[feature] Store admin actions in the db, prevent conflicting actions (#2167)

internal/processing/admin/actions.go

@@ -0,0 +1,159 @@
+// 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"
+	"sync"
+	"time"
+
+	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
+	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
+	"github.com/superseriousbusiness/gotosocial/internal/log"
+	"github.com/superseriousbusiness/gotosocial/internal/state"
+	"golang.org/x/exp/slices"
+)
+
+func errActionConflict(action *gtsmodel.AdminAction) gtserror.WithCode {
+	err := gtserror.NewfAt(
+		4, // Include caller's function name.
+		"an action (%s) is currently running (duration %s) which conflicts with the attempted action",
+		action.Key(), time.Since(action.CreatedAt),
+	)
+
+	const help = "wait until this action is complete and try again"
+	return gtserror.NewErrorConflict(err, err.Error(), help)
+}
+
+type Actions struct {
+	r     map[string]*gtsmodel.AdminAction
+	state *state.State
+
+	// Not embedded struct,
+	// to shield from access
+	// by outside packages.
+	m sync.Mutex
+}
+
+// Run runs the given admin action by executing the supplied function.
+//
+// Run handles locking, action insertion and updating, so you don't have to!
+//
+// If an action is already running which overlaps/conflicts with the
+// given action, an ErrorWithCode 409 will be returned.
+//
+// If execution of the provided function returns errors, the errors
+// will be updated on the provided admin action in the database.
+func (a *Actions) Run(
+	ctx context.Context,
+	action *gtsmodel.AdminAction,
+	f func(context.Context) gtserror.MultiError,
+) gtserror.WithCode {
+	actionKey := action.Key()
+
+	// LOCK THE MAP HERE, since we're
+	// going to do some operations on it.
+	a.m.Lock()
+
+	// Bail if an action with
+	// this key is already running.
+	running, ok := a.r[actionKey]
+	if ok {
+		a.m.Unlock()
+		return errActionConflict(running)
+	}
+
+	// Action with this key not
+	// yet running, create it.
+	if err := a.state.DB.PutAdminAction(ctx, action); err != nil {
+		err = gtserror.Newf("db error putting admin action %s: %w", actionKey, err)
+
+		// Don't store in map
+		// if there's an error.
+		a.m.Unlock()
+		return gtserror.NewErrorInternalError(err)
+	}
+
+	// Action was inserted,
+	// store in map.
+	a.r[actionKey] = action
+
+	// UNLOCK THE MAP HERE, since
+	// we're done modifying it for now.
+	a.m.Unlock()
+
+	// Do the rest of the work asynchronously.
+	a.state.Workers.ClientAPI.Enqueue(func(ctx context.Context) {
+		// Run the thing and collect errors.
+		if errs := f(ctx); errs != nil {
+			action.Errors = make([]string, 0, len(errs))
+			for _, err := range errs {
+				action.Errors = append(action.Errors, err.Error())
+			}
+		}
+
+		// Action is no longer running:
+		// remove from running map.
+		a.m.Lock()
+		delete(a.r, actionKey)
+		a.m.Unlock()
+
+		// Mark as completed in the db,
+		// storing errors for later review.
+		action.CompletedAt = time.Now()
+		if err := a.state.DB.UpdateAdminAction(ctx, action, "completed_at", "errors"); err != nil {
+			log.Errorf(ctx, "db error marking action %s as completed: %q", actionKey, err)
+		}
+	})
+
+	return nil
+}
+
+// GetRunning sounds like a threat, but it actually just
+// returns all of the currently running actions held by
+// the Actions struct, ordered by ID descending.
+func (a *Actions) GetRunning() []*gtsmodel.AdminAction {
+	a.m.Lock()
+	defer a.m.Unlock()
+
+	// Assemble all currently running actions.
+	running := make([]*gtsmodel.AdminAction, 0, len(a.r))
+	for _, action := range a.r {
+		running = append(running, action)
+	}
+
+	// Order by ID descending (creation date).
+	slices.SortFunc(
+		running,
+		func(a *gtsmodel.AdminAction, b *gtsmodel.AdminAction) bool {
+			return a.ID > b.ID
+		},
+	)
+
+	return running
+}
+
+// TotalRunning is a sequel to the classic
+// 1972 environmental-themed science fiction
+// film Silent Running, starring Bruce Dern.
+func (a *Actions) TotalRunning() int {
+	a.m.Lock()
+	defer a.m.Unlock()
+
+	return len(a.r)
+}