[feature] persist worker queues to db (#3042)

* persist queued worker tasks to database on shutdown, fill worker queues from database on startup

* ensure the tasks are sorted by creation time before pushing them

* add migration to insert WorkerTask{} into database, add test for worker task persistence

* add test for recovering worker queues from database

* quick tweak

* whoops we ended up with double cleaner job scheduling

* insert each task separately, because bun is throwing some reflection error??

* add specific checking of cancelled worker contexts

* add http request signing to deliveries recovered from database

* add test for outgoing public key ID being correctly set on delivery

* replace select with Queue.PopCtx()

* get rid of loop now we don't use it

* remove field now we don't use it

* ensure that signing func is set

* header values weren't being copied over 🤦

* use ptr for httpclient.Request in delivery

* move worker queue filling to later in server init process

* fix rebase issues

* make logging less shouty

* use slices.Delete() instead of copying / reslicing

* have database return tasks in ascending order instead of sorting them

* add a 1 minute timeout to persisting worker queues

internal/processing/admin/workertask.go

@@ -0,0 +1,426 @@
+// GoToSocial
+// Copyright (C) GoToSocial Authors admin@gotosocial.org
+// SPDX-License-Identifier: AGPL-3.0-or-later
+//
+// 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 admin
+
+import (
+	"context"
+	"fmt"
+	"slices"
+	"time"
+
+	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
+	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
+	"github.com/superseriousbusiness/gotosocial/internal/log"
+	"github.com/superseriousbusiness/gotosocial/internal/messages"
+	"github.com/superseriousbusiness/gotosocial/internal/transport"
+	"github.com/superseriousbusiness/gotosocial/internal/transport/delivery"
+)
+
+// NOTE:
+// Having these functions in the processor, which is
+// usually the intermediary that performs *processing*
+// between the HTTP route handlers and the underlying
+// database / storage layers is a little odd, so this
+// may be subject to change!
+//
+// For now at least, this is a useful place that has
+// access to the underlying database, workers and
+// causes no dependency cycles with this use case!
+
+// FillWorkerQueues recovers all serialized worker tasks from the database
+// (if any!), and pushes them to each of their relevant worker queues.
+func (p *Processor) FillWorkerQueues(ctx context.Context) error {
+	log.Info(ctx, "rehydrate!")
+
+	// Get all persisted worker tasks from db.
+	//
+	// (database returns these as ASCENDING, i.e.
+	// returned in the order they were inserted).
+	tasks, err := p.state.DB.GetWorkerTasks(ctx)
+	if err != nil {
+		return gtserror.Newf("error fetching worker tasks from db: %w", err)
+	}
+
+	var (
+		// Counts of each task type
+		// successfully recovered.
+		delivery  int
+		federator int
+		client    int
+
+		// Failed recoveries.
+		errors int
+	)
+
+loop:
+
+	// Handle each persisted task, removing
+	// all those we can't handle. Leaving us
+	// with a slice of tasks we can safely
+	// delete from being persisted in the DB.
