control plane: add request id to all error pages (#2149)

* controlplane: add request id to all error pages

- use a single http error handler for both envoy and go control plane
- add http lib style status text for our custom statuses.

Signed-off-by: Bobby DeSimone <bobbydesimone@gmail.com>

internal/httputil/errors.go

@@ -3,9 +3,9 @@ package httputil
 import (
 	"html/template"
 	"net/http"
+	"net/url"
 
 	"github.com/pomerium/pomerium/internal/frontend"
-	"github.com/pomerium/pomerium/internal/log"
 	"github.com/pomerium/pomerium/internal/telemetry/requestid"
 )
 
@@ -15,8 +15,12 @@ var errorTemplate = template.Must(frontend.NewTemplates())
 type HTTPError struct {
 	// HTTP status codes as registered with IANA.
 	Status int
-	// Err is the wrapped error
+	// Err is the wrapped error.
 	Err error
+	// DebugURL is the URL to the debug endpoint.
+	DebugURL *url.URL
+	// The request ID.
+	RequestID string
 }
 
 // NewError returns an error that contains a HTTP status and error.
@@ -36,32 +40,35 @@ func (e *HTTPError) Unwrap() error { return e.Err }
 // It does not otherwise end the request; the caller should ensure no further
 // writes are done to w.
 func (e *HTTPError) ErrorResponse(w http.ResponseWriter, r *http.Request) {
-	// indicate to clients that the error originates from Pomerium, not the app
-	w.Header().Set(HeaderPomeriumResponse, "true")
-	w.WriteHeader(e.Status)
-
-	log.FromRequest(r).Info().Err(e).Msg("httputil: ErrorResponse")
-	requestID := requestid.FromContext(r.Context())
-
+	reqID := e.RequestID
+	if e.RequestID == "" {
+		// if empty, try to grab from the request id from the request context
+		reqID = requestid.FromContext(r.Context())
+	}
 	response := struct {
 		Status     int
 		Error      string
-		StatusText string `json:"-"`
-		RequestID  string `json:",omitempty"`
-		CanDebug   bool   `json:"-"`
-		Version    string `json:"-"`
+		StatusText string   `json:"-"`
+		RequestID  string   `json:",omitempty"`
+		CanDebug   bool     `json:"-"`
+		Version    string   `json:"-"`
+		DebugURL   *url.URL `json:",omitempty"`
 	}{
 		Status:     e.Status,
 		StatusText: http.StatusText(e.Status),
 		Error:      e.Error(),
-		RequestID:  requestID,
-		CanDebug:   e.Status/100 == 4,
+		RequestID:  reqID,
+		CanDebug:   e.Status/100 == 4 && (e.DebugURL != nil || reqID != ""),
+		DebugURL:   e.DebugURL,
 	}
+	// indicate to clients that the error originates from Pomerium, not the app
+	w.Header().Set(HeaderPomeriumResponse, "true")
 
 	if r.Header.Get("Accept") == "application/json" {
 		RenderJSON(w, e.Status, response)
 		return
 	}
 	w.Header().Set("Content-Type", "text/html; charset=UTF-8")
+	w.WriteHeader(e.Status)
 	errorTemplate.ExecuteTemplate(w, "error.html", response)
 }