"""
.. hidden-code-block:: text
:label: View Licence Agreement <br>
sosw - Serverless Orchestrator of Serverless Workers
The MIT License (MIT)
Copyright (C) 2024 sosw core contributors <info@sosw.app>
Permission is hereby granted, free of charge, to any person obtaining a copy
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copies of the Software, and to permit persons to whom the Software is
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The above copyright notice and this permission notice shall be included in all
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
"""
__all__ = ['DynamoDbClient', 'clean_dynamo_table']
__author__ = "Nikolay Grishchenko, Sophie Fogel, Gil Halperin, Mark Bulgakov"
__version__ = "1.7"
try:
from aws_lambda_powertools import Logger
logger = Logger(child=True)
except ImportError:
import logging
logger = logging.getLogger()
logger.setLevel(logging.INFO)
import boto3
import datetime
import json
import os
import time
import pprint
from collections import defaultdict
from typing import Dict, List, Optional, Tuple, Union
from boto3.dynamodb.types import TypeSerializer, TypeDeserializer
from .benchmark import benchmark
from .helpers import chunks, to_bool
[docs]
class DynamoDbClient:
"""
Has default methods for different types of DynamoDB tables.
The current implementation supports only one fixed table during initialization,
but you are free to initialize multiple simultaneous dynamo_clients in your Lambda with different configs.
Config should have a mapping for the field types and required fields.
Config example:
.. code-block:: python
{
'row_mapper': {
'col_name_1': 'N', # Number
'col_name_2': 'S', # String
},
'required_fields': ['col_name_1']
'table_name': 'some_table_name', # If a table is not specified, this table will be used.
'hash_key': 'the_hash_key',
'dont_json_loads_results': True # Use this if you don't want to convert json strings into json
}
"""
def __init__(self, config):
assert isinstance(config, dict), "Config must be provided during DynamoDbClient initialization"
# If this is a test, make sure the table is a test table
if os.environ.get('STAGE') == 'test' and 'table_name' in config:
assert config['table_name'].startswith('autotest_') or config['table_name'] == 'config', \
f"Bad table name {config['table_name']} in autotest"
self.config = config
# create a dynamodb client
self.dynamo_client = boto3.client('dynamodb', region_name=config.get('region_name'))
# storage for table description(s)
self._table_descriptions: Optional[Dict[str, Dict]] = {}
# initialize table store
self._table_capacity = {}
self.identify_dynamo_capacity(table_name=self.config['table_name'])
self.stats = defaultdict(int)
if not hasattr(self, 'row_mapper'):
self.row_mapper = self.config.get('row_mapper')
self.type_serializer = TypeSerializer()
self.type_deserializer = TypeDeserializer()
[docs]
def identify_dynamo_capacity(self, table_name=None):
"""
Identify and store the table capacity for a given table on the object.
In case the table has ON DEMAND (PAY_PER_REQUEST) BillingMode the ProvisionedThroughput is missing.
Arguments:
table_name {str} -- short name of the dynamo db table to analyze
"""
# Use the config value if not provided
if table_name is None:
table_name = self.config['table_name']
logger.debug("Got `table_name` from config: %s", table_name)
logger.debug("DynamoDB table name identified as %s", table_name)
# Fetch the actual configuration of the dynamodb table directly for
table_description = self._describe_table(table_name)
# Hash to the capacity
try:
table_capacity = table_description["Table"]["ProvisionedThroughput"]
self._table_capacity[table_name] = {
'read': int(table_capacity["ReadCapacityUnits"]),
'write': int(table_capacity["WriteCapacityUnits"]),
}
except KeyError:
pass
def _describe_table(self, table_name: Optional[str] = None) -> Dict:
"""
Returns description of the table from AWS. Response like:
https://boto3.amazonaws.com/v1/documentation/api/latest/reference/services/dynamodb.html#DynamoDB.Client.describe_table
:return: Description of the table
"""
table_name = self._get_validate_table_name(table_name)
if self._table_descriptions and table_name in self._table_descriptions:
logger.debug("Description taken from cache for table %s: %s ", table_name,
self._table_descriptions[table_name])
return self._table_descriptions[table_name]
else:
table_description = self.dynamo_client.describe_table(TableName=table_name)
self._table_descriptions[table_name] = table_description
logger.debug("Description for table %s received from API and cached: %s ", table_name,
self._table_descriptions[table_name])
return self._table_descriptions[table_name]
[docs]
def get_table_keys(self, table_name: Optional[str] = None) -> Tuple[str, Optional[str]]:
"""
Returns table's hash key name and range key name
:param table_name:
:return: hash key and range key names
"""
table_description = self._describe_table(table_name)
key_schema: List[Dict[str, str]] = table_description['Table']['KeySchema']
hash_key = range_key = None
for key in key_schema:
if key['KeyType'] == 'HASH':
hash_key = key['AttributeName']
elif key['KeyType'] == 'RANGE':
range_key = key['AttributeName']
return hash_key, range_key
[docs]
def get_table_indexes(self, table_name: Optional[str] = None) -> Dict:
"""
Returns **active** indexes of the table: their hash key, range key, and projection type.
.. code-block:: python
{
'index_1_name': {
'projection_type': 'ALL', # One of: 'ALL'|'KEYS_ONLY'|'INCLUDE'
'hash_key': 'the_hash_key_column_name',
'range_key': 'the_range_key_column_name', # Can be None if the index has no range key
'provisioned_throughput': {
'write_capacity': 5,
'read_capacity': 10
}
},
'index_2_name': ...