+	for i := 0; i < len(tasks); {
+		var err error
+
+		// Task at index.
+		task := tasks[i]
+
+		// Appropriate task count
+		// pointer to increment.
+		var counter *int
+
+		// Attempt to recovery persisted
+		// task depending on worker type.
+		switch task.WorkerType {
+		case gtsmodel.DeliveryWorker:
+			err = p.pushDelivery(ctx, task)
+			counter = &delivery
+		case gtsmodel.FederatorWorker:
+			err = p.pushFederator(ctx, task)
+			counter = &federator
+		case gtsmodel.ClientWorker:
+			err = p.pushClient(ctx, task)
+			counter = &client
+		default:
+			err = fmt.Errorf("invalid worker type %d", task.WorkerType)
+		}
+
+		if err != nil {
+			log.Errorf(ctx, "error pushing task %d: %v", task.ID, err)
+
+			// Drop error'd task from slice.
+			tasks = slices.Delete(tasks, i, i+1)
+
+			// Incr errors.
+			errors++
+			continue loop
+		}
+
+		// Increment slice
+		// index & counter.
+		(*counter)++
+		i++
+	}
+
+	// Tasks that worker successfully pushed
+	// to their appropriate workers, we can
+	// safely now remove from the database.
+	for _, task := range tasks {
+		if err := p.state.DB.DeleteWorkerTaskByID(ctx, task.ID); err != nil {
+			log.Errorf(ctx, "error deleting task from db: %v", err)
+		}
+	}
+
+	// Log recovered tasks.
+	log.WithContext(ctx).
+		WithField("delivery", delivery).
+		WithField("federator", federator).
+		WithField("client", client).
+		WithField("errors", errors).
+		Info("recovered queued tasks")
+
+	return nil
+}
+
+// PersistWorkerQueues pops all queued worker tasks (that are themselves persistable, i.e. not
+// dereference tasks which are just function ptrs), serializes and persists them to the database.
+func (p *Processor) PersistWorkerQueues(ctx context.Context) error {
+	log.Info(ctx, "dehydrate!")
+
+	var (
+		// Counts of each task type
+		// successfully persisted.
+		delivery  int
+		federator int
+		client    int
+
+		// Failed persists.
+		errors int
+
+		// Serialized tasks to persist.
+		tasks []*gtsmodel.WorkerTask
+	)
+
+	for {
+		// Pop all queued deliveries.
+		task, err := p.popDelivery()
+		if err != nil {
+			log.Errorf(ctx, "error popping delivery: %v", err)
+			errors++ // incr error count.
+			continue
+		}
+
+		if task == nil {
+			// No more queue
+			// tasks to pop!
+			break
+		}
+
+		// Append serialized task.
+		tasks = append(tasks, task)
+		delivery++ // incr count
+	}
+
+	for {
+		// Pop queued federator msgs.
+		task, err := p.popFederator()
+		if err != nil {
+			log.Errorf(ctx, "error popping federator message: %v", err)
+			errors++ // incr count
+			continue
+		}
+
+		if task == nil {
+			// No more queue
+			// tasks to pop!
+			break
+		}
+
+		// Append serialized task.
+		tasks = append(tasks, task)
+		federator++ // incr count
+	}
+
+	for {
+		// Pop queued client msgs.
+		task, err := p.popClient()
+		if err != nil {
+			log.Errorf(ctx, "error popping client message: %v", err)
+			continue
+		}
+
+		if task == nil {
+			// No more queue
+			// tasks to pop!
+			break
+		}
+
+		// Append serialized task.
+		tasks = append(tasks, task)
+		client++ // incr count
+	}
+
+	// Persist all serialized queued worker tasks to database.
+	if err := p.state.DB.PutWorkerTasks(ctx, tasks); err != nil {
