[bugfix] internal server error on search not found (#1590)

* add error value wrapping, include status code / not found flags from transport errors, update error usages

Signed-off-by: kim <grufwub@gmail.com>

* add code commenting for gtserror functions

Signed-off-by: kim <grufwub@gmail.com>

---------

Signed-off-by: kim <grufwub@gmail.com>

internal/federation/authenticate.go

@@ -25,6 +25,7 @@
 	"encoding/pem"
 	"errors"
 	"fmt"
+	"net/http"
 	"net/url"
 	"strings"
 
@@ -226,7 +227,7 @@ func (f *federator) AuthenticateFederatedRequest(ctx context.Context, requestedU
 		// The actual http call to the remote server is made right here in the Dereference function.
 		b, err := trans.Dereference(ctx, requestingPublicKeyID)
 		if err != nil {
-			if errors.Is(err, transport.ErrGone) {
+			if gtserror.StatusCode(err) == http.StatusGone {
 				// if we get a 410 error it means the account that owns this public key has been deleted;
 				// we should add a tombstone to our database so that we can avoid trying to deref it in future
 				if err := f.HandleGone(ctx, requestingPublicKeyID); err != nil {

internal/federation/dereferencing/error.go

@@ -19,10 +19,10 @@
 package dereferencing
 
 import (
-	"errors"
 	"fmt"
+	"net/http"
 
-	"github.com/superseriousbusiness/gotosocial/internal/transport"
+	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
 )
 
 // ErrDB denotes that a proper error has occurred when doing
@@ -96,22 +96,21 @@ func newErrOther(err error) error {
 }
 
 func wrapDerefError(derefErr error, fluff string) error {
-	var (
-		err          error
-		errWrongType *ErrWrongType
-	)
-
+	// Wrap with fluff.
+	err := derefErr
 	if fluff != "" {
 		err = fmt.Errorf("%s: %w", fluff, derefErr)
 	}
 
-	switch {
-	case errors.Is(derefErr, transport.ErrGone):
-		err = NewErrNotRetrievable(err)
-	case errors.As(derefErr, &errWrongType):
-		err = newErrWrongType(err)
-	default:
-		err = newErrTransportError(err)
+	// Check for unretrievable HTTP status code errors.
+	if code := gtserror.StatusCode(derefErr); // nocollapse
+	code == http.StatusGone || code == http.StatusNotFound {
+		return NewErrNotRetrievable(err)
+	}
+
+	// Check for other untrievable errors.
+	if gtserror.NotFound(derefErr) {
+		return NewErrNotRetrievable(err)
 	}
 
 	return err

internal/federation/federatingprotocol.go

@@ -31,6 +31,7 @@
 	"github.com/superseriousbusiness/activity/streams/vocab"
 	"github.com/superseriousbusiness/gotosocial/internal/ap"
 	"github.com/superseriousbusiness/gotosocial/internal/db"
+	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
 	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
 	"github.com/superseriousbusiness/gotosocial/internal/log"
 	"github.com/superseriousbusiness/gotosocial/internal/transport"
@@ -210,7 +211,7 @@ func (f *federator) AuthenticatePostInbox(ctx context.Context, w http.ResponseWr
 		transport.WithFastfail(ctx), username, publicKeyOwnerURI, false,
 	)
 	if err != nil {
-		if errors.Is(err, transport.ErrGone) {
+		if gtserror.StatusCode(err) == http.StatusGone {
 			// This is the same case as the http.StatusGone check above.
 			// It can happen here and not there because there's a race
 			// where the sending server starts sending account deletion

internal/gtserror/error.go

@@ -0,0 +1,60 @@
+/*
+   GoToSocial
+   Copyright (C) 2021-2023 GoToSocial Authors admin@gotosocial.org
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU Affero General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU Affero General Public License for more details.
+
+   You should have received a copy of the GNU Affero General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+package gtserror
+
+import (
+	"codeberg.org/gruf/go-errors/v2"
+)
+
+// package private error key type.
+type errkey int
+
+const (
+	// error value keys.
+	_ errkey = iota
+	statusCodeKey
+	notFoundKey
+)
+
+// StatusCode checks error for a stored status code value. For example
+// an error from an outgoing HTTP request may be stored, or an API handler
+// expected response status code may be stored.
+func StatusCode(err error) int {
+	i, _ := errors.Value(err, statusCodeKey).(int)
+	return i
+}
+
+// WithStatusCode will wrap the given error to store provided status code,
+// returning wrapped error. See StatusCode() for example use-cases.
+func WithStatusCode(err error, code int) error {
+	return errors.WithValue(err, statusCodeKey, code)
+}
+
+// NotFound checks error for a stored "not found" flag. For example
+// an error from an outgoing HTTP request due to DNS lookup.
+func NotFound(err error) bool {
+	_, ok := errors.Value(err, notFoundKey).(struct{})
+	return ok
+}
+
+// SetNotFound will wrap the given error to store a "not found" flag,
+// returning wrapped error. See NotFound() for example use-cases.
+func SetNotFound(err error) error {
+	return errors.WithValue(err, notFoundKey, struct{}{})
+}

