Allowlist Error Messages (#907)

* allow certain error logs

src/plugins/nginx.go

@@ -47,7 +47,8 @@ var (
 		re.MustCompile(`.*\[alert\].*`),
 		re.MustCompile(`.*\[crit\].*`),
 	}
-	warningRegex = re.MustCompile(`.*\[warn\].*`)
+	warningRegex    = re.MustCompile(`.*\[warn\].*`)
+	ignoreErrorList = re.MustCompile(`.*(usage report| license expired).*`)
 )
 
 // Nginx is the metadata of our nginx binary
@@ -619,13 +620,13 @@ func (n *Nginx) tailLog(logFile string, errorChannel chan string) {
 	for {
 		select {
 		case d := <-data:
-			if warningRegex.MatchString(d) && n.config.Nginx.TreatWarningsAsErrors {
+			if warningRegex.MatchString(d) && n.config.Nginx.TreatWarningsAsErrors && !ignoreErrorList.MatchString(d) {
 				errorChannel <- d
 				return
 			}
 
 			for _, errorRegex := range reloadErrorList {
-				if errorRegex.MatchString(d) {
+				if errorRegex.MatchString(d) && !ignoreErrorList.MatchString(d) {
 					errorChannel <- d
 					return
 				}

src/plugins/nginx_test.go

@@ -1171,6 +1171,24 @@ func TestNginx_monitorLog(t *testing.T) {
 			treatWarningsAsErrors: false,
 			expected:              "",
 		},
+		{
+			name:                  "ignore error log: usage report ",
+			errorLog:              "2025/06/25 15:08:04 [error] 123456#123456: certificate verify error: (10:certificate has expired) during usage report",
+			treatWarningsAsErrors: false,
+			expected:              "",
+		},
+		{
+			name:                  "ignore error log: license expired ",
+			errorLog:              "2025/06/25 15:07:24 [alert] 123456#123456: license expired; the grace period will end in 71 days",
+			treatWarningsAsErrors: false,
+			expected:              "",
+		},
+		{
+			name:                  "ignore error log: usaage report 400",
+			errorLog:              "2024/12/25 15:00:04 [error] 123456#123456: server returned 400 during usage report",
+			treatWarningsAsErrors: false,
+			expected:              "",
+		},
 	}
 
 	for _, test := range tests {