pkg/prometheus/promcfg*.go: Validate EnforcedBodySizeLimit

Related to #4282

Signed-off-by: Jayapriya Pai <slashpai9@gmail.com>

pkg/prometheus/promcfg.go

@@ -1804,10 +1804,22 @@ func (l *limitEnforcer) addBodySizeLimitsToYAML(cfg yaml.MapSlice, enforcedLimit
 		return cfg
 	}
 
+	if !validInput("^(0[K,M,G,T,P,E]*B$|[1-9]\\d+[K,M,G,T,P,E]*B$)", enforcedLimit) {
+		level.Warn(l.logger).Log("msg", "body_size_limit provided is invalid it should be a format of size",
+			"enforcedBodySizeLimit", enforcedLimit)
+		return cfg
+	}
+
 	if l.prometheusVersion.LT(semver.MustParse("2.28.0")) {
 		level.Warn(l.logger).Log("msg", "body_size_limit is only available starting from prometheus 2.28.0",
 			"version", l.prometheusVersion)
 		return cfg
 	}
+
 	return append(cfg, yaml.MapItem{Key: "body_size_limit", Value: enforcedLimit})
 }
+
+func validInput(regex, input string) bool {
+	matched, _ := regexp.MatchString(regex, input)
+	return matched
+}

pkg/prometheus/promcfg_test.go

@@ -5802,6 +5802,31 @@ alerting:
 			enforcedBodySizeLimit: "",
 			expected:              expectNoLimit,
 		},
+		{
+			version:               "v2.28.0",
+			enforcedBodySizeLimit: "0B",
+			expected:              fmt.Sprintf(expectLimit, "0B"),
+		},
+		{
+			version:               "v2.28.0",
+			enforcedBodySizeLimit: "100",
+			expected:              expectNoLimit,
+		},
+		{
+			version:               "v2.28.0",
+			enforcedBodySizeLimit: "200kb",
+			expected:              expectNoLimit,
+		},
+		{
+			version:               "v2.28.0",
+			enforcedBodySizeLimit: "300 MB",
+			expected:              expectNoLimit,
+		},
+		{
+			version:               "v2.28.0",
+			enforcedBodySizeLimit: "300M",
+			expected:              expectNoLimit,
+		},
 	} {
 		t.Run(fmt.Sprintf("%s enforcedBodySizeLimit(%s)", tc.version, tc.enforcedBodySizeLimit), func(t *testing.T) {
 			cg := NewConfigGenerator(log.NewLogfmtLogger(os.Stdout))