Class: Synthra::MigrationGenerator

Inherits:
Object
  • Object
show all
Defined in:
lib/synthra/migration_generator.rb

Overview

Schema Migration Generator

Generate database migrations from schema changes. Works with the ContractsRegistry to track versions and produce Rails-compatible migrations.

Examples:

Generate migration from diff

MigrationGenerator.generate(
  from: "User@v1.0.0",
  to: "User@v2.0.0",
  output: "db/migrate/"
)

CLI

$ synthra schema migrate User --from v1.0.0 --to v2.0.0

Constant Summary collapse

TYPE_MAP =

Type mapping from Synthra to ActiveRecord

{
  "text" => "string",
  "name" => "string",
  "email" => "string",
  "url" => "string",
  "paragraph" => "text",
  "uuid" => "uuid",
  "number" => "integer",
  "integer" => "integer",
  "float" => "float",
  "money" => "decimal, precision: 10, scale: 2",
  "decimal" => "decimal, precision: 10, scale: 2",
  "boolean" => "boolean",
  "timestamp" => "datetime",
  "datetime" => "datetime",
  "date" => "date",
  "time" => "time",
  "object" => "jsonb",
  "json" => "jsonb",
  "binary" => "binary",
  "array" => "text, array: true"
}.freeze

Class Method Summary collapse

Class Method Details

.build_create_table_migration(schema) ⇒ Object (private) 



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# File 'lib/synthra/migration_generator.rb', line 240

def build_create_table_migration(schema)
  table_name = pluralize(underscore(schema.name))
  class_name = "Create#{pluralize(schema.name)}"

  columns = schema.fields.map do |field|
    ar_type = TYPE_MAP[field.type_name] || "string"
    null = field.optional? || field.nullable? ? "null: true" : "null: false"

    if field.name == "id"
      nil # Skip id, handled by primary key
    else
      "      t.#{ar_type.split(',').first} :#{field.name}, #{null}"
    end
  end.compact

  # Check for timestamps
  has_created_at = schema.fields.any? { |f| f.name == "created_at" }
  has_updated_at = schema.fields.any? { |f| f.name == "updated_at" }

  timestamps = if has_created_at && has_updated_at
                 columns.reject! { |c| c.include?(":created_at") || c.include?(":updated_at") }
                 "\n      t.timestamps"
               else
                 ""
               end

  <<~MIGRATION
    # frozen_string_literal: true

    # Generated by Synthra
    # Schema: #{schema.name}

    class #{class_name} < ActiveRecord::Migration[7.1]
      def change
        create_table :#{table_name}, id: :uuid do |t|
    #{columns.join("\n")}#{timestamps}
        end
      end
    end
  MIGRATION
end

.build_migration(old_schema, new_schema, diff, options) ⇒ Object (private) 



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# File 'lib/synthra/migration_generator.rb', line 178

def build_migration(old_schema, new_schema, diff, options)
  table_name = pluralize(underscore(new_schema.name))
  class_name = "Migrate#{old_schema.name}To#{new_schema.name.sub(/.*/, '')}"

  # If versions exist in names
  if old_schema.name.include?("@") || new_schema.name.include?("@")
    old_version = old_schema.name.split("@").last rescue "v1"
    new_version = new_schema.name.split("@").last rescue "v2"
    class_name = "Migrate#{old_schema.name.split('@').first}#{old_version.gsub('.', '')}To#{new_version.gsub('.', '')}"
  else
    class_name = "Update#{new_schema.name}Schema"
  end

  changes = []

  # Added columns
  diff[:added].each do |name|
    field = diff[:new_fields][name]
    ar_type = TYPE_MAP[field.type_name] || "string"
    null = field.optional? || field.nullable? ? "null: true" : "null: false"
    changes << "    add_column :#{table_name}, :#{name}, :#{ar_type}, #{null}"
  end

  # Removed columns
  diff[:removed].each do |name|
    field = diff[:old_fields][name]
    ar_type = TYPE_MAP[field.type_name] || "string"
    changes << "    remove_column :#{table_name}, :#{name}, :#{ar_type}"
  end

  # Type changes
  diff[:type_changed].each do |name|
    old_field = diff[:old_fields][name]
    new_field = diff[:new_fields][name]
    new_type = TYPE_MAP[new_field.type_name] || "string"
    changes << "    change_column :#{table_name}, :#{name}, :#{new_type}  # was: #{old_field.type_name}"
  end

  # Nullable changes
  diff[:nullable_changed].each do |name|
    next if diff[:type_changed].include?(name)

    new_field = diff[:new_fields][name]
    null = new_field.optional? || new_field.nullable?
    changes << "    change_column_null :#{table_name}, :#{name}, #{null}"
  end

  <<~MIGRATION
    # frozen_string_literal: true

    # Generated by Synthra
    # From: #{old_schema.name}
    # To: #{new_schema.name}

    class #{class_name} < ActiveRecord::Migration[7.1]
      def change
    #{changes.join("\n")}
      end
    end
  MIGRATION
end

.calculate_diff(old_schema, new_schema) ⇒ Object (private) 



