DynamoDB Movies Example

5/12/2018 - 1:21 AM

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Get DynamoDB Local on Docker:

This will get it going:

$ docker run -itd --name dynamodb-local -p 8000:8000 rbekker87/dynamodb-local:latest

For Data Persistence:

$ docker run -itd --name dynamodb-local \
  -p 8000:8000 \
  -v /tmp/shared-local-instance.db:/shared-local-instance.db \
  rbekker87/dynamodb-local:latest

Download the Dataset:

$ wget https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/samples/moviedata.zip
$ unzip moviedata.zip

Create the Table:

# create the table with year (HASH) and title (STRING) attributes

from __future__ import print_function
import boto3

dynamodb = boto3.resource('dynamodb', region_name='us-west-2', endpoint_url="http://localhost:8000")

table = dynamodb.create_table(
    TableName='Movies',
    KeySchema=[
        {
            'AttributeName': 'year',
            'KeyType': 'HASH'
        },
        {
            'AttributeName': 'title',
            'KeyType': 'RANGE'
        }
    ],
    AttributeDefinitions=[
        {
            'AttributeName': 'year',
            'AttributeType': 'N'
        },
        {
            'AttributeName': 'title',
            'AttributeType': 'S'
        },

    ],
    ProvisionedThroughput={
        'ReadCapacityUnits': 10,
        'WriteCapacityUnits': 10
    }
)

print("Table status:", table.table_status)

Load the Bulk Data from Json and Insert:

# Bulk load data from json to dynamodb

from __future__ import print_function # Python 2/3 compatibility
import boto3
import json
import decimal

dynamodb = boto3.resource('dynamodb', region_name='us-west-2', endpoint_url="http://localhost:8000")

table = dynamodb.Table('Movies')

with open("moviedata.json") as json_file:
    movies = json.load(json_file, parse_float = decimal.Decimal)
    for movie in movies:
        year = int(movie['year'])
        title = movie['title']
        info = movie['info']

        print("Adding movie:", year, title)

        table.put_item(
           Item={
               'year': year,
               'title': title,
               'info': info,
            }
        )

Single PutItem:

from __future__ import print_function # Python 2/3 compatibility
import boto3
import json
import decimal

class DecimalEncoder(json.JSONEncoder):
    def default(self, o):
        if isinstance(o, decimal.Decimal):
            if abs(o) % 1 > 0:
                return float(o)
            else:
                return int(o)
        return super(DecimalEncoder, self).default(o)

dynamodb = boto3.resource('dynamodb', region_name='us-west-2', endpoint_url="http://localhost:8000")
table = dynamodb.Table('Movies')

title = "The Big New Movie"
year = 2015

response = table.put_item(
   Item={
        'year': year,
        'title': title,
        'info': {
            'plot':"Nothing happens at all.",
            'rating': decimal.Decimal(0)
        }
    }
)

print("PutItem succeeded:")
print(json.dumps(response, indent=4, cls=DecimalEncoder))

Single GetItem:

from __future__ import print_function # Python 2/3 compatibility
import boto3
import json
import decimal
from boto3.dynamodb.conditions import Key, Attr
from botocore.exceptions import ClientError

# Helper class to convert a DynamoDB item to JSON.
class DecimalEncoder(json.JSONEncoder):
    def default(self, o):
        if isinstance(o, decimal.Decimal):
            if o % 1 > 0:
                return float(o)
            else:
                return int(o)
        return super(DecimalEncoder, self).default(o)

dynamodb = boto3.resource("dynamodb", region_name='us-west-2', endpoint_url="http://localhost:8000")

table = dynamodb.Table('Movies')

title = "The Big New Movie"
year = 2015

try:
    response = table.get_item(
        Key={
            'year': year,
            'title': title
        }
    )
except (ClientError, KeyError) as e:
        print_(e)

    #print(e.response['Error']['Message'])

else:
    item = response['Item']
    print("GetItem succeeded:")
    print(json.dumps(item, indent=4, cls=DecimalEncoder))

Update Item:

from __future__ import print_function # Python 2/3 compatibility
import boto3
import json
import decimal

