SQS / Client / send_message

send_message

SQS.Client.send_message(**kwargs)

Delivers a message to the specified queue.

Warning

A message can include only XML, JSON, and unformatted text. The following Unicode characters are allowed. For more information, see the W3C specification for characters.

#x9 | #xA | #xD | #x20 to #xD7FF | #xE000 to #xFFFD | #x10000 to #x10FFFF

If a message contains characters outside the allowed set, Amazon SQS rejects the message and returns an InvalidMessageContents error. Ensure that your message body includes only valid characters to avoid this exception.

See also: AWS API Documentation

Request Syntax

response = client.send_message(
    QueueUrl='string',
    MessageBody='string',
    DelaySeconds=123,
    MessageAttributes={
        'string': {
            'StringValue': 'string',
            'BinaryValue': b'bytes',
            'StringListValues': [
                'string',
            ],
            'BinaryListValues': [
                b'bytes',
            ],
            'DataType': 'string'
        }
    },
    MessageSystemAttributes={
        'string': {
            'StringValue': 'string',
            'BinaryValue': b'bytes',
            'StringListValues': [
                'string',
            ],
            'BinaryListValues': [
                b'bytes',
            ],
            'DataType': 'string'
        }
    },
    MessageDeduplicationId='string',
    MessageGroupId='string'
)
Parameters:

  • QueueUrl (string) –

    [REQUIRED]

    The URL of the Amazon SQS queue to which a message is sent.

    Queue URLs and names are case-sensitive.

  • MessageBody (string) –

    [REQUIRED]

    The message to send. The minimum size is one character. The maximum size is 1 MiB or 1,048,576 bytes

    Warning

    A message can include only XML, JSON, and unformatted text. The following Unicode characters are allowed. For more information, see the W3C specification for characters.

    #x9 | #xA | #xD | #x20 to #xD7FF | #xE000 to #xFFFD | #x10000 to #x10FFFF

    If a message contains characters outside the allowed set, Amazon SQS rejects the message and returns an InvalidMessageContents error. Ensure that your message body includes only valid characters to avoid this exception.

  • DelaySeconds (integer) –

    The length of time, in seconds, for which to delay a specific message. Valid values: 0 to 900. Maximum: 15 minutes. Messages with a positive DelaySeconds value become available for processing after the delay period is finished. If you don’t specify a value, the default value for the queue applies.

    Note

    When you set FifoQueue, you can’t set DelaySeconds per message. You can set this parameter only on a queue level.

  • MessageAttributes (dict) –

    Each message attribute consists of a Name, Type, and Value. For more information, see Amazon SQS message attributes in the Amazon SQS Developer Guide.

    • (string) –

      • (dict) –

        The user-specified message attribute value. For string data types, the Value attribute has the same restrictions on the content as the message body. For more information, see SendMessage.

        Name, type, value and the message body must not be empty or null. All parts of the message attribute, including Name, Type, and Value, are part of the message size restriction (1 MiB or 1,048,576 bytes).

        • StringValue (string) –

          Strings are Unicode with UTF-8 binary encoding. For a list of code values, see ASCII Printable Characters.

        • BinaryValue (bytes) –

          Binary type attributes can store any binary data, such as compressed data, encrypted data, or images.

        • StringListValues (list) –

          Not implemented. Reserved for future use.

          • (string) –

        • BinaryListValues (list) –

          Not implemented. Reserved for future use.

          • (bytes) –

        • DataType (string) – [REQUIRED]

          Amazon SQS supports the following logical data types: String, Number, and Binary. For the Number data type, you must use StringValue.

          You can also append custom labels. For more information, see Amazon SQS Message Attributes in the Amazon SQS Developer Guide.

  • MessageSystemAttributes (dict) –

    The message system attribute to send. Each message system attribute consists of a Name, Type, and Value.

    Warning

    • Currently, the only supported message system attribute is AWSTraceHeader. Its type must be String and its value must be a correctly formatted X-Ray trace header string.

    • The size of a message system attribute doesn’t count towards the total size of a message.

    • (string) –

      • (dict) –

        The user-specified message system attribute value. For string data types, the Value attribute has the same restrictions on the content as the message body. For more information, see SendMessage.

        Name, type, value and the message body must not be empty or null.

        • StringValue (string) –

          Strings are Unicode with UTF-8 binary encoding. For a list of code values, see ASCII Printable Characters.

        • BinaryValue (bytes) –

          Binary type attributes can store any binary data, such as compressed data, encrypted data, or images.

        • StringListValues (list) –

          Not implemented. Reserved for future use.

          • (string) –

        • BinaryListValues (list) –

          Not implemented. Reserved for future use.

          • (bytes) –

        • DataType (string) – [REQUIRED]

          Amazon SQS supports the following logical data types: String, Number, and Binary. For the Number data type, you must use StringValue.

          You can also append custom labels. For more information, see Amazon SQS Message Attributes in the Amazon SQS Developer Guide.

  • MessageDeduplicationId (string) –

    This parameter applies only to FIFO (first-in-first-out) queues.

    The token used for deduplication of sent messages. If a message with a particular MessageDeduplicationId is sent successfully, any messages sent with the same MessageDeduplicationId are accepted successfully but aren’t delivered during the 5-minute deduplication interval. For more information, see Exactly-once processing in the Amazon SQS Developer Guide.