}
.. note::
In case the table has ON DEMAND (PAY_PER_REQUEST) BillingMode the provisioned_throughput is missing.
"""
indexes = {}
table_description = self._describe_table(table_name)['Table']
local_secondary_indexes = table_description.get('LocalSecondaryIndexes', [])
global_secondary_indexes = table_description.get('GlobalSecondaryIndexes', [])
for index in local_secondary_indexes + global_secondary_indexes:
if index.get('IndexStatus') is not None and index.get('IndexStatus') != 'ACTIVE':
# Only global sec. indexes has IndexStatus, and if it's not ready for use, we don't return it
continue
name = index['IndexName']
projection_type = index['Projection']['ProjectionType'] # 'ALL'|'KEYS_ONLY'|'INCLUDE'
key_schema = index['KeySchema']
hash_key = range_key = None
for key in key_schema:
if key['KeyType'] == 'HASH':
hash_key = key['AttributeName']
elif key['KeyType'] == 'RANGE':
range_key = key['AttributeName']
indexes[name] = {
'projection_type': projection_type,
'hash_key': hash_key,
}
if range_key:
indexes[name]['range_key'] = range_key
# Get write & read capacity.
# global sec. indexes have their own capacities, while a local sec. index uses the capacity of the table.
if index.get('ProvisionedThroughput') or table_description.get('ProvisionedThroughput'):
write_capacity = index.get('ProvisionedThroughput', {}).get('WriteCapacityUnits') or \
table_description['ProvisionedThroughput']['WriteCapacityUnits']
read_capacity = index.get('ProvisionedThroughput', {}).get('ReadCapacityUnits') or \
table_description['ProvisionedThroughput']['ReadCapacityUnits']
indexes[name]['provisioned_throughput'] = {
'write_capacity': write_capacity,
'read_capacity': read_capacity
}
return indexes
[docs]
def dynamo_to_dict(self, dynamo_row: Dict, strict: bool = None, fetch_all_fields: Optional[bool] = None) -> Dict:
"""
Convert the ugly DynamoDB syntax of the row, to regular dictionary.
We currently support only String or Numeric values. Latest ones are converted to int or float.
Takes settings from row_mapper.
e.g.: {'key1': {'N': '3'}, 'key2': {'S': 'value2'}}
will convert to: {'key1': 3, 'key2': 'value2'}
:param dict dynamo_row: DynamoDB row item
:param bool strict: DEPRECATED.
:param bool fetch_all_fields: If False only row_mapper fields will be extracted from dynamo_row, else, all
fields will be extracted from dynamo_row.
:return: The row in a key-value format
:rtype: dict
"""
if strict is not None:
logger.warning("dynamo_to_dict `strict` variable is deprecated in sosw 0.7.13+. "
"Please replace it's usage with `fetch_all_fields` (and reverse the boolean value)")
fetch_all_fields = fetch_all_fields if fetch_all_fields is not None else False if strict is None else not strict
result = {}
# Get fields from dynamo_row which are present in row mapper
if not fetch_all_fields:
for key, key_type in self.row_mapper.items():
val_dict = dynamo_row.get(key) # Ex: {'N': "1234"} or {'S': "myvalue"}
if val_dict:
val = val_dict.get(key_type) # Ex: 1234 or "myvalue"
if val is None and key_type not in val_dict:
real_type = list(val_dict.keys())[0]
raise ValueError(f"'{key}' is expected to be of type '{key_type}' in row_mapper, "
f"but real value is of type '{real_type}'")
# type_deserializer.deserialize() parses 'N' to `Decimal` type but it cant be parsed to a datetime
# so we cast it to either an integer or a float.
if key_type == 'N':
result[key] = float(val) if '.' in val else int(val)
elif key_type == 'M':
result[key] = self.dynamo_to_dict(val, fetch_all_fields=True)
elif key_type == 'S':
# Try to load to a dictionary if looks like JSON.
if val.startswith('{') and val.endswith('}') and \
not self.config.get('dont_json_loads_results'):
try:
result[key] = json.loads(val)
except ValueError:
logger.warning("A JSON-looking string failed to parse: %s", val)
result[key] = val
else:
result[key] = val
else:
result[key] = self.type_deserializer.deserialize(val_dict)
# Get all fields from dynamo_row
else:
for key, val_dict in dynamo_row.items():
for val_type, val in val_dict.items():
# type_deserializer.deserialize() parses 'N' to `Decimal` type but it cant be parsed to a datetime
# so we cast it to either an integer or a float.
if val_type == 'N':
result[key] = float(val) if '.' in val else int(val)
elif val_type == 'M':
result[key] = self.dynamo_to_dict(val, fetch_all_fields=True)
elif val_type == 'S':
# Try to load to a dictionary if looks like JSON.
if val.startswith('{') and val.endswith('}') and \
not self.config.get('dont_json_loads_results'):
try:
result[key] = json.loads(val)
except ValueError:
logger.warning("A JSON-looking string failed to parse: %s", val)
result[key] = val
else:
result[key] = val
else:
result[key] = self.type_deserializer.deserialize(val_dict)
assert all(True for x in self.config['required_fields'] if result.get(x)), "Some `required_fields` are missing"
return result
[docs]
def dict_to_dynamo(self, row_dict, add_prefix=None, strict=True):
"""
Convert the row from regular dictionary to the ugly DynamoDB syntax. Takes settings from row_mapper.
e.g. {'key1': 'value1', 'key2': 'value2'}
will convert to: {'key1': {'Type1': 'value1'}, 'key2': {'Type2': 'value2'}}
:param dict row_dict: A row we want to convert to dynamo syntax.
