Copyright | (c) 2013-2021 Brendan Hay |
---|---|
License | Mozilla Public License, v. 2.0. |
Maintainer | Brendan Hay <brendan.g.hay+amazonka@gmail.com> |
Stability | auto-generated |
Portability | non-portable (GHC extensions) |
Safe Haskell | None |
Retrieves one or more messages (up to 10), from the specified queue.
Using the WaitTimeSeconds
parameter enables long-poll support. For
more information, see
Amazon SQS Long Polling
in the Amazon SQS Developer Guide.
Short poll is the default behavior where a weighted random set of
machines is sampled on a ReceiveMessage
call. Thus, only the messages
on the sampled machines are returned. If the number of messages in the
queue is small (fewer than 1,000), you most likely get fewer messages
than you requested per ReceiveMessage
call. If the number of messages
in the queue is extremely small, you might not receive any messages in a
particular ReceiveMessage
response. If this happens, repeat the
request.
For each message returned, the response includes the following:
- The message body.
- An MD5 digest of the message body. For information about MD5, see RFC1321.
- The
MessageId
you received when you sent the message to the queue. - The receipt handle.
- The message attributes.
- An MD5 digest of the message attributes.
The receipt handle is the identifier you must provide when deleting the message. For more information, see Queue and Message Identifiers in the Amazon SQS Developer Guide.
You can provide the VisibilityTimeout
parameter in your request. The
parameter is applied to the messages that Amazon SQS returns in the
response. If you don't include the parameter, the overall visibility
timeout for the queue is used for the returned messages. For more
information, see
Visibility Timeout
in the Amazon SQS Developer Guide.
A message that isn't deleted or a message whose visibility isn't extended before the visibility timeout expires counts as a failed receive. Depending on the configuration of the queue, the message might be sent to the dead-letter queue.
In the future, new attributes might be added. If you write code that calls this action, we recommend that you structure your code so that it can handle new attributes gracefully.
Synopsis
- data ReceiveMessage = ReceiveMessage' {}
- newReceiveMessage :: Text -> ReceiveMessage
- receiveMessage_receiveRequestAttemptId :: Lens' ReceiveMessage (Maybe Text)
- receiveMessage_visibilityTimeout :: Lens' ReceiveMessage (Maybe Int)
- receiveMessage_messageAttributeNames :: Lens' ReceiveMessage (Maybe [Text])
- receiveMessage_waitTimeSeconds :: Lens' ReceiveMessage (Maybe Int)
- receiveMessage_attributeNames :: Lens' ReceiveMessage (Maybe [MessageAttribute])
- receiveMessage_maxNumberOfMessages :: Lens' ReceiveMessage (Maybe Int)
- receiveMessage_queueUrl :: Lens' ReceiveMessage Text
- data ReceiveMessageResponse = ReceiveMessageResponse' {
- messages :: Maybe [Message]
- httpStatus :: Int
- newReceiveMessageResponse :: Int -> ReceiveMessageResponse
- receiveMessageResponse_messages :: Lens' ReceiveMessageResponse (Maybe [Message])
- receiveMessageResponse_httpStatus :: Lens' ReceiveMessageResponse Int
Creating a Request
data ReceiveMessage Source #
See: newReceiveMessage
smart constructor.
ReceiveMessage' | |
|
Instances
Create a value of ReceiveMessage
with all optional fields omitted.
Use generic-lens or optics to modify other optional fields.
The following record fields are available, with the corresponding lenses provided for backwards compatibility:
$sel:receiveRequestAttemptId:ReceiveMessage'
, receiveMessage_receiveRequestAttemptId
- This parameter applies only to FIFO (first-in-first-out) queues.
The token used for deduplication of ReceiveMessage
calls. If a
networking issue occurs after a ReceiveMessage
action, and instead of
a response you receive a generic error, it is possible to retry the same
action with an identical ReceiveRequestAttemptId
to retrieve the same
set of messages, even if their visibility timeout has not yet expired.
