Tutorial: Perform basic Kinesis Data Streams operations using the Amazon CLI
This section describes basic use of a Kinesis data stream from the command line using the Amazon CLI. Be sure you are familiar with the concepts discussed in Amazon Kinesis Data Streams Terminology and concepts.
Note
After you create a stream, your account incurs nominal charges for Kinesis Data Streams usage because Kinesis Data Streams is not eligible for the Amazon Free Tier. When you are finished with this tutorial, delete your Amazon resources to stop incurring charges. For more information, see Step 4: Clean up.
Step 1: Create a stream
Your first step is to create a stream and verify that it was successfully created. Use the following command to create a stream named "Foo":
aws kinesis create-stream --stream-name Foo
Next, issue the following command to check on the stream's creation progress:
aws kinesis describe-stream-summary --stream-name Foo
You should get output that is similar to the following example:
{ "StreamDescriptionSummary": { "StreamName": "Foo", "StreamARN": "arn:aws:kinesis:us-west-2:123456789012:stream/Foo", "StreamStatus": "CREATING", "RetentionPeriodHours": 48, "StreamCreationTimestamp": 1572297168.0, "EnhancedMonitoring": [ { "ShardLevelMetrics": [] } ], "EncryptionType": "NONE", "OpenShardCount": 3, "ConsumerCount": 0 } }
In this example, the stream has a status CREATING, which means it is not yet ready to use. Check again in a few moments, and you should see output similar to the following example:
{ "StreamDescriptionSummary": { "StreamName": "Foo", "StreamARN": "arn:aws:kinesis:us-west-2:123456789012:stream/Foo", "StreamStatus": "ACTIVE", "RetentionPeriodHours": 48, "StreamCreationTimestamp": 1572297168.0, "EnhancedMonitoring": [ { "ShardLevelMetrics": [] } ], "EncryptionType": "NONE", "OpenShardCount": 3, "ConsumerCount": 0 } }
There is information in this output that you don't need for this tutorial. The
important information for now is "StreamStatus": "ACTIVE"
, which tells you
that the stream is ready to be used, and the information on the single shard that you
requested. You can also verify the existence of your new stream by using the
list-streams
command, as shown here:
aws kinesis list-streams
Output:
{
"StreamNames": [
"Foo"
]
}
Step 2: Put a record
Now that you have an active stream, you are ready to put some data. For this
tutorial, you will use the simplest possible command, put-record
, which
puts a single data record containing the text "testdata" into the stream:
aws kinesis put-record --stream-name Foo --partition-key 123 --data testdata
This command, if successful, will result in output similar to the following example:
{
"ShardId": "shardId-000000000000",
"SequenceNumber": "49546986683135544286507457936321625675700192471156785154"
}
Congratulations, you just added data to a stream! Next you will see how to get data out of the stream.
Step 3: Get the record
GetShardIterator
Before you can get data from the stream, you must obtain the shard iterator for the
shard you are interested in. A shard iterator represents the position of the stream and
shard from which the consumer (get-record
command in this case) will read.
You'll use the get-shard-iterator
command as follows:
aws kinesis get-shard-iterator --shard-id shardId-000000000000 --shard-iterator-type TRIM_HORIZON --stream-name Foo
Recall that the aws kinesis
commands have a Kinesis Data Streams API behind them, so if
you are curious about any of the parameters shown, you can read about them in the GetShardIterator
API reference topic. Successful execution will result in output similar to the following
example:
{
"ShardIterator": "AAAAAAAAAAHSywljv0zEgPX4NyKdZ5wryMzP9yALs8NeKbUjp1IxtZs1Sp+KEd9I6AJ9ZG4lNR1EMi+9Md/nHvtLyxpfhEzYvkTZ4D9DQVz/mBYWRO6OTZRKnW9gd+efGN2aHFdkH1rJl4BL9Wyrk+ghYG22D2T1Da2EyNSH1+LAbK33gQweTJADBdyMwlo5r6PqcP2dzhg="
}
The long string of seemingly random characters is the shard iterator (yours will be
different). You must copy/paste the shard iterator into the get command, shown next.
Shard iterators have a valid lifetime of 300 seconds, which should be enough time for
you to copy/paste the shard iterator into the next command. You must remove any newlines
from your shard iterator before pasting to the next command. If you get an error message
that the shard iterator is no longer valid, run the get-shard-iterator
command again.
GetRecords
The get-records
command gets data from the stream, and it resolves to a
call to GetRecords
in
the Kinesis Data Streams API. 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.
