Migration

Add migration id

Migrtion Id should be unique and usually it follow date version for example <MIGRATION_NAME>_<yyyymmdd>. Migration script only runs once and it stores the migration id in the database, if you need to rerun the migration you need to change the version by updating yyyymmdd.

Add up/down scripts to execute

up is for loading

down is for unloading.

In this example, we are renaming status field in Property.

// MongoDB field to update
const fieldToUpdate = 'status';

// Update values mapping
const updateMapping = {
  CREATED: 'created',
  LISTED: 'listed',
  INCOMPLETE: 'incomplete'
};

/**
 * Updates the "status" field in a collection from "CREATED" to "created" and from "LISTED" to "listed":
 */
@injectable()
export class PropertyStatusMigration {
    private readonly logger: CdmLogger.ILogger;

    constructor(
        @inject(TYPES.PropertyRepository)
        private propertyRepository: IBaseRepository<IPropertyType>,
        @inject('Logger')
        logger: CdmLogger.ILogger,
    ) {
        this.logger = logger.child({ className: PropertyStatusMigration.name });
    }

    get id(): string {
        return 'PropertyStatusMigration_20230603';
    }

    get data(): IPropertyTypeInput[] {
        return propertyTypes;
    }

    async up(): Promise<void> {
        await this.down();
        this.propertyRepository.bulkUpdate(    { [fieldToUpdate]: { $in: ['CREATED', 'LISTED', 'INCOMPLETE'] } },
        [
          {
            $set: {
              [fieldToUpdate]: {
                $cond: {
                  if: { $eq: [`$${fieldToUpdate}`, 'CREATED'] },
                  then: updateMapping.CREATED,
                  else: {
                    $cond: {
                      if: { $eq: [`$${fieldToUpdate}`, 'LISTED'] },
                      then: updateMapping.LISTED,
                      else: updateMapping.INCOMPLETE
                    }
                  }
                }
              }
            }
          }
        ],
        function(err, result) {
          if (err) {
            this.logger.error('Error updating documents:', err);
          } else {
            this.logger.debug('Documents updated successfully.');
          }
        })
        this.logger.info(`PropertyStatusMigration_20230603 Property Status migration done!`);
    }

    async down(): Promise<void> {
        this.logger.info(`Nothing to do`);
    }
}

Migration scritp runs when the backend server start and it runs down first before up script.

Bind to Migration Container

/**
 * Local services and exposed microservices to serve remote connections.
 * Operates within in the Gateway.
 *
 */
export const localContainerModule: (settings) => interfaces.ContainerModule = () =>
    new ContainerModule((bind: interfaces.Bind) => {
        ..... rest of the code ...
        bind('MongodbMigration').to(PropertyStatusMigration).whenTargetNamed(PropertyStatusMigration.name);
    
    });

Add to the feature

export default new Feature(
    {
       ... rest...
        createContainerFunc: [localContainerModule],
    });