feat(authn): add templatized error page

ref CNOUS/mse#3907

internal/proxy/director/layer/authn/oidc/layer.go

@@ -14,5 +14,5 @@ func NewLayer(store sessions.Store, funcs ...OptionFunc) *authn.Layer {
 		httpTransport:     opts.HTTPTransport,
 		httpClientTimeout: opts.HTTPClientTimeout,
 		store:             store,
-	})
+	}, opts.AuthnOptions...)
 }

internal/proxy/director/layer/authn/oidc/options.go

@@ -3,11 +3,14 @@ package oidc
 import (
 	"net/http"
 	"time"
+
+	"forge.cadoles.com/cadoles/bouncer/internal/proxy/director/layer/authn"
 )
 
 type Options struct {
 	HTTPTransport     *http.Transport
 	HTTPClientTimeout time.Duration
+	AuthnOptions      []authn.OptionFunc
 }
 
 type OptionFunc func(opts *Options)
@@ -24,10 +27,17 @@ func WithHTTPClientTimeout(timeout time.Duration) OptionFunc {
 	}
 }
 
+func WithAuthnOptions(funcs ...authn.OptionFunc) OptionFunc {
+	return func(opts *Options) {
+		opts.AuthnOptions = funcs
+	}
+}
+
 func NewOptions(funcs ...OptionFunc) *Options {
 	opts := &Options{
 		HTTPTransport:     http.DefaultTransport.(*http.Transport),
 		HTTPClientTimeout: 30 * time.Second,
+		AuthnOptions:      make([]authn.OptionFunc, 0),
 	}
 
 	for _, fn := range funcs {