From 5797d6ace3d4e7f5207deba35e73c729de019c25 Mon Sep 17 00:00:00 2001
From: John Tzikas <nronas@gmail.com>
Date: Wed, 18 Nov 2020 00:01:20 +0200
Subject: [PATCH] Add logic to skip duplicate table errors when initializing db
 (#16270)

* Add logic to skip duplicate table errors when initializing db

* Update store/sqlstore/supplier.go

Co-authored-by: Gabe Jackson <gabe@coffeepowered.co>

* Handle mysql and pg table already exist errors

* Apply PR suggestions
* Fix typo on IsDuplicate
* Update mysql error link to point to the official one

Co-authored-by: Gabe Jackson <gabe@coffeepowered.co>
---
 store/sqlstore/supplier.go      | 41 ++++++++++++++++++++++++++-------
 store/sqlstore/supplier_test.go | 21 +++++++++++++++++
 2 files changed, 54 insertions(+), 8 deletions(-)

diff --git a/store/sqlstore/supplier.go b/store/sqlstore/supplier.go
index 921a7fbfb1..3fb03cbc46 100644
--- a/store/sqlstore/supplier.go
+++ b/store/sqlstore/supplier.go
@@ -7,7 +7,6 @@ import (
 	"context"
 	dbsql "database/sql"
 	"encoding/json"
-	"errors"
 	"fmt"
 	"os"
 	"strings"
@@ -15,6 +14,8 @@ import (
 	"sync/atomic"
 	"time"
 
+	"github.com/pkg/errors"
+
 	sq "github.com/Masterminds/squirrel"
 	"github.com/dyatlov/go-opengraph/opengraph"
 	"github.com/go-sql-driver/mysql"
@@ -28,10 +29,12 @@ import (
 )
 
 const (
-	INDEX_TYPE_FULL_TEXT = "full_text"
-	INDEX_TYPE_DEFAULT   = "default"
-	DB_PING_ATTEMPTS     = 18
-	DB_PING_TIMEOUT_SECS = 10
+	INDEX_TYPE_FULL_TEXT       = "full_text"
+	INDEX_TYPE_DEFAULT         = "default"
+	PG_DUP_TABLE_ERROR_CODE    = "42P07"      // see https://github.com/lib/pq/blob/master/error.go#L268
+	MYSQL_DUP_TABLE_ERROR_CODE = uint16(1050) // see https://dev.mysql.com/doc/mysql-errors/5.7/en/server-error-reference.html#error_er_table_exists_error
+	DB_PING_ATTEMPTS           = 18
+	DB_PING_TIMEOUT_SECS       = 10
 )
 
 const (
@@ -176,9 +179,12 @@ func NewSqlSupplier(settings model.SqlSettings, metrics einterfaces.MetricsInter
 	supplier.stores.productNotices = newSqlProductNoticesStore(supplier)
 	err := supplier.GetMaster().CreateTablesIfNotExists()
 	if err != nil {
-		mlog.Critical("Error creating database tables.", mlog.Err(err))
-		time.Sleep(time.Second)
-		os.Exit(EXIT_CREATE_TABLE)
+		if IsDuplicate(err) {
+			mlog.Warn("Duplicate key error occurred; assuming table already created and proceeding.", mlog.Err(err))
+		} else {
+			mlog.Critical("Error creating database tables.", mlog.Err(err))
+			os.Exit(EXIT_CREATE_TABLE)
+		}
 	}
 
 	err = upgradeDatabase(supplier, model.CurrentVersion)
@@ -1319,3 +1325,22 @@ func convertMySQLFullTextColumnsToPostgres(columnNames string) string {
 
 	return concatenatedColumnNames
 }
+
+// IsDuplicate checks whether an error is a duplicate key error, which comes when processes are competing on creating the same
+// tables in the database.
+func IsDuplicate(err error) bool {
+	var pqErr *pq.Error
+	var mysqlErr *mysql.MySQLError
+	switch {
+	case errors.As(errors.Cause(err), &pqErr):
+		if pqErr.Code == PG_DUP_TABLE_ERROR_CODE {
+			return true
+		}
+	case errors.As(errors.Cause(err), &mysqlErr):
+		if mysqlErr.Number == MYSQL_DUP_TABLE_ERROR_CODE {
+			return true
+		}
+	}
+
+	return false
+}
diff --git a/store/sqlstore/supplier_test.go b/store/sqlstore/supplier_test.go
index 9168b14fbd..87fc4474bc 100644
--- a/store/sqlstore/supplier_test.go
+++ b/store/sqlstore/supplier_test.go
@@ -4,12 +4,16 @@
 package sqlstore_test
 
 import (
+	"fmt"
 	"regexp"
 	"sync"
 	"testing"
 
+	"github.com/go-sql-driver/mysql"
+	"github.com/lib/pq"
 	"github.com/mattermost/gorp"
 	_ "github.com/mattn/go-sqlite3"
+	"github.com/pkg/errors"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 
@@ -314,6 +318,23 @@ func TestGetAllConns(t *testing.T) {
 	}
 }
 
+func TestIsDuplicate(t *testing.T) {
+	testErrors := map[error]bool{
+		&pq.Error{Code: "42P06"}:                                       false,
+		&pq.Error{Code: sqlstore.PG_DUP_TABLE_ERROR_CODE}:              true,
+		&mysql.MySQLError{Number: uint16(1000)}:                        false,
+		&mysql.MySQLError{Number: sqlstore.MYSQL_DUP_TABLE_ERROR_CODE}: true,
+		errors.New("Random error"):                                     false,
+	}
+
+	for err, expected := range testErrors {
+		t.Run(fmt.Sprintf("Should return %t for %s", expected, err.Error()), func(t *testing.T) {
+			t.Parallel()
+			assert.Equal(t, expected, sqlstore.IsDuplicate(err))
+		})
+	}
+}
+
 func makeSqlSettings(driver string) *model.SqlSettings {
 	switch driver {
 	case model.DATABASE_DRIVER_POSTGRES: