SPIRE OIDC Discovery Provider

The SPIRE OIDC Discovery Provider is a small helper that provides a minimal implementation of a subset of the OIDC discovery document as related to exposing a JSON Web Key Set (JWKS) for JSON Web Token (JWT) validation.

It provides the following endpoints:

Verb	Path	Description
GET	/.well-known/openid-configuration	Returns the OIDC discovery document
GET	/keys	Returns the JWKS for JWT validation
GET	/ready	Returns http.OK (200) as soon as requests can be served. (disabled by default)
GET	/live	Returns http.OK (200) as soon as a keyset is available, otherwise http.InternalServerError (500). (disabled by default)

The provider by default relies on ACME to obtain TLS certificates that it uses to serve the documents securely.

Configuration

Command Line Configuration

The provider has the following command line flags:

Flag	Description	Default
-config	Path on disk to the HCL Configuration file	oidc-discovery-provider.conf

HCL Configuration

The configuration file is required by the provider. It contains HCL encoded configurables.

Key	Type	Required?	Description	Default
acme	section	required[1]	Provides the ACME configuration.
serving_cert_file	section	required[1][4]	Provides the serving certificate configuration.
allow_insecure_scheme	string	optional[3]	Serves OIDC configuration response with HTTP url.	false
domains	strings	required	One or more domains the provider is being served from.
experimental	section	optional	The experimental options that are subject to change or removal.
insecure_addr	string	optional[3]	Exposes the service on http.
set_key_use	bool	optional	If true, the use parameter on JWKs will be set to sig.	false
listen_socket_path	string	required[1][3]	Path on disk to listen with a Unix Domain Socket. Unix platforms only.
log_format	string	optional	Format of the logs (either "TEXT" or "JSON")	""
log_level	string	required	Log level (one of "error","warn","info","debug")	"info"
log_path	string	optional	Path on disk to write the log.
log_requests	bool	optional	If true, all HTTP requests are logged at the debug level	false
server_api	section	required[2]	Provides SPIRE Server API details.
workload_api	section	required[2]	Provides Workload API details.
health_checks	section	optional	Enable and configure health check endpoints

experimental	Type	Required?	Description	Default
listen_named_pipe_name	string	required[1][3]	Pipe name to listen with a named pipe. Windows only.

Considerations for Unix platforms

[1]: One of acme, serving_cert_file or listen_socket_path must be defined.

[3]: The allow_insecure_scheme should only be used in a local development environment for testing purposes. It only works in conjunction with insecure_addr or listen_socket_path.

Considerations for Windows platforms

[1]: One of acme, serving_cert_file or listen_named_pipe_name must be defined.

[3]: The allow_insecure_scheme should only be used in a local development environment for testing purposes. It only works in conjunction with insecure_addr or listen_named_pipe_name.

Considerations for all platforms

[2]: One of server_api or workload_api must be defined. The provider relies on one of these two APIs to obtain the public key material used to construct the JWKS document.

The domains configurable contains the list of domains the provider is expected to be served from. If a request is received from a domain other than one in the list (as determined by the Host or X-Forwarded-Host header), it will be rejected. Likewise, when ACME is used, the domains list contains the allowed domains for which certificates will be obtained. The TLS handshake will terminate if another domain is requested.

[4]: SPIRE OIDC Discovery provider monitors and reloads the files provided in the serving_cert_file configuration at runtime.

ACME Section

Key	Type	Required?	Description	Default
cache_dir	string	optional	The directory used to cache the ACME-obtained credentials. Disabled if explicitly set to the empty string	"./.acme-cache"
directory_url	string	optional	The ACME directory URL to use. Uses Let's Encrypt if unset.	"https://acme-v01.api.letsencrypt.org/directory"
email	string	required	The email address used to register with the ACME service
tos_accepted	bool	required	Indicates explicit acceptance of the ACME service Terms of Service. Must be true.

Serving Certificate Section

Key	Type	Required?	Description	Default
cert_file_path	string	required	The certificate file path, the file must contain PEM encoded data.
key_file_path	string	required	The private key file path, the file must contain PEM encoded data.
file_sync_interval	duration	optional	Controls how frequently the service polls the files for changes.	1 minute
addr	string	optional	Exposes the service on the given address.	:443

Server API Section

Key	Type	Required?	Description	Default
address	string	required	SPIRE Server API gRPC target address. Only the unix name system is supported. See https://github.com/grpc/grpc/blob/master/doc/naming.md. Unix platforms only.
experimental	section	optional	The experimental options that are subject to change or removal.
poll_interval	duration	optional	How often to poll for changes to the public key material.	"10s"

experimental	Type	Required?	Description	Default
named_pipe_name	string	required	Pipe name of the SPIRE Server API named pipe. Windows only.

Workload API Section

Key	Type	Required?	Description	Default
experimental	section	optional	The experimental options that are subject to change or removal.
socket_path	string	required	Path on disk to the Workload API Unix Domain socket. Unix platforms only.
poll_interval	duration	optional	How often to poll for changes to the public key material.	"10s"
trust_domain	string	required	Trust domain of the workload. This is used to pick the bundle out of the Workload API response.

experimental	Description	Default
named_pipe_name	Pipe name of the Workload API named pipe. Windows only.

