[feature/performance] Fail fast when doing remote transport calls inside incoming request contexts (#1119)

* [feature/performance] Fail fast when doing remote transport calls inside incoming request contexts

* [chore] Reduce outgoing request timeout to 15s

* log error messages when fastfailing

* use context.Value() instead of wrapped context, wrap error with fastfail instead of extra log entry

* add fast-fail context key test

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

internal/federation/authenticate.go

@@ -216,7 +216,7 @@ func (f *federator) AuthenticateFederatedRequest(ctx context.Context, requestedU
 		}
 
 		log.Tracef("proceeding with dereference for uncached public key %s", requestingPublicKeyID)
-		trans, err := f.transportController.NewTransportForUsername(ctx, requestedUsername)
+		trans, err := f.transportController.NewTransportForUsername(transport.WithFastfail(ctx), requestedUsername)
 		if err != nil {
 			errWithCode := gtserror.NewErrorInternalError(fmt.Errorf("error creating transport for %s: %s", requestedUsername, err))
 			log.Debug(errWithCode)

internal/federation/dereferencing/account.go

@@ -87,6 +87,11 @@ type GetRemoteAccountParams struct {
 //
 // If a local account is passed into this function for whatever reason (hey, it happens!), then it
 // will be returned from the database without making any remote calls.
+//
+// Even if a fastfail context is used, and something goes wrong, an account might still be returned instead
+// of an error, if we already had the account in our database (in other words, if we just needed to try
+// fingering/refreshing the account again). The rationale for this is that it's more useful to be able
+// to provide *something* to the caller, even if that something is not necessarily 100% up to date.
 func (d *deref) GetRemoteAccount(ctx context.Context, params GetRemoteAccountParams) (foundAccount *gtsmodel.Account, err error) {
 	/*
 		In this function we want to retrieve a gtsmodel representation of a remote account, with its proper

internal/federation/federatingprotocol.go

@@ -34,6 +34,7 @@ import (
 	"github.com/superseriousbusiness/gotosocial/internal/federation/dereferencing"
 	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
 	"github.com/superseriousbusiness/gotosocial/internal/log"
+	"github.com/superseriousbusiness/gotosocial/internal/transport"
 	"github.com/superseriousbusiness/gotosocial/internal/uris"
 	"github.com/superseriousbusiness/gotosocial/internal/util"
 )
@@ -191,7 +192,7 @@ func (f *federator) AuthenticatePostInbox(ctx context.Context, w http.ResponseWr
 		}
 
 		// we don't have an entry for this instance yet so dereference it
-		i, err = f.GetRemoteInstance(ctx, username, &url.URL{
+		i, err = f.GetRemoteInstance(transport.WithFastfail(ctx), username, &url.URL{
 			Scheme: publicKeyOwnerURI.Scheme,
 			Host:   publicKeyOwnerURI.Host,
 		})
@@ -205,7 +206,7 @@ func (f *federator) AuthenticatePostInbox(ctx context.Context, w http.ResponseWr
 		}
 	}
 
-	requestingAccount, err := f.GetRemoteAccount(ctx, dereferencing.GetRemoteAccountParams{
+	requestingAccount, err := f.GetRemoteAccount(transport.WithFastfail(ctx), dereferencing.GetRemoteAccountParams{
 		RequestingUsername: username,
 		RemoteAccountID:    publicKeyOwnerURI,
 	})

internal/httpclient/client.go

@@ -95,7 +95,7 @@ func New(cfg Config) *Client {
 	var c Client
 
 	d := &net.Dialer{
-		Timeout:   30 * time.Second,
+		Timeout:   15 * time.Second,
 		KeepAlive: 30 * time.Second,
 		Resolver:  &net.Resolver{},
 	}

internal/processing/account/get.go

@@ -29,6 +29,7 @@ import (
 	"github.com/superseriousbusiness/gotosocial/internal/federation/dereferencing"
 	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
 	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
+	"github.com/superseriousbusiness/gotosocial/internal/transport"
 )
 
 func (p *processor) Get(ctx context.Context, requestingAccount *gtsmodel.Account, targetAccountID string) (*apimodel.Account, gtserror.WithCode) {
@@ -93,7 +94,7 @@ func (p *processor) getAccountFor(ctx context.Context, requestingAccount *gtsmod
 			return nil, gtserror.NewErrorInternalError(fmt.Errorf("error parsing url %s: %s", targetAccount.URI, err))
 		}
 
