def _wipe_dynamodb_table(table: Table) -> None:
"""
Based off https://stackoverflow.com/a/61641725
"""
# get the table keys - assume AttributeName exists
table_key_names = [str(key["AttributeName"]) for key in table.key_schema]
"""
NOTE: there are reserved attributes for key names, please see https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/ReservedWords.html
if a hash or range key is in the reserved word list, you will need to use the ExpressionAttributeNames parameter
described at https://boto3.amazonaws.com/v1/documentation/api/latest/reference/services/dynamodb.html#DynamoDB.Table.scan
"""
# Only retrieve the keys for each item in the table (minimize data transfer)
projection_expression = ", ".join(table_key_names)
response = table.scan(ProjectionExpression=projection_expression)
data = response.get("Items")
assert data is not None, f"Expected items, got {data}"
while "LastEvaluatedKey" in response:
response = table.scan(
ProjectionExpression=projection_expression,
ExclusiveStartKey=response["LastEvaluatedKey"],
)
data.extend(response["Items"])
with table.batch_writer() as batch:
for each in data:
batch.delete_item(Key={key: each[key] for key in table_key_names})
def get_all_counts(cls, table: Table) -> t.Dict[str, int]:
response = table.scan(FilterExpression=Attr("PK").eq(cls._get_pkey()))
return {
t.cast(str, item["SK"]).split("#", 1)[1]:
int(t.cast(Decimal, item["WriteCount"]))
for item in response["Items"]
}
def _table_is_empty(table: Table) -> bool:
"""
fun fact: some_table.item_count? It's only updated every 6 hours.
you have to do a scan.
"""
items = table.scan()["Items"]
if items:
return False # Something's in there!
return True
def scan_info(table: Table, house: str) -> Union[Any, bool]:
try:
db_response = table.scan(
FilterExpression=Attr('house').eq(house.lower()))
items = db_response['Items']
return items
except Exception as e:
print("Something went wrong: ", e)
return False
def _dump_dynamodb_table(table: Table) -> Optional[str]:
"""
Outputs a nicely-formatted Python list of all the items in the table.
(you may need a `from decimal import Decimal` to interact with it, though.)
"""
items = table.scan()["Items"]
if not items:
return None
return pretty_format(items)
def from_time_range(cls,
table: Table,
hash_type: str,
start_time: str = None,
end_time: str = None) -> t.List[t.Dict]:
"""
Given a hash type and time range, give me all the hashes found for that type and time range
"""
if start_time is None:
start_time = datetime.datetime.min.isoformat()
if end_time is None:
end_time = datetime.datetime.max.isoformat()
return table.scan(
FilterExpression=Key("SK").eq(hash_type)
& Key("UpdatedAt").between(start_time, end_time),
ProjectionExpression=cls.DEFAULT_PROJ_EXP,
).get("Items", [])
def seed_fake_data_if_needed(pac_table: Table):
if pac_table.scan()['Count'] != 0:
return
print("Seeding data")
for _ in range(100):
price = random.choice([499, 999, 1999])
status = Status.Available
funder = '0x1234'
signer = random_eth_address()
pac_table.put_item(
Item={
'id': signer, # using signer as the unique id
'price': str(price),
'status': status.name,
'price_status': "{}-{}".format(price, status.name),
'funder': funder,
'signer': signer,
'updated': datetime.now().isoformat()
})