internal/transport/deliver.go

@@ -29,6 +29,7 @@
 	"codeberg.org/gruf/go-byteutil"
 	apiutil "github.com/superseriousbusiness/gotosocial/internal/api/util"
 	"github.com/superseriousbusiness/gotosocial/internal/config"
+	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
 )
 
 func (t *transport) BatchDeliver(ctx context.Context, b []byte, recipients []*url.URL) error {
@@ -96,7 +97,8 @@ func (t *transport) Deliver(ctx context.Context, b []byte, to *url.URL) error {
 
 	if code := resp.StatusCode; code != http.StatusOK &&
 		code != http.StatusCreated && code != http.StatusAccepted {
-		return fmt.Errorf("POST request to %s failed: %s", urlStr, resp.Status)
+		err := fmt.Errorf("POST request to %s failed: %s", urlStr, resp.Status)
+		return gtserror.WithStatusCode(err, resp.StatusCode)
 	}
 
 	return nil

internal/transport/dereference.go

@@ -20,7 +20,6 @@
 
 import (
 	"context"
-	"errors"
 	"fmt"
 	"io"
 	"net/http"
@@ -28,15 +27,10 @@
 
 	apiutil "github.com/superseriousbusiness/gotosocial/internal/api/util"
 	"github.com/superseriousbusiness/gotosocial/internal/config"
+	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
 	"github.com/superseriousbusiness/gotosocial/internal/uris"
 )
 
-// ErrGone is returned from Dereference when the remote resource returns 410 GONE.
-// This is useful in cases where we're processing a delete of a resource that's already
-// been removed from the remote server, so we know we don't need to keep trying to
-// dereference it.
-var ErrGone = errors.New("remote resource returned HTTP code 410 GONE")
-
 func (t *transport) Dereference(ctx context.Context, iri *url.URL) ([]byte, error) {
 	// if the request is to us, we can shortcut for certain URIs rather than going through
 	// the normal request flow, thereby saving time and energy
@@ -72,12 +66,10 @@ func (t *transport) Dereference(ctx context.Context, iri *url.URL) ([]byte, erro
 	}
 	defer rsp.Body.Close()
 
-	switch rsp.StatusCode {
-	case http.StatusOK:
-		return io.ReadAll(rsp.Body)
-	case http.StatusGone:
-		return nil, ErrGone
-	default:
-		return nil, fmt.Errorf("GET request to %s failed: %s", iriStr, rsp.Status)
+	if rsp.StatusCode != http.StatusOK {
+		err := fmt.Errorf("GET request to %s failed: %s", iriStr, rsp.Status)
+		return nil, gtserror.WithStatusCode(err, rsp.StatusCode)
 	}
+
+	return io.ReadAll(rsp.Body)
 }

internal/transport/derefinstance.go

@@ -30,6 +30,7 @@
 
 	apimodel "github.com/superseriousbusiness/gotosocial/internal/api/model"
 	apiutil "github.com/superseriousbusiness/gotosocial/internal/api/util"
+	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
 	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
 	"github.com/superseriousbusiness/gotosocial/internal/id"
 	"github.com/superseriousbusiness/gotosocial/internal/log"
@@ -102,7 +103,8 @@ func dereferenceByAPIV1Instance(ctx context.Context, t *transport, iri *url.URL)
 	defer resp.Body.Close()
 
 	if resp.StatusCode != http.StatusOK {
-		return nil, fmt.Errorf("GET request to %s failed: %s", iriStr, resp.Status)
+		err := fmt.Errorf("GET request to %s failed: %s", iriStr, resp.Status)
+		return nil, gtserror.WithStatusCode(err, resp.StatusCode)
 	}
 
 	b, err := io.ReadAll(resp.Body)
@@ -252,7 +254,8 @@ func callNodeInfoWellKnown(ctx context.Context, t *transport, iri *url.URL) (*ur
 	defer resp.Body.Close()
 
 	if resp.StatusCode != http.StatusOK {
-		return nil, fmt.Errorf("callNodeInfoWellKnown: GET request to %s failed: %s", iriStr, resp.Status)
+		err := fmt.Errorf("GET request to %s failed: %s", iriStr, resp.Status)
+		return nil, gtserror.WithStatusCode(err, resp.StatusCode)
 	}
 