# Helper class to convert a DynamoDB item to JSON.
class DecimalEncoder(json.JSONEncoder):
    def default(self, o):
        if isinstance(o, decimal.Decimal):
            if o % 1 > 0:
                return float(o)
            else:
                return int(o)
        return super(DecimalEncoder, self).default(o)

dynamodb = boto3.resource('dynamodb', region_name='us-west-2', endpoint_url="http://localhost:8000")

table = dynamodb.Table('Movies')

title = "The Big New Movie"
year = 2015

response = table.update_item(
    Key={
        'year': year,
        'title': title
    },
    UpdateExpression="set info.rating = :r, info.plot = :p, info.actors = :a",
    ExpressionAttributeValues={
        ':r': decimal.Decimal(5.5),
        ':p': "Everything happens all at once.",
        ':a': ["Larry", "Moe", "Curly"]
    },
    ReturnValues="UPDATED_NEW"
)

print("UpdateItem succeeded:")
print(json.dumps(response, indent=4, cls=DecimalEncoder))

Atomic Updates:

from __future__ import print_function # Python 2/3 compatibility
import boto3
import json
import decimal

# Helper class to convert a DynamoDB item to JSON.
class DecimalEncoder(json.JSONEncoder):
    def default(self, o):
        if isinstance(o, decimal.Decimal):
            if o % 1 > 0:
                return float(o)
            else:
                return int(o)
        return super(DecimalEncoder, self).default(o)

dynamodb = boto3.resource('dynamodb', region_name='us-west-2', endpoint_url="http://localhost:8000")

table = dynamodb.Table('Movies')

title = "The Big New Movie"
year = 2015

response = table.update_item(
    Key={
        'year': year,
        'title': title
    },
    UpdateExpression="set info.rating = info.rating - :val",
    ExpressionAttributeValues={
        ':val': decimal.Decimal(1)
    },
    ReturnValues="UPDATED_NEW"
)

print("UpdateItem succeeded:")
print(json.dumps(response, indent=4, cls=DecimalEncoder))

Conditional Updates:

from __future__ import print_function # Python 2/3 compatibility
import boto3
from botocore.exceptions import ClientError
import json
import decimal

# Helper class to convert a DynamoDB item to JSON.
class DecimalEncoder(json.JSONEncoder):
    def default(self, o):
        if isinstance(o, decimal.Decimal):
            if o % 1 > 0:
                return float(o)
            else:
                return int(o)
        return super(DecimalEncoder, self).default(o)

dynamodb = boto3.resource('dynamodb', region_name='us-west-2', endpoint_url="http://localhost:8000")

table = dynamodb.Table('Movies')

title = "The Big New Movie"
year = 2015

# Conditional update (will fail)
print("Attempting conditional update...")

try:
    response = table.update_item(
        Key={
            'year': year,
            'title': title
        },
        UpdateExpression="remove info.actors[0]",
        ConditionExpression="size(info.actors) = :num",
        ExpressionAttributeValues={
            ':num': 3
        },
        ReturnValues="UPDATED_NEW"
    )
except ClientError as e:
    if e.response['Error']['Code'] == "ConditionalCheckFailedException":
        print(e.response['Error']['Message'])
    else:
        raise
else:
    print("UpdateItem succeeded:")
    print(json.dumps(response, indent=4, cls=DecimalEncoder))

Conditional Delete:

from __future__ import print_function # Python 2/3 compatibility
import boto3
from botocore.exceptions import ClientError
import json
import decimal

# Helper class to convert a DynamoDB item to JSON.
class DecimalEncoder(json.JSONEncoder):
    def default(self, o):
        if isinstance(o, decimal.Decimal):
            if o % 1 > 0:
                return float(o)
            else:
                return int(o)
        return super(DecimalEncoder, self).default(o)

dynamodb = boto3.resource('dynamodb', region_name='us-west-2', endpoint_url="http://localhost:8000")

table = dynamodb.Table('Movies')

title = "The Big New Movie"
year = 2015

print("Attempting a conditional delete...")

try:
    response = table.delete_item(
        Key={
            'year': year,
            'title': title
        },
        ConditionExpression="info.rating <= :val",
        ExpressionAttributeValues= {
            ":val": decimal.Decimal(5)
        }
    )
except ClientError as e:
    if e.response['Error']['Code'] == "ConditionalCheckFailedException":
        print(e.response['Error']['Message'])
    else:
        raise
else:
    print("DeleteItem succeeded:")
    print(json.dumps(response, indent=4, cls=DecimalEncoder))