Health Checks Section

Health checks are enabled by adding health_checks {} to the configuration. The health checks endpoints are hosted on a dedicated listener on localhost.

• The "ready" state is determined by the availability of keys fetched via the workload/server API. If the keys where fetched successfully but can't be fetched anymore (e.g. workload or server API can't be reached), the server is still determined ready for the threshold interval.
• The "live" state is either determined by the availability of keys fetched via the workload/server API or the threshold interval after the server started serving requests. If the keys where fetched successfully but can't be fetched anymore (e.g. workload/server API can't be reached), the server is still determined live for the threshold interval.

The threshold interval is currently set to 5 times the workload/server APIs poll interval, but at least 3 minutes. Both states respond with a 200 OK status code for success or 500 Internal Server Error for failure.

Key	Type	Required?	Description	Default
bind_port	string	optional	override default listener bind port	"8008"
ready_path	string	optional	override default ready path	"/ready"
live_path	string	optional	override default live path	"/live"

Examples (Unix platforms)

Server API and ACME

log_level = "debug"
domains = ["mypublicdomain.test"]
acme {
    cache_dir = "/some/path/on/disk/to/cache/creds"
    email = "email@domain.test"
    tos_accepted = true
}
server_api {
    address = "unix:///tmp/spire-server/private/api.sock"
}

Workload API and ACME

log_level = "debug"
domains = ["mypublicdomain.test"]
acme {
    cache_dir = "/some/path/on/disk/to/cache/creds"
    email = "email@domain.test"
    tos_accepted = true
}
workload_api {
    socket_path = "/tmp/spire-agent/public/api.sock"
    trust_domain = "domain.test"
}

Server API and Serving Certificate

log_level = "debug"
domains = ["mypublicdomain.test"]
serving_cert_file {
 cert_file_path = "/some/path/on/disk/to/cert.pem"
 key_file_path = "/some/path/on/disk/to/key.pem"
}
server_api {
    address = "unix:///tmp/spire-server/private/api.sock"
}

Workload API and Serving Certificate

log_level = "debug"
domains = ["mypublicdomain.test"]
serving_cert_file {
 cert_file_path = "/some/path/on/disk/to/cert.pem"
 key_file_path = "/some/path/on/disk/to/key.pem"
}
workload_api {
    socket_path = "/tmp/spire-agent/public/api.sock"
    trust_domain = "domain.test"
}

Listening on a Unix Socket

The following configuration has the OIDC Discovery Provider listen for requests on the given socket. This can be used in conjunction with a webserver like Nginx, Apache, or Envoy which supports reverse proxying to a unix socket.

log_level = "debug"
domains = ["mypublicdomain.test"]
listen_socket_path = "/run/oidc-discovery-provider/server.sock"

workload_api {
    socket_path = "/tmp/spire-agent/private/api.sock"
    trust_domain = "domain.test"
}

A minimal Nginx configuration that proxies all traffic to the OIDC Discovery Provider's socket might look like this.

daemon off;
 events {}
 http {
   access_log /dev/stdout;
   upstream oidc {
     server unix:/run/oidc-discovery-provider/server.sock;
   }
   server {
     # ... Any TLS and listening config you may need
     location / {
       proxy_pass http://oidc;
     }
   }
 }

Examples (Windows)

Server API and ACME

log_level = "debug"
domains = ["mypublicdomain.test"]
acme {
    cache_dir = "c:\\some\\path\\on\\disk\\to\\cache\\creds"
    email = "email@domain.test"
    tos_accepted = true
}
server_api {
    experimental {
        named_pipe_name = "\\spire-server\\private\\api"
    }
}

Workload API and ACME

log_level = "debug"
domains = ["mypublicdomain.test"]
acme {
    cache_dir = "c:\\some\\path\\on\\disk\\to\\cache\\creds"
    email = "email@domain.test"
    tos_accepted = true
}
workload_api {
    experimental {
        named_pipe_name = "\\spire-agent\\public\\api"
    }
    trust_domain = "domain.test"
}

Server API and Serving Certificate

log_level = "debug"
domains = ["mypublicdomain.test"]
serving_cert_file {
    cert_file_path = "c:\\some\\path\\on\\disk\\to\\cert.pem"
    key_file_path = "c:\\some\\path\\on\\disk\\to\\key.pem"
}
server_api {
    experimental {
        named_pipe_name = "\\spire-server\\private\\api"
    }
}

Workload API and Serving Certificate

log_level = "debug"
domains = ["mypublicdomain.test"]
serving_cert_file {
 cert_file_path = "c:\\some\\path\\on\\disk\\to\\cert.pem"
 key_file_path = "c:\\some\\path\\on\\disk\\to\\key.pem"
}
workload_api {
    experimental {
        named_pipe_name = "\\spire-agent\\public\\api"
    }
    trust_domain = "domain.test"
}

Listening on a Named Pipe

The following configuration has the OIDC Discovery Provider listen for requests on the given named pipe. This can be used in conjunction with a webserver that supports reverse proxying to a named pipe.

log_level = "debug"
domains = ["mypublicdomain.test"]
experimental {
    listen_named_pipe_name = "oidc-discovery-provider"
}

workload_api {
    experimental {
        named_pipe_name = "\\spire-agent\\public\\api"
    }
    trust_domain = "domain.test"
}