1 files changed, 157 insertions, 0 deletions
diff --git a/internal/workers/worker_msg.go b/internal/workers/worker_msg.go
new file mode 100644
index 000000000..1920c964e
--- /dev/null
+++ b/internal/workers/worker_msg.go
@@ -0,0 +1,157 @@
+// 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) {
+	// Check whether workers are
+	// set (is already running).
+	ok := (len(p.workers) > 0)
+	if ok {
+		return
+	}
+
+	// Allocate new msg workers slice.
+	p.workers = make([]*MsgWorker[T], n)
+	for i := range p.workers {
+
+		// Allocate new MsgWorker[T]{}.
+		p.workers[i] = new(MsgWorker[T])
+		p.workers[i].Process = p.Process
+		p.workers[i].Queue = &p.Queue
+
+		// Attempt to start worker.
+		// Return bool not useful
+		// here, as true = started,
+		// false = already running.
+		_ = p.workers[i].Start()
+	}
+}
+
+// Stop will attempt to stop contained Worker{}s.
+func (p *MsgWorkerPool[T]) Stop() {
+	// Check whether workers are
+	// set (is currently running).
+	ok := (len(p.workers) == 0)
+	if ok {
+		return
+	}
+
+	// Stop all running workers.
+	for i := range p.workers {
+
+		// return bool not useful
+		// here, as true = stopped,
+		// false = never running.
+		_ = p.workers[i].Stop()
+	}
+
+	// Unset workers slice.
+	p.workers = p.workers[:0]
+}
+
+// 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")
+	}
+
+	for {
+		// Block until pop next message.
+		msg, ok := w.Queue.PopCtx(ctx)
+		if !ok {
+			return
+		}
+
+		// Attempt to process popped message type.
+		if err := w.Process(ctx, msg); err != nil {
+			log.Errorf(ctx, "%p: error processing: %v", w, err)
+		}
+	}
+}