initial commit

internal/parser/error.go

@@ -0,0 +1,67 @@
+package parser
+
+import (
+	"fmt"
+	"regexp"
+	"strconv"
+	"time"
+)
+
+// ErrorEntry holds a parsed nginx error log entry.
+type ErrorEntry struct {
+	Time    time.Time
+	Level   string // debug/info/notice/warn/error/crit/alert/emerg
+	PID     int
+	TID     int
+	ConnID  int // 0 if not present
+	Message string
+}
+
+// errorLogRe matches nginx error log format.
+// Groups: time, level, pid, tid, connID (optional), message
+var errorLogRe = regexp.MustCompile(
+	`^(\d{4}/\d{2}/\d{2} \d{2}:\d{2}:\d{2}) \[(\w+)\] (\d+)#(\d+): (?:\*(\d+) )?(.+)$`,
+)
+
+const errorTimeLayout = "2006/01/02 15:04:05"
+
+// ParseErrorLine parses a single nginx error log line.
+// Returns an error for malformed lines.
+func ParseErrorLine(line string) (ErrorEntry, error) {
+	m := errorLogRe.FindStringSubmatch(line)
+	if m == nil {
+		return ErrorEntry{}, fmt.Errorf("error: no match: %q", line)
+	}
+
+	t, err := time.ParseInLocation(errorTimeLayout, m[1], time.UTC)
+	if err != nil {
+		return ErrorEntry{}, fmt.Errorf("error: parse time %q: %w", m[1], err)
+	}
+
+	pid, err := strconv.Atoi(m[3])
+	if err != nil {
+		return ErrorEntry{}, fmt.Errorf("error: parse pid %q: %w", m[3], err)
+	}
+
+	tid, err := strconv.Atoi(m[4])
+	if err != nil {
+		return ErrorEntry{}, fmt.Errorf("error: parse tid %q: %w", m[4], err)
+	}
+
+	var connID int
+	if m[5] != "" {
+		connID, err = strconv.Atoi(m[5])
+		if err != nil {
+			return ErrorEntry{}, fmt.Errorf("error: parse connid %q: %w", m[5], err)
+		}
+	}
+
+	return ErrorEntry{
+		Time:    t,
+		Level:   m[2],
+		PID:     pid,
+		TID:     tid,
+		ConnID:  connID,
+		Message: m[6],
+	}, nil
+}