:param str add_prefix: A string prefix to add to the key in the result dict. Useful for queries like update.
:param bool strict: If False, will get the type from the value in the dict (this works for numbers and
strings). If True, won't add them if they're not in the required_fields, and if they
are, will raise an error. Uses ``boto3.types.TypeSerializer`` for type conversion,
but before that automatically guesses that numeric values should become ``N`` type,
boolean types or 'true/false' strings - ``B``, dictionaries - ``M`` recursively.
:return: DynamoDB Task item
:rtype: dict
"""
if add_prefix is None:
add_prefix = ''
result = {}
# Keys from row mapper
for key, key_type in self.row_mapper.items():
val = row_dict.get(key)
if val is not None:
key_with_prefix = f"{add_prefix}{key}"
if key_type == 'BOOL':
result[key_with_prefix] = {'BOOL': to_bool(val)}
elif key_type == 'N':
result[key_with_prefix] = {'N': str(val)}
elif key_type == 'S':
result[key_with_prefix] = {'S': str(val)}
elif key_type == 'M':
result[key_with_prefix] = {'M': self.dict_to_dynamo(val, strict=False)}
else:
result[key_with_prefix] = self.type_serializer.serialize(val)
result_keys = result.keys()
if add_prefix:
result_keys = [x[len(add_prefix):] for x in result.keys()]
# Keys which are not in row mapper
for key in list(set(row_dict.keys()) - set(result_keys)):
if not strict:
val = row_dict.get(key)
key_with_prefix = f"{add_prefix}{key}"
if isinstance(val, bool) or (isinstance(val, str) and val.lower() in ['false', 'true']):
result[key_with_prefix] = {'BOOL': to_bool(val)}
elif isinstance(val, (int, float)) or (isinstance(val, str) and val.isnumeric()):
result[key_with_prefix] = {'N': str(val)}
elif isinstance(val, str):
result[key_with_prefix] = {'S': str(val)}
elif isinstance(val, dict):
result[key_with_prefix] = {'M': self.dict_to_dynamo(val, strict=False)}
else:
result[key_with_prefix] = self.type_serializer.serialize(val)
else:
if key not in self.config.get('required_fields', []):
logger.warning("Field %s is missing from row_mapper, so we can't convert it to DynamoDB "
"syntax. This is not a required field, so we continue, but please investigate "
"row: %s", key, row_dict)
else:
raise ValueError(f"Field {key} is missing from row_mapper, so we can't convert it to DynamoDB "
f"syntax. This is a required field, so we can not continue. Row: {row_dict}")
logger.debug("dict_to_dynamo result: %s", result)
return result
[docs]
def get_by_query(self, keys: Dict, table_name: Optional[str] = None, index_name: Optional[str] = None,
comparisons: Optional[Dict] = None, max_items: Optional[int] = None,
filter_expression: Optional[str] = None, strict: bool = None, return_count: bool = False,
desc: bool = False, fetch_all_fields: bool = None, expr_attrs_names: list = None,
consistent_read: bool = None) -> Union[List[Dict], int]:
"""
Get an item from a table, by some keys. Can specify an index.
If an index is not specified, will query the table.
IMPORTANT: You must specify the rows you expect to be converted in row mapper in config, otherwise you won't
get them in the result.
If you want to get items from dynamo by non-key attributes, this method is not for you.
:param dict keys: Keys and values of the items we get.
You must specify the hash key, and can optionally also add the range key.
Example, in a table where the hash key is 'hk' and the range key is 'rk':
* {'hk': 'cat', 'rk': '123'}
* {'hk': 'cat'}
Optional
:param str table_name: Name of the dynamo table. If not specified, will use table_name from the config.
:param str index_name: Name of the secondary index in the table. If not specified, will query the table itself.
:param dict comparisons: Type of comparison for each key. If a key is not mentioned, comparison type will be =.
Valid values: `=`, `<`, `<=`, `>`, `>=`, `begins_with`.
Comparisons only work for the range key.
Example: if keys={'hk': 'cat', 'rk': 100} and comparisons={'rk': '<='} -> will get items where rk <= 100
:param int max_items: Limit the number of items to fetch.
:param str filter_expression: Supports regular comparisons and `between`. Input must be a regular human string
e.g. 'key <= 42', 'name = marta', 'foo between 10 and 20', etc.
:param bool strict: DEPRECATED.
:param bool return_count: If True, will return the number of items in the result instead of the items themselves
:param bool desc: By default (False) the the values will be sorted ascending by the SortKey.
To reverse the order set the argument `desc = True`.
:param bool fetch_all_fields: If False, will only get the attributes specified in the row mapper.
If True, will get all attributes. Default is False.
:param list expr_attrs_names: List of attributes names, in case if an attribute name begins with a number or
contains a space, a special character, or a reserved word, you must use an expression attribute name to
replace that attribute's name in the expression.