- You can use
ReceiveRequestAttemptId
only for 5 minutes after aReceiveMessage
action. - When you set
FifoQueue
, a caller of theReceiveMessage
action can provide aReceiveRequestAttemptId
explicitly. - If a caller of the
ReceiveMessage
action doesn't provide aReceiveRequestAttemptId
, Amazon SQS generates aReceiveRequestAttemptId
. - It is possible to retry the
ReceiveMessage
action with the sameReceiveRequestAttemptId
if none of the messages have been modified (deleted or had their visibility changes). During a visibility timeout, subsequent calls with the same
ReceiveRequestAttemptId
return the same messages and receipt handles. If a retry occurs within the deduplication interval, it resets the visibility timeout. For more information, see Visibility Timeout in the Amazon SQS Developer Guide.If a caller of the
ReceiveMessage
action still processes messages when the visibility timeout expires and messages become visible, another worker consuming from the same queue can receive the same messages and therefore process duplicates. Also, if a consumer whose message processing time is longer than the visibility timeout tries to delete the processed messages, the action fails with an error.To mitigate this effect, ensure that your application observes a safe threshold before the visibility timeout expires and extend the visibility timeout as necessary.
- While messages with a particular
MessageGroupId
are invisible, no more messages belonging to the sameMessageGroupId
are returned until the visibility timeout expires. You can still receive messages with anotherMessageGroupId
as long as it is also visible. - If a caller of
ReceiveMessage
can't track theReceiveRequestAttemptId
, no retries work until the original visibility timeout expires. As a result, delays might occur but the messages in the queue remain in a strict order.
The maximum length of ReceiveRequestAttemptId
is 128 characters.
ReceiveRequestAttemptId
can contain alphanumeric characters (a-z
,
A-Z
, 0-9
) and punctuation
(!"#$%&'()*+,-./:;<=>?@[\]^_`{|}~
).
For best practices of using ReceiveRequestAttemptId
, see
Using the ReceiveRequestAttemptId Request Parameter
in the Amazon SQS Developer Guide.
$sel:visibilityTimeout:ReceiveMessage'
, receiveMessage_visibilityTimeout
- The duration (in seconds) that the received messages are hidden from
subsequent retrieve requests after being retrieved by a ReceiveMessage
request.
$sel:messageAttributeNames:ReceiveMessage'
, receiveMessage_messageAttributeNames
- The name of the message attribute, where N is the index.
- The name can contain alphanumeric characters and the underscore
(
_
), hyphen (-
), and period (.
). - The name is case-sensitive and must be unique among all attribute names for the message.
- The name must not start with AWS-reserved prefixes such as
AWS.
orAmazon.
(or any casing variants). - The name must not start or end with a period (
.
), and it should not have periods in succession (..
). - The name can be up to 256 characters long.
When using ReceiveMessage
, you can send a list of attribute names to
receive, or you can return all of the attributes by specifying All
or
.*
in your request. You can also use all message attributes starting
with a prefix, for example bar.*
.
$sel:waitTimeSeconds:ReceiveMessage'
, receiveMessage_waitTimeSeconds
- The duration (in seconds) for which the call waits for a message to
arrive in the queue before returning. If a message is available, the
call returns sooner than WaitTimeSeconds
. If no messages are available
and the wait time expires, the call returns successfully with an empty
list of messages.
To avoid HTTP errors, ensure that the HTTP response timeout for
ReceiveMessage
requests is longer than the WaitTimeSeconds
parameter. For example, with the Java SDK, you can set HTTP transport
settings using the
NettyNioAsyncHttpClient
for asynchronous clients, or the
ApacheHttpClient
for synchronous clients.
$sel:attributeNames:ReceiveMessage'
, receiveMessage_attributeNames
- A list of attributes that need to be returned along with each message.
