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# SPDX-License-Identifier: MIT-0
#
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# software and associated documentation files (the "Software"), to deal in the Software
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# permit persons to whom the Software is furnished to do so.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
# INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
# PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
# HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
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import boto3
import botocore
import json
import os
from datetime import datetime
import decimal
from boto3.dynamodb.conditions import Key, Attr
def read_table_configuration(tablename,key):
    dynamodb = boto3.resource('dynamodb')
    table = dynamodb.Table(tablename)
    response = table.query(KeyConditionExpression=Key('targetTableName').eq(key))
    return response
tablemapping='{"rules": [{"rule-type": "selection","rule-id": "1","rule-name": "1","object-locator": {"schema-name": "SchemaName","table-name": "TableName"},"rule-action": "include","filters": [{"filter-type": "source","column-name": "FilterColumnName","filter-conditions": [{"filter-operator": "FilterColumnOperator","value": "StartValue"}]}]}]}'
tablemappingbetween='{"rules": [{"rule-type": "selection","rule-id": "1","rule-name": "1","object-locator": {"schema-name": "SchemaName","table-name": "TableName"},"rule-action": "include","filters": [{"filter-type": "source","column-name": "FilterColumnName","filter-conditions": [{"filter-operator": "FilterColumnOperator","start-value": "StartValue","end-value": "EndValue"}]}]}]}'
tmsimple='{"rules": [{"rule-type": "selection","rule-id": "1","rule-name": "1","object-locator": {"schema-name": "SchemaName","table-name": "TableName"},"rule-action": "include"}]}'
def create_replication_task_for_table(tablename,DynamoDBKey,tablemapping,SourceEndpointArn,TargetEndpointArn,ReplicationInstanceArn,ReplicationTaskIdentifier,replication_task_settings):
    c=boto3.client('dms')
    ReplicationTaskIdentifierName = ReplicationTaskIdentifier + "-"+DynamoDBKey
    response=c.create_replication_task(
    ReplicationTaskIdentifier=ReplicationTaskIdentifierName,
    SourceEndpointArn=SourceEndpointArn,
    TargetEndpointArn=TargetEndpointArn,
    ReplicationInstanceArn=ReplicationInstanceArn,
    MigrationType='full-load',
    ReplicationTaskSettings=replication_task_settings,
    TableMappings=tablemapping,)
    return response

def check_task_status(dmstaskarn):
    client = boto3.client('dms')
    response = client.describe_replication_tasks(
        Filters=[
            {
                'Name': 'replication-task-arn',
                'Values': [
                    dmstaskarn
                ]
            }
        ], WithoutSettings=True

    )
    return response

def lambda_handler(event, context):
    try:
        SArn=os.getenv('SOURCE_ENDPOINT_ARN')
        TArn=os.getenv('TARGET_ENDPOINT_ARN')
        InstanceArn=event['replicationInstanceArn']
        table=os.getenv('DYNAMODBTABLE').strip()
        DDKey=event['DYNAMODB_KEY']
        table_config=read_table_configuration(table,DDKey)
        startvalue=''
        filtercolumn=''
        filteroperator=''
        t=''
        for i in table_config['Items']:
            activeflag=i['activeflag']
            schemaname=i['sourceSchema']
            tablename=i['sourceTable']
            try:
                startvalue=i['startvalue']
                endvalue=i['endvalue']
                filtercolumn=i['filtercolumn']
                filteroperator=i['filteroperator']
            except Exception as e:
                print("assuming full load: %s" % str(e))
                startvalue=''
        TaskId=schemaname+"-"+tablename.replace('_','-')+"-TaskIdentifer"
        if activeflag=='Y':
            if filteroperator=='gte' or filteroperator=='lte' or filteroperator=='eq' or filteroperator=='noteq' :
                t=tablemapping
                t=t.replace('StartValue',startvalue).replace('FilterColumnName',filtercolumn).replace('FilterColumnOperator',filteroperator).replace('SchemaName',schemaname).replace('TableName',tablename)
            elif filteroperator=='between' or filteroperator=='between':
                t=tablemappingbetween
                sValue = startvalue
                eValue = endvalue
                t=t.replace('StartValue',sValue).replace('EndValue',eValue).replace('FilterColumnName',filtercolumn).replace('FilterColumnOperator',filteroperator).replace('SchemaName',schemaname).replace('TableName',tablename)
            else:
                t=tmsimple
                t=t.replace('SchemaName',schemaname).replace('TableName',tablename)
            print(t)
            replication_task_settings=''
            try:
                replication_task_settings=i['replication_task_settings']
                print(replication_task_settings)
            except Exception as e:
                print("assuming full load: %s" % str(e))
                replication_task_settings = '{"Logging": {"EnableLogging": true,"LogComponents": [{"Id": "SOURCE_UNLOAD","Severity": "LOGGER_SEVERITY_DEFAULT"},{"Id": "SOURCE_CAPTURE","Severity": "LOGGER_SEVERITY_DEFAULT"},{"Id": "TARGET_LOAD","Severity": "LOGGER_SEVERITY_DEFAULT"},{"Id": "TARGET_APPLY","Severity": "LOGGER_SEVERITY_INFO"},{"Id": "TASK_MANAGER","Severity": "LOGGER_SEVERITY_DEBUG"}]}}'
            response=create_replication_task_for_table(table,DDKey,t,SArn,TArn,InstanceArn,TaskId,replication_task_settings)
            taskArn = response['ReplicationTask']['ReplicationTaskArn']
            print('taskArn',taskArn)

            status=check_task_status(taskArn)['ReplicationTasks'][0]['Status']
            while (status.lower() in ['creating','moving','deleting', 'failed','failed-move','modifying','ready']):
                print('Task Status:',status)
                if (status.lower() in ['deleting', 'failed','failed-move']):
                    return {'result':'FAILED'}
                elif (status.lower() in ['ready']):
                    return {'result':'SUCCEEDED','taskArn':response['ReplicationTask']['ReplicationTaskArn'],"DYNAMODB_KEY":DDKey,'replicationInstanceArn':event['replicationInstanceArn']}
                status=check_task_status(taskArn)['ReplicationTasks'][0]['Status']

    except Exception as e:
        print("Exception thrown: %s" % str(e))
        return {'result':'FAILED'}