Article

Migrating Python 2 to 3 Across 450 Repositories

How we used AI-assisted code analysis to automate and orchestrate one of the largest Python migrations I've ever been part of.

PythonMigrationAIInfrastructure

Migrating from Python 2 to 3 is a well-understood problem — but doing it across 450+ repositories with zero downtime is a coordination challenge.

The Scale

  • 450+ repositories
  • Thousands of source files
  • Multiple service dependencies
  • Zero tolerance for production downtime

AI-Assisted Analysis

We leveraged Claude Code to automate data extraction across all repositories. The AI helped us:

  • Scan every repository for Python 2-specific patterns
  • Classify migration complexity per repo
  • Identify dependency chains and migration order
  • Generate initial migration candidates

Phased Rollout Strategy

  1. Analysis phase: AI-powered scanning of all 450+ repos
  2. Prioritization: Critical path services first, leaf services last
  3. Automated migration: Bulk conversion with manual review for edge cases
  4. Integration testing: Rigorous testing at each phase
  5. Production cutover: Phased rollouts maintaining 100% availability

Results

100% system availability throughout the transition. The AI-assisted approach reduced the manual analysis effort by an estimated 80%.