    • Every message must have a unique MessageDeduplicationId,

      • You may provide a MessageDeduplicationId explicitly.

      • If you aren’t able to provide a MessageDeduplicationId and you enable ContentBasedDeduplication for your queue, Amazon SQS uses a SHA-256 hash to generate the MessageDeduplicationId using the body of the message (but not the attributes of the message).

      • If you don’t provide a MessageDeduplicationId and the queue doesn’t have ContentBasedDeduplication set, the action fails with an error.

      • If the queue has ContentBasedDeduplication set, your MessageDeduplicationId overrides the generated one.

    • When ContentBasedDeduplication is in effect, messages with identical content sent within the deduplication interval are treated as duplicates and only one copy of the message is delivered.

    • If you send one message with ContentBasedDeduplication enabled and then another message with a MessageDeduplicationId that is the same as the one generated for the first MessageDeduplicationId, the two messages are treated as duplicates and only one copy of the message is delivered.

    Note

    The MessageDeduplicationId is available to the consumer of the message (this can be useful for troubleshooting delivery issues).

    If a message is sent successfully but the acknowledgement is lost and the message is resent with the same MessageDeduplicationId after the deduplication interval, Amazon SQS can’t detect duplicate messages.

    Amazon SQS continues to keep track of the message deduplication ID even after the message is received and deleted.

    The maximum length of MessageDeduplicationId is 128 characters. MessageDeduplicationId can contain alphanumeric characters ( a-z, A-Z, 0-9) and punctuation ( !"#$%&'()*+,-./:;<=>?@[\]^_`{|}~).

    For best practices of using MessageDeduplicationId, see Using the MessageDeduplicationId Property in the Amazon SQS Developer Guide.

  • MessageGroupId (string) –

    MessageGroupId is an attribute used in Amazon SQS FIFO (First-In-First-Out) and standard queues. In FIFO queues, MessageGroupId organizes messages into distinct groups. Messages within the same message group are always processed one at a time, in strict order, ensuring that no two messages from the same group are processed simultaneously. In standard queues, using MessageGroupId enables fair queues. It is used to identify the tenant a message belongs to, helping maintain consistent message dwell time across all tenants during noisy neighbor events. Unlike FIFO queues, messages with the same MessageGroupId can be processed in parallel, maintaining the high throughput of standard queues.

    • FIFO queues: MessageGroupId acts as the tag that specifies that a message belongs to a specific message group. Messages that belong to the same message group are processed in a FIFO manner (however, messages in different message groups might be processed out of order). To interleave multiple ordered streams within a single queue, use MessageGroupId values (for example, session data for multiple users). In this scenario, multiple consumers can process the queue, but the session data of each user is processed in a FIFO fashion. If you do not provide a MessageGroupId when sending a message to a FIFO queue, the action fails. ReceiveMessage might return messages with multiple MessageGroupId values. For each MessageGroupId, the messages are sorted by time sent.

    • **Standard queues:**Use MessageGroupId in standard queues to enable fair queues. The MessageGroupId identifies the tenant a message belongs to. A tenant can be any entity that shares a queue with others, such as your customer, a client application, or a request type. When one tenant sends a disproportionately large volume of messages or has messages that require longer processing time, fair queues ensure other tenants’ messages maintain low dwell time. This preserves quality of service for all tenants while maintaining the scalability and throughput of standard queues. We recommend that you include a MessageGroupId in all messages when using fair queues.

    The length of MessageGroupId is 128 characters. Valid values: alphanumeric characters and punctuation (!"#$%&'()*+,-./:;<=>?@[\]^_`{|}~).

    For best practices of using MessageGroupId, see Using the MessageGroupId Property in the Amazon SQS Developer Guide.

Return type:

dict

Returns:

Response Syntax

{
    'MD5OfMessageBody': 'string',
    'MD5OfMessageAttributes': 'string',
    'MD5OfMessageSystemAttributes': 'string',
    'MessageId': 'string',
    'SequenceNumber': 'string'
}

Response Structure

  • (dict) –

    The MD5OfMessageBody and MessageId elements.

    • MD5OfMessageBody (string) –

      An MD5 digest of the non-URL-encoded message body string. You can use this attribute to verify that Amazon SQS received the message correctly. Amazon SQS URL-decodes the message before creating the MD5 digest. For information about MD5, see RFC1321.

    • MD5OfMessageAttributes (string) –

      An MD5 digest of the non-URL-encoded message attribute string. You can use this attribute to verify that Amazon SQS received the message correctly. Amazon SQS URL-decodes the message before creating the MD5 digest. For information about MD5, see RFC1321.

    • MD5OfMessageSystemAttributes (string) –

      An MD5 digest of the non-URL-encoded message system attribute string. You can use this attribute to verify that Amazon SQS received the message correctly. Amazon SQS URL-decodes the message before creating the MD5 digest.

    • MessageId (string) –

      An attribute containing the MessageId of the message sent to the queue. For more information, see Queue and Message Identifiers in the Amazon SQS Developer Guide.

    • SequenceNumber (string) –

      This parameter applies only to FIFO (first-in-first-out) queues.

      The large, non-consecutive number that Amazon SQS assigns to each message.

      The length of SequenceNumber is 128 bits. SequenceNumber continues to increase for a particular MessageGroupId.

Exceptions