+		return gtserror.Newf("error putting tasks in db: %w", err)
+	}
+
+	// Log recovered tasks.
+	log.WithContext(ctx).
+		WithField("delivery", delivery).
+		WithField("federator", federator).
+		WithField("client", client).
+		WithField("errors", errors).
+		Info("persisted queued tasks")
+
+	return nil
+}
+
+// pushDelivery parses a valid delivery.Delivery{} from serialized task data and pushes to queue.
+func (p *Processor) pushDelivery(ctx context.Context, task *gtsmodel.WorkerTask) error {
+	dlv := new(delivery.Delivery)
+
+	// Deserialize the raw worker task data into delivery.
+	if err := dlv.Deserialize(task.TaskData); err != nil {
+		return gtserror.Newf("error deserializing delivery: %w", err)
+	}
+
+	var tsport transport.Transport
+
+	if uri := dlv.ActorID; uri != "" {
+		// Fetch the actor account by provided URI from db.
+		account, err := p.state.DB.GetAccountByURI(ctx, uri)
+		if err != nil {
+			return gtserror.Newf("error getting actor account %s from db: %w", uri, err)
+		}
+
+		// Fetch a transport for request signing for actor's account username.
+		tsport, err = p.transport.NewTransportForUsername(ctx, account.Username)
+		if err != nil {
+			return gtserror.Newf("error getting transport for actor %s: %w", uri, err)
+		}
+	} else {
+		var err error
+
+		// No actor was given, will be signed by instance account.
+		tsport, err = p.transport.NewTransportForUsername(ctx, "")
+		if err != nil {
+			return gtserror.Newf("error getting instance account transport: %w", err)
+		}
+	}
+
+	// Using transport, add actor signature to delivery.
+	if err := tsport.SignDelivery(dlv); err != nil {
+		return gtserror.Newf("error signing delivery: %w", err)
+	}
+
+	// Push deserialized task to delivery queue.
+	p.state.Workers.Delivery.Queue.Push(dlv)
+
+	return nil
+}
+
+// popDelivery pops delivery.Delivery{} from queue and serializes as valid task data.
+func (p *Processor) popDelivery() (*gtsmodel.WorkerTask, error) {
+
+	// Pop waiting delivery from the delivery worker.
+	delivery, ok := p.state.Workers.Delivery.Queue.Pop()
+	if !ok {
+		return nil, nil
+	}
+
+	// Serialize the delivery task data.
+	data, err := delivery.Serialize()
+	if err != nil {
+		return nil, gtserror.Newf("error serializing delivery: %w", err)
+	}
+
+	return &gtsmodel.WorkerTask{
+		// ID is autoincrement
+		WorkerType: gtsmodel.DeliveryWorker,
+		TaskData:   data,
+		CreatedAt:  time.Now(),
+	}, nil
+}
+
+// pushClient parses a valid messages.FromFediAPI{} from serialized task data and pushes to queue.
+func (p *Processor) pushFederator(ctx context.Context, task *gtsmodel.WorkerTask) error {
+	var msg messages.FromFediAPI
+
+	// Deserialize the raw worker task data into message.
+	if err := msg.Deserialize(task.TaskData); err != nil {
+		return gtserror.Newf("error deserializing federator message: %w", err)
+	}
+
+	if rcv := msg.Receiving; rcv != nil {
+		// Only a placeholder receiving account will be populated,
+		// fetch the actual model from database by persisted ID.
+		account, err := p.state.DB.GetAccountByID(ctx, rcv.ID)
+		if err != nil {
+			return gtserror.Newf("error fetching receiving account %s from db: %w", rcv.ID, err)
+		}
+