Example, if the list ['session', 'key'] is received, then a new dict will be assigned to
`ExpressionAttributeNames`:
{'#session': 'session', '#key': 'key'}
:param bool consistent_read: If True , then the operation uses strongly consistent reads;
otherwise, the operation uses eventually consistent reads. Default is False
:return: List of items from the table, each item in key-value format
OR the count if `return_count` is True
"""
if strict is not None:
logger.warning("get_by_query `strict` variable is deprecated in sosw 0.7.13+. "
"Please replace it's usage with `fetch_all_fields` (and reverse the boolean value)")
fetch_all_fields = fetch_all_fields if fetch_all_fields is not None else False if strict is None else not strict
table_name = self._get_validate_table_name(table_name)
filter_values = self.dict_to_dynamo(keys, add_prefix=':', strict=False)
cond_expr_parts = []
for key_attr_name in keys:
# Check if key attribute name is in `expr_attrs_names`, and create a prefix
# We add this prefix in case need to use `ExpressionAttributeNames`
expr_attr_prefix = '#' if expr_attrs_names and key_attr_name in expr_attrs_names else ''
# Find comparison for key. The formatting of conditions could be different, so a little spaghetti.
if key_attr_name.startswith('st_between_'): # This is just a marker to construct a custom expression later
compr = 'between'
elif key_attr_name.startswith('en_between_'): # This attribute is used in the expression with st_between
continue
elif comparisons:
compr = comparisons.get(key_attr_name) or '='
else:
compr = '='
if compr == 'begins_with':
cond_expr_parts.append(f"begins_with ({expr_attr_prefix}{key_attr_name}, :{key_attr_name})")
elif compr == 'between':
key = key_attr_name[11:]
expr_attr_prefix = '#' if expr_attrs_names and key in expr_attrs_names else ''
cond_expr_parts.append(f"{expr_attr_prefix}{key} between :st_between_{key} and :en_between_{key}")
else:
assert compr in ('=', '<', '<=', '>', '>='), f"Comparison not valid: {compr} for {key_attr_name}"
cond_expr_parts.append(f"{expr_attr_prefix}{key_attr_name} {compr} :{key_attr_name}")
cond_expr = " AND ".join(cond_expr_parts)
select = (
'ALL_ATTRIBUTES' if index_name is None else 'ALL_PROJECTED_ATTRIBUTES') if not return_count else 'COUNT'
logger.debug(cond_expr, filter_values)
query_args = {
'TableName': table_name,
'Select': select,
'ExpressionAttributeValues': filter_values, # Ex: {':key1_name': 'key1_value', ...}
'KeyConditionExpression': cond_expr, # Ex: "key1_name = :key1_name AND ..."
}
if consistent_read is not None:
if index_name is not None and consistent_read is True:
raise ValueError(f"Strongly Consistent Read is not available on Global Secondary Indexes.")
logger.debug("Forcing ConsistentRead in query args of get_by_query to: %s", consistent_read)
query_args['ConsistentRead'] = consistent_read
# In case of any of the attributes names are in the list of Reserved Words in DynamoDB or other situations when,
# there is a need to specify ExpressionAttributeNames, then a dict should be passed to the query.
if expr_attrs_names:
query_args['ExpressionAttributeNames'] = {f'#{el}': el for el in expr_attrs_names}
# In case we have a filter expression, we parse it and add variables (values) to the ExpressionAttributeValues
# Expression is also transformed to use these variables.
if filter_expression:
expr, values = self._parse_filter_expression(filter_expression)
query_args['FilterExpression'] = expr
query_args['ExpressionAttributeValues'].update(values)
if index_name:
query_args['IndexName'] = index_name
if max_items:
query_args['PaginationConfig'] = {'MaxItems': max_items}
if return_count:
raise Exception(f"DynamoDbCLient.get_by_query does not support `max_items` and `return_count` together")
if desc:
query_args['ScanIndexForward'] = False
logger.debug("Querying dynamo: %s", query_args)
paginator = self.dynamo_client.get_paginator('query')
response_iterator = paginator.paginate(**query_args)
result = []
if return_count:
return sum([page['Count'] for page in response_iterator])
for page in response_iterator:
result += [self.dynamo_to_dict(x, fetch_all_fields=fetch_all_fields) for x in page['Items']]
self.stats['dynamo_get_queries'] += 1
if max_items and len(result) >= max_items:
break
return result[:max_items] if max_items else result
def _parse_filter_expression(self, expression: str) -> Tuple[str, Dict]:
"""
Converts FilterExpression to Dynamo syntax. We still do not support some operators. Feel free to implement:
https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Expressions.OperatorsAndFunctions.html
Supported: regular comparators, between, attribute_[not_]exists
:return: Returns a tuple of the transformed expression and extracted variables already Dynamo formatted.