-		a, err := p.federator.GetRemoteAccount(ctx, dereferencing.GetRemoteAccountParams{
+		a, err := p.federator.GetRemoteAccount(transport.WithFastfail(ctx), dereferencing.GetRemoteAccountParams{
 			RequestingUsername:    requestingAccount.Username,
 			RemoteAccountID:       targetAccountURI,
 			RemoteAccountHost:     targetAccount.Domain,

internal/processing/federation/getfollowers.go

@@ -26,6 +26,7 @@ import (
 	"github.com/superseriousbusiness/activity/streams"
 	"github.com/superseriousbusiness/gotosocial/internal/federation/dereferencing"
 	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
+	"github.com/superseriousbusiness/gotosocial/internal/transport"
 )
 
 func (p *processor) GetFollowers(ctx context.Context, requestedUsername string, requestURL *url.URL) (interface{}, gtserror.WithCode) {
@@ -41,7 +42,7 @@ func (p *processor) GetFollowers(ctx context.Context, requestedUsername string,
 		return nil, errWithCode
 	}
 
-	requestingAccount, err := p.federator.GetRemoteAccount(ctx, dereferencing.GetRemoteAccountParams{
+	requestingAccount, err := p.federator.GetRemoteAccount(transport.WithFastfail(ctx), dereferencing.GetRemoteAccountParams{
 		RequestingUsername: requestedUsername,
 		RemoteAccountID:    requestingAccountURI,
 	})

internal/processing/federation/getfollowing.go

@@ -26,6 +26,7 @@ import (
 	"github.com/superseriousbusiness/activity/streams"
 	"github.com/superseriousbusiness/gotosocial/internal/federation/dereferencing"
 	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
+	"github.com/superseriousbusiness/gotosocial/internal/transport"
 )
 
 func (p *processor) GetFollowing(ctx context.Context, requestedUsername string, requestURL *url.URL) (interface{}, gtserror.WithCode) {
@@ -41,7 +42,7 @@ func (p *processor) GetFollowing(ctx context.Context, requestedUsername string,
 		return nil, errWithCode
 	}
 
-	requestingAccount, err := p.federator.GetRemoteAccount(ctx, dereferencing.GetRemoteAccountParams{
+	requestingAccount, err := p.federator.GetRemoteAccount(transport.WithFastfail(ctx), dereferencing.GetRemoteAccountParams{
 		RequestingUsername: requestedUsername,
 		RemoteAccountID:    requestingAccountURI,
 	})

internal/processing/federation/getoutbox.go

@@ -27,6 +27,7 @@ import (
 	"github.com/superseriousbusiness/gotosocial/internal/db"
 	"github.com/superseriousbusiness/gotosocial/internal/federation/dereferencing"
 	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
+	"github.com/superseriousbusiness/gotosocial/internal/transport"
 )
 
 func (p *processor) GetOutbox(ctx context.Context, requestedUsername string, page bool, maxID string, minID string, requestURL *url.URL) (interface{}, gtserror.WithCode) {
@@ -42,7 +43,7 @@ func (p *processor) GetOutbox(ctx context.Context, requestedUsername string, pag
 		return nil, errWithCode
 	}
 
-	requestingAccount, err := p.federator.GetRemoteAccount(ctx, dereferencing.GetRemoteAccountParams{
+	requestingAccount, err := p.federator.GetRemoteAccount(transport.WithFastfail(ctx), dereferencing.GetRemoteAccountParams{
 		RequestingUsername: requestedUsername,
 		RemoteAccountID:    requestingAccountURI,
 	})

internal/processing/federation/getstatus.go

@@ -26,6 +26,7 @@ import (
 	"github.com/superseriousbusiness/activity/streams"
 	"github.com/superseriousbusiness/gotosocial/internal/federation/dereferencing"
 	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
+	"github.com/superseriousbusiness/gotosocial/internal/transport"
 )
 
 func (p *processor) GetStatus(ctx context.Context, requestedUsername string, requestedStatusID string, requestURL *url.URL) (interface{}, gtserror.WithCode) {
@@ -41,7 +42,7 @@ func (p *processor) GetStatus(ctx context.Context, requestedUsername string, req
 		return nil, errWithCode
 	}
 
