2020/08/17 - Amazon Kinesis - 2 updated api methods
Changes Updates API to latest version.
{'ChildShards': [{'HashKeyRange': {'EndingHashKey': 'string',
'StartingHashKey': 'string'},
'ParentShards': ['string'],
'ShardId': 'string'}]}
Gets data records from a Kinesis data stream's shard.
Specify a shard iterator using the ShardIterator parameter. The shard iterator specifies the position in the shard from which you want to start reading data records sequentially. If there are no records available in the portion of the shard that the iterator points to, GetRecords returns an empty list. It might take multiple calls to get to a portion of the shard that contains records.
You can scale by provisioning multiple shards per stream while considering service limits (for more information, see Amazon Kinesis Data Streams Limits in the Amazon Kinesis Data Streams Developer Guide ). Your application should have one thread per shard, each reading continuously from its stream. To read from a stream continually, call GetRecords in a loop. Use GetShardIterator to get the shard iterator to specify in the first GetRecords call. GetRecords returns a new shard iterator in NextShardIterator . Specify the shard iterator returned in NextShardIterator in subsequent calls to GetRecords . If the shard has been closed, the shard iterator can't return more data and GetRecords returns null in NextShardIterator . You can terminate the loop when the shard is closed, or when the shard iterator reaches the record with the sequence number or other attribute that marks it as the last record to process.
Each data record can be up to 1 MiB in size, and each shard can read up to 2 MiB per second. You can ensure that your calls don't exceed the maximum supported size or throughput by using the Limit parameter to specify the maximum number of records that GetRecords can return. Consider your average record size when determining this limit. The maximum number of records that can be returned per call is 10,000.
The size of the data returned by GetRecords varies depending on the utilization of the shard. The maximum size of data that GetRecords can return is 10 MiB. If a call returns this amount of data, subsequent calls made within the next 5 seconds throw ProvisionedThroughputExceededException . If there is insufficient provisioned throughput on the stream, subsequent calls made within the next 1 second throw ProvisionedThroughputExceededException . GetRecords doesn't return any data when it throws an exception. For this reason, we recommend that you wait 1 second between calls to GetRecords . However, it's possible that the application will get exceptions for longer than 1 second.
To detect whether the application is falling behind in processing, you can use the MillisBehindLatest response attribute. You can also monitor the stream using CloudWatch metrics and other mechanisms (see Monitoring in the Amazon Kinesis Data Streams Developer Guide ).
Each Amazon Kinesis record includes a value, ApproximateArrivalTimestamp , that is set when a stream successfully receives and stores a record. This is commonly referred to as a server-side time stamp, whereas a client-side time stamp is set when a data producer creates or sends the record to a stream (a data producer is any data source putting data records into a stream, for example with PutRecords ). The time stamp has millisecond precision. There are no guarantees about the time stamp accuracy, or that the time stamp is always increasing. For example, records in a shard or across a stream might have time stamps that are out of order.
This operation has a limit of five transactions per second per shard.
See also: AWS API Documentation
Request Syntax
client.get_records(
ShardIterator='string',
Limit=123
)
string
[REQUIRED]
The position in the shard from which you want to start sequentially reading data records. A shard iterator specifies this position using the sequence number of a data record in the shard.
integer
The maximum number of records to return. Specify a value of up to 10,000. If you specify a value that is greater than 10,000, GetRecords throws InvalidArgumentException . The default value is 10,000.
dict
Response Syntax
{
'Records': [
{
'SequenceNumber': 'string',
'ApproximateArrivalTimestamp': datetime(2015, 1, 1),
'Data': b'bytes',
'PartitionKey': 'string',
'EncryptionType': 'NONE'|'KMS'
},
],
'NextShardIterator': 'string',
'MillisBehindLatest': 123,
'ChildShards': [
{
'ShardId': 'string',
'ParentShards': [
'string',
],
'HashKeyRange': {
'StartingHashKey': 'string',
'EndingHashKey': 'string'
}
},
]
}
Response Structure
(dict) --
Represents the output for GetRecords .
Records (list) --
The data records retrieved from the shard.
(dict) --
The unit of data of the Kinesis data stream, which is composed of a sequence number, a partition key, and a data blob.
SequenceNumber (string) --
The unique identifier of the record within its shard.
ApproximateArrivalTimestamp (datetime) --
The approximate time that the record was inserted into the stream.
Data (bytes) --
The data blob. The data in the blob is both opaque and immutable to Kinesis Data Streams, which does not inspect, interpret, or change the data in the blob in any way. When the data blob (the payload before base64-encoding) is added to the partition key size, the total size must not exceed the maximum record size (1 MiB).
PartitionKey (string) --
Identifies which shard in the stream the data record is assigned to.
EncryptionType (string) --
The encryption type used on the record. This parameter can be one of the following values:
NONE : Do not encrypt the records in the stream.
KMS : Use server-side encryption on the records in the stream using a customer-managed AWS KMS key.
NextShardIterator (string) --
The next position in the shard from which to start sequentially reading data records. If set to null , the shard has been closed and the requested iterator does not return any more data.
MillisBehindLatest (integer) --
The number of milliseconds the GetRecords response is from the tip of the stream, indicating how far behind current time the consumer is. A value of zero indicates that record processing is caught up, and there are no new records to process at this moment.
ChildShards (list) --
(dict) --
ShardId (string) --
ParentShards (list) --
(string) --
HashKeyRange (dict) --
The range of possible hash key values for the shard, which is a set of ordered contiguous positive integers.