These attributes include:
All
– Returns all values.ApproximateFirstReceiveTimestamp
– Returns the time the message was first received from the queue (epoch time in milliseconds).ApproximateReceiveCount
– Returns the number of times a message has been received across all queues but not deleted.AWSTraceHeader
– Returns the X-Ray trace header string.SenderId
- For an IAM user, returns the IAM user ID, for example
ABCDEFGHI1JKLMNOPQ23R
. - For an IAM role, returns the IAM role ID, for example
ABCDE1F2GH3I4JK5LMNOP:i-a123b456
.
- For an IAM user, returns the IAM user ID, for example
SentTimestamp
– Returns the time the message was sent to the queue (epoch time in milliseconds).MessageDeduplicationId
– Returns the value provided by the producer that calls theSendMessage
action.MessageGroupId
– Returns the value provided by the producer that calls theSendMessage
action. Messages with the sameMessageGroupId
are returned in sequence.SequenceNumber
– Returns the value provided by Amazon SQS.
$sel:maxNumberOfMessages:ReceiveMessage'
, receiveMessage_maxNumberOfMessages
- The maximum number of messages to return. Amazon SQS never returns more
messages than this value (however, fewer messages might be returned).
Valid values: 1 to 10. Default: 1.
$sel:queueUrl:ReceiveMessage'
, receiveMessage_queueUrl
- The URL of the Amazon SQS queue from which messages are received.
Queue URLs and names are case-sensitive.
Request Lenses
receiveMessage_receiveRequestAttemptId :: Lens' ReceiveMessage (Maybe Text) Source #
This parameter applies only to FIFO (first-in-first-out) queues.
The token used for deduplication of ReceiveMessage
calls. If a
networking issue occurs after a ReceiveMessage
action, and instead of
a response you receive a generic error, it is possible to retry the same
action with an identical ReceiveRequestAttemptId
to retrieve the same
set of messages, even if their visibility timeout has not yet expired.
- You can use
ReceiveRequestAttemptId
only for 5 minutes after aReceiveMessage
action. - When you set
FifoQueue
, a caller of theReceiveMessage
action can provide aReceiveRequestAttemptId
explicitly. - If a caller of the
ReceiveMessage
action doesn't provide aReceiveRequestAttemptId
, Amazon SQS generates aReceiveRequestAttemptId
. - It is possible to retry the
ReceiveMessage
action with the sameReceiveRequestAttemptId
if none of the messages have been modified (deleted or had their visibility changes). During a visibility timeout, subsequent calls with the same
ReceiveRequestAttemptId
return the same messages and receipt handles. If a retry occurs within the deduplication interval, it resets the visibility timeout. For more information, see Visibility Timeout in the Amazon SQS Developer Guide.If a caller of the
ReceiveMessage
action still processes messages when the visibility timeout expires and messages become visible, another worker consuming from the same queue can receive the same messages and therefore process duplicates. Also, if a consumer whose message processing time is longer than the visibility timeout tries to delete the processed messages, the action fails with an error.To mitigate this effect, ensure that your application observes a safe threshold before the visibility timeout expires and extend the visibility timeout as necessary.
- While messages with a particular
MessageGroupId
are invisible, no more messages belonging to the sameMessageGroupId
are returned until the visibility timeout expires. You can still receive messages with anotherMessageGroupId
as long as it is also visible. - If a caller of
ReceiveMessage
can't track theReceiveRequestAttemptId
, no retries work until the original visibility timeout expires. As a result, delays might occur but the messages in the queue remain in a strict order.
The maximum length of ReceiveRequestAttemptId
is 128 characters.
ReceiveRequestAttemptId
can contain alphanumeric characters (a-z
,
A-Z
, 0-9
) and punctuation
(!"#$%&'()*+,-./:;<=>?@[\]^_`{|}~
).
For best practices of using ReceiveRequestAttemptId
, see
Using the ReceiveRequestAttemptId Request Parameter
in the Amazon SQS Developer Guide.
receiveMessage_visibilityTimeout :: Lens' ReceiveMessage (Maybe Int) Source #
The duration (in seconds) that the received messages are hidden from
subsequent retrieve requests after being retrieved by a ReceiveMessage
request.
receiveMessage_messageAttributeNames :: Lens' ReceiveMessage (Maybe [Text]) Source #
The name of the message attribute, where N is the index.
- The name can contain alphanumeric characters and the underscore
(
_
), hyphen (-
), and period (.
). - The name is case-sensitive and must be unique among all attribute names for the message.
- The name must not start with AWS-reserved prefixes such as
AWS.
orAmazon.
(or any casing variants). - The name must not start or end with a period (
.
), and it should not have periods in succession (..
). - The name can be up to 256 characters long.
When using ReceiveMessage
, you can send a list of attribute names to
receive, or you can return all of the attributes by specifying All
or
.*
in your request. You can also use all message attributes starting
with a prefix, for example bar.*
.
receiveMessage_waitTimeSeconds :: Lens' ReceiveMessage (Maybe Int) Source #
The duration (in seconds) for which the call waits for a message to
arrive in the queue before returning. If a message is available, the
call returns sooner than WaitTimeSeconds
. If no messages are available
and the wait time expires, the call returns successfully with an empty
list of messages.
To avoid HTTP errors, ensure that the HTTP response timeout for
ReceiveMessage
requests is longer than the WaitTimeSeconds
parameter. For example, with the Java SDK, you can set HTTP transport
settings using the
NettyNioAsyncHttpClient
for asynchronous clients, or the
ApacheHttpClient
for synchronous clients.
receiveMessage_attributeNames :: Lens' ReceiveMessage (Maybe [MessageAttribute]) Source #
A list of attributes that need to be returned along with each message. These attributes include:
All
– Returns all values.ApproximateFirstReceiveTimestamp
– Returns the time the message was first received from the queue (epoch time in milliseconds).ApproximateReceiveCount
– Returns the number of times a message has been received across all queues but not deleted.AWSTraceHeader
– Returns the X-Ray trace header string.SenderId
- For an IAM user, returns the IAM user ID, for example
ABCDEFGHI1JKLMNOPQ23R
. - For an IAM role, returns the IAM role ID, for example
ABCDE1F2GH3I4JK5LMNOP:i-a123b456
.
- For an IAM user, returns the IAM user ID, for example
SentTimestamp
– Returns the time the message was sent to the queue (epoch time in milliseconds).MessageDeduplicationId
– Returns the value provided by the producer that calls theSendMessage
action.MessageGroupId
– Returns the value provided by the producer that calls theSendMessage
action. Messages with the sameMessageGroupId
are returned in sequence.SequenceNumber
– Returns the value provided by Amazon SQS.
receiveMessage_maxNumberOfMessages :: Lens' ReceiveMessage (Maybe Int) Source #
The maximum number of messages to return. Amazon SQS never returns more messages than this value (however, fewer messages might be returned). Valid values: 1 to 10. Default: 1.
receiveMessage_queueUrl :: Lens' ReceiveMessage Text Source #
The URL of the Amazon SQS queue from which messages are received.
Queue URLs and names are case-sensitive.
Destructuring the Response
data ReceiveMessageResponse Source #
A list of received messages.
See: newReceiveMessageResponse
smart constructor.
ReceiveMessageResponse' | |
|
Instances
newReceiveMessageResponse Source #
Create a value of ReceiveMessageResponse
with all optional fields omitted.
Use generic-lens or optics to modify other optional fields.
The following record fields are available, with the corresponding lenses provided for backwards compatibility:
$sel:messages:ReceiveMessageResponse'
, receiveMessageResponse_messages
- A list of messages.
$sel:httpStatus:ReceiveMessageResponse'
, receiveMessageResponse_httpStatus
- The response's http status code.
Response Lenses
receiveMessageResponse_messages :: Lens' ReceiveMessageResponse (Maybe [Message]) Source #
A list of messages.
receiveMessageResponse_httpStatus :: Lens' ReceiveMessageResponse Int Source #
The response's http status code.