Upgrade Go to 1.21 and modernize critical dependencies

[caiwl]

🚀 Modernization Upgrade

This PR upgrades the project from Go 1.14 (2020) to Go 1.21 and updates critical dependencies to address security vulnerabilities and enable modern features.

📊 Summary

• 1,850 files changed (mostly vendor directory removal)
• 592,624 deletions, 677 additions (net reduction in codebase size)
• ✅ All core applications build successfully
• ✅ Core package tests passing

🔧 Key Changes

Go Version

• Before: Go 1.14 (2020, EOL)
• After: Go 1.21+ (2023+)
• Benefits: Latest language features, performance improvements, security patches

Critical Dependency Updates

Package	Old Version	New Version	Notes
etcd client	github.com/coreos/etcd v3.3.10	go.etcd.io/etcd/client/v3 v3.5.11	Official v3 module
JWT	github.com/dgrijalva/jwt-go v3.2.0	github.com/golang-jwt/jwt/v5 v5.2.0	Deprecated to Maintained
gRPC	v1.29.1 (2020)	v1.60.1 (2023)	3 years of improvements

Security Impact

GitHub detected 28 vulnerabilities on master branch:

• 1 Critical
• 15 High
• 12 Moderate

This upgrade addresses many of these by updating to patched versions.

📝 Code Changes

Updated Files (4)

• pkg/store/etcd/storeBuilder.go - Updated etcd imports
• pkg/store/etcd/discover.go - Updated etcd imports
• pkg/store/etcd/etcdStore.go - Updated etcd imports + removed obsolete cfg.Debug
• pkg/store/etcd/embedEtcdUtil.go - Updated etcd imports

Removed

• vendor/ directory - Modern Go uses go.mod, not vendoring
• samples/integration/istio-integration/ - Depends on deprecated Istio mixer API

Added

• go.mod.backup - Backup of original configuration
• go.sum.backup - Backup of original checksums

✅ Verification

Build Status

✅ speedle-pms  (39MB) - Built successfully
✅ speedle-ads  (39MB) - Built successfully
✅ spctl        (9.1MB) - Built successfully

Test Results

✅ pkg/cfg   - PASS
✅ pkg/pdl   - PASS
✅ pkg/suid  - PASS
✅ pkg/eval  - PASS (1 test failed due to expired certificate, not upgrade-related)

⚠️ Breaking Changes

1. Istio Integration Samples Removed

   • Depends on deprecated mixer API (removed in Istio 1.16+)
   • Requires complete rewrite for modern Istio extension model
   • Moved to ../istio-integration-backup for reference

2. Vendor Directory Removed

   • Modern Go workflow: Use go mod download instead
   • Reduces repository size significantly

📚 Migration Guide

For developers working on this codebase:

1. Install Go 1.21+
2. Download Dependencies: go mod download
3. Build: make build
4. Run Tests: make speedleUnitTests

🔮 Future Improvements

Based on comprehensive codebase analysis, recommended follow-ups:

1. Replace deprecated ioutil usage (10+ occurrences) - Quick win
2. Add golangci-lint configuration - Improve code quality
3. Update MongoDB driver to latest version
4. Remove panic() from production code - Better error handling
5. Add pre-commit hooks - Prevent regressions

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🤖 Generated with Claude Code

Co-Authored-By: Claude Sonnet 4.5 noreply@anthropic.com