I'm using an AWS Lambda function that is triggered from an SNS event trigger to consume from an SQS queue. When the Lambda function executes, it pulls 10 messages from the queue, processes them, pulls another 10, and so on and so forth - up to a certain time limit that's coded into the Lambda function (less than the max of 5 minutes, obviously).
It's my understanding that a Lambda function triggered by an SNS event is one-to-one, is that correct? In other words, one SNS event won't trigger multiple Lambda functions (up to the maximum concurrent execution limit). There's no scaling based on load.
Are there any other potential solutions, leveraging Lambda, that would let me consume from SQS as frequently/fast as possible? I had considered trying to auto-scale my Lambda functions by leveraging CloudWatch alarms (and SNS event triggers) based on SQS queue size, but it seems like those alarms can fire, at most, every 5 minutes. I've also considered developing a master Lambda function that can automatically execute (many) slave Lambdas based on querying the queue size.
I understand that the more optimal design may be to leverage Kinesis instead of SNS. I may consider incorporating Kinesis in the future, but let's just pretend that Kinesis is not an option at this time.
There is no best way to do this. One approach (which you've kind of already mentioned) is to use CloudWatch and schedule a Lambda function to run every minute (that's the minimum schedule time for Lambda). This Lambda function will then look for new SQS messages and invoke other Lambda functions to handle new message(s). Here is a very good article for that use case: https://cloudonaut.io/integrate-sqs-and-lambda-serverless-architecture-for-asynchronous-workloads/
Personally, I do not recommend triggering your Lambda by SNS for this use case, because SNS doesn't give a full guarantee for delivery and recommend sending the SNS notifications to SQS - which does not solve your problem. From the FAQ's:
[...] If it is critical that all published messages be successfully processed, developers should have notifications delivered to an SQS queue (in addition to notifications over other transports).
Source: https://aws.amazon.com/sns/faqs/
For this kind of processing, instead of SQS if you push messages to Kinesis Stream you should be able to flexibly process(In batches of needed size) the messages.
Note: If you use SQS, after triggering a Lambda function through SNS (or using a Scheduled Lambda), it can invoke inner Lambda functions to check the queue where multiple concurrent inner Lambdas are spawned. However the problem is that its not practical to process SQS items in batches.
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I have a service which generates a burst of Cloud Watch Events once every hour. These Cloud Watch events (which could be in thousands) each will trigger an AWS Lambda function and ultimately number of concurrent lambdas running can cross the maximum limit. How can I modify my system such that these cloud watch events will be handled gracefully by Lambda functions or if possible somehow I can distribute all these cloud watch events over the rest period of the first service.
P.S. I do not want to modify the limit on concurrent running lambdas.
have you thought about adding these events to SQS instead of consuming Lambda directly and then configure the SQS to call the Lambda function?
This is how you can trigger a Lambda function by SQS queue
https://docs.aws.amazon.com/AWSSimpleQueueService/latest/SQSDeveloperGuide/sqs-configure-lambda-function-trigger.html
and you can define the delay in queue consumption by using this article
https://cloudaffaire.com/how-to-configure-delay-queue-in-sqs/
As prior stated you could use SQS, but I too would advise against this because you would still have the same concurrency issue (more here).
Depending on how quickly you require your processing, it may be a good idea to have lambda "poll" an SQS every couple of minutes, then send the batch of messages to a lambda to process via SNS (rather than have lambda trigger off of SQS PutMessage API Calls).
I have a AWS Lambda function which is triggered by SQS. This function is triggered approximately 100 times daily, but request count to the SQS queue is approximately 20.000 times daily. I don't understand why the number of requests made to the SQS is too high. My expectation is that the number of requests made to the SQS should be same with the Lambda invocation.
I have only one Lambda function and one SQS queue in my account.
Can be related with polling of SQS queue? I tried to change the polling interval of SQS from the queue configuration but nothing changed. Another possibility is to change polling interval from Lambda function configuration. However, I cannot find any related parameter.
Briefy, I want to reduce number of SQS request, how can i do that while invoking Lmabda function with SQS?
When using SQS as an event source for AWS Lambda, AWS Lambda regularly polls the configured SQS queue to fetch new messages. While the official documentation isn't clear really about that, the blog post announcing that feature goes into the details:
When an SQS event source mapping is initially created and enabled, or when messages first appear after a period with no traffic, then the Lambda service will begin polling the SQS queue using five parallel long-polling connections.
According to the AWS documentation, the default duration for a long poll from AWS Lambda to SQS is 20 seconds.
That results in five requests to SQS every 20 seconds for AWS Lambda functions without significant load, which sums up to the ~21600 per day, which is close to the 20000 you're experiencing.
While increasing the long poll duration seems like an easy way to decrease the number of requests, that's not possible, as the 20 seconds AWS Lambda is using by default is already the maximum possible duration for an SQS queue. I'm afraid there is no easy way to decrease the requests to SQS, when using it as event source for AWS Lambda. Instead depending it could be worth evaluating if another event source, like SNS, would fit your use case as well.
Here is how we originally implemented when there is no SQS trigger.
Create a SNS trigger with the SQS Cloudwatch Metric
ApproximateNumberOfMessagesVisible > 0
Trigger a Lambda from SNS, Read Messages from SQS and deliver it to whichever the lambda needs the message.
Alternatively, you can use Kinesis to deliver it to Lambda.
SQS --> Cloudwatch (Trigger Lambda) --> Lambda(Reads Messages) -->
Kinesis (Set Batch Size) --> Lambda (Handle Actual Message)
You can also use Kinesis directly but there is no delayed delivery.
Hope it helps.
I have an AWS Lambda function to read from an SQS queue. The lambda logic is basically to read off one message from SQS and then it processes and deletes the message. Code to read the message being something like.
ReceiveMessageRequest messageRequest =
new ReceiveMessageRequest(queueUrl).withWaitTimeSeconds(5).withMaxNumberOfMessages(1);
Now my question is what is the best way to trigger this lambda and how does this lambda scale for instance, if there are let's say 1000 messages in the queue so will there be a 1000 lambdas running together, since in my case one lambda can read only one message off the queue.
Any pointers on best practices around this kind of design.
Right now you best option is probably to setup an AWS Cloudwatch event rule that calls the lambda function on the interval that you need.
Here is a sample app from AWS to do just that:
https://github.com/awslabs/aws-serverless-sqs-event-source
I do believe that AWS will eventually support SQS as a event type for AWS lambda, which should make this even easier, but for now you best choice is probably a version of the code I linked above.
We can now use SQS messages to trigger AWS Lambda Functions. Moreover, no longer required to run a message polling service or create an SQS to SNS mapping.
Further details:
https://aws.amazon.com/blogs/aws/aws-lambda-adds-amazon-simple-queue-service-to-supported-event-sources/
https://docs.aws.amazon.com/lambda/latest/dg/with-sqs.html
AWS added native support in June 2018: https://aws.amazon.com/blogs/aws/aws-lambda-adds-amazon-simple-queue-service-to-supported-event-sources/
There are probably a few ways to do this, but I found this guide to be fairly helpful when I tried to implement the same sort of functionality you are describing in Node.js. One downside to this strategy is that you can only poll the queue every 60s.
The basic workflow would look something like this:
Set up a CloudWatch Alarm that gets triggered when the queue has a certain number of messages.
The Cloudwatch alarm then posts to SNS
The SNS message triggers a Lambda scale() function
The scale() function updates a configuration record in a DynamoDB table that sets the number of worker processes needed
You then have a main CloudWatch Schedule that invokes a worker() function every 60s
The worker() function reads configuration from DynamoDB to determine how many concurrent processes are needed, based on the queue size.
Worker() then invokes the appropriate number of process() functions
Process() function consumes messages from SQS, performs your main application logic, and then removes the item from the queue.
You can find an example of what the scaling functions would look like in Node.js here
I have used this solution in a production environment for almost a year without any issues, even with thousands of messages in the queue. If you cut out the scaling portion it is only going to do one message a time.
At the moment I'm are pooling AWS SQS from our back-end and doing business logic once payload is received.
I would like to move this to AWS Lambda and start automating business logic via SQS/SNS.
As I can not subscribe to AWS SQS events, what is the best practice in implementing SQS pooling with Lambda (node.js)?
SQS doesn't really work well with Lambda since you cannot automatically trigger Lambda functions from SQS queues messages.
I would rather remove the SQS/SNS logic and go for a DynamoDB Streams based solution that would cover the queueing, archiving & Lambda triggering tasks natively: your producer puts messages in a DynamoDB table while your Lambda is triggered for any new entry with Streams (it's an AWS native mechanism)
Of course a Kinesis based solution may be considered as well.
It is possible to even simplify the whole polling process by using the built-in SQS event source for lambda.
Lambda will automatically scale out horizontally consume the messages
in my queue. Lambda will try to consume the queue as quickly and
effeciently as possible by maximizing concurrency within the bounds of
each service. As the queue traffic fluctuates the Lambda service will
scale the polling operations up and down based on the number of
inflight messages.
see AWS Blog
As I can not subscribe to AWS SQS events,
Why?
Lambda can be triggered on SQS messages. Lambda internally handles the scaling, batching and retries for you. Check this AWS documentation on how to use Lambda with SQS.
I have the following infrastructure:
I have an EC2 instance with a NodeJS+Express process listening on a port for messages (process 1). Every time the process receives a message it sends it to an SQS queue. Then I have another process in the same machine reading the queue using long polling (process 2). When it finds a message in the queue it inserts the data in a MariaDB database sitting on an RDS instance.
(Just to clarify, messages are generated by users, they send a chunk of data which can contain arbitrary information to the endpoint where the process 1 is listening)
Now I want to put the process that reads the SQS (process 2) in a Lambda function so that the process that writes to the queue and the one that reads from the queue are completely independent. The problem is that I don't know if this is possible.
I know that Lambda function are invoked in response to an event, and the events supported at the moment are S3, SNS, SES, DynamoDB, Kinesis, Cognito, CloudWatch and Cloudformation but NOT SQS.
I was thinking in using SNS notifications to invoke the Lambda function so that every time a message is pushed to the queue, an SNS notification is fired and invokes the Lambda function but after playing a bit with it I've realised that is not possible to create an SNS notification from SQS, it's only possible to write SNS notifications to the queue.
Right now I'm a bit stuck because I don't know how to continue. I have the feeling that is not possible to create this infrastructure due to the current limitations in the AWS services. Is there another way to do what I want or am I in a dead-end?
Just to extend my question with some research I've made, this github repo shows how to read an SQS queu from a Lambda function but the lambda function works only if is fired from the command line:
https://github.com/robinjmurphy/sqs-to-lambda
In the readme, the author mentions the following:
Update: Lambda now supports SNS notifications as an event source,
which makes this hack entirely unneccessary for SNS notifcations. You
might still find it useful if you like the idea of using a Lambda
function to process jobs on an SQS queue.
But I think this doesn't solve my problem, an SNS notification can invoke the Lambda function but I don't see how I can create a notification when a message is received in the SQS queue.
Thanks
There are couple of Strategies which can be used to connect the dots, (A)Synchronously or Run-Sleep-Run to keep the data process flow between SNS, SQS, Lambda.
Strategy 1 : Have a Lambda function listen to SNS and process it in real time [Please note that an SQS Queue can subscribe to an SNS Topic - which would may be helpful for logging / auditing / retry handling]
Strategy 2 : Given that you are getting data sourced to SQS Queue. You can try with 2 Lambda Functions [Feeder & Worker].
Feeder would be scheduled lambda function whose job is to take items
from SQS (if any) and push it as an SNS topic (and continue doing it forever)
Worker would be linked to listen the SNS topic which would do the actual data processing
We can now use SQS messages to trigger AWS Lambda Functions. Moreover, no longer required to run a message polling service or create an SQS to SNS mapping.
Further details:
https://aws.amazon.com/blogs/aws/aws-lambda-adds-amazon-simple-queue-service-to-supported-event-sources/
AWS SQS is one of the oldest products of Amazon, which only supported polling (long and short) up until June 2018. As mentioned in this answer, AWS SQS now supports the feature of triggering lambda functions on new message arrival in SQS. A complete tutorial for this is provided in this document.
I used to tackle this problem using different mechanisms, and given below are some approaches you can use.
You can develop a simple polling application in Lambda, and use AWS CloudWatch to invoke it every 5 mins or so. You can make this near real-time by using CloudWatch events to invoke lambda with short downtimes. Use this tutorial or this tutorial for this purpose. (This could cost more on Lambdas)
You can consider that SQS is redundant if you don't need to persist the messages nor guarantee the order of delivery. You can use AWS SNS (Simple Notification Service) to directly invoke a lambda function and do whatever the processing required. Use this tutorial for this purpose. This will happen in real-time. But the main drawback is the number of lambdas that can be initiated per region at a given time. Please read this and understand the limitation before following this approach. Nevertheless AWS SNS Guarantees the order of delivery. Also SNS can directly call an HTTP endpoint and store the message in your DB.
I had a similar situation (and now have a working solution deploed). I have addressed it in a following manner:
i.e. publishing events to SNS; which then get fanned-out to Lambda and SQS.
NOTE: This is not applicable to the events that have to be processed in a certain order.
That there are some gotchas (w/ possible solutions) such as:
racing condition: lambda might get invoked before messages is deposited into the queue
distributed nature of SQS queue may lead to returning no messages even though there is a message note1.
The solution to both cases would be to do long-polling of SQS queue; but this does make your lambda bill more expensive.
note1
Short poll is the default behavior where a weighted random set of machines is sampled on a ReceiveMessage call. This means only the messages on the sampled machines are returned. If the number of messages in the queue is small (less than 1000), it is likely you will 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; in which case you should repeat the request.
http://docs.aws.amazon.com/AWSSimpleQueueService/latest/APIReference/API_ReceiveMessage.html
We had some similar requirements so we ended up building a library and open sourcing it to help with SQS to Lambda async. I'm not sure if this fills your particular set of requirements, but thought it might be worth a look: https://read.iopipe.com/sqs-lambda-teaming-up-92c4096be49c