End to End Example

package main

import (
	"bufio"
	"context"
	"fmt"
	"os"
	"strings"
	"time"
)

type Severity string

const (
	SeverityInfo     Severity = "INFO"
	SeverityWarning  Severity = "WARNING"
	SeverityCritical Severity = "CRITICAL"
	SeverityUnknown  Severity = "UNKNOWN"
)

type Classifier interface {
	Classify(ctx context.Context, line string) (Severity, error)
}

// Mock classifier.
// Replace this with a real LLM-backed implementation later.
type mockLLMClassifier struct{}

func (mockLLMClassifier) Classify(ctx context.Context, line string) (Severity, error) {
	select {
	case <-ctx.Done():
		return SeverityUnknown, ctx.Err()
	default:
	}

	lower := strings.ToLower(line)

	switch {
	case strings.Contains(lower, "panic"),
		strings.Contains(lower, "fatal"),
		strings.Contains(lower, "critical"),
		strings.Contains(lower, "out of memory"):
		return SeverityCritical, nil

	case strings.Contains(lower, "warn"),
		strings.Contains(lower, "deprecated"),
		strings.Contains(lower, "retry"):
		return SeverityWarning, nil

	default:
		return SeverityInfo, nil
	}
}

func colorize(sev Severity) string {
	switch sev {
	case SeverityInfo:
		return "\033[32mINFO\033[0m" // green

	case SeverityWarning:
		return "\033[33mWARNING\033[0m" // yellow

	case SeverityCritical:
		return "\033[31mCRITICAL\033[0m" // red

	default:
		return "\033[37mUNKNOWN\033[0m" // white
	}
}

func main() {
	var clf Classifier = mockLLMClassifier{}

	counts := map[Severity]int{
		SeverityInfo:     0,
		SeverityWarning:  0,
		SeverityCritical: 0,
		SeverityUnknown:  0,
	}

	scanner := bufio.NewScanner(os.Stdin)

	for scanner.Scan() {
		line := strings.TrimSpace(scanner.Text())
		if line == "" {
			continue
		}

		ctx, cancel := context.WithTimeout(
			context.Background(),
			5*time.Second,
		)

		sev, err := clf.Classify(ctx, line)
		cancel()

		if err != nil {
			fmt.Fprintf(os.Stderr, "classify error: %v\n", err)
			sev = SeverityUnknown
		}

		counts[sev]++

		fmt.Printf("%-18s | %s\n", colorize(sev), line)
	}

	if err := scanner.Err(); err != nil {
		fmt.Fprintf(os.Stderr, "read error: %v\n", err)
		os.Exit(2)
	}

	fmt.Printf(
		"\nsummary: info=%d warning=%d critical=%d unknown=%d\n",
		counts[SeverityInfo],
		counts[SeverityWarning],
		counts[SeverityCritical],
		counts[SeverityUnknown],
	)

	// Fail CI/CD if any critical log was seen.
	if counts[SeverityCritical] > 0 {
		os.Exit(1)
	}
}

printf 'pod started\nreadiness probe slow\nBack-off restarting failed\ncontainer CrashLoopBackOff\n' \
| go run ./cmd/triage

INFO     | pod started
WARNING  | readiness probe slow
CRITICAL | Back-off restarting failed container CrashLoopBackOff
summary: info=1 warning=1 critical=1 unknown=0

echo "exit code: $?"
exit code: 1