From f841a766d761a627e5f9a5e4fb958b8dcdc3e1be Mon Sep 17 00:00:00 2001
From: Augustin Husson <husson.augustin@gmail.com>
Date: Thu, 31 Oct 2024 12:11:25 +0100
Subject: [PATCH] Add promql expression to the usage block (fix #8)

Signed-off-by: Augustin Husson <husson.augustin@gmail.com>
---
 README.md                  | 15 ++++++++++-----
 database/database.go       |  8 ++++----
 pkg/api/v1/metric_usage.go |  7 ++++---
 source/rules/rules.go      | 14 ++++++++------
 4 files changed, 26 insertions(+), 18 deletions(-)

diff --git a/README.md b/README.md
index f690f5b..e9912d6 100644
--- a/README.md
+++ b/README.md
@@ -24,24 +24,28 @@ This tool provides an API that can be used to get the usage for each metrics col
         {
           "prom_link": "https://prometheus.demo.do.prometheus.io",
           "group_name": "node-exporter.rules",
-          "name": "instance:node_num_cpu:sum"
+          "name": "instance:node_num_cpu:sum",
+          "expression": "count without (cpu, mode) (node_cpu_seconds_total{job=\"node\",mode=\"idle\"})"
         },
         {
           "prom_link": "https://prometheus.demo.do.prometheus.io",
           "group_name": "node-exporter.rules",
-          "name": "instance:node_cpu_utilisation:rate5m"
+          "name": "instance:node_cpu_utilisation:rate5m",
+          "expression": "1 - avg without (cpu) (sum without (mode) (rate(node_cpu_seconds_total{job=\"node\",mode=~\"idle|iowait|steal\"}[5m])))"
         }
       ],
       "alertRules": [
         {
           "prom_link": "https://prometheus.demo.do.prometheus.io",
           "group_name": "node-exporter",
-          "name": "NodeCPUHighUsage"
+          "name": "NodeCPUHighUsage",
+          "expression": "sum without (mode) (avg without (cpu) (rate(node_cpu_seconds_total{job=\"node\",mode!=\"idle\"}[2m]))) * 100 > 90"
         },
         {
           "prom_link": "https://prometheus.demo.do.prometheus.io",
           "group_name": "node-exporter",
-          "name": "NodeSystemSaturation"
+          "name": "NodeSystemSaturation",
+          "expression": "node_load1{job=\"node\"} / count without (cpu, mode) (node_cpu_seconds_total{job=\"node\",mode=\"idle\"}) > 2"
         }
       ]
     }
@@ -52,7 +56,8 @@ This tool provides an API that can be used to get the usage for each metrics col
         {
           "prom_link": "https://prometheus.demo.do.prometheus.io",
           "group_name": "ansible managed alert rules",
-          "name": "NodeCPUUtilizationHigh"
+          "name": "NodeCPUUtilizationHigh",
+          "expression": "instance:node_cpu_utilisation:rate5m * 100 > ignoring (severity) node_cpu_utilization_percent_threshold{severity=\"critical\"}"
         }
       ]
     }
diff --git a/database/database.go b/database/database.go
index 52e2e81..0e801a4 100644
--- a/database/database.go
+++ b/database/database.go
@@ -192,16 +192,16 @@ func mergeSlice[T comparable](old, new []T) []T {
 	if len(new) == 0 {
 		return old
 	}
-	for _, oldDashboard := range old {
+	for _, a := range old {
 		found := false
-		for _, newDashboard := range new {
-			if oldDashboard == newDashboard {
+		for _, b := range new {
+			if a == b {
 				found = true
 				break
 			}
 		}
 		if !found {
-			new = append(new, oldDashboard)
+			new = append(new, a)
 		}
 	}
 	return new
diff --git a/pkg/api/v1/metric_usage.go b/pkg/api/v1/metric_usage.go
index 0a6882b..f759f19 100644
--- a/pkg/api/v1/metric_usage.go
+++ b/pkg/api/v1/metric_usage.go
@@ -14,9 +14,10 @@
 package v1
 
 type RuleUsage struct {
-	PromLink  string `json:"prom_link"`
-	GroupName string `json:"group_name"`
-	Name      string `json:"name"`
+	PromLink   string `json:"prom_link"`
+	GroupName  string `json:"group_name"`
+	Name       string `json:"name"`
+	Expression string `json:"expression"`
 }
 
 type MetricUsage struct {
diff --git a/source/rules/rules.go b/source/rules/rules.go
index a5cc4c1..189ec9c 100644
--- a/source/rules/rules.go
+++ b/source/rules/rules.go
@@ -93,9 +93,10 @@ func extractMetricUsageFromRules(ruleGroups []v1.RuleGroup, source string) map[s
 				populateUsage(metricUsage,
 					metricNames,
 					modelAPIV1.RuleUsage{
-						PromLink:  source,
-						GroupName: ruleGroup.Name,
-						Name:      v.Name,
+						PromLink:   source,
+						GroupName:  ruleGroup.Name,
+						Name:       v.Name,
+						Expression: v.Query,
 					},
 					false,
 				)
@@ -108,9 +109,10 @@ func extractMetricUsageFromRules(ruleGroups []v1.RuleGroup, source string) map[s
 				populateUsage(metricUsage,
 					metricNames,
 					modelAPIV1.RuleUsage{
-						PromLink:  source,
-						GroupName: ruleGroup.Name,
-						Name:      v.Name,
+						PromLink:   source,
+						GroupName:  ruleGroup.Name,
+						Name:       v.Name,
+						Expression: v.Query,
 					},
 					true,
 				)