start replacing client + federator + media workers with new worker + queue types

internal/workers/worker_msg.go

@@ -0,0 +1,145 @@
+// 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 workers
+
+import (
+	"context"
+
+	"codeberg.org/gruf/go-runners"
+	"codeberg.org/gruf/go-structr"
+	"github.com/superseriousbusiness/gotosocial/internal/log"
+	"github.com/superseriousbusiness/gotosocial/internal/queue"
+	"github.com/superseriousbusiness/gotosocial/internal/util"
+)
+
+// MsgWorkerPool wraps multiple MsgWorker{}s in
+// a singular struct for easy multi start / stop.
+type MsgWorkerPool[Msg any] struct {
+
+	// Process handles queued message types.
+	Process func(context.Context, Msg) error
+
+	// Queue is embedded queue.StructQueue{}
+	// passed to each of the pool Worker{}s.
+	Queue queue.StructQueue[Msg]
+
+	// internal fields.
+	workers []*MsgWorker[Msg]
+}
+
+// Init will initialize the worker pool queue with given struct indices.
+func (p *MsgWorkerPool[T]) Init(indices []structr.IndexConfig) {
+	p.Queue.Init(structr.QueueConfig[T]{Indices: indices})
+}
+
+// Start will attempt to start 'n' Worker{}s.
+func (p *MsgWorkerPool[T]) Start(n int) (ok bool) {
+	if ok = (len(p.workers) == 0); ok {
+		p.workers = make([]*MsgWorker[T], n)
+		for i := range p.workers {
+			p.workers[i] = new(MsgWorker[T])
+			p.workers[i].Process = p.Process
+			p.workers[i].Queue = &p.Queue
+			ok = p.workers[i].Start() && ok
+		}
+	}
+	return
+}
+
+// Stop will attempt to stop contained Worker{}s.
+func (p *MsgWorkerPool[T]) Stop() (ok bool) {
+	if ok = (len(p.workers) > 0); ok {
+		for i := range p.workers {
+			ok = p.workers[i].Stop() && ok
+			p.workers[i] = nil
+		}
+		p.workers = p.workers[:0]
+	}
+	return
+}
+
+// MsgWorker wraps a processing function to
+// feed from a queue.StructQueue{} for messages
+// to process. It does so in a single goroutine
+// with state management utilities.
+type MsgWorker[Msg any] struct {
+
+	// Process handles queued message types.
+	Process func(context.Context, Msg) error
+
+	// Queue is the Delivery{} message queue
+	// that delivery worker will feed from.
+	Queue *queue.StructQueue[Msg]
+
+	// internal fields.
+	service runners.Service
+}
+
+// Start will attempt to start the Worker{}.
+func (w *MsgWorker[T]) Start() bool {
+	return w.service.GoRun(w.run)
+}
+
+// Stop will attempt to stop the Worker{}.
+func (w *MsgWorker[T]) Stop() bool {
+	return w.service.Stop()
+}
+
+// run wraps process to restart on any panic.
+func (w *MsgWorker[T]) run(ctx context.Context) {
+	if w.Process == nil || w.Queue == nil {
+		panic("not yet initialized")
+	}
+	log.Infof(ctx, "%p: starting worker", w)
+	defer log.Infof(ctx, "%p: stopped worker", w)
+	util.Must(func() { w.process(ctx) })
+}
+
+// process is the main delivery worker processing routine.
+func (w *MsgWorker[T]) process(ctx context.Context) {
+	if w.Process == nil || w.Queue == nil {
+		// we perform this check here just
+		// to ensure the compiler knows these
+		// variables aren't nil in the loop,
+		// even if already checked by caller.
+		panic("not yet initialized")
+	}
+
+loop:
+	for {
+		select {
+		// Worker ctx done.
+		case <-ctx.Done():
+			return
+
+		// New message enqueued!
+		case <-w.Queue.Wait():
+		}
+
+		// Try pop next message.
+		msg, ok := w.Queue.Pop()
+		if !ok {
+			continue loop
+		}
+
+		// Attempt to process popped message type.
+		if err := w.Process(ctx, msg); err != nil {
+			log.Errorf(ctx, "%p: error processing: %v", w, err)
+		}
+	}
+}