CODEWITHSUNDEEP
scalaapache-camelthrottling
FelixHJ
FelixHJ

Reputation: 1101

Example for syntax for throttle

I have a simple route that moves messages from SQS into my local database:

class DlrSqsToDb extends RouteBuilder {
  """aws-sqs://123467890/test-queue?amazonSQSClient=%23awsSqsClient&amazonSQSEndpoint=https://sqs.eu-west-1.amazonaws.com""" ==> {
    setHeader("dlr_body", body)
    setHeader("msgid", "someid")
    to("sql:insert into camel_test (msgid, dlr_body) VALUES (:#msgid,:#dlr_body)?dataSource=dataSource")
  }
}

I want to throttle this so that sqs handles peaks, but so that the load on my local database is limited. I can do a delay() for example, but not throttle():

....
 """aws-sqs://123467890/test-queue?amazonSQSClient=%23awsSqsClient&amazonSQSEndpoint=https://sqs.eu-west-1.amazonaws.com""" ==> {
delay(3000)
....

works but

....
 """aws-sqs://123467890/test-queue?amazonSQSClient=%23awsSqsClient&amazonSQSEndpoint=https://sqs.eu-west-1.amazonaws.com""" ==> {
throttle(1)
....

cannot compile: 

[error]  found   : Int(1)
[error]  required: org.apache.camel.scala.Frequency
[error]     throttle(1)

and

....
 """aws-sqs://123467890/test-queue?amazonSQSClient=%23awsSqsClient&amazonSQSEndpoint=https://sqs.eu-west-1.amazonaws.com""" ==> {
throttle(new org.apache.camel.scala.Frequency(1,3000))
....

compiles but crashes with an error: 

.... because of Definition has no children on Throttle[{1} request per 3000 millis -> []]

what is the proper syntax for using throttle in scala?

Upvotes: 0

Views: 299

Answers (1)

melps
melps

Reputation: 1247

Try wrapping the next 'to' in the block of the throttle like so:

"""aws-sqs://123467890/test-queue?amazonSQSClient=%23awsSqsClient&amazonSQSEndpoint=https://sqs.eu-west-1.amazonaws.com""" ==> {
      setHeader("dlr_body", body)
      setHeader("msgid", "someid")
      throttle(1 per (3 seconds)) {
        to("sql:insert into camel_test (msgid, dlr_body) VALUES (:#msgid,:#dlr_body)?dataSource=dataSource")
      }
  }

This is untested, but I suspect it's because of the block syntax that you need to be explicit about making the final 'to' a child of throttle. Sadly I found camels scala dsl to be very fussy about the ordering of statements but very lax about what actually compiles.

Upvotes: 1

Related Questions