core/http/jwt/jwks/config.go

package jwks

import (
	"net/http"
	"time"
)

// Options represents the configuration options for a JWKs.
type Config struct {

	// Client is the HTTP client used to get the JWKs via HTTP.
	Client *http.Client

	// RefreshErrorHandler is a function that consumes errors that happen during a JWKs refresh. This is only effectual
	// if RefreshInterval is not nil.
	RefreshErrorHandler ErrorHandler

	// RefreshInterval is the duration to refresh the JWKs in the background via a new HTTP request. If this is not nil,
	// then a background refresh will be requested in a separate goroutine at this interval until the JWKs method
	// EndBackground is called.
	RefreshInterval time.Duration

	// RefreshRateLimit limits the rate at which refresh requests are granted. Only one refresh request can be queued
	// at a time any refresh requests received while there is already a queue are ignored. It does not make sense to
	// have RefreshInterval's value shorter than this.
	RefreshRateLimit time.Duration

	// RefreshTimeout is the duration for the context used to create the HTTP request for a refresh of the JWKs. This
	// defaults to one minute. This is only effectual if RefreshInterval is not nil.
	RefreshTimeout time.Duration

	// RefreshUnknownKID indicates that the JWKs refresh request will occur every time a kid that isn't cached is seen.
	// Without specifying a RefreshInterval a malicious client could self-sign X JWTs, send them to this service,
	// then cause potentially high network usage proportional to X.
	RefreshUnknownKID bool
}

var defaultConfig = Config{
	Client:         http.DefaultClient,
	RefreshTimeout: time.Minute,
}

func applyConfigDefaults(config *Config) {
	if config.Client == nil {
		config.Client = defaultConfig.Client
	}

	if config.RefreshErrorHandler == nil {
		config.RefreshErrorHandler = defaultConfig.RefreshErrorHandler
	}

	if config.RefreshInterval < 0 {
		config.RefreshInterval = defaultConfig.RefreshInterval
	}

	if config.RefreshRateLimit < 0 {
		config.RefreshRateLimit = defaultConfig.RefreshRateLimit
	}

	if config.RefreshTimeout <= 0 {
		config.RefreshTimeout = defaultConfig.RefreshTimeout
	}
}