Query by Year:

from __future__ import print_function # Python 2/3 compatibility
import boto3
import json
import decimal
from boto3.dynamodb.conditions import Key, Attr

# Helper class to convert a DynamoDB item to JSON.
class DecimalEncoder(json.JSONEncoder):
    def default(self, o):
        if isinstance(o, decimal.Decimal):
            if o % 1 > 0:
                return float(o)
            else:
                return int(o)
        return super(DecimalEncoder, self).default(o)

dynamodb = boto3.resource('dynamodb', region_name='us-west-2', endpoint_url="http://localhost:8000")

table = dynamodb.Table('Movies')

print("Movies from 1985")

response = table.query(
    KeyConditionExpression=Key('year').eq(1985)
)

for i in response['Items']:
    print(i['year'], ":", i['title'])

Query by Year and Title between two letters:

from __future__ import print_function # Python 2/3 compatibility
import boto3
import json
import decimal
from boto3.dynamodb.conditions import Key, Attr

# Helper class to convert a DynamoDB item to JSON.
class DecimalEncoder(json.JSONEncoder):
    def default(self, o):
        if isinstance(o, decimal.Decimal):
            return str(o)
        return super(DecimalEncoder, self).default(o)

dynamodb = boto3.resource('dynamodb', region_name='us-west-2', endpoint_url="http://localhost:8000")

table = dynamodb.Table('Movies')

print("Movies from 1992 - titles A-L, with genres and lead actor")

response = table.query(
    ProjectionExpression="#yr, title, info.genres, info.actors[0]",
    ExpressionAttributeNames={ "#yr": "year" }, # Expression Attribute Names for Projection Expression only.
    KeyConditionExpression=Key('year').eq(1992) & Key('title').between('A', 'L')
)

for i in response[u'Items']:
    print(json.dumps(i, cls=DecimalEncoder))

Scan and Filter:

from __future__ import print_function # Python 2/3 compatibility
import boto3
import json
import decimal
from boto3.dynamodb.conditions import Key, Attr

# Helper class to convert a DynamoDB item to JSON.
class DecimalEncoder(json.JSONEncoder):
    def default(self, o):
        if isinstance(o, decimal.Decimal):
            if o % 1 > 0:
                return float(o)
            else:
                return int(o)
        return super(DecimalEncoder, self).default(o)

dynamodb = boto3.resource('dynamodb', region_name='us-west-2', endpoint_url="http://localhost:8000")

table = dynamodb.Table('Movies')

fe = Key('year').between(1950, 1959);
pe = "#yr, title, info.rating"
# Expression Attribute Names for Projection Expression only.
ean = { "#yr": "year", }
esk = None


response = table.scan(
    FilterExpression=fe,
    ProjectionExpression=pe,
    ExpressionAttributeNames=ean
    )

for i in response['Items']:
    print(json.dumps(i, cls=DecimalEncoder))

while 'LastEvaluatedKey' in response:
    response = table.scan(
        ProjectionExpression=pe,
        FilterExpression=fe,
        ExpressionAttributeNames= ean,
        ExclusiveStartKey=response['LastEvaluatedKey']
        )

    for i in response['Items']:
        print(json.dumps(i, cls=DecimalEncoder))

Delete the Table:

from __future__ import print_function # Python 2/3 compatibility
import boto3

dynamodb = boto3.resource('dynamodb', region_name='us-west-2', endpoint_url="http://localhost:8000")
table = dynamodb.Table('Movies')
table.delete()

Resources:

https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/GettingStarted.Python.02.html#GettingStarted.Python.02.01

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DynamoDB Movies Example

Get DynamoDB Local on Docker:

Download the Dataset:

Create the Table:

Load the Bulk Data from Json and Insert:

Single PutItem:

Single GetItem:

Update Item:

Atomic Updates:

Conditional Updates:

Conditional Delete:

Query by Year:

Query by Year and Title between two letters:

Scan and Filter:

Delete the Table:

Resources: