From eb018c417d990a14681e478ca535ff49c559e337 Mon Sep 17 00:00:00 2001
From: "Grot (@grafanabot)" <43478413+grafanabot@users.noreply.github.com>
Date: Tue, 15 Jun 2021 04:49:40 -0400
Subject: [PATCH] Alerting: Fix alert migration RefID generation (#35667)
 (#35679)

* Alerting: Fix alert migration RefID generation

if the alert has more than 26 conditions

* Remove TODO comment

* Make similar change under pkg/expr

(cherry picked from commit c997f646ccf7588129fe0ccbc016b74480e6c50f)

Co-authored-by: Sofia Papagiannaki <papagian@users.noreply.github.com>
---
 pkg/expr/translate/translate.go                   | 14 +++++++++-----
 .../sqlstore/migrations/ualert/cond_trans.go      | 15 ++++++++++-----
 2 files changed, 19 insertions(+), 10 deletions(-)

diff --git a/pkg/expr/translate/translate.go b/pkg/expr/translate/translate.go
index fb2b3192ff2..f7f77ba572c 100644
--- a/pkg/expr/translate/translate.go
+++ b/pkg/expr/translate/translate.go
@@ -13,6 +13,7 @@ import (
 	"github.com/grafana/grafana/pkg/models"
 	"github.com/grafana/grafana/pkg/services/ngalert/eval"
 	ngmodels "github.com/grafana/grafana/pkg/services/ngalert/models"
+	"github.com/grafana/grafana/pkg/util"
 )
 
 // DashboardAlertConditions turns dashboard alerting conditions into server side expression queries and a
@@ -279,10 +280,6 @@ const alpha = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
 
 // getNewRefID finds first capital letter in the alphabet not in use
 // to use for a new RefID. It errors if it runs out of letters.
-//
-// TODO: Research if there is a limit. If so enforce is by
-// number of queries not letters. If no limit generate more types
-// of refIDs.
 func getNewRefID(refIDs map[string][]int) (string, error) {
 	for _, r := range alpha {
 		sR := string(r)
@@ -291,7 +288,14 @@ func getNewRefID(refIDs map[string][]int) (string, error) {
 		}
 		return sR, nil
 	}
-	return "", fmt.Errorf("ran out of letters when creating expression")
+	for i := 0; i < 20; i++ {
+		sR := util.GenerateShortUID()
+		if _, ok := refIDs[sR]; ok {
+			continue
+		}
+		return sR, nil
+	}
+	return "", fmt.Errorf("failed to generate unique RefID")
 }
 
 // getRelativeDuration turns the alerting durations for dashboard conditions
diff --git a/pkg/services/sqlstore/migrations/ualert/cond_trans.go b/pkg/services/sqlstore/migrations/ualert/cond_trans.go
index 047fcd29cf4..d96d999ac27 100644
--- a/pkg/services/sqlstore/migrations/ualert/cond_trans.go
+++ b/pkg/services/sqlstore/migrations/ualert/cond_trans.go
@@ -6,6 +6,8 @@ import (
 	"sort"
 	"strings"
 	"time"
+
+	"github.com/grafana/grafana/pkg/util"
 )
 
 func transConditions(set dashAlertSettings, orgID int64, dsUIDMap dsUIDLookup) (*condition, error) {
@@ -211,10 +213,6 @@ const alpha = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
 
 // getNewRefID finds first capital letter in the alphabet not in use
 // to use for a new RefID. It errors if it runs out of letters.
-//
-// TODO: Research if there is a limit. If so enforce is by
-// number of queries not letters. If no limit generate more types
-// of refIDs.
 func getNewRefID(refIDs map[string][]int) (string, error) {
 	for _, r := range alpha {
 		sR := string(r)
@@ -223,7 +221,14 @@ func getNewRefID(refIDs map[string][]int) (string, error) {
 		}
 		return sR, nil
 	}
-	return "", fmt.Errorf("ran out of letters when creating expression")
+	for i := 0; i < 20; i++ {
+		sR := util.GenerateShortUID()
+		if _, ok := refIDs[sR]; ok {
+			continue
+		}
+		return sR, nil
+	}
+	return "", fmt.Errorf("failed to generate unique RefID")
 }
 
 // getRelativeDuration turns the alerting durations for dashboard conditions