+		// Set the now populated
+		// receiving account model.
+		msg.Receiving = account
+	}
+
+	if req := msg.Requesting; req != nil {
+		// Only a placeholder requesting account will be populated,
+		// fetch the actual model from database by persisted ID.
+		account, err := p.state.DB.GetAccountByID(ctx, req.ID)
+		if err != nil {
+			return gtserror.Newf("error fetching requesting account %s from db: %w", req.ID, err)
+		}
+
+		// Set the now populated
+		// requesting account model.
+		msg.Requesting = account
+	}
+
+	// Push populated task to the federator queue.
+	p.state.Workers.Federator.Queue.Push(&msg)
+
+	return nil
+}
+
+// popFederator pops messages.FromFediAPI{} from queue and serializes as valid task data.
+func (p *Processor) popFederator() (*gtsmodel.WorkerTask, error) {
+
+	// Pop waiting message from the federator worker.
+	msg, ok := p.state.Workers.Federator.Queue.Pop()
+	if !ok {
+		return nil, nil
+	}
+
+	// Serialize message task data.
+	data, err := msg.Serialize()
+	if err != nil {
+		return nil, gtserror.Newf("error serializing federator message: %w", err)
+	}
+
+	return &gtsmodel.WorkerTask{
+		// ID is autoincrement
+		WorkerType: gtsmodel.FederatorWorker,
+		TaskData:   data,
+		CreatedAt:  time.Now(),
+	}, nil
+}
+
+// pushClient parses a valid messages.FromClientAPI{} from serialized task data and pushes to queue.
+func (p *Processor) pushClient(ctx context.Context, task *gtsmodel.WorkerTask) error {
+	var msg messages.FromClientAPI
+
+	// Deserialize the raw worker task data into message.
+	if err := msg.Deserialize(task.TaskData); err != nil {
+		return gtserror.Newf("error deserializing client message: %w", err)
+	}
+
+	if org := msg.Origin; org != nil {
+		// Only a placeholder origin account will be populated,
+		// fetch the actual model from database by persisted ID.
+		account, err := p.state.DB.GetAccountByID(ctx, org.ID)
+		if err != nil {
+			return gtserror.Newf("error fetching origin account %s from db: %w", org.ID, err)
+		}
+
+		// Set the now populated
+		// origin account model.
+		msg.Origin = account
+	}
+
+	if trg := msg.Target; trg != nil {
+		// Only a placeholder target account will be populated,
+		// fetch the actual model from database by persisted ID.
+		account, err := p.state.DB.GetAccountByID(ctx, trg.ID)
+		if err != nil {
+			return gtserror.Newf("error fetching target account %s from db: %w", trg.ID, err)
+		}
+
+		// Set the now populated
+		// target account model.
+		msg.Target = account
+	}
+
+	// Push populated task to the federator queue.
+	p.state.Workers.Client.Queue.Push(&msg)
+
+	return nil
+}
+
+// popClient pops messages.FromClientAPI{} from queue and serializes as valid task data.
+func (p *Processor) popClient() (*gtsmodel.WorkerTask, error) {
+
+	// Pop waiting message from the client worker.
+	msg, ok := p.state.Workers.Client.Queue.Pop()
+	if !ok {
+		return nil, nil
+	}
+
+	// Serialize message task data.
+	data, err := msg.Serialize()
+	if err != nil {
+		return nil, gtserror.Newf("error serializing client message: %w", err)
+	}
+
+	return &gtsmodel.WorkerTask{
+		// ID is autoincrement
+		WorkerType: gtsmodel.ClientWorker,
+		TaskData:   data,
+		CreatedAt:  time.Now(),
+	}, nil
+}

internal/processing/admin/workertask_test.go

@@ -0,0 +1,421 @@
+// GoToSocial
+// Copyright (C) GoToSocial Authors admin@gotosocial.org
+// SPDX-License-Identifier: AGPL-3.0-or-later
+//
+// 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 admin_test
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+	"testing"
+
+	"github.com/stretchr/testify/suite"
+	"github.com/superseriousbusiness/gotosocial/internal/ap"
+	"github.com/superseriousbusiness/gotosocial/internal/gtscontext"
+	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
+	"github.com/superseriousbusiness/gotosocial/internal/httpclient"
+	"github.com/superseriousbusiness/gotosocial/internal/messages"
+	"github.com/superseriousbusiness/gotosocial/internal/transport/delivery"
+	"github.com/superseriousbusiness/gotosocial/testrig"
+)
+
+var (
+	// TODO: move these test values into
+	// the testrig test models area. They'll
+	// need to be as both WorkerTask and as
+	// the raw types themselves.
+
+	testDeliveries = []*delivery.Delivery{
+		{
+			ObjectID: "https://google.com/users/bigboy/follow/1",
+			TargetID: "https://askjeeves.com/users/smallboy",
+			Request:  toRequest("POST", "https://askjeeves.com/users/smallboy/inbox", []byte("data!"), http.Header{"Host": {"https://askjeeves.com"}}),
+		},
+		{
+			Request: toRequest("GET", "https://google.com", []byte("uwu im just a wittle seawch engwin"), http.Header{"Host": {"https://google.com"}}),
+		},
+	}
+
+	testFederatorMsgs = []*messages.FromFediAPI{
+		{
+			APObjectType:   ap.ObjectNote,
+			APActivityType: ap.ActivityCreate,
+			TargetURI:      "https://gotosocial.org",
+			Requesting:     &gtsmodel.Account{ID: "654321"},
+			Receiving:      &gtsmodel.Account{ID: "123456"},
+		},
+		{
+			APObjectType:   ap.ObjectProfile,
+			APActivityType: ap.ActivityUpdate,
+			TargetURI:      "https://uk-queen-is-dead.org",
+			Requesting:     &gtsmodel.Account{ID: "123456"},
+			Receiving:      &gtsmodel.Account{ID: "654321"},
+		},
+	}
+
+	testClientMsgs = []*messages.FromClientAPI{
+		{
+			APObjectType:   ap.ObjectNote,
+			APActivityType: ap.ActivityCreate,
+			TargetURI:      "https://gotosocial.org",
+			Origin:         &gtsmodel.Account{ID: "654321"},
+			Target:         &gtsmodel.Account{ID: "123456"},
+		},
+		{
+			APObjectType:   ap.ObjectProfile,
+			APActivityType: ap.ActivityUpdate,
+			TargetURI:      "https://uk-queen-is-dead.org",
+			Origin:         &gtsmodel.Account{ID: "123456"},
+			Target:         &gtsmodel.Account{ID: "654321"},
+		},
+	}
+)
+
+type WorkerTaskTestSuite struct {
+	AdminStandardTestSuite
+}
+
+func (suite *WorkerTaskTestSuite) TestFillWorkerQueues() {
+	ctx, cncl := context.WithCancel(context.Background())
+	defer cncl()
+
+	var tasks []*gtsmodel.WorkerTask
+
+	for _, dlv := range testDeliveries {
+		// Serialize all test deliveries.
+		data, err := dlv.Serialize()
+		if err != nil {
+			panic(err)
+		}
+
+		// Append each serialized delivery to tasks.
+		tasks = append(tasks, &gtsmodel.WorkerTask{
+			WorkerType: gtsmodel.DeliveryWorker,
+			TaskData:   data,
+		})
+	}
+
+	for _, msg := range testFederatorMsgs {
+		// Serialize all test messages.
+		data, err := msg.Serialize()
+		if err != nil {
+			panic(err)
+		}
+
+		if msg.Receiving != nil {
+			// Quick hack to bypass database errors for non-existing
+			// accounts, instead we just insert this into cache ;).
+			suite.state.Caches.DB.Account.Put(msg.Receiving)
+			suite.state.Caches.DB.AccountSettings.Put(&gtsmodel.AccountSettings{
+				AccountID: msg.Receiving.ID,
+			})
+		}
+
+		if msg.Requesting != nil {
+			// Quick hack to bypass database errors for non-existing