 	b, err := io.ReadAll(resp.Body)
@@ -303,7 +306,8 @@ func callNodeInfo(ctx context.Context, t *transport, iri *url.URL) (*apimodel.No
 	defer resp.Body.Close()
 
 	if resp.StatusCode != http.StatusOK {
-		return nil, fmt.Errorf("callNodeInfo: GET request to %s failed: %s", iriStr, resp.Status)
+		err := fmt.Errorf("GET request to %s failed: %s", iriStr, resp.Status)
+		return nil, gtserror.WithStatusCode(err, resp.StatusCode)
 	}
 
 	b, err := io.ReadAll(resp.Body)

internal/transport/derefmedia.go

@@ -24,6 +24,8 @@
 	"io"
 	"net/http"
 	"net/url"
+
+	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
 )
 
 func (t *transport) DereferenceMedia(ctx context.Context, iri *url.URL) (io.ReadCloser, int64, error) {
@@ -46,7 +48,8 @@ func (t *transport) DereferenceMedia(ctx context.Context, iri *url.URL) (io.Read
 
 	// Check for an expected status code
 	if rsp.StatusCode != http.StatusOK {
-		return nil, 0, fmt.Errorf("GET request to %s failed: %s", iriStr, rsp.Status)
+		err := fmt.Errorf("GET request to %s failed: %s", iriStr, rsp.Status)
+		return nil, 0, gtserror.WithStatusCode(err, rsp.StatusCode)
 	}
 
 	return rsp.Body, rsp.ContentLength, nil

internal/transport/transport.go

@@ -25,6 +25,7 @@
 	"errors"
 	"fmt"
 	"io"
+	"net"
 	"net/http"
 	"net/url"
 	"strconv"
@@ -36,6 +37,7 @@
 	errorsv2 "codeberg.org/gruf/go-errors/v2"
 	"codeberg.org/gruf/go-kv"
 	"github.com/go-fed/httpsig"
+	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
 	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
 	"github.com/superseriousbusiness/gotosocial/internal/httpclient"
 	"github.com/superseriousbusiness/gotosocial/internal/log"
@@ -56,6 +58,7 @@ type Transport interface {
 
 	// Deliver sends an ActivityStreams object.
 	Deliver(ctx context.Context, b []byte, to *url.URL) error
+
 	// BatchDeliver sends an ActivityStreams object to multiple recipients.
 	BatchDeliver(ctx context.Context, b []byte, recipients []*url.URL) error
 
@@ -65,10 +68,13 @@ type Transport interface {
 
 	// Dereference fetches the ActivityStreams object located at this IRI with a GET request.
 	Dereference(ctx context.Context, iri *url.URL) ([]byte, error)
+
 	// DereferenceMedia fetches the given media attachment IRI, returning the reader and filesize.
 	DereferenceMedia(ctx context.Context, iri *url.URL) (io.ReadCloser, int64, error)
+
 	// DereferenceInstance dereferences remote instance information, first by checking /api/v1/instance, and then by checking /.well-known/nodeinfo.
 	DereferenceInstance(ctx context.Context, iri *url.URL) (*gtsmodel.Instance, error)
+
 	// Finger performs a webfinger request with the given username and domain, and returns the bytes from the response body.
 	Finger(ctx context.Context, targetUsername string, targetDomain string) ([]byte, error)
 }
@@ -207,6 +213,10 @@ func (t *transport) do(r *http.Request, signer func(*http.Request) error) (*http
 		} else if errors.As(err, &x509.UnknownAuthorityError{}) {
 			// Unknown authority errors we do NOT recover from
 			return nil, err
+		} else if dnserr := (*net.DNSError)(nil); // nocollapse
+		errors.As(err, &dnserr) && dnserr.IsNotFound {
+			// DNS lookup failure, this domain does not exist
+			return nil, gtserror.SetNotFound(err)
 		}
 
 		if fastFail {
@@ -219,7 +229,7 @@ func (t *transport) do(r *http.Request, signer func(*http.Request) error) (*http
 			backoff = time.Duration(i) * baseBackoff
 		}
 
-		l.Errorf("backing off for %s after http request error: %v", backoff.String(), err)
+		l.Errorf("backing off for %s after http request error: %v", backoff, err)
 
 		select {
 		// Request ctx cancelled
@@ -228,7 +238,6 @@ func (t *transport) do(r *http.Request, signer func(*http.Request) error) (*http
 
 		// Backoff for some time
 		case <-time.After(backoff):
-			backoff *= 2
 		}
 	}