amazon-dynamodb cleanUpOldData


Example

public static void cleanUpOldData(AmazonDynamoDB amazonDynamoDB, String dynamoDBTablesPrefix, String tableName,
                                  String dateRangeField, String dateHashKey, String dateIndex, Class clazz) {
    log.info(String.format("Cleaning old data from table: %s", tableName));

    long cleanUpDateInMillis = (new Date()).getTime() - CLEAN_UP_TIME_MILLIS;
    SimpleDateFormat dateFormatter = new SimpleDateFormat(DYNAMO_DATE_FORMAT);
    final TimeZone utcTimeZone = TimeZone.getTimeZone("UTC");
    dateFormatter.setTimeZone(utcTimeZone);
    String cleanUpDate = dateFormatter.format(cleanUpDateInMillis);

    Calendar calendar = Calendar.getInstance(utcTimeZone);
    calendar.setTimeInMillis(cleanUpDateInMillis);

    final String dailyHashKey = String.format("%s_%s", calendar.get(Calendar.YEAR), calendar.get(Calendar.DAY_OF_YEAR));
    final String pastDayHashKey = String.format("%s_%s", calendar.get(Calendar.YEAR), calendar.get(Calendar.DAY_OF_YEAR)-1);

    final String fullTableName = dynamoDBTablesPrefix + "_" + tableName;
    final DynamoDBMapperConfig dbMapperConfig = new DynamoDBMapperConfig(new DynamoDBMapperConfig.TableNameOverride(fullTableName));
    DynamoDBMapper mapper = new DynamoDBMapper(amazonDynamoDB, dbMapperConfig);
    DynamoDBTableMapper dbTableMapper = mapper.newTableMapper(clazz);

    final QueryResultPage dailyResultPage = getDailyQueryResultPage(dateRangeField, dateHashKey, dateIndex, cleanUpDate, dailyHashKey, dbTableMapper);
    final QueryResultPage pastDayResultPage = getDailyQueryResultPage(dateRangeField, dateHashKey, dateIndex, cleanUpDate, pastDayHashKey, dbTableMapper);

    deleteOldData(dbTableMapper, dailyResultPage, pastDayResultPage);

    log.info(String.format("Completed cleaning old data from table: %s, %s items were deleted", tableName,
            dailyResultPage.getCount() + pastDayResultPage.getCount()));
}

private static QueryResultPage getDailyQueryResultPage(String dateRangeField, String dateHashKey, String dateIndex,
                                                       String cleanUpDate, String dayHashKey, DynamoDBTableMapper dbTableMapper) {
    HashMap<String, String > nameMap = new HashMap<>();
    nameMap.put("#date", dateRangeField);
    nameMap.put("#day", dateHashKey);
    HashMap<String, AttributeValue> valueMap = new HashMap<>();
    valueMap.put(":date", new AttributeValue().withS(cleanUpDate)) ;
    valueMap.put(":day", new AttributeValue().withS(dayHashKey));

    final DynamoDBQueryExpression dbQueryExpression = new DynamoDBQueryExpression()
            .withIndexName(dateIndex)
            .withConsistentRead(false)
            .withKeyConditionExpression("#day = :day and #date < :date")
            .withExpressionAttributeNames(nameMap)
            .withExpressionAttributeValues(valueMap);
    return dbTableMapper.query(dbQueryExpression);
}

private static void deleteOldData(DynamoDBTableMapper dbTableMapper, QueryResultPage dailyResultPage, QueryResultPage pastDayResultPage) {
    if (dailyResultPage.getCount() > 0) {
        dbTableMapper.batchDelete(dailyResultPage.getResults());
    }
    if (pastDayResultPage.getCount() > 0) {
        dbTableMapper.batchDelete(pastDayResultPage.getResults());
    }
}