From 7af095399587e5266cf5b0a6f5bae027c7f40f96 Mon Sep 17 00:00:00 2001
From: Jorge Turrado Ferrero <Jorge_turrado@hotmail.es>
Date: Fri, 4 Nov 2022 15:58:08 +0100
Subject: [PATCH] fix(prometheus scaler): Detect Inf before casting float to
 int (#3762)

* fix(prometheus scaler): Detect Inf before casting float to int

Signed-off-by: Jorge Turrado <jorge_turrado@hotmail.es>

* Improve the log message

Signed-off-by: Jorge Turrado <jorge_turrado@hotmail.es>

Signed-off-by: Jorge Turrado <jorge_turrado@hotmail.es>
---
 CHANGELOG.md                          |  1 +
 pkg/scalers/prometheus_scaler.go      | 10 ++++++++
 pkg/scalers/prometheus_scaler_test.go | 36 +++++++++++++++++++++++++++
 3 files changed, 47 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 036febe38e0..4ae27c0482f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -63,6 +63,7 @@ To learn more about active deprecations, we recommend checking [GitHub Discussio
 - **General:** Provide patch for CVE-2022-3172 vulnerability ([#3690](https://github.com/kedacore/keda/issues/3690))
 - **General:** Respect optional parameter inside envs for ScaledJobs ([#3568](https://github.com/kedacore/keda/issues/3568))
 - **Azure Blob Scaler** Store forgotten logger ([#3811](https://github.com/kedacore/keda/issues/3811))
+- **Prometheus Scaler:** Treat Inf the same as Null result ([#3644](https://github.com/kedacore/keda/issues/3644))
 
 ### Deprecations
 
diff --git a/pkg/scalers/prometheus_scaler.go b/pkg/scalers/prometheus_scaler.go
index e8450331d91..4a64c27aca2 100644
--- a/pkg/scalers/prometheus_scaler.go
+++ b/pkg/scalers/prometheus_scaler.go
@@ -5,6 +5,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
+	"math"
 	"net/http"
 	url_pkg "net/url"
 	"strconv"
@@ -297,6 +298,15 @@ func (s *prometheusScaler) ExecutePromQuery(ctx context.Context) (float64, error
 		}
 	}
 
+	if math.IsInf(v, 0) {
+		if s.metadata.ignoreNullValues {
+			return 0, nil
+		}
+		err := fmt.Errorf("promtheus query returns %f", v)
+		s.logger.Error(err, "Error converting prometheus value")
+		return -1, err
+	}
+
 	return v, nil
 }
 
diff --git a/pkg/scalers/prometheus_scaler_test.go b/pkg/scalers/prometheus_scaler_test.go
index 2ac606c4615..674622cac7a 100644
--- a/pkg/scalers/prometheus_scaler_test.go
+++ b/pkg/scalers/prometheus_scaler_test.go
@@ -228,6 +228,42 @@ var testPromQueryResult = []prometheusQromQueryResultTestData{
 		ignoreNullValues: true,
 		unsafeSsl:        true,
 	},
+	{
+		name:             "+Inf",
+		bodyStr:          `{"data":{"result":[{"value": ["1", "+Inf"]}]}}`,
+		responseStatus:   http.StatusOK,
+		expectedValue:    0,
+		isError:          false,
+		ignoreNullValues: true,
+		unsafeSsl:        true,
+	},
+	{
+		name:             "+Inf but shouldn't ignore ",
+		bodyStr:          `{"data":{"result":[{"value": ["1", "+Inf"]}]}}`,
+		responseStatus:   http.StatusOK,
+		expectedValue:    -1,
+		isError:          true,
+		ignoreNullValues: false,
+		unsafeSsl:        true,
+	},
+	{
+		name:             "-Inf",
+		bodyStr:          `{"data":{"result":[{"value": ["1", "-Inf"]}]}}`,
+		responseStatus:   http.StatusOK,
+		expectedValue:    0,
+		isError:          false,
+		ignoreNullValues: true,
+		unsafeSsl:        true,
+	},
+	{
+		name:             "-Inf but shouldn't ignore ",
+		bodyStr:          `{"data":{"result":[{"value": ["1", "-Inf"]}]}}`,
+		responseStatus:   http.StatusOK,
+		expectedValue:    -1,
+		isError:          true,
+		ignoreNullValues: false,
+		unsafeSsl:        true,
+	},
 }
 
 func TestPrometheusScalerExecutePromQuery(t *testing.T) {