Class: Lyra::Schema::Diff

Inherits:
Object
  • Object
show all
Defined in:
lib/lyra/schema/diff.rb

Overview

Compares schemas and produces human-readable difference reports

Constant Summary collapse

SEVERITIES =

Severity levels for different types of changes

{
  model_added: :info,
  model_removed: :breaking,
  column_added: :info,
  column_removed: :breaking,
  column_type_changed: :breaking,
  column_nullable_changed: :warning,
  column_limit_changed: :warning,
  pii_field_added: :warning,
  pii_field_removed: :info,
  event_name_changed: :breaking,
  event_prefix_changed: :warning,
  config_changed: :info
}.freeze

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.compare(old_schema, new_schema) ⇒ Object 



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# File 'lib/lyra/schema/diff.rb', line 24

def compare(old_schema, new_schema)
  new.compare(old_schema, new_schema)
end

.format_report(differences) ⇒ Object 



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# File 'lib/lyra/schema/diff.rb', line 28

def format_report(differences)
  new.format_report(differences)
end

Instance Method Details

#compare(old_schema, new_schema) ⇒ Object 



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# File 'lib/lyra/schema/diff.rb', line 33

def compare(old_schema, new_schema)
  differences = []

  # Compare models (normalize keys to strings for comparison)
  old_models = normalize_keys(old_schema[:models] || {})
  new_models = normalize_keys(new_schema[:models] || {})

  # Check for removed models
  (old_models.keys - new_models.keys).each do |model_name|
    differences << {
      type: :model_removed,
      severity: SEVERITIES[:model_removed],
      model: model_name,
      message: "Model '#{model_name}' was removed from monitoring"
    }
  end

  # Check for added models
  (new_models.keys - old_models.keys).each do |model_name|
    differences << {
      type: :model_added,
      severity: SEVERITIES[:model_added],
      model: model_name,
      message: "Model '#{model_name}' was added to monitoring"
    }
  end

  # Compare existing models
  (old_models.keys & new_models.keys).each do |model_name|
    differences += compare_model(
      model_name,
      old_models[model_name],
      new_models[model_name]
    )
  end

  # Compare configuration changes
  differences += compare_configuration(
    old_schema[:configuration] || {},
    new_schema[:configuration] || {}
  )

  differences
end

#compare_column(model_name, col_name, old_col, new_col) ⇒ Object 



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# File 'lib/lyra/schema/diff.rb', line 144

def compare_column(model_name, col_name, old_col, new_col)
  differences = []

  # Use string keys (columns are already normalized)
  old_type = old_col["type"]
  new_type = new_col["type"]
  old_nullable = old_col["nullable"]
  new_nullable = new_col["nullable"]
  old_limit = old_col["limit"]
  new_limit = new_col["limit"]
  old_pii = old_col["pii"]
  new_pii = new_col["pii"]

  # Type change
  if old_type != new_type
    differences << {
      type: :column_type_changed,
      severity: SEVERITIES[:column_type_changed],
      model: model_name,
      column: col_name,
      old_value: old_type,
      new_value: new_type,
      message: "#{model_name}.#{col_name} type changed: #{old_type} -> #{new_type}"
    }
  end

  # Nullable change
  if old_nullable != new_nullable
    differences << {
      type: :column_nullable_changed,
      severity: SEVERITIES[:column_nullable_changed],
      model: model_name,
      column: col_name,
      old_value: old_nullable,
      new_value: new_nullable,
      message: "#{model_name}.#{col_name} nullable changed: #{old_nullable} -> #{new_nullable}"
    }
  end

  # Limit change
  if old_limit != new_limit
    differences << {
      type: :column_limit_changed,
      severity: SEVERITIES[:column_limit_changed],
      model: model_name,
      column: col_name,
      old_value: old_limit,
      new_value: new_limit,
      message: "#{model_name}.#{col_name} limit changed: #{old_limit} -> #{new_limit}"
    }
  end

  # PII detection change
  if old_pii != new_pii
    type = new_pii ? :pii_field_added : :pii_field_removed
    differences << {
      type: type,
      severity: SEVERITIES[type],
      model: model_name,
      column: col_name,
      message: "#{model_name}.#{col_name} PII status changed: #{old_pii} -> #{new_pii}"
    }
  end

  differences
end

#compare_columns(model_name, old_columns, new_columns) ⇒ Object 



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# File 'lib/lyra/schema/diff.rb', line 106

def compare_columns(model_name, old_columns, new_columns)
  differences = []

