MM-9728: Online migration for advanced permissions phase 2 (#8744)

* MM-9728: Online migration for advanced permissions phase 2

* Add unit tests for new store functions.

* Move migration specific code to own file.

* Add migration state function test.

* Style fixes.

* Add i18n strings.

* Fix mocks.

* Add TestMain to migrations package tests.

* Fix typo.

* Fix review comments.

* Fix up the "Check if migration is done" check to actually work.

1 files changed, 166 insertions, 0 deletions

diff --git a/migrations/worker.go b/migrations/worker.go
new file mode 100644
index 000000000..7a64dd609
--- /dev/null
+++ b/migrations/worker.go
@@ -0,0 +1,166 @@
+// Copyright (c) 2018-present Mattermost, Inc. All Rights Reserved.
+// See License.txt for license information.
+
+package migrations
+
+import (
+	"context"
+	"net/http"
+	"time"
+
+	"github.com/mattermost/mattermost-server/app"
+	"github.com/mattermost/mattermost-server/jobs"
+	"github.com/mattermost/mattermost-server/mlog"
+	"github.com/mattermost/mattermost-server/model"
+)
+
+const (
+	TIME_BETWEEN_BATCHES = 100
+)
+
+type Worker struct {
+	name      string
+	stop      chan bool
+	stopped   chan bool
+	jobs      chan model.Job
+	jobServer *jobs.JobServer
+	app       *app.App
+}
+
+func (m *MigrationsJobInterfaceImpl) MakeWorker() model.Worker {
+	worker := Worker{
+		name:      "Migrations",
+		stop:      make(chan bool, 1),
+		stopped:   make(chan bool, 1),
+		jobs:      make(chan model.Job),
+		jobServer: m.App.Jobs,
+		app:       m.App,
+	}
+
+	return &worker
+}
+
+func (worker *Worker) Run() {
+	mlog.Debug("Worker started", mlog.String("worker", worker.name))
+
+	defer func() {
+		mlog.Debug("Worker finished", mlog.String("worker", worker.name))
+		worker.stopped <- true
+	}()
+
+	for {
+		select {
+		case <-worker.stop:
+			mlog.Debug("Worker received stop signal", mlog.String("worker", worker.name))
+			return
+		case job := <-worker.jobs:
+			mlog.Debug("Worker received a new candidate job.", mlog.String("worker", worker.name))
+			worker.DoJob(&job)
+		}
+	}
+}
+
+func (worker *Worker) Stop() {
+	mlog.Debug("Worker stopping", mlog.String("worker", worker.name))
+	worker.stop <- true
+	<-worker.stopped
+}
+
+func (worker *Worker) JobChannel() chan<- model.Job {
+	return worker.jobs
+}
+
+func (worker *Worker) DoJob(job *model.Job) {
+	if claimed, err := worker.jobServer.ClaimJob(job); err != nil {
+		mlog.Info("Worker experienced an error while trying to claim job",
+			mlog.String("worker", worker.name),
+			mlog.String("job_id", job.Id),
+			mlog.String("error", err.Error()))
+		return
+	} else if !claimed {
+		return
+	}
+
+	cancelCtx, cancelCancelWatcher := context.WithCancel(context.Background())
+	cancelWatcherChan := make(chan interface{}, 1)
+	go worker.app.Jobs.CancellationWatcher(cancelCtx, job.Id, cancelWatcherChan)
+
+	defer cancelCancelWatcher()
+
+	for {
+		select {
+		case <-cancelWatcherChan:
+			mlog.Debug("Worker: Job has been canceled via CancellationWatcher", mlog.String("worker", worker.name), mlog.String("job_id", job.Id))
+			worker.setJobCanceled(job)
+			return
+
+		case <-worker.stop:
+			mlog.Debug("Worker: Job has been canceled via Worker Stop", mlog.String("worker", worker.name), mlog.String("job_id", job.Id))
+			worker.setJobCanceled(job)
+			return
+
+		case <-time.After(TIME_BETWEEN_BATCHES * time.Millisecond):
+			done, progress, err := worker.runMigration(job.Data[JOB_DATA_KEY_MIGRATION], job.Data[JOB_DATA_KEY_MIGRATION_LAST_DONE])
+			if err != nil {
+				mlog.Error("Worker: Failed to run migration", mlog.String("worker", worker.name), mlog.String("job_id", job.Id), mlog.String("error", err.Error()))
+				worker.setJobError(job, err)
+				return
+			} else if done {
+				mlog.Info("Worker: Job is complete", mlog.String("worker", worker.name), mlog.String("job_id", job.Id))
+				worker.setJobSuccess(job)
+				return
+			} else {
+				job.Data[JOB_DATA_KEY_MIGRATION_LAST_DONE] = progress
+				if err := worker.app.Jobs.UpdateInProgressJobData(job); err != nil {
+					mlog.Error("Worker: Failed to update migration status data for job", mlog.String("worker", worker.name), mlog.String("job_id", job.Id), mlog.String("error", err.Error()))
+					worker.setJobError(job, err)
+					return
+				}
+			}
+		}
+	}
+}
+
+func (worker *Worker) setJobSuccess(job *model.Job) {
+	if err := worker.app.Jobs.SetJobSuccess(job); err != nil {
+		mlog.Error("Worker: Failed to set success for job", mlog.String("worker", worker.name), mlog.String("job_id", job.Id), mlog.String("error", err.Error()))
+		worker.setJobError(job, err)
+	}
+}
+
+func (worker *Worker) setJobError(job *model.Job, appError *model.AppError) {
+	if err := worker.app.Jobs.SetJobError(job, appError); err != nil {
+		mlog.Error("Worker: Failed to set job error", mlog.String("worker", worker.name), mlog.String("job_id", job.Id), mlog.String("error", err.Error()))
+	}
+}
+
+func (worker *Worker) setJobCanceled(job *model.Job) {
+	if err := worker.app.Jobs.SetJobCanceled(job); err != nil {
+		mlog.Error("Worker: Failed to mark job as canceled", mlog.String("worker", worker.name), mlog.String("job_id", job.Id), mlog.String("error", err.Error()))
+	}
+}
+
+// Return parameters:
+// - whether the migration is completed on this run (true) or still incomplete (false).
+// - the updated lastDone string for the migration.
+// - any error which may have occurred while running the migration.
+func (worker *Worker) runMigration(key string, lastDone string) (bool, string, *model.AppError) {
+	var done bool
+	var progress string
+	var err *model.AppError
+
+	switch key {
+	case model.MIGRATION_KEY_ADVANCED_PERMISSIONS_PHASE_2:
+		done, progress, err = worker.runAdvancedPermissionsPhase2Migration(lastDone)
+	default:
+		return false, "", model.NewAppError("MigrationsWorker.runMigration", "migrations.worker.run_migration.unknown_key", map[string]interface{}{"key": key}, "", http.StatusInternalServerError)
+	}
+
+	if done {
+		if result := <-worker.app.Srv.Store.System().Save(&model.System{Name: key, Value: "true"}); result.Err != nil {
+			return false, "", result.Err
+		}
+	}
+
+	return done, progress, err
+}