Camel Components

Sample

A sampling throttler allows you to extract a sample of the exchanges from the traffic through a route.

image

The Sample EIP selects a single message in a given time period or every nth message. This selected message is allowed to pass through, and all other messages are stopped.

Options

The Sample eip supports the following options which are listed below.

Name Description Default Type

note

The note for this node.

String

description

The description for this node.

String

disabled

Whether to disable this EIP from the route during build time. Once an EIP has been disabled then it cannot be enabled later at runtime.

false

Boolean

samplePeriod

The period between samples, using a time-based approach. Default is 1 second.

1000

String

messageFrequency

The frequency of samples as a message count, using a message-frequency approach. For example, a value of 5 means every 5th message is sampled.

Long

Message Body

The message body at each side of the Sample EIP: EIP input is the body it needs, EIP output the body after it, and Steps the body its own steps start with.

Side Body Description

EIP output

unchanged

Lets one message in a period through and stops the others: the body stays as it was.

The bodies are the ones with the default options. A side that is not listed is not known, and tooling does not guess it. The carriers are described in the Camel Catalog.

Exchange properties

The Sample eip has no exchange properties.

Using Sample EIP

In the example below, we sample one message per second (default time period):

  • Java

  • XML

  • YAML

from("direct:sample")
    .sample()
    .to("direct:sampled");
<route>
    <from uri="direct:sample"/>
    <sample/>
    <to uri="direct:sampled"/>
</route>
- route:
    from:
      uri: direct:sample
      steps:
        - sample: {}
        - to:
            uri: direct:sampled

Sampling using time period

The default time period is 1 second, but this can easily be configured. For example, to sample one message per 5 seconds, you can do:

  • Java

  • XML

  • YAML

from("direct:sample")
    .sample(Duration.ofSeconds(5))
    .to("direct:sampled");
<route>
    <from uri="direct:sample"/>
    <sample samplePeriod="5s"/>
    <to uri="direct:sampled"/>
</route>
- route:
    from:
      uri: direct:sample
      steps:
        - sample:
            samplePeriod: 5s
        - to:
            uri: direct:sampled

Sampling using message frequency

The Sample EIP can also be configured to sample based on frequency instead of a time period.

For example, to sample every 10th message you can do:

  • Java

  • XML

  • YAML

from("direct:sample")
    .sample(10)
    .to("direct:sampled");
<route>
    <from uri="direct:sample"/>
    <sample messageFrequency="10"/>
    <to uri="direct:sampled"/>
</route>
- route:
    from:
      uri: direct:sample
      steps:
        - sample:
            messageFrequency: 10
        - to:
            uri: direct:sampled

Sampling with wiretap

The sampling throttler will stop all exchanges not included in the sample. This may be undesirable if you want to perform custom processing on the sample while still allowing all 10 messages to flow to an endpoint after the sample EIP.

For this use case, you can combine the sample EIP with wiretap EIP. In the example below, we sample every 10th message and send it to direct:sampleProcessing, while all 10 messages are still sent to direct:regularProcessing.

  • Java

  • XML

  • YAML

from("direct:start")
  .wireTap("direct:sample")
  .to("direct:regularProcessing");

from("direct:sample")
  .sample(10)
  .to("direct:sampleProcessing");
<route>
    <from uri="direct:start"/>
    <wireTap uri="direct:sample"/>
    <to uri="direct:regularProcessing"/>
</route>

<route>
    <from uri="direct:sample"/>
    <sample messageFrequency="10"/>
    <to uri="direct:sampleProcessing"/>
</route>
- route:
    from:
      uri: direct:start
      steps:
        - wireTap:
            uri: direct:sample
        - to:
            uri: direct:regularProcessing
- route:
    from:
      uri: direct:sample
      steps:
        - sample:
            messageFrequency: 10
        - to:
            uri: direct:sampleProcessing