Add metrics for mobile versions snapshots (#28191)

* Add metrics for mobile versions snapshots

* Add notifications disabled and fix lint

* Address feedback

* Verify all references to JobTypeActiveUsers

* Fix typos

* Improve platform values

* Add test and MySQL support

server/channels/jobs/mobile_session_metadata/scheduler.go

@@ -0,0 +1,20 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+package mobile_session_metadata
+
+import (
+	"time"
+
+	"github.com/mattermost/mattermost/server/public/model"
+	"github.com/mattermost/mattermost/server/v8/channels/jobs"
+)
+
+const schedFreq = 24 * time.Hour
+
+func MakeScheduler(jobServer *jobs.JobServer) *jobs.PeriodicScheduler {
+	isEnabled := func(cfg *model.Config) bool {
+		return *cfg.MetricsSettings.EnableClientMetrics
+	}
+	return jobs.NewPeriodicScheduler(jobServer, model.JobTypeMobileSessionMetadata, schedFreq, isEnabled)
+}

server/channels/jobs/mobile_session_metadata/worker.go

@@ -0,0 +1,42 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+package mobile_session_metadata
+
+import (
+	"github.com/mattermost/mattermost/server/public/model"
+	"github.com/mattermost/mattermost/server/public/shared/mlog"
+	"github.com/mattermost/mattermost/server/v8/channels/jobs"
+	"github.com/mattermost/mattermost/server/v8/channels/store"
+	"github.com/mattermost/mattermost/server/v8/einterfaces"
+)
+
+func MakeWorker(jobServer *jobs.JobServer, store store.Store, getMetrics func() einterfaces.MetricsInterface) *jobs.SimpleWorker {
+	const workerName = "MobileSessionMetadata"
+
+	isEnabled := func(cfg *model.Config) bool {
+		return *cfg.MetricsSettings.EnableClientMetrics
+	}
+	execute := func(logger mlog.LoggerIFace, job *model.Job) error {
+		defer jobServer.HandleJobPanic(logger, job)
+
+		metrics := getMetrics()
+		if metrics == nil {
+			return nil
+		}
+
+		versions, err := store.Session().GetMobileSessionMetadata()
+		if err != nil {
+			return err
+		}
+
+		metrics.ClearMobileClientSessionMetadata()
+		for _, v := range versions {
+			metrics.ObserveMobileClientSessionMetadata(v.Version, v.Platform, v.Count, v.NotificationDisabled)
+		}
+
+		return nil
+	}
+	worker := jobs.NewSimpleWorker(workerName, jobServer, execute, isEnabled)
+	return worker
+}