Hi everyone Is it possible to dagster not to skip op if some

Question

Hi everyone Is it possible to dagster not to skip op if some inputs are optional and not provided

Andrei Duralei · Answer

For example ``` op out= output1 Out is required=True output2 Out is required=False def op1 if something yield Output else yield Output yield Output op def op2 output1 str output2 Optional str = None do something graph def my graph output1 output2 = op1 op2 output1 output2 ```

Andrei Duralei · Answer

op2 will not trigger even if output2 is optional parameter for this op and not being returned from op1

Adam Ward · Answer

Have you tried setting the default value for `output2` to an empty string instead ` ` This is only a guess but I suspect that op2 does not trigger as it does not have a value for all dependencies

Andrei Duralei · Answer

It doesn t work too I mean empty string It has default value None for output2 and output1 is returned by op1

Adam Ward · Answer

I personally deal more in assets than ops You may want to consider using an asset for `op2` and defining a <https docs dagster io concepts assets software defined assets non argument dependencies|non argument dependency> If I m understanding what you are looking for that should allow you to execute `op2` without waiting for input from `output2`

Andrei Duralei · Answer

Actually I need output1 or output2 from op1 to start processing op2 I think it not my case disappointed

Adam Ward · Answer

Oh ok What if you passed the return value from op1 as a tuple with the second value defaulting to an empty string This would ensure that op2 always receives the dependent value triggering a run ``` op out= output Out is required=True def op1 if something yield Output else yield Output Output op def op2 output tuple do something``` Think that might work

Adam Ward · Answer

Full disclosure I cannot test this right now so I apologise if these suggestions miss the mark Just brainstorming out loud with you here slightly smiling face

Andrei Duralei · Answer

I think it should work I was thinking about it as last solution because it will require for me to check and skip ops between op1 and op2 by my self This example is just to simplify my request

Adam Ward · Answer

Ah It s never quite as simple as we hope is it wink

Andrei Duralei · Answer

For sure

Adam Ward · Answer

Best of luck shamrock