-	requestingAccount, err := p.federator.GetRemoteAccount(ctx, dereferencing.GetRemoteAccountParams{
+	requestingAccount, err := p.federator.GetRemoteAccount(transport.WithFastfail(ctx), dereferencing.GetRemoteAccountParams{
 		RequestingUsername: requestedUsername,
 		RemoteAccountID:    requestingAccountURI,
 	})

internal/processing/federation/getstatusreplies.go

@@ -28,6 +28,7 @@ import (
 	"github.com/superseriousbusiness/gotosocial/internal/federation/dereferencing"
 	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
 	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
+	"github.com/superseriousbusiness/gotosocial/internal/transport"
 )
 
 func (p *processor) GetStatusReplies(ctx context.Context, requestedUsername string, requestedStatusID string, page bool, onlyOtherAccounts bool, minID string, requestURL *url.URL) (interface{}, gtserror.WithCode) {
@@ -43,7 +44,7 @@ func (p *processor) GetStatusReplies(ctx context.Context, requestedUsername stri
 		return nil, errWithCode
 	}
 
-	requestingAccount, err := p.federator.GetRemoteAccount(ctx, dereferencing.GetRemoteAccountParams{
+	requestingAccount, err := p.federator.GetRemoteAccount(transport.WithFastfail(ctx), dereferencing.GetRemoteAccountParams{
 		RequestingUsername: requestedUsername,
 		RemoteAccountID:    requestingAccountURI,
 	})

internal/processing/federation/getuser.go

@@ -27,6 +27,7 @@ import (
 	"github.com/superseriousbusiness/activity/streams/vocab"
 	"github.com/superseriousbusiness/gotosocial/internal/federation/dereferencing"
 	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
+	"github.com/superseriousbusiness/gotosocial/internal/transport"
 	"github.com/superseriousbusiness/gotosocial/internal/uris"
 )
 
@@ -53,7 +54,7 @@ func (p *processor) GetUser(ctx context.Context, requestedUsername string, reque
 
 		// if we're not already handshaking/dereferencing a remote account, dereference it now
 		if !p.federator.Handshaking(ctx, requestedUsername, requestingAccountURI) {
-			requestingAccount, err := p.federator.GetRemoteAccount(ctx, dereferencing.GetRemoteAccountParams{
+			requestingAccount, err := p.federator.GetRemoteAccount(transport.WithFastfail(ctx), dereferencing.GetRemoteAccountParams{
 				RequestingUsername: requestedUsername,
 				RemoteAccountID:    requestingAccountURI,
 			})

internal/processing/media/getfile.go

@@ -31,6 +31,7 @@ import (
 	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
 	"github.com/superseriousbusiness/gotosocial/internal/log"
 	"github.com/superseriousbusiness/gotosocial/internal/media"
+	"github.com/superseriousbusiness/gotosocial/internal/transport"
 	"github.com/superseriousbusiness/gotosocial/internal/uris"
 )
 
@@ -141,11 +142,11 @@ func (p *processor) getAttachmentContent(ctx context.Context, requestingAccount
 		// large version and derive a thumbnail from it, so use the normal recaching procedure: fetch the media,
 		// process it, then return the thumbnail data
 		data = func(innerCtx context.Context) (io.ReadCloser, int64, error) {
-			transport, err := p.transportController.NewTransportForUsername(innerCtx, requestingUsername)
+			t, err := p.transportController.NewTransportForUsername(innerCtx, requestingUsername)
 			if err != nil {
 				return nil, 0, err
 			}
-			return transport.DereferenceMedia(innerCtx, remoteMediaIRI)
+			return t.DereferenceMedia(transport.WithFastfail(innerCtx), remoteMediaIRI)
 		}
 	} else {
 		// if it's the full-sized version being requested, we can cheat a bit by streaming data to the user as
@@ -172,12 +173,12 @@ func (p *processor) getAttachmentContent(ctx context.Context, requestingAccount
 		attachmentContent.Content = io.NopCloser(bufferedReader)
 
 		data = func(innerCtx context.Context) (io.ReadCloser, int64, error) {
-			transport, err := p.transportController.NewTransportForUsername(innerCtx, requestingUsername)
+			t, err := p.transportController.NewTransportForUsername(innerCtx, requestingUsername)
 			if err != nil {
 				return nil, 0, err
 			}
 
