Alternative channel usage ifempty

[narsapuramvijaykumar]

Hello Team,

I'm looking for an option under DSL-2 if a process-B fails to generate the required input(channelB2C) for process-C then it has to utilize the input from process-A(channelA2C).

I have tried the ifEmpty operator, if-else conditions under workflow and also params declaration to achieve the same and haven't got a fruitful solution post multiple attempts..!!

Thanks in advance.

Regards,
Vijay N

[bentsherman]

I think what you would need to do here is merge the channels from A and B and apply the if-else logic in a map operator. You will need some kind of key, like a sample id, with which to join the two channels correctly. Here's a rough example:

ch_a2c = proc_a() // each item looks like [sample_id, a_data]
ch_b2c = proc_b() // each item looks like [sample_id, b_data]

ch_a_or_b = ch_a2c
    | join(ch_b2c)
    | map { sample_id, a_data, b_data -> [sample_id, b_data ?: a_data] }

proc_c(ch_a_or_b)