In the following example of the get-records
command:
aws kinesis get-records --shard-iterator AAAAAAAAAAHSywljv0zEgPX4NyKdZ5wryMzP9yALs8NeKbUjp1IxtZs1Sp+KEd9I6AJ9ZG4lNR1EMi+9Md/nHvtLyxpfhEzYvkTZ4D9DQVz/mBYWRO6OTZRKnW9gd+efGN2aHFdkH1rJl4BL9Wyrk+ghYG22D2T1Da2EyNSH1+LAbK33gQweTJADBdyMwlo5r6PqcP2dzhg=
If you are running this tutorial from a Unix-type command processor such as bash, you can automate the acquisition of the shard iterator using a nested command, like this:
SHARD_ITERATOR=$(aws kinesis get-shard-iterator --shard-id shardId-000000000000 --shard-iterator-type TRIM_HORIZON --stream-name Foo --query 'ShardIterator') aws kinesis get-records --shard-iterator $SHARD_ITERATOR
If you are running this tutorial from a system that supports PowerShell, you can automate acquisition of the shard iterator using a command such as this:
aws kinesis get-records --shard-iterator ((aws kinesis get-shard-iterator --shard-id shardId-000000000000 --shard-iterator-type TRIM_HORIZON --stream-name Foo).split('"')[4])
The successful result of the get-records
command will request records
from your stream for the shard that you specified when you obtained the shard iterator,
as in the following example:
{
"Records":[ {
"Data":"dGVzdGRhdGE=",
"PartitionKey":"123”,
"ApproximateArrivalTimestamp": 1.441215410867E9,
"SequenceNumber":"49544985256907370027570885864065577703022652638596431874"
} ],
"MillisBehindLatest":24000,
"NextShardIterator":"AAAAAAAAAAEDOW3ugseWPE4503kqN1yN1UaodY8unE0sYslMUmC6lX9hlig5+t4RtZM0/tALfiI4QGjunVgJvQsjxjh2aLyxaAaPr+LaoENQ7eVs4EdYXgKyThTZGPcca2fVXYJWL3yafv9dsDwsYVedI66dbMZFC8rPMWc797zxQkv4pSKvPOZvrUIudb8UkH3VMzx58Is="
}
Note that get-records
is described above as a
request, which means you may receive zero or more records even
if there are records in your stream. Any records returned may not represent all the
records currently in your stream. This is normal, and production code will poll the
stream for records at appropriate intervals. This polling speed will vary depending on
your specific application design requirements.
In your record in this part of the tutorial, you will notice that the data appears to
be garbage – and it's not the clear text testdata
we sent. This is
due to the way put-record
uses Base64 encoding to allow you to send binary
data. However, the Kinesis Data Streams support in the Amazon CLI does not provide Base64
decoding because Base64 decoding to raw binary content printed
to stdout can lead to undesired behavior and potential security issues on certain
platforms and terminals. If you use a Base64 decoder (for example, https://www.base64decode.org/dGVzdGRhdGE=
you will see that it is, in fact,
testdata
. This is sufficient for the sake of this tutorial because, in
practice, the Amazon CLI is rarely used to consume data. More often, it is used to monitor
the state of the stream and obtain information, as shown previously
(describe-stream
and list-streams
). For more information
about the KCL, see Developing Custom Consumers with Shared Throughput Using KCL
get-records
doesn't always return all records in the stream/shard
specified. When that happens, use the NextShardIterator
from the last
result to get the next set of records. If more data were being put into the stream,
which is the normal situation in production applications, you could keep polling for
data using get-records
each time. However, if you do not call
get-records
using the next shard iterator within the 300 second shard
iterator lifetime, you will get an error message, and you must use the
get-shard-iterator
command to get a fresh shard iterator.
Also provided in this output is MillisBehindLatest
, which is the number
of milliseconds the GetRecords operation's response is from the tip of the
stream, indicating how far behind current time the consumer is. A value of zero
indicates record processing is caught up, and there are no new records to process at
this moment. In the case of this tutorial, you may see a number that's quite large if
you've been taking time to read along as you go. By default, data records stay in a
stream for 24 hours waiting for you to retrieve them. This time frame is called the
retention period and it is configurable up to 365 days.
A successful get-records
result will always have a
NextShardIterator
even if there are no more records currently in the
stream. This is a polling model that assumes a producer is potentially putting more
records into the stream at any given time. Although you can write your own polling
routines, if you use the previously mentioned KCL for developing consumer applications,
this polling is taken care of for you.
If you call get-records
until there are no more records in the stream and
shard you are pulling from, you will see output with empty records similar to the
following example:
{
"Records": [],
"NextShardIterator": "AAAAAAAAAAGCJ5jzQNjmdhO6B/YDIDE56jmZmrmMA/r1WjoHXC/kPJXc1rckt3TFL55dENfe5meNgdkyCRpUPGzJpMgYHaJ53C3nCAjQ6s7ZupjXeJGoUFs5oCuFwhP+Wul/EhyNeSs5DYXLSSC5XCapmCAYGFjYER69QSdQjxMmBPE/hiybFDi5qtkT6/PsZNz6kFoqtDk="
}
Step 4: Clean up
Delete your stream to free up resources and avoid unintended charges to your account. Do this any time you have created a stream and will not be using it, because charges accrue per stream whether you are putting and getting data with it or not. The clean-up command is as follows:
aws kinesis delete-stream --stream-name Foo
Success results in no output. Use describe-stream
to check on the
deletion progress:
aws kinesis describe-stream-summary --stream-name Foo
If you execute this command immediately after the delete command, you will see output similar to the following example:
{ "StreamDescriptionSummary": { "StreamName": "samplestream", "StreamARN": "arn:aws:kinesis:us-west-2:123456789012:stream/samplestream", "StreamStatus": "ACTIVE",
After the stream is fully deleted, describe-stream
will result in a "not
found" error:
A client error (ResourceNotFoundException) occurred when calling the DescribeStreamSummary operation:
Stream Foo under account 123456789012 not found.