-			readCloser, fileSize, err := transport.DereferenceMedia(innerCtx, remoteMediaIRI)
+			readCloser, fileSize, err := t.DereferenceMedia(transport.WithFastfail(innerCtx), remoteMediaIRI)
 			if err != nil {
 				return nil, 0, err
 			}

internal/processing/search.go

@@ -34,6 +34,7 @@ import (
 	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
 	"github.com/superseriousbusiness/gotosocial/internal/log"
 	"github.com/superseriousbusiness/gotosocial/internal/oauth"
+	"github.com/superseriousbusiness/gotosocial/internal/transport"
 	"github.com/superseriousbusiness/gotosocial/internal/util"
 )
 
@@ -161,13 +162,13 @@ func (p *processor) searchStatusByURI(ctx context.Context, authed *oauth.Auth, u
 
 	if resolve {
 		// This is a non-local status and we're allowed to resolve, so dereference it
-		status, statusable, err := p.federator.GetRemoteStatus(ctx, authed.Account.Username, uri, true, true)
+		status, statusable, err := p.federator.GetRemoteStatus(transport.WithFastfail(ctx), authed.Account.Username, uri, true, true)
 		if err != nil {
 			return nil, fmt.Errorf("searchStatusByURI: error fetching remote status %q: %v", uriStr, err)
 		}
 
 		// Attempt to dereference the status thread while we are here
-		p.federator.DereferenceRemoteThread(ctx, authed.Account.Username, uri, status, statusable)
+		p.federator.DereferenceRemoteThread(transport.WithFastfail(ctx), authed.Account.Username, uri, status, statusable)
 	}
 
 	return nil, nil
@@ -190,7 +191,7 @@ func (p *processor) searchAccountByURI(ctx context.Context, authed *oauth.Auth,
 	}
 
 	// we don't have it yet, try to find it remotely
-	return p.federator.GetRemoteAccount(ctx, dereferencing.GetRemoteAccountParams{
+	return p.federator.GetRemoteAccount(transport.WithFastfail(ctx), dereferencing.GetRemoteAccountParams{
 		RequestingUsername: authed.Account.Username,
 		RemoteAccountID:    uri,
 		Blocking:           true,
@@ -209,7 +210,7 @@ func (p *processor) searchAccountByMention(ctx context.Context, authed *oauth.Au
 	}
 
 	// we don't have it yet, try to find it remotely
-	return p.federator.GetRemoteAccount(ctx, dereferencing.GetRemoteAccountParams{
+	return p.federator.GetRemoteAccount(transport.WithFastfail(ctx), dereferencing.GetRemoteAccountParams{
 		RequestingUsername:    authed.Account.Username,
 		RemoteAccountUsername: username,
 		RemoteAccountHost:     domain,

internal/processing/util.go

@@ -28,6 +28,7 @@ import (
 	"github.com/superseriousbusiness/gotosocial/internal/federation/dereferencing"
 	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
 	"github.com/superseriousbusiness/gotosocial/internal/id"
+	"github.com/superseriousbusiness/gotosocial/internal/transport"
 	"github.com/superseriousbusiness/gotosocial/internal/util"
 )
 
@@ -56,7 +57,7 @@ func GetParseMentionFunc(dbConn db.DB, federator federation.Federator) gtsmodel.
 			if originAccount.Domain == "" {
 				requestingUsername = originAccount.Username
 			}
-			remoteAccount, err := federator.GetRemoteAccount(ctx, dereferencing.GetRemoteAccountParams{
+			remoteAccount, err := federator.GetRemoteAccount(transport.WithFastfail(ctx), dereferencing.GetRemoteAccountParams{
 				RequestingUsername:    requestingUsername,
 				RemoteAccountUsername: username,
 				RemoteAccountHost:     domain,

internal/transport/context.go

@@ -0,0 +1,43 @@
+/*
+   GoToSocial
+   Copyright (C) 2021-2022 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 transport
+
+import "context"
+
+// ctxkey is our own unique context key type to prevent setting outside package.
+type ctxkey string
+
+// fastfailkey is our unique context key to indicate fast-fail is enabled.
+var fastfailkey = ctxkey("ff")
+
+// WithFastfail returns a Context which indicates that any http requests made
+// with it should return after the first failed attempt, instead of retrying.
+//
+// This can be used to fail quickly when you're making an outgoing http request
+// inside the context of an incoming http request, and you want to be able to
+// provide a snappy response to the user, instead of retrying + backing off.
+func WithFastfail(parent context.Context) context.Context {
+	return context.WithValue(parent, fastfailkey, struct{}{})
+}
+
+// IsFastfail returns true if the given context was created by WithFastfail.
+func IsFastfail(ctx context.Context) bool {
+	_, ok := ctx.Value(fastfailkey).(struct{})
+	return ok
+}

internal/transport/context_test.go

@@ -0,0 +1,34 @@
+/*
+   GoToSocial
+   Copyright (C) 2021-2022 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 transport_test
+
+import (
+	"context"
+	"testing"
+
+	"github.com/superseriousbusiness/gotosocial/internal/transport"
+)
+
+func TestFastFailContext(t *testing.T) {
+	ctx := context.Background()
+	ctx = transport.WithFastfail(ctx)
+	if !transport.IsFastfail(ctx) {
+		t.Fatal("failed to set fast-fail context key")
+	}
+}

internal/transport/transport.go

@@ -23,6 +23,7 @@ import (
 	"crypto"
 	"crypto/x509"
 	"errors"
+	"fmt"
 	"io"
 	"net/http"
 	"net/url"
@@ -33,25 +34,41 @@ import (
 	errorsv2 "codeberg.org/gruf/go-errors/v2"
 	"codeberg.org/gruf/go-kv"
 	"github.com/go-fed/httpsig"
-	"github.com/superseriousbusiness/activity/pub"
 	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
 	"github.com/superseriousbusiness/gotosocial/internal/httpclient"
 	"github.com/superseriousbusiness/gotosocial/internal/log"
 )
 
-// Transport wraps the pub.Transport interface with some additional functionality for fetching remote media.
+// Transport implements the pub.Transport interface with some additional functionality for fetching remote media.
 //
 // Since the transport has the concept of 'shortcuts' for fetching data locally rather than remotely, it is
 // not *always* the case that calling a Transport function does an http call, but it usually will for remote
 // hosts or resources for which a shortcut isn't provided by the transport controller (also in this package).
+//
+// For any of the transport functions, if a Fastfail context is passed in as the first parameter, the function
+// will return after the first transport failure, instead of retrying + backing off.
 type Transport interface {
-	pub.Transport
+	/*
+		POST functions
+	*/
+
+	// 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
+
+	/*
+		GET functions
+	*/
+
+	// 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, targetDomains string) ([]byte, error)
+	Finger(ctx context.Context, targetUsername string, targetDomain string) ([]byte, error)
 }
 
 // transport implements the Transport interface
@@ -106,6 +123,10 @@ func (t *transport) do(r *http.Request, signer func(*http.Request) error, retryO
 		return nil, errors.New("too many failed attempts")
 	}
 
+	// Check whether request should fast fail, we check this
+	// before loop as each context.Value() requires mutex lock.
+	fastFail := IsFastfail(r.Context())
+
 	// Start a log entry for this request
 	l := log.WithFields(kv.Fields{
 		{"pubKeyID", t.pubKeyID},
@@ -156,6 +177,9 @@ func (t *transport) do(r *http.Request, signer func(*http.Request) error, retryO
 		} else if errors.As(err, &x509.UnknownAuthorityError{}) {
 			// Unknown authority errors we do NOT recover from
 			return nil, err
+		} else if fastFail {
+			// on fast-fail, don't bother backoff/retry
+			return nil, fmt.Errorf("%w (fast fail)", err)
 		}
 
 		l.Errorf("backing off for %s after http request error: %v", backoff.String(), err)