+			// accounts, instead we just insert this into cache ;).
+			suite.state.Caches.DB.Account.Put(msg.Requesting)
+			suite.state.Caches.DB.AccountSettings.Put(&gtsmodel.AccountSettings{
+				AccountID: msg.Requesting.ID,
+			})
+		}
+
+		// Append each serialized message to tasks.
+		tasks = append(tasks, &gtsmodel.WorkerTask{
+			WorkerType: gtsmodel.FederatorWorker,
+			TaskData:   data,
+		})
+	}
+
+	for _, msg := range testClientMsgs {
+		// Serialize all test messages.
+		data, err := msg.Serialize()
+		if err != nil {
+			panic(err)
+		}
+
+		if msg.Origin != nil {
+			// Quick hack to bypass database errors for non-existing
+			// accounts, instead we just insert this into cache ;).
+			suite.state.Caches.DB.Account.Put(msg.Origin)
+			suite.state.Caches.DB.AccountSettings.Put(&gtsmodel.AccountSettings{
+				AccountID: msg.Origin.ID,
+			})
+		}
+
+		if msg.Target != nil {
+			// Quick hack to bypass database errors for non-existing
+			// accounts, instead we just insert this into cache ;).
+			suite.state.Caches.DB.Account.Put(msg.Target)
+			suite.state.Caches.DB.AccountSettings.Put(&gtsmodel.AccountSettings{
+				AccountID: msg.Target.ID,
+			})
+		}
+
+		// Append each serialized message to tasks.
+		tasks = append(tasks, &gtsmodel.WorkerTask{
+			WorkerType: gtsmodel.ClientWorker,
+			TaskData:   data,
+		})
+	}
+
+	// Persist all test worker tasks to the database.
+	err := suite.state.DB.PutWorkerTasks(ctx, tasks)
+	suite.NoError(err)
+
+	// Fill the worker queues from persisted task data.
+	err = suite.adminProcessor.FillWorkerQueues(ctx)
+	suite.NoError(err)
+
+	var (
+		// Recovered
+		// task counts.
+		ndelivery  int
+		nfederator int
+		nclient    int
+	)
+
+	// Fetch current gotosocial instance account, for later checks.
+	instanceAcc, err := suite.state.DB.GetInstanceAccount(ctx, "")
+	suite.NoError(err)
+
+	for {
+		// Pop all queued delivery tasks from worker queue.
+		dlv, ok := suite.state.Workers.Delivery.Queue.Pop()
+		if !ok {
+			break
+		}
+
+		// Incr count.
+		ndelivery++
+
+		// Check that we have this message in slice.
+		err = containsSerializable(testDeliveries, dlv)
+		suite.NoError(err)
+
+		// Check that delivery request context has instance account pubkey.
+		pubKeyID := gtscontext.OutgoingPublicKeyID(dlv.Request.Context())
+		suite.Equal(instanceAcc.PublicKeyURI, pubKeyID)
+		signfn := gtscontext.HTTPClientSignFunc(dlv.Request.Context())
+		suite.NotNil(signfn)
+	}
+
+	for {
+		// Pop all queued federator messages from worker queue.
+		msg, ok := suite.state.Workers.Federator.Queue.Pop()
+		if !ok {
+			break
+		}
+
+		// Incr count.
+		nfederator++
+
+		// Check that we have this message in slice.
+		err = containsSerializable(testFederatorMsgs, msg)
+		suite.NoError(err)
+	}
+
+	for {
+		// Pop all queued client messages from worker queue.
+		msg, ok := suite.state.Workers.Client.Queue.Pop()
+		if !ok {
+			break
+		}
+
+		// Incr count.
+		nclient++
+
+		// Check that we have this message in slice.
+		err = containsSerializable(testClientMsgs, msg)
+		suite.NoError(err)
+	}
+
+	// Ensure recovered task counts as expected.
+	suite.Equal(len(testDeliveries), ndelivery)
+	suite.Equal(len(testFederatorMsgs), nfederator)
+	suite.Equal(len(testClientMsgs), nclient)
+}
+
+func (suite *WorkerTaskTestSuite) TestPersistWorkerQueues() {
+	ctx, cncl := context.WithCancel(context.Background())
+	defer cncl()
+
+	// Push all test worker tasks to their respective queues.
+	suite.state.Workers.Delivery.Queue.Push(testDeliveries...)
+	suite.state.Workers.Federator.Queue.Push(testFederatorMsgs...)
+	suite.state.Workers.Client.Queue.Push(testClientMsgs...)
+
+	// Persist the worker queued tasks to database.
