Mono repo -> Master (#22553)

Combines the following repositories into one:

https://github.com/mattermost/mattermost-server
https://github.com/mattermost/mattermost-webapp
https://github.com/mattermost/focalboard
https://github.com/mattermost/mattermost-plugin-playbooks

server/channels/store/sqlstore/context.go

@@ -0,0 +1,42 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+package sqlstore
+
+import (
+	"context"
+)
+
+// storeContextKey is the base type for all context keys for the store.
+type storeContextKey string
+
+// contextValue is a type to hold some pre-determined context values.
+type contextValue string
+
+// Different possible values of contextValue.
+const (
+	useMaster contextValue = "useMaster"
+)
+
+// WithMaster adds the context value that master DB should be selected for this request.
+func WithMaster(ctx context.Context) context.Context {
+	return context.WithValue(ctx, storeContextKey(useMaster), true)
+}
+
+// hasMaster is a helper function to check whether master DB should be selected or not.
+func hasMaster(ctx context.Context) bool {
+	if v := ctx.Value(storeContextKey(useMaster)); v != nil {
+		if res, ok := v.(bool); ok && res {
+			return true
+		}
+	}
+	return false
+}
+
+// DBXFromContext is a helper utility that returns the sqlx DB handle from a given context.
+func (ss *SqlStore) DBXFromContext(ctx context.Context) *sqlxDBWrapper {
+	if hasMaster(ctx) {
+		return ss.GetMasterX()
+	}
+	return ss.GetReplicaX()
+}