Add scan-config command to extract env placeholders from config files

[BLemine]

Summary

Adds a new scan-config command that extracts environment variable placeholders (${VAR} and ${VAR:default}) from Spring Boot and Quarkus configuration files (YAML and .properties formats). The command distinguishes between required variables (no default) and optional variables (with defaults), and can validate that all required variables are defined in local .env or .env.example files.

Key Changes

• New command scan-config (cmd/scan_config.go):

  • Scans one or more YAML or .properties config files for ${VAR} and ${VAR:default} placeholders
  • Supports multiple output formats: human-readable, JSON, and quiet (names only)
  • Integrates with existing .env parser to compare against local/example files
  • Implements --strict mode to exit with error if required variables are missing
  • Flags: --files, --format, --local, --example, --strict, --json, --quiet

• New internal/configscan package with modular extraction logic:

  • types.go: Core Placeholder and ScanResult types
  • extract.go: Regex-based placeholder extraction with deduplication
  • yaml.go: YAML file parsing with recursive tree walking to build key paths
  • props.go: Java .properties file parsing
  • Comprehensive test coverage for all extraction scenarios

• Test suite covering:

  • Placeholder extraction from various formats (required, optional, embedded, duplicates)
  • YAML parsing with nested keys and array indices
  • .properties file parsing with comments and edge cases
  • Default value extraction and preservation
  • Strict comparison logic for missing variables

• Documentation in README with usage examples, flag descriptions, and sample config formats

• Integration: Registered new command in cmd/root.go and added gopkg.in/yaml.v3 dependency

Implementation Details

• Placeholder regex validates variable names ([A-Z_][A-Z0-9_]*) to avoid false positives
• YAML walker builds dot-notation paths (e.g., spring.datasource.url) and array indices (e.g., servers.0.host)
• Deduplication prevents duplicate reporting of the same variable in the same source location
• Optional variables (with defaults) are tracked separately from required ones for clear reporting

https://claude.ai/code/session_011LtAmNkYuy2HPHQwL8dZyP