+	err := suite.adminProcessor.PersistWorkerQueues(ctx)
+	suite.NoError(err)
+
+	// Fetch all the persisted tasks from database.
+	tasks, err := suite.state.DB.GetWorkerTasks(ctx)
+	suite.NoError(err)
+
+	var (
+		// Persisted
+		// task counts.
+		ndelivery  int
+		nfederator int
+		nclient    int
+	)
+
+	// Check persisted task data.
+	for _, task := range tasks {
+		switch task.WorkerType {
+		case gtsmodel.DeliveryWorker:
+			var dlv delivery.Delivery
+
+			// Incr count.
+			ndelivery++
+
+			// Deserialize the persisted task data.
+			err := dlv.Deserialize(task.TaskData)
+			suite.NoError(err)
+
+			// Check that we have this delivery in slice.
+			err = containsSerializable(testDeliveries, &dlv)
+			suite.NoError(err)
+
+		case gtsmodel.FederatorWorker:
+			var msg messages.FromFediAPI
+
+			// Incr count.
+			nfederator++
+
+			// Deserialize the persisted task data.
+			err := msg.Deserialize(task.TaskData)
+			suite.NoError(err)
+
+			// Check that we have this message in slice.
+			err = containsSerializable(testFederatorMsgs, &msg)
+			suite.NoError(err)
+
+		case gtsmodel.ClientWorker:
+			var msg messages.FromClientAPI
+
+			// Incr count.
+			nclient++
+
+			// Deserialize the persisted task data.
+			err := msg.Deserialize(task.TaskData)
+			suite.NoError(err)
+
+			// Check that we have this message in slice.
+			err = containsSerializable(testClientMsgs, &msg)
+			suite.NoError(err)
+
+		default:
+			suite.T().Errorf("unexpected worker type: %d", task.WorkerType)
+		}
+	}
+
+	// Ensure persisted task counts as expected.
+	suite.Equal(len(testDeliveries), ndelivery)
+	suite.Equal(len(testFederatorMsgs), nfederator)
+	suite.Equal(len(testClientMsgs), nclient)
+}
+
+func (suite *WorkerTaskTestSuite) SetupTest() {
+	suite.AdminStandardTestSuite.SetupTest()
+	// we don't want workers running
+	testrig.StopWorkers(&suite.state)
+}
+
+func TestWorkerTaskTestSuite(t *testing.T) {
+	suite.Run(t, new(WorkerTaskTestSuite))
+}
+
+// containsSerializeable returns whether slice of serializables contains given serializable entry.
+func containsSerializable[T interface{ Serialize() ([]byte, error) }](expect []T, have T) error {
+	// Serialize wanted value.
+	bh, err := have.Serialize()
+	if err != nil {
+		panic(err)
+	}
+
+	var strings []string
+
+	for _, t := range expect {
+		// Serialize expected value.
+		be, err := t.Serialize()
+		if err != nil {
+			panic(err)
+		}
+
+		// Alloc as string.
+		se := string(be)
+
+		if se == string(bh) {
+			// We have this entry!
+			return nil
+		}
+
+		// Add to serialized strings.
+		strings = append(strings, se)
+	}
+
+	return fmt.Errorf("could not find %s in %s", string(bh), strings)
+}
+
+// urlStr simply returns u.String() or "" if nil.
+func urlStr(u *url.URL) string {
+	if u == nil {
+		return ""
+	}
+	return u.String()
+}
+
+// accountID simply returns account.ID or "" if nil.
+func accountID(account *gtsmodel.Account) string {
+	if account == nil {
+		return ""
+	}
+	return account.ID
+}
+
+// toRequest creates httpclient.Request from HTTP method, URL and body data.
+func toRequest(method string, url string, body []byte, hdr http.Header) *httpclient.Request {
+	var rbody io.Reader
+	if body != nil {
+		rbody = bytes.NewReader(body)
+	}
+	req, err := http.NewRequest(method, url, rbody)
+	if err != nil {
+		panic(err)
+	}
+	for key, values := range hdr {
+		for _, value := range values {
+			req.Header.Add(key, value)
+		}
+	}
+	return httpclient.WrapRequest(req)
+}
+
+// toJSON marshals input type as JSON data.
+func toJSON(a any) []byte {
+	b, err := json.Marshal(a)
+	if err != nil {
+		panic(err)
+	}
+	return b
+}