internet-connection-monitor v1.3.0 - Network Failure Phase Detection

[NickBorgers]

Summary

This release adds network failure phase detection and Chrome error code capture to provide precise diagnostics about which network layer failed (DNS, TCP, TLS, or HTTP) and the specific error that occurred.

🎉 Major Features

Network Failure Phase Detection

Automatically determines which network layer failed by analyzing timing data:

• dns - DNS resolution failed (hostname couldn't be resolved)
• tcp - TCP connection failed (DNS succeeded, but couldn't connect)
• tls - TLS handshake failed (connection established, but TLS negotiation failed)
• http - HTTP request failed (all connections succeeded, but HTTP request/response failed)
• unknown - Failure phase couldn't be determined

Chrome Error Code Capture

Captures and reports specific Chrome network error codes:

• DNS: ERR_NAME_NOT_RESOLVED, ERR_DNS_TIMED_OUT, ERR_DNS_SERVER_FAILED
• TCP: ERR_CONNECTION_REFUSED, ERR_CONNECTION_RESET, ERR_CONNECTION_TIMED_OUT
• TLS: ERR_SSL_PROTOCOL_ERROR, ERR_CERT_AUTHORITY_INVALID, ERR_CERT_DATE_INVALID
• HTTP: ERR_ABORTED, ERR_TIMED_OUT, ERR_EMPTY_RESPONSE

🔧 Configuration Options

No configuration changes required - the feature works automatically!

📊 Example Output

DNS Failure:

{
  "error": {
    "error_type": "ERR_NAME_NOT_RESOLVED",
    "error_message": "page load error net::ERR_NAME_NOT_RESOLVED",
    "failure_phase": "dns"
  },
  "timings": {
    "dns_lookup_ms": null,
    "tcp_connection_ms": null,
    "total_duration_ms": 107
  },
  "metadata": {
    "version": "1.3.0"
  }
}

TCP Timeout:

{
  "error": {
    "error_type": "ERR_CONNECTION_TIMED_OUT",
    "error_message": "page load error net::ERR_CONNECTION_TIMED_OUT",
    "failure_phase": "tcp"
  },
  "timings": {
    "dns_lookup_ms": 12,
    "tcp_connection_ms": null,
    "total_duration_ms": 30001
  }
}

🐛 Bug Fixes

• Fixed Elasticsearch index template to properly separate error fields from status fields
• Updated schema version to 2 with proper field mappings

📝 Technical Details

Implementation

• New Files:

  • internal/browser/network_listener.go - Captures Chrome network events
  • internal/browser/error_classifier.go - Infers failure phase from timing data
  • internal/browser/error_classifier_test.go - Comprehensive unit tests
  • GRAFANA_DASHBOARD_UPDATES.md - Guide for updating dashboards

• Modified Files:

  • internal/browser/controller_impl.go - Integrated network event capture
  • internal/models/result.go - Added FailurePhase field
  • elasticsearch-index-template.json - Updated schema for new fields
  • Documentation updates in README and ELASTICSEARCH_AND_GRAFANA.md

Testing

• ✅ Unit tests for phase inference logic (12 test cases)
• ✅ Unit tests for error code parsing (11 test cases)
• ✅ Docker build successful
• ✅ Integration tested with real DNS failures
• ✅ Verified JSON output matches specification

Breaking Changes

None - This is a non-breaking change (v1.3.0, minor version bump):

• Adds new optional field failure_phase to error object
• Changes error_type values from generic (timeout, dns) to specific Chrome codes
• Existing queries continue to work
• Dashboards will continue to function (though recommended to update)

📚 Documentation

All documentation has been updated:

• README.md with feature descriptions and examples
• ELASTICSEARCH_AND_GRAFANA.md with query examples
• GRAFANA_DASHBOARD_UPDATES.md with dashboard update guide
• Inline code documentation

🔍 Grafana Dashboard Updates

See GRAFANA_DASHBOARD_UPDATES.md for instructions on adding:

• "Failures by Phase" pie chart
• "Error Types by Phase" table
• Updated "Recent Failures" table with failure_phase column

Example queries:

# All DNS failures
error.failure_phase: "dns"

# Specific Chrome error
error.error_type: "ERR_NAME_NOT_RESOLVED"

# TLS certificate issues
error.failure_phase: "tls"

🚀 Next Steps After Merge

1. Tag release: git tag internet-connection-monitor-v1.3.0
2. Push tag: git push origin internet-connection-monitor-v1.3.0
3. Create GitHub release with gh release create (see CLAUDE.md)
4. CI/CD will automatically build and push Docker images
5. Update Grafana dashboards using GRAFANA_DASHBOARD_UPDATES.md

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