defined in introspection_expiry_claim. If introspection_interval is larger than 0 and less than the TTL passed by expiry claim defined in introspection_expiry_claim, use introspection_interval.
introspection_addon_headers string[] False Array of strings. Used to append additional header values to the introspection HTTP request. If the specified header does not exist in origin request, value will not be appended.

NOTE: encrypt_fields = {"client_secret"} is also defined in the schema, which means that the field will be stored encrypted in etcd. See encrypted storage fields.

Scenarios

:::tip

Tutorial: Use Keycloak with API Gateway to secure APIs

:::

This plugin offers two scenarios:

  1. Authentication between Services: Set bearer_only to true and configure the introspection_endpoint or public_key attribute. In this scenario, APISIX will reject requests without a token or invalid token in the request header.

  2. Authentication between Browser and Identity Providers: Set bearer_only to false. After successful authentication, this plugin can obtain and manage the token in the cookie, and subsequent requests will use the token. In this mode, the user session will be stored in the browser as a cookie and this data is encrypted, so you have to set a key for encryption via session.secret.

Token introspection

Token introspection validates a request by verifying the token with an OAuth 2.0 authorization server.

You should first create a trusted client in the identity server and generate a valid JWT token for introspection.

The image below shows an example token introspection flow via a Gateway:

token introspection

The example below shows how you can enable the Plugin on Route. The Route below will protect the Upstream by introspecting the token provided in the request header:

:::note You can fetch the admin_key from config.yaml and save to an environment variable with the following command:

admin_key=$(yq '.deployment.admin.admin_key[0].key' conf/config.yaml | sed 's/"//g')

:::

curl http://127.0.0.1:9180/apisix/admin/routes/5 -H "X-API-KEY: $admin_key" -X PUT -d '
{
  "uri": "/get",
  "plugins":{
    "openid-connect":{
      "client_id": "${CLIENT_ID}",
      "client_secret": "${CLIENT_SECRET}",
      "discovery": "${DISCOVERY_ENDPOINT}",
      "introspection_endpoint": "${INTROSPECTION_ENDPOINT}",
      "bearer_only": true,
      "realm": "master",
      "introspection_endpoint_auth_method": "client_secret_basic"
    }
  },
  "upstream":{
    "type": "roundrobin",
    "nodes":{
      "httpbin.org:443":1
    }
  }
}'

Now, to access the Route:

curl -i -X GET http://127.0.0.1:9080/get -H "Host: httpbin.org" -H "Authorization: Bearer {JWT_TOKEN}"

In this example, the Plugin enforces that the access token and the Userinfo object be set in the request headers.

When the OAuth 2.0 authorization server returns an expire time with the token, it is cached in APISIX until expiry. For more details, read:

  1. lua-resty-openidc's documentation and source code.
  2. exp field in the RFC's Introspection Response section.

Introspecting with public key

You can also provide the public key of the JWT token for verification. If you have provided a public key and a token introspection endpoint, the public key workflow will be executed instead of verification through an identity server. This is useful if you want to reduce network calls and speedup the process.

The example below shows how you can add public key introspection to a Route:

curl http://127.0.0.1:9180/apisix/admin/routes/5 -H "X-API-KEY: $admin_key" -X PUT -d '
{
  "uri": "/get",
  "plugins":{
    "openid-connect":{
      "client_id": "${CLIENT_ID}",
      "client_secret": "${CLIENT_SECRET}",
      "discovery": "${DISCOVERY_ENDPOINT}",
      "bearer_only": true,
      "realm": "master",
      "token_signing_alg_values_expected": "RS256",
      "public_key": "-----BEGIN PUBLIC KEY-----
      {public_key}
      -----END PUBLIC KEY-----"
    }
  },
  "upstream":{
    "type": "roundrobin",
    "nodes":{
      "httpbin.org:443":1
    }
  }
}'

In this example, the Plugin can only enforce that the access token should be set in the request headers.

Authentication through OIDC Relying Party flow

When an incoming request does not contain an access token in its header nor in an appropriate session cookie, the Plugin can act as an OIDC Relying Party and redirect to the authorization endpoint of the identity provider to go through the OIDC authorization code flow.

Once the user has authenticated with the identity provider, the Plugin will obtain and manage the access token and further interaction with the identity provider. The access token will be stored in a session cookie.

The example below adds the Plugin with this mode of operation to the Route:

curl http://127.0.0.1:9180/apisix/admin/routes/5 -H "X-API-KEY: $admin_key" -X PUT -d '
{
  "uri": "/get",
  "plugins": {
    "openid-connect": {
      "client_id": "${CLIENT_ID}",
      "client_secret": "${CLIENT_SECRET}",
      "discovery": "${DISCOVERY_ENDPOINT}",
      "bearer_only": false,
      "realm": "master"
    }
  },
  "upstream": {
    "type": "roundrobin",
    "nodes": {
      "httpbin.org:443": 1
    }
  }
}'

In this example, the Plugin can enforce that the access token, the ID token, and the UserInfo object to be set in the request headers.

Troubleshooting

This section covers a few commonly seen issues when working with this plugin to help you troubleshoot.

APISIX Cannot Connect to OpenID provider

If APISIX fails to resolve or cannot connect to the OpenID provider, double check the DNS settings in your configuration file config.yaml and modify as needed.

No Session State Found

If you encounter a 500 internal server error with the following message in the log when working with authorization code flow, there could be a number of reasons.

the error request to the redirect_uri path, but there's no session state found

1. Misconfigured Redirection URI

A common misconfiguration is to configure the redirect_uri the same as the URI of the route. When a user initiates a request to visit the protected resource, the request directly hits the redirection URI with no session cookie in the request, which leads to the no session state found error.

To properly configure the redirection URI, make sure that the redirect_uri matches the route where the plugin is configured, without being fully identical. For instance, a correct configuration would be to configure uri of the route to /api/v1/* and the path portion of the redirect_uri to /api/v1/redirect.

You should also ensure that the redirect_uri include the scheme, such as http or https.

2. Missing Session Secret

If you deploy APISIX in the standalone mode, make sure that session.secret is configured.

User sessions are stored in browser as cookies and encrypted with session secret. The secret is automatically generated and saved to etcd if no secret is configured through the session.secret attribute. However, in standalone mode, etcd is no longer the configuration center. Therefore, you should explicitly configure session.secret for this plugin in the YAML configuration center apisix.yaml.

3. Cookie Not Sent or Absent

Check if the SameSite cookie attribute is properly set (i.e. if your application needs to send the cookie cross sites) to see if this could be a factor that prevents the cookie being saved to the browser's cookie jar or being sent from the browser.

4. Upstream Sent Too Big Header

If you have NGINX sitting in front of APISIX to proxy client traffic, see if you observe the following error in NGINX's error.log:

upstream sent too big header while reading response header from upstream

If so, try adjusting proxy_buffers, proxy_buffer_size, and proxy_busy_buffers_size to larger values.

5. Invalid Client Secret

Verify if client_secret is valid and correct. An invalid client_secret would lead to an authentication failure and no token shall be returned and stored in session.