  # Removed columns
  (old_columns.keys - new_columns.keys).each do |col_name|
    differences << {
      type: :column_removed,
      severity: SEVERITIES[:column_removed],
      model: model_name,
      column: col_name,
      message: "Column '#{col_name}' removed from #{model_name}"
    }
  end

  # Added columns
  (new_columns.keys - old_columns.keys).each do |col_name|
    col_info = new_columns[col_name]
    msg = "Column '#{col_name}' added to #{model_name}"
    msg += " (PII: #{col_info["pii_type"]})" if col_info["pii"]

    differences << {
      type: :column_added,
      severity: SEVERITIES[:column_added],
      model: model_name,
      column: col_name,
      pii: col_info["pii"],
      message: msg
    }
  end

  # Changed columns
  (old_columns.keys & new_columns.keys).each do |col_name|
    differences += compare_column(model_name, col_name, old_columns[col_name], new_columns[col_name])
  end

  differences
end

#compare_configuration(old_config, new_config) ⇒ Object 



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# File 'lib/lyra/schema/diff.rb', line 243

def compare_configuration(old_config, new_config)
  differences = []

  # Normalize to string keys for comparison
  old_cfg = normalize_keys(old_config)
  new_cfg = normalize_keys(new_config)

  %w[mode strict_schema projection_mode].each do |key|
    old_val = old_cfg[key]
    new_val = new_cfg[key]

    # Normalize values to strings for comparison
    old_val_str = old_val.to_s if old_val
    new_val_str = new_val.to_s if new_val

    if old_val_str != new_val_str
      differences << {
        type: :config_changed,
        severity: SEVERITIES[:config_changed],
        key: key,
        old_value: old_val,
        new_value: new_val,
        message: "Configuration '#{key}' changed: #{old_val} -> #{new_val}"
      }
    end
  end

  differences
end

#compare_events(model_name, old_events, new_events) ⇒ Object 



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# File 'lib/lyra/schema/diff.rb', line 211

def compare_events(model_name, old_events, new_events)
  differences = []

  # Check for event name changes (removed + added = renamed)
  removed_events = old_events.keys - new_events.keys
  added_events = new_events.keys - old_events.keys

  # Detect renames by matching operations
  removed_events.each do |old_name|
    old_op = old_events[old_name]["operation"]

    matching_new = added_events.find do |new_name|
      new_events[new_name]["operation"] == old_op
    end

    if matching_new
      differences << {
        type: :event_name_changed,
        severity: SEVERITIES[:event_name_changed],
        model: model_name,
        old_value: old_name,
        new_value: matching_new,
        operation: old_op,
        message: "#{model_name} event renamed: #{old_name} -> #{matching_new}"
      }
      added_events.delete(matching_new)
    end
  end

  differences
end

#compare_model(model_name, old_model, new_model) ⇒ Object 



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# File 'lib/lyra/schema/diff.rb', line 78

def compare_model(model_name, old_model, new_model)
  differences = []

  # Access with string keys (models are already normalized)
  old_prefix = old_model["event_prefix"]
  new_prefix = new_model["event_prefix"]

  # Compare event prefix
  if old_prefix != new_prefix
    differences << {
      type: :event_prefix_changed,
      severity: SEVERITIES[:event_prefix_changed],
      model: model_name,
      old_value: old_prefix,
      new_value: new_prefix,
      message: "#{model_name} event_prefix changed: '#{old_prefix}' -> '#{new_prefix}'"
    }
  end

  # Compare columns
  differences += compare_columns(model_name, old_model["columns"] || {}, new_model["columns"] || {})

  # Compare events
  differences += compare_events(model_name, old_model["events"] || {}, new_model["events"] || {})

  differences
end

#format_report(differences) ⇒ Object 



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# File 'lib/lyra/schema/diff.rb', line 273

def format_report(differences)
  return "No schema changes detected." if differences.empty?

  lines = ["Schema Changes Detected:"]
  lines << "=" * 60

  grouped = differences.group_by { |d| d[:severity] }

  [:breaking, :warning, :info].each do |severity|
    next unless grouped[severity]&.any?

    lines << ""
    icon = severity_icon(severity)
    lines << "#{icon} #{severity.to_s.upcase} (#{grouped[severity].size}):"
    lines << "-" * 40

    grouped[severity].each do |diff|
      lines << "  - #{diff[:message]}"
    end
  end

  lines << ""
  lines << "=" * 60

  # Add action suggestions
  if grouped[:breaking]&.any?
    lines << ""
    lines << "ACTION REQUIRED: Breaking changes detected."
    lines << "Run 'rake lyra:schema:update' to create a new schema version."
  end

  lines.join("\n")
end