How to use lastRetry.message in retryStrategy conditional expressions

[chabala]

#9937 asked for (and #10987 delivered) the workflow result status message to be exposed for conditional retry expressions to use. The example in #9937 seems to be the only documentation on how to use it.

I've tried to use it like so:

retryStrategy:
    limit: "10"
    expression: "lastRetry.message.contains('imminent node shutdown') || lastRetry.message.contains('pod deleted')"

but was given this error:

error in entry template execution: unable to evaluate expression 'lastRetry.message.contains('imminent node shutdown') || lastRetry.message.contains('pod deleted')': invalid operation: int(string) (1:19) | lastRetry.message.contains('imminent node shutdown') || lastRetry.message.contains('pod deleted') | ..................^

Am I not using this correctly?

[chabala]

Apparently the syntax above (from #9937) is invalid, but this works:

retryStrategy:
    limit: "10"
    expression: >-
      lastRetry.message contains 'imminent node shutdown' || lastRetry.message contains 'pod deleted'

[MasonM]

Hi @chabala! The expression given in retryStrategy.expression is evaluated using expr: https://expr-lang.org/docs/language-definition

expr evaluates lastRetry.message.contains(...) by checking for a contains() function on the string type, which doesn't exist. As you discovered, the contains operator will do what you want, and you could simplify it a bit using the matches operator:

retryStrategy:
    limit: "10"
    expression: lastRetry.message matches 'imminent node shutdown|pod deleted'

[chabala]

Thank you, that's even more concise. I did discover expr and that strings do not have a contains() (counter to the example in #9937) and the expr playground helped me concoct my alternate syntax.

Do you think this would be more apparent to someone with more Go experience?

I think the documentation around Retries and Conditional Retries specifically would benefit from more and varied concrete examples.

[MasonM]

You're right, the docs could be improved. I entered #14656 to do that.