error-pattern-analyzer

Error Pattern Analyzer

Identify recurring error patterns and systemic issues in your codebase.

When to Use

• Same errors appearing repeatedly
• Investigating production incidents
• Prioritizing bug fixes
• Finding root causes
• Analyzing error trends

Error Classification

By Frequency

Category	Frequency	Priority
Critical	>100/hour	P0 - Immediate
High	10-100/hour	P1 - Same day
Medium	1-10/hour	P2 - This week
Low	<1/hour	P3 - Backlog

By Impact

interface ErrorImpact {
  affectedUsers: number;
  revenue: 'blocking' | 'degraded' | 'none';
  dataIntegrity: 'at_risk' | 'safe';
  cascading: boolean; // Does it cause other failures?
}

Pattern Detection Workflow

Step 1: Collect Error Data

interface ErrorRecord {
  timestamp: Date;
  errorType: string;
  message: string;
  stackTrace: string;
  context: {
    userId?: string;
    endpoint?: string;
    input?: unknown;
    environment: string;
  };
  metadata: Record<string, unknown>;
}

// Aggregate errors over time window
async function collectErrors(
  timeRange: { start: Date; end: Date }
): Promise<ErrorRecord[]> {
  return errorStore.query({
    timestamp: { $gte: timeRange.start, $lte: timeRange.end }
  });
}

Step 2: Group by Similarity

function groupErrors(errors: ErrorRecord[]): ErrorGroup[] {
  const groups = new Map<string, ErrorRecord[]>();

  for (const error of errors) {
    // Create fingerprint from error type + normalized message
    const fingerprint = createFingerprint(error);
    const existing = groups.get(fingerprint) || [];
    existing.push(error);
    groups.set(fingerprint, existing);
  }

  return Array.from(groups.entries()).map(([fp, errs]) => ({
    fingerprint: fp,
    count: errs.length,
    firstSeen: errs[0].timestamp,
    lastSeen: errs[errs.length - 1].timestamp,
    sample: errs[0],
    affectedUsers: new Set(errs.map(e => e.context.userId)).size
  }));
}

function createFingerprint(error: ErrorRecord): string {
  // Normalize message (remove variable parts)
  const normalizedMessage = error.message
    .replace(/\b[0-9a-f]{8,}\b/gi, '<ID>') // UUIDs, hashes
    .replace(/\d{4}-\d{2}-\d{2}/g, '<DATE>') // Dates
    .replace(/\d+/g, '<N>'); // Numbers

  // Use first meaningful stack frame
  const keyFrame = extractKeyFrame(error.stackTrace);

  return `${error.errorType}:${normalizedMessage}:${keyFrame}`;
}