"""
assert isinstance(expression, str), f"Filter expression must be a string: {expression}"
words = [x.strip() for x in expression.split()]
# Filter Expression should be 2, 3 or 5 words. See doc for more details.
# This must be a function
if len(words) == 2:
operator, key = words
assert operator.lower() in ('attribute_exists', 'attribute_not_exists')
result_expr, result_values = f"{operator} ({key})", {}
# This must be a regular comparison
elif len(words) == 3:
key, operator, value = words
assert operator in ('=', '<>', '<', '<=', '>', '>='), f"Unsupported operator for filtering: {expression}"
# It is important to add prefix to value here to avoid attribute naming conflicts for example
# in conditional_update expressions. e.g you update some field only if it's value is matching condition.
result_expr = f"{key} {operator} :filter_{key}"
result_values = self.dict_to_dynamo({f"filter_{key}": words[-1]}, add_prefix=':', strict=False)
# This must be `between` statement.
elif len(words) == 5:
assert (words[1].lower(), words[3].lower()) == ('between', 'and'), \
f"Unsupported expression for Filtering: {expression}"
key = words[0]
result_expr = f"{key} between :st_between_{key} and :en_between_{key}"
result_values = self.dict_to_dynamo({
f"st_between_{key}": words[2],
f"en_between_{key}": words[4]
}, add_prefix=':', strict=False)
else:
raise ValueError(f"Unsupported expression for Filtering: {expression}")
return result_expr, result_values
[docs]
def get_by_scan(self, attrs=None, table_name=None, index_name=None, strict=None, fetch_all_fields=None,
consistent_read=None):
"""
Scans a table. Don't use this method if you want to select by keys. It is SLOW compared to get_by_query.
Careful - don't make queries of too many items, this could run for a long time.
Optional:
:param dict attrs: Attribute names and values of the items we get. Can be empty to get the whole table.
:param str table_name: Name of the dynamo table. If not specified, will use table_name from the config.
:param str index_name: Name of the dynamo table index. If not specified, will use index_name from the config.
If not specified also in the config, will scan the table itself without any index.
:param bool consistent_read: If True , then the operation uses strongly consistent reads;
otherwise, the operation uses eventually consistent reads. Default is False
:param bool strict: DEPRECATED.
:param bool fetch_all_fields: If False, will only get the attributes specified in the row mapper.
If True, will get all attributes. Default is False.
:return: List of items from the table, each item in key-value format
:rtype: list
"""
if strict is not None:
logger.warning("get_by_query `strict` variable is deprecated in sosw 0.7.13+. "
"Please replace it's usage with `fetch_all_fields` (and reverse the boolean value)")
fetch_all_fields = fetch_all_fields if fetch_all_fields is not None else False if strict is None else not strict
response_iterator = self._build_scan_iterator(attrs, table_name, index_name, consistent_read)
result = []
for page in response_iterator:
result += [self.dynamo_to_dict(x, fetch_all_fields=fetch_all_fields) for x in page['Items']]
self.stats['dynamo_scan_queries'] += 1
return result
[docs]
def get_by_scan_generator(self, attrs=None, table_name=None, index_name=None, strict=None, fetch_all_fields=None,
consistent_read=None):
"""
Scans a table. Don't use this method if you want to select by keys. It is SLOW compared to get_by_query.
Careful - don't make queries of too many items, this could run for a long time.
Same as get_by_scan, but yields parts of the results.
Optional:
:param dict attrs: Attribute names and values of the items we get. Can be empty to get the whole table.
:param str table_name: Name of the dynamo table. If not specified, will use table_name from the config.
:param str index_name: Name of the dynamo table index. If not specified, will use index_name from the config.
If not specified also in the config, will scan the table itself without any index.
:param bool consistent_read: If True , then the operation uses strongly consistent reads;
otherwise, the operation uses eventually consistent reads. Default uses this settings of boto3 (False).
:param bool strict: DEPRECATED.
:param bool fetch_all_fields: If False, will only get the attributes specified in the row mapper.
If false, will get all attributes. Default is True.
:return: List of items from the table, each item in key-value format
:rtype: list
"""
if strict is not None:
logger.warning("get_by_query `strict` variable is deprecated in sosw 0.7.13+. "
"Please replace it's usage with `fetch_all_fields` (and reverse the boolean value)")
fetch_all_fields = fetch_all_fields if fetch_all_fields is not None else False if strict is None else not strict
response_iterator = self._build_scan_iterator(attrs, table_name, index_name, consistent_read)
for page in response_iterator:
self.stats['dynamo_scan_queries'] += 1
yield [self.dynamo_to_dict(x, fetch_all_fields=fetch_all_fields) for x in page['Items']]
def _build_scan_iterator(self, attrs=None, table_name=None, index_name=None, consistent_read=None):
table_name = self._get_validate_table_name(table_name)
filter_values = None
cond_expr = None
if attrs:
filter_values = self.dict_to_dynamo(attrs, add_prefix=':', strict=False)
cond_expr_parts = []
for key_attr_name in attrs:
cond_expr_parts.append(f"{key_attr_name} = :{key_attr_name}")
cond_expr = " AND ".join(cond_expr_parts)
query_args = {
'TableName': table_name,
'Select': 'ALL_ATTRIBUTES',
}
if consistent_read is not None:
logger.debug("Forcing ConsistentRead in query args of _build_scan_iterator to: %s", consistent_read)
query_args['ConsistentRead'] = consistent_read
if cond_expr:
query_args['FilterExpression'] = cond_expr
if filter_values:
query_args['ExpressionAttributeValues'] = filter_values
index_name = index_name or self.config.get('index_name')
if index_name:
query_args['IndexName'] = index_name
logger.debug("Scanning dynamo: %s", query_args)
paginator = self.dynamo_client.get_paginator('scan')
response_iterator = paginator.paginate(**query_args)
return response_iterator
[docs]
def batch_get_items_one_table(self, keys_list, table_name=None, max_retries=0, retry_wait_base_time=0.2,
strict=None, fetch_all_fields=None, consistent_read=None):
"""
Gets a batch of items from a single dynamo table.
