From 8b5862d44b057384f1656ac63c9f32b7dffc0dcf Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C5=81ukasz=20Mierzwa?= <l.mierzwa@gmail.com>
Date: Fri, 30 Nov 2018 23:14:59 +0000
Subject: [PATCH] chore(api): store cluster as a dict

This will allow silences to be grouped by cluster rather than by alertmanager instance
---
 alerts.go                       | 15 +++++++++------
 internal/models/alertmanager.go |  2 +-
 internal/slices/slices.go       | 21 +++++++++++++++++++++
 internal/slices/slices_test.go  | 19 +++++++++++++++++++
 4 files changed, 50 insertions(+), 7 deletions(-)

diff --git a/alerts.go b/alerts.go
index 267c7f189..404d78886 100644
--- a/alerts.go
+++ b/alerts.go
@@ -2,11 +2,13 @@ package main
 
 import (
 	"sort"
-	"strings"
 
 	"github.com/prymitive/karma/internal/alertmanager"
 	"github.com/prymitive/karma/internal/filters"
 	"github.com/prymitive/karma/internal/models"
+	"github.com/prymitive/karma/internal/slices"
+
+	log "github.com/sirupsen/logrus"
 )
 
 func getFiltersFromQuery(filterStrings []string) ([]filters.FilterT, bool) {
@@ -41,7 +43,11 @@ func getUpstreams() models.AlertmanagerAPISummary {
 	for _, upstream := range upstreams {
 		members := upstream.ClusterMemberNames()
 		sort.Strings(members)
-		key := strings.Join(members[:], "\n")
+		key, err := slices.StringSliceToSHA1(members)
+		if err != nil {
+			log.Errorf("slices.StringSliceToSHA1 error: %s", err)
+			continue
+		}
 		if _, found := clusters[key]; !found {
 			clusters[key] = members
 		}
@@ -63,10 +69,7 @@ func getUpstreams() models.AlertmanagerAPISummary {
 			summary.Counters.Failed++
 		}
 	}
-
-	for _, cluster := range clusters {
-		summary.Clusters = append(summary.Clusters, cluster)
-	}
+	summary.Clusters = clusters
 
 	return summary
 }
diff --git a/internal/models/alertmanager.go b/internal/models/alertmanager.go
index 718322822..6c7596d44 100644
--- a/internal/models/alertmanager.go
+++ b/internal/models/alertmanager.go
@@ -47,5 +47,5 @@ type AlertmanagerAPICounters struct {
 type AlertmanagerAPISummary struct {
 	Counters  AlertmanagerAPICounters `json:"counters"`
 	Instances []AlertmanagerAPIStatus `json:"instances"`
-	Clusters  [][]string              `json:"clusters"`
+	Clusters  map[string][]string     `json:"clusters"`
 }
diff --git a/internal/slices/slices.go b/internal/slices/slices.go
index a18d400e3..47cddf4fb 100644
--- a/internal/slices/slices.go
+++ b/internal/slices/slices.go
@@ -1,5 +1,10 @@
 package slices
 
+import (
+	"crypto/sha1"
+	"fmt"
+)
+
 // BoolInSlice returns true if given bool is found in a slice of bools
 func BoolInSlice(boolArray []bool, value bool) bool {
 	for _, s := range boolArray {
@@ -19,3 +24,19 @@ func StringInSlice(stringArray []string, value string) bool {
 	}
 	return false
 }
+
+// StringSliceToSHA1 returns a SHA1 hash computed from a slice of strings
+func StringSliceToSHA1(stringArray []string) (string, error) {
+	h := sha1.New()
+	for _, s := range stringArray {
+		_, err := h.Write([]byte(s))
+		if err != nil {
+			return "", err
+		}
+		_, err = h.Write([]byte("\n"))
+		if err != nil {
+			return "", err
+		}
+	}
+	return fmt.Sprintf("%x", h.Sum(nil)), nil
+}
diff --git a/internal/slices/slices_test.go b/internal/slices/slices_test.go
index dee989619..2e5fc01d1 100644
--- a/internal/slices/slices_test.go
+++ b/internal/slices/slices_test.go
@@ -111,3 +111,22 @@ func TestBoolInSlice(t *testing.T) {
 		}
 	}
 }
+
+func TestStringSliceToSHA1(t *testing.T) {
+	s, err := slices.StringSliceToSHA1([]string{"a", "b", "c"})
+	if err != nil {
+		t.Errorf("StringSliceToSHA1() returned error: %s", err)
+	}
+	if s == "" {
+		t.Errorf("StringSliceToSHA1() returned empty string")
+	}
+}
+
+func BenchmarkStringSliceToSHA1(b *testing.B) {
+	for _, stringSliceTest := range stringSliceTests {
+		_, err := slices.StringSliceToSHA1(stringSliceTest.array)
+		if err != nil {
+			b.Errorf("StringSliceToSHA1() returned error: %s", err)
+		}
+	}
+}