Conditional Execution

Learn how to conditionally execute a transformation filter.

A conditional property if can be configured on each filter to determine if that filter should be applied or skipped. When a filter is skipped, message flow to the next filter without any modification.

if configuration accepts a Simple Connect Expression that must return to true or false. If the configured expression does not evaluate to a boolean value the filter chain will fail.

Theif property supports (simple expression)

The boolean value returned from the filter condition can be inverted by setting the property invert to true.

For example, the below filter will only be applied on message having a log message containing “BadCredentialsException”

filters.TagSecurityException.type=io.streamthoughts.kafka.connect.filepulse.filter.AppendFilter
filters.TagSecurityException.if={{ contains(data.logmessage, BadCredentialsException) }}
filters.TagSecurityException.invert=false
filters.TagSecurityException.field=tags
filters.TagSecurityException.values=SecurityAlert

These conditional functions are available for use with the if config property :

Function	Since	Description	Syntax
`and`	`2.4.0`	Checks if all of the given conditional expressions are `true`.	`{{ and(booleanExpression1, booleanExpression2, ...) }}`
`contains`		Returns `true` if an array field’s value contains the specified value	`{{ contains(field, value) }}`
`ends_with`		Returns `true` if an a string field’s value end with the specified string suffix	`{{ ends_with(field, suffix) }}`
`equals`		Returns `true` if an a string or number fields’s value equals the specified value	`{{ equals(field, value) }}`
`exists`		Returns `true` if an the specified field exists	`{{ exists(struct, field) }}`
`gt`	`2.4.0`	Executes “greater than operation” on two values and returns `true` if the first value is greater than the second value, `false`, otherwise.	`{{ gt(expressionValue1, expressionValue2) }}`
`is_null`		Returns `true` if a field’s value is null	`{{ is_null(field) }}`
`lt`	`2.4.0`	Executes “less than operation” on two values and returns `true` if the first value is less than the second value, `false`, otherwise.	`{{ lt(expressionValue1, expressionValue2) }}`
`matches`		Returns `true` if a field’s value match the specified regex	`{{ matches(field, regex) }}`
`starts_with`		Returns `true` if an a string field’s value start with the specified string prefix	`{{ starts_with(field, prefix) }}`
`or`	`2.4.0`	Checks if at least one of the given conditional expressions is `true`..	`{{ or(booleanExpression1, booleanExpression2, ...) }}`

Limitations :

conditions cannot be used to easily create pipeline branching.

Last modified April 6, 2022: docs: fix missing archive (8c1e46d0)