Only accepts keys, can't query by other columns.
:param list keys_list: A list of the keys of the items we want to get. Gets the items that match the given keys.
If some key doesn't exist - it just skips it and gets the others.
e.g. [{'hash_col': '1, 'range_col': 2}, {'hash_col': 3}]
- will get a row where `hash_col` is 1 and `range_col` is 2, and also all rows where
`hash_col` is 3.
Optional
:param str table_name:
:param int max_retries: If failed to get some items, retry this many times. Waiting between retries is
multiplied by 2 after each retry, so `retries` shouldn't be a big number.
Default is 1.
:param int retry_wait_base_time: Wait this much time after first retry. Will wait twice longer in each retry.
:param bool strict: DEPRECATED.
:param bool fetch_all_fields: If False, will only get the attributes specified in the row mapper.
If True, will get all attributes. Default is False.
:param bool consistent_read: If True , then the operation uses strongly consistent reads;
otherwise, the operation uses eventually consistent reads. Default is False
:return: List of items from the table
:rtype: list
"""
if strict is not None:
logger.warning("batch_get_items_one_table `strict` variable is deprecated in sosw 0.7.13+. "
"Please replace it's usage with `fetch_all_fields` (and reverse the boolean value)")
fetch_all_fields = fetch_all_fields if fetch_all_fields is not None else False if strict is None else not strict
table_name = self._get_validate_table_name(table_name)
# Convert given keys to dynamo syntax
query_keys = [self.dict_to_dynamo(item) for item in keys_list]
# Check if we skipped something - if we did, try again.
def get_unprocessed_keys(db_result):
return 'UnprocessedKeys' in db_result and db_result['UnprocessedKeys'] \
and table_name in db_result['UnprocessedKeys'] and db_result['UnprocessedKeys'][table_name]['Keys']
all_items = []
for query_keys_chunk in chunks(query_keys, 100):
batch_get_item_query = {
'RequestItems': {
table_name: {
'Keys': query_keys_chunk,
}
}
}
if consistent_read is not None:
logger.debug("Forcing ConsistentRead in batch_get_item_query to %s", consistent_read)
batch_get_item_query['RequestItems'][table_name]['ConsistentRead'] = consistent_read
logger.debug("batch_get_item query: %s", batch_get_item_query)
latest_result = self.dynamo_client.batch_get_item(**batch_get_item_query)
logger.debug("latest_result: %s", latest_result)
unprocessed_keys = get_unprocessed_keys(latest_result)
all_items += latest_result['Responses'][table_name]
logger.debug("batch_get_items_one_table response: %s", latest_result)
if unprocessed_keys:
# Retry several times
retry_num = 0
wait_time = retry_wait_base_time
while unprocessed_keys and retry_num < max_retries:
logger.warning("batch_get_item action did NOT finish successfully.")
time.sleep(wait_time)
batch_get_item_query['RequestItems'][table_name]['Keys'] = unprocessed_keys
latest_result = self.dynamo_client.batch_get_item(**batch_get_item_query)
logger.debug("latest_result: %s", latest_result)
all_items += latest_result['Responses'][table_name]
retry_num += 1
wait_time *= 2
unprocessed_keys = get_unprocessed_keys(latest_result)
# After the retries still we have a bad result... then raise Exception
if get_unprocessed_keys(latest_result):
raise Exception(f"batch_get_items action failed for table {table_name}, keys_list {keys_list}")
result = []
for item in all_items:
result.append(self.dynamo_to_dict(item, fetch_all_fields=fetch_all_fields))
return result
def build_put_query(self, row, table_name=None, overwrite_existing=True):
table_name = self._get_validate_table_name(table_name)
dynamo_formatted_row = self.dict_to_dynamo(row, strict=False)
query = {
'TableName': table_name,
'Item': dynamo_formatted_row
}
if not overwrite_existing:
hash_key = self.config['hash_key']
query['ConditionExpression'] = f"attribute_not_exists({hash_key})"
return query
def build_delete_query(self, delete_keys: Dict, table_name: str = None):
table_name = self._get_validate_table_name(table_name)
dynamo_formatted_row = self.dict_to_dynamo(delete_keys, strict=False)
query = {
'TableName': table_name,
'Key': dynamo_formatted_row
}
return query
[docs]
def put(self, row: Dict, table_name: str = None, overwrite_existing: bool = True):
"""
Writes the row to the DynamoDB table.
:param row: The row to add to the table. key is column name, value is value.
:param table_name: Name of the dynamo table to add the row to.
:param overwrite_existing: Overwrite the existing row if True, otherwise will raise an exception if exists.
.. warning::
``overwrite_existing`` option requires the config to have a 'hash_key' parameter with a name of a field.