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# File 'lib/synthra/migration_generator.rb', line 159

def calculate_diff(old_schema, new_schema)
  old_fields = old_schema.fields.each_with_object({}) { |f, h| h[f.name] = f }
  new_fields = new_schema.fields.each_with_object({}) { |f, h| h[f.name] = f }

  {
    added: new_fields.keys - old_fields.keys,
    removed: old_fields.keys - new_fields.keys,
    type_changed: (old_fields.keys & new_fields.keys).select do |name|
      old_fields[name].type_name != new_fields[name].type_name
    end,
    nullable_changed: (old_fields.keys & new_fields.keys).select do |name|
      old_fields[name].nullable? != new_fields[name].nullable? ||
        old_fields[name].optional? != new_fields[name].optional?
    end,
    old_fields: old_fields,
    new_fields: new_fields
  }
end

.create_table(schema, output: nil) ⇒ String

Generate initial migration for a schema

Parameters:

  • schema (Schema, String) —

    schema to migrate

  • output (String) (defaults to: nil) —

    output directory

Returns:

  • (String) —

    migration content or file path



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# File 'lib/synthra/migration_generator.rb', line 126

def create_table(schema, output: nil)
  schema = resolve_schema(schema) if schema.is_a?(String)

  migration = build_create_table_migration(schema)

  if output
    write_migration(migration, output, nil, schema, action: "create")
  else
    migration
  end
end

.from_files(old_path:, new_path:, output: nil) ⇒ String

Generate migration from two schema files

Parameters:

  • old_path (String) —

    path to old schema

  • new_path (String) —

    path to new schema

  • output (String) (defaults to: nil) —

    output directory

Returns:

  • (String) —

    migration content or file path



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# File 'lib/synthra/migration_generator.rb', line 97

def from_files(old_path:, new_path:, output: nil)
  old_reg = Synthra::Registry.new
  old_reg.load_file(old_path)
  old_schemas = old_reg.schemas.values

  new_reg = Synthra::Registry.new
  new_reg.load_file(new_path)
  new_schemas = new_reg.schemas.values

  # Match by name
  old_schema = old_schemas.first
  new_schema = new_schemas.first

  diff = calculate_diff(old_schema, new_schema)
  migration = build_migration(old_schema, new_schema, diff, {})

  if output
    write_migration(migration, output, old_schema, new_schema)
  else
    migration
  end
end

.generate(from:, to:, output: nil, **options) ⇒ String

Generate a migration from schema changes

Parameters:

  • from (String) —

    source schema/version

  • to (String) —

    target schema/version

  • output (String) (defaults to: nil) —

    output directory

  • options (Hash) —

    generation options

Returns:

  • (String) —

    migration file path



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# File 'lib/synthra/migration_generator.rb', line 76

def generate(from:, to:, output: nil, **options)
  from_schema = resolve_schema(from)
  to_schema = resolve_schema(to)

  diff = calculate_diff(from_schema, to_schema)
  migration = build_migration(from_schema, to_schema, diff, options)

  if output
    write_migration(migration, output, from_schema, to_schema)
  else
    migration
  end
end

.pluralize(str) ⇒ Object (private)

Simple pluralization



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# File 'lib/synthra/migration_generator.rb', line 56

def pluralize(str)
  if str.end_with?('s', 'x', 'z', 'ch', 'sh')
    "#{str}es"
  elsif str.end_with?('y') && !%w[a e i o u].include?(str[-2])
    "#{str[0..-2]}ies"
  else
    "#{str}s"
  end
end

.resolve_schema(identifier) ⇒ Object (private) 



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# File 'lib/synthra/migration_generator.rb', line 140

def resolve_schema(identifier)
  # Handle versioned identifiers like "User@v1.0.0"
  if identifier.include?("@")
    name, version = identifier.split("@")
    contracts = Synthra::ContractsRegistry.new("contracts")
    contract = contracts.get(name, version: version)
    raise ArgumentError, "Contract not found: #{identifier}" unless contract

    # Rebuild schema from contract
    reg = Synthra::Registry.new
    reg.load_string(contract[:dsl_content])
    reg.schemas.values.first
  elsif Synthra.registry.schema?(identifier)
    Synthra.registry.schema(identifier)
  else
    raise ArgumentError, "Schema not found: #{identifier}"
  end
end

.underscore(str) ⇒ Object (private)

Convert CamelCase to snake_case



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# File 'lib/synthra/migration_generator.rb', line 49

def underscore(str)
  str.gsub(/([A-Z]+)([A-Z][a-z])/, '\1_\2')
     .gsub(/([a-z\d])([A-Z])/, '\1_\2')
     .downcase
end

.write_migration(content, output_dir, old_schema, new_schema, action: "update") ⇒ Object (private) 



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# File 'lib/synthra/migration_generator.rb', line 282

def write_migration(content, output_dir, old_schema, new_schema, action: "update")
  FileUtils.mkdir_p(output_dir)

  timestamp = Time.now.strftime("%Y%m%d%H%M%S")
  schema_name = underscore(new_schema.name)

  filename = case action
             when "create"
               "#{timestamp}_create_#{pluralize(schema_name)}.rb"
             else
               "#{timestamp}_update_#{schema_name}.rb"
             end

  path = File.join(output_dir, filename)
  File.write(path, content)
  path
end