StartingHashKey (string) --
The starting hash key of the hash key range.
EndingHashKey (string) --
The ending hash key of the hash key range.
{'ShardFilter': {'ShardId': 'string',
'Timestamp': 'timestamp',
'Type': 'AFTER_SHARD_ID | AT_TRIM_HORIZON | FROM_TRIM_HORIZON '
'| AT_LATEST | AT_TIMESTAMP | FROM_TIMESTAMP'}}
Lists the shards in a stream and provides information about each shard. This operation has a limit of 100 transactions per second per data stream.
Warning
This API is a new operation that is used by the Amazon Kinesis Client Library (KCL). If you have a fine-grained IAM policy that only allows specific operations, you must update your policy to allow calls to this API. For more information, see Controlling Access to Amazon Kinesis Data Streams Resources Using IAM .
See also: AWS API Documentation
Request Syntax
client.list_shards(
StreamName='string',
NextToken='string',
ExclusiveStartShardId='string',
MaxResults=123,
StreamCreationTimestamp=datetime(2015, 1, 1),
ShardFilter={
'Type': 'AFTER_SHARD_ID'|'AT_TRIM_HORIZON'|'FROM_TRIM_HORIZON'|'AT_LATEST'|'AT_TIMESTAMP'|'FROM_TIMESTAMP',
'ShardId': 'string',
'Timestamp': datetime(2015, 1, 1)
}
)
string
The name of the data stream whose shards you want to list.
You cannot specify this parameter if you specify the NextToken parameter.
string
When the number of shards in the data stream is greater than the default value for the MaxResults parameter, or if you explicitly specify a value for MaxResults that is less than the number of shards in the data stream, the response includes a pagination token named NextToken . You can specify this NextToken value in a subsequent call to ListShards to list the next set of shards.
Don't specify StreamName or StreamCreationTimestamp if you specify NextToken because the latter unambiguously identifies the stream.
You can optionally specify a value for the MaxResults parameter when you specify NextToken . If you specify a MaxResults value that is less than the number of shards that the operation returns if you don't specify MaxResults , the response will contain a new NextToken value. You can use the new NextToken value in a subsequent call to the ListShards operation.
Warning
Tokens expire after 300 seconds. When you obtain a value for NextToken in the response to a call to ListShards , you have 300 seconds to use that value. If you specify an expired token in a call to ListShards , you get ExpiredNextTokenException .
string
Specify this parameter to indicate that you want to list the shards starting with the shard whose ID immediately follows ExclusiveStartShardId .
If you don't specify this parameter, the default behavior is for ListShards to list the shards starting with the first one in the stream.
You cannot specify this parameter if you specify NextToken .
integer
The maximum number of shards to return in a single call to ListShards . The minimum value you can specify for this parameter is 1, and the maximum is 10,000, which is also the default.
When the number of shards to be listed is greater than the value of MaxResults , the response contains a NextToken value that you can use in a subsequent call to ListShards to list the next set of shards.
datetime
Specify this input parameter to distinguish data streams that have the same name. For example, if you create a data stream and then delete it, and you later create another data stream with the same name, you can use this input parameter to specify which of the two streams you want to list the shards for.
You cannot specify this parameter if you specify the NextToken parameter.
dict
Type (string) -- [REQUIRED]
ShardId (string) --
Timestamp (datetime) --
dict
Response Syntax
{
'Shards': [
{
'ShardId': 'string',
'ParentShardId': 'string',
'AdjacentParentShardId': 'string',
'HashKeyRange': {
'StartingHashKey': 'string',
'EndingHashKey': 'string'
},
'SequenceNumberRange': {
'StartingSequenceNumber': 'string',
'EndingSequenceNumber': 'string'
}
},
],
'NextToken': 'string'
}
Response Structure
(dict) --
Shards (list) --
An array of JSON objects. Each object represents one shard and specifies the IDs of the shard, the shard's parent, and the shard that's adjacent to the shard's parent. Each object also contains the starting and ending hash keys and the starting and ending sequence numbers for the shard.
(dict) --
A uniquely identified group of data records in a Kinesis data stream.
ShardId (string) --
The unique identifier of the shard within the stream.
ParentShardId (string) --
The shard ID of the shard's parent.
AdjacentParentShardId (string) --
The shard ID of the shard adjacent to the shard's parent.
HashKeyRange (dict) --
The range of possible hash key values for the shard, which is a set of ordered contiguous positive integers.
StartingHashKey (string) --
The starting hash key of the hash key range.
EndingHashKey (string) --
The ending hash key of the hash key range.
SequenceNumberRange (dict) --
The range of possible sequence numbers for the shard.
StartingSequenceNumber (string) --
The starting sequence number for the range.
EndingSequenceNumber (string) --
The ending sequence number for the range. Shards that are in the OPEN state have an ending sequence number of null .
NextToken (string) --
When the number of shards in the data stream is greater than the default value for the MaxResults parameter, or if you explicitly specify a value for MaxResults that is less than the number of shards in the data stream, the response includes a pagination token named NextToken . You can specify this NextToken value in a subsequent call to ListShards to list the next set of shards. For more information about the use of this pagination token when calling the ListShards operation, see ListShardsInput$NextToken .
Warning
Tokens expire after 300 seconds. When you obtain a value for NextToken in the response to a call to ListShards , you have 300 seconds to use that value. If you specify an expired token in a call to ListShards , you get ExpiredNextTokenException .