"""
table_name = self._get_validate_table_name(table_name)
if not overwrite_existing:
assert 'hash_key' in self.config, \
"Missing 'hash_key' parameter in the dynamo_db config. You must provide it in order to use the " \
"'create' method, or 'overwrite_existing=False' option."
put_query = self.build_put_query(row, table_name, overwrite_existing)
logger.debug("Put to DB: %s", put_query)
dynamo_response = self.dynamo_client.put_item(**put_query)
logger.debug("Response from dynamo %s", dynamo_response)
self.stats['dynamo_put_queries'] += 1
[docs]
def create(self, row: Dict, table_name: str = None):
"""
Uses the mechanism of the ``put`` method, but first validates that the item with same hash & [range] key[s]
does not exist in the table. Otherwise raises: ``ConditionalCheckFailedException``
.. warning:: This method requires the config to have a 'hash_key' parameter with a name of a field.
:param row:
:param table_name:
"""
self.put(row, table_name, overwrite_existing=False)
# @benchmark
[docs]
def update(self, keys: Dict, attributes_to_update: Optional[Dict] = None,
attributes_to_increment: Optional[Dict] = None, table_name: Optional[str] = None,
condition_expression: Optional[str] = None, attributes_to_remove: Optional[List[str]] = None):
"""
Updates an item in DynamoDB. Will create a new item if doesn't exist.
IMPORTANT - If you want to make sure it exists, use ``patch`` method
:param dict keys:
Keys and values of the row we update.
Example, in a table where the hash key is 'hk' and the range key is 'rk':
{'hk': 'cat', 'rk': '123'}
:param dict attributes_to_update:
Dict of the attributes to be updated.
Can contain both existing attributes and new attributes.
Will update existing, and create new attributes.
Example: {'col_name': 'some_value'}
:param dict attributes_to_increment:
Attribute names to increment, and the value to increment by. If the attribute doesn't exist, will create it.
Example: {'some_counter': '3'}
:param list attributes_to_remove: Will remove these attributes from the record
:param str condition_expression: Condition Expression that must be fulfilled on the object to update.
:param str table_name: Name of the table
"""
table_name = self._get_validate_table_name(table_name)
if not attributes_to_update and not attributes_to_increment and not attributes_to_remove:
raise ValueError(f"In dynamodb.update, please specify either attributes_to_update "
f"or attributes_to_increment or attributes_to_remove")
expression_attributes = {}
update_set_val_expr_parts = []
attribute_values = {}
if attributes_to_update:
for col in attributes_to_update:
update_set_val_expr_parts.append(f"#{col} = :{col}")
expression_attributes[f"#{col}"] = col
if attributes_to_increment:
for col in attributes_to_increment:
update_set_val_expr_parts.append(f"#{col} = if_not_exists(#{col}, :zero) + :{col}")
expression_attributes[f"#{col}"] = col
attribute_values.update({'zero': '0'})
keys = self.dict_to_dynamo(keys, strict=False)
attribute_values.update((attributes_to_update or {}))
attribute_values.update(attributes_to_increment or {})
attribute_values = self.dict_to_dynamo(attribute_values.copy(), add_prefix=":", strict=False)
update_expr_parts = []
if update_set_val_expr_parts:
set_expression = "SET " + ", ".join(update_set_val_expr_parts)
update_expr_parts.append(set_expression)
if attributes_to_remove:
remove_expression = "REMOVE " + ", ".join(attributes_to_remove)
update_expr_parts.append(remove_expression)
update_item_query = {
'Key': keys, # Ex. {'key_name': 'key_value', ...}
'TableName': table_name,
'UpdateExpression': " ".join(update_expr_parts) # Ex. "SET #attr_name = :attr_name ..."
}
if expression_attributes:
update_item_query['ExpressionAttributeNames'] = expression_attributes # Ex. {'#attr_name': 'attr_name', ..}
if attribute_values:
update_item_query['ExpressionAttributeValues'] = attribute_values # Ex. {':attr_name': 'some_value', ...}
if condition_expression:
expr, values = self._parse_filter_expression(condition_expression)
update_item_query['ConditionExpression'] = expr
if values:
update_item_query['ExpressionAttributeValues'] = update_item_query.get('ExpressionAttributeValues', {})
update_item_query['ExpressionAttributeValues'].update(values)
logger.debug("Updating an item, query: %s", update_item_query)
response = self.dynamo_client.update_item(**update_item_query)
logger.debug("Update result: %s", response)
self.stats['dynamo_update_queries'] += 1
[docs]
def patch(self, keys: Dict, attributes_to_update: Optional[Dict] = None,
attributes_to_increment: Optional[Dict] = None, table_name: Optional[str] = None,
attributes_to_remove: Optional[List[str]] = None):
"""
Updates an item in DynamoDB. Will fail if an item with these keys does not exist.
"""
hash_key = self.config['hash_key']
condition_expression = f'attribute_exists {hash_key}'
self.update(keys=keys, attributes_to_update=attributes_to_update,
attributes_to_increment=attributes_to_increment, table_name=table_name,
condition_expression=condition_expression,
attributes_to_remove=attributes_to_remove)
[docs]
def delete(self, keys: Dict, table_name: Optional[str] = None):
"""
:param dict keys: Keys and values of the row we delete.
:param table_name:
"""
query = self.build_delete_query(keys, table_name)
self.dynamo_client.delete_item(**query)
def make_put_transaction_item(self, row, table_name=None):
return {'Put': self.build_put_query(row, table_name)}
def make_delete_transaction_item(self, row, table_name):
return {'Delete': self.build_delete_query(row, table_name)}
[docs]
def transact_write(self, *transactions: Dict):
"""
Executes many write transaction. Can execute operations on different tables.
