From 723902f4cbdc9ef3bb6311ef92d7d89f76c0a126 Mon Sep 17 00:00:00 2001
From: Agniva De Sarker <agnivade@yahoo.co.in>
Date: Mon, 14 Jun 2021 15:00:18 +0530
Subject: [PATCH] MM-35030: Hoist GetDBVersion before creating store (#17764)

* MM-35030: Hoist GetDBVersion before creating store

The creation of the store included running the migrations
which means that SQL statements would be executed before
we could make the check for DB version.

We perform the DB check before running the migrations.

https://mattermost.atlassian.net/browse/MM-35030

```release-note
NONE
```

* fix lint error
---
 app/server.go           | 14 --------------
 store/sqlstore/store.go | 17 +++++++++++++++++
 2 files changed, 17 insertions(+), 14 deletions(-)

diff --git a/app/server.go b/app/server.go
index 8352e947cd..5bac16c67d 100644
--- a/app/server.go
+++ b/app/server.go
@@ -20,7 +20,6 @@ import (
 	"os/exec"
 	"path"
 	"runtime"
-	"strconv"
 	"strings"
 	"sync"
 	"sync/atomic"
@@ -360,19 +359,6 @@ func NewServer(options ...Option) (*Server, error) {
 	if s.newStore == nil {
 		s.newStore = func() (store.Store, error) {
 			s.sqlStore = sqlstore.New(s.Config().SqlSettings, s.Metrics)
-			if s.sqlStore.DriverName() == model.DATABASE_DRIVER_POSTGRES {
-				ver, err2 := s.sqlStore.GetDbVersion(true)
-				if err2 != nil {
-					return nil, errors.Wrap(err2, "cannot get DB version")
-				}
-				intVer, err2 := strconv.Atoi(ver)
-				if err2 != nil {
-					return nil, errors.Wrap(err2, "cannot parse DB version")
-				}
-				if intVer < sqlstore.MinimumRequiredPostgresVersion {
-					return nil, fmt.Errorf("minimum required postgres version is %s; found %s", sqlstore.VersionString(sqlstore.MinimumRequiredPostgresVersion), sqlstore.VersionString(intVer))
-				}
-			}
 
 			lcl, err2 := localcachelayer.NewLocalCacheLayer(
 				retrylayer.New(s.sqlStore),
diff --git a/store/sqlstore/store.go b/store/sqlstore/store.go
index 5da80a96f0..c42d8dc575 100644
--- a/store/sqlstore/store.go
+++ b/store/sqlstore/store.go
@@ -179,6 +179,23 @@ func New(settings model.SqlSettings, metrics einterfaces.MetricsInterface) *SqlS
 
 	store.initConnection()
 
+	if *settings.DriverName == model.DATABASE_DRIVER_POSTGRES {
+		ver, err := store.GetDbVersion(true)
+		if err != nil {
+			mlog.Critical("Cannot get DB version.", mlog.Err(err))
+			os.Exit(ExitGenericFailure)
+		}
+		intVer, err := strconv.Atoi(ver)
+		if err != nil {
+			mlog.Critical("Cannot parse DB version.", mlog.Err(err))
+			os.Exit(ExitGenericFailure)
+		}
+		if intVer < MinimumRequiredPostgresVersion {
+			mlog.Critical("Minimum Postgres version requirements not met.", mlog.String("Found", VersionString(intVer)), mlog.String("Wanted", VersionString(MinimumRequiredPostgresVersion)))
+			os.Exit(ExitGenericFailure)
+		}
+	}
+
 	err := store.migrate(migrationsDirectionUp)
 	if err != nil {
 		mlog.Critical("Failed to apply database migrations.", mlog.Err(err))