Will split transactions to chunks - because transact_write_items accepts up to 10 actions.
WARNING: If you're expecting a transaction on more than 10 operations - AWS DynamoDB doesn't support it.
.. code-block:: python
dynamo_db_client = DynamoDbClient(config)
t1 = dynamo_db_client.make_put_transaction_item(row, table_name='table1')
t2 = dynamo_db_client.make_delete_transaction_item(row, table_name='table2')
dynamo_db_client.transact_write(t1, t2)
"""
supported_actions = ['Put', 'Delete']
for t in transactions:
assert isinstance(t, dict), "transaction must be a dictionary"
assert len(t) == 1, "one transaction must contain only one operation"
action = list(t.keys())[0]
assert action in supported_actions, f"Bad action '{action}'. " \
f"Supported actions: {', '.join(supported_actions)}"
assert isinstance(t[action], dict), f"transaction[{action}] must be a dictionary. bad type: " \
f"{type(t[action])}"
for t_chunk in chunks(transactions, 10):
logger.debug("Transactions: %s", t_chunk)
response = self.dynamo_client.transact_write_items(TransactItems=t_chunk)
self.stats['dynamo_transact_write_operations'] += 1
logger.debug("Response from transact_write_items: %s", response)
def _get_validate_table_name(self, table_name=None):
if table_name is None:
table_name = self.config.get('table_name')
if table_name is None:
raise RuntimeError("Failed to dynamo action. no 'table_name' in config and table_name wasn't "
"specified in the arguments.")
if os.environ.get('STAGE') == 'test':
assert table_name.startswith('autotest_') or table_name == 'config', f"Bad table name in test: {table_name}"
return table_name
[docs]
def get_stats(self):
"""
Return statistics of operations performed by current instance of the Class.
:return: - dict - key: int statistics.
"""
return self.stats
[docs]
def get_capacity(self, table_name=None):
"""Fetches capacity for data tables
Keyword Arguments:
table_name {str} -- DynamoDB (default: {None})
Returns:
dict -- read/write capacity for the table requested or None for ON_DEMAND (PAY_PER_REQUEST) tables
"""
if table_name is None:
logger.debug(self.config)
table_name = self.config['table_name']
if table_name not in self._table_descriptions:
logger.debug("Getting description from API because not cached yet: %s", table_name)
self.identify_dynamo_capacity(table_name=table_name)
if table_name in self._table_capacity.keys():
logger.debug("Found capacity in the cache for table %s: %s", table_name, self._table_capacity[table_name])
return self._table_capacity[table_name]
[docs]
def sleep_db(self, last_action_time: datetime.datetime, action: str, table_name=None):
"""
Sleeps between calls to dynamodb (if it needs to).
Uses the table's capacity to decide how long it needs to sleep.
No need to sleep for ON DEMAND (PAY_PER_REQUEST) tables.
:param last_action_time: Last time when we did this action (read/write) to this dynamo table
:param action: "read" or "write"
"""
if table_name is None:
logger.debug(self.config)
table_name = self.config['table_name']
# No need to sleep for ON DEMAND (PAY_PER_REQUEST) tables.
if not self.get_capacity(table_name=table_name):
return
capacity = self.get_capacity()[action] # Capacity per second
# No need to sleep for ON DEMAND (PAY_PER_REQUEST) tables.
if capacity == 0:
return
time_between_actions = 1 / capacity
time_elapsed = datetime.datetime.now().timestamp() - last_action_time.timestamp()
time_to_sleep = time_between_actions - time_elapsed
if time_to_sleep > 0:
logger.debug("Sleeping %s sec", time_to_sleep)
time.sleep(time_to_sleep)
[docs]
def reset_stats(self):
"""
Cleans statistics.
"""
self.stats = defaultdict(int)
[docs]
def clean_dynamo_table(table_name='autotest_dynamo_db', keys=('hash_col', 'range_col'), filter_expression=None):
"""
Cleans the DynamoDB Table. Only for autotest tables.
:param str table_name: name of the table
:param tuple keys: the keys of the table
:param str filter_expression: Supports regular comparisons and `between`. Input must be a regular human string
e.g. 'key <= 42', 'name = marta', 'foo between 10 and 20', etc.
.. warning:: There are some reserved words that woud not work with
Filter Expression in case they are attribute names. Fix this one day.
"""
assert table_name.startswith('autotest_')
client = boto3.client('dynamodb')
paginator = client.get_paginator('scan')
stats = defaultdict(int)
query_args = {
'TableName': table_name,
'Select': 'ALL_ATTRIBUTES',
}
if filter_expression:
# We use DynamoDbClient class only for static method to construct Filter Expression. No need for config.
dynamo_client = DynamoDbClient(config={'row_mapper': {'name': 'S', }})
query_args['FilterExpression'] = {}
expr, values = dynamo_client._parse_filter_expression(filter_expression)
query_args['FilterExpression'] = expr
query_args['ExpressionAttributeValues'] = values
response_iterator = paginator.paginate(**query_args)
for page in response_iterator:
stats['dynamo_scan_queries'] += 1
for row in page['Items']:
client.delete_item(
TableName=table_name,
Key={key: row[key] for key in keys}
)
stats['deleted'] += 1
logger.debug("clean_dynamo_table() of %s: %s", table_name, stats)
logger.info(f"clean_dynamo_table() of %s: %s", table_name, stats)