Hi All, I'm just starting diving into dagster and hoping to use it to refactor some of our (simple) data pipelines at for my place of work. I'm trying to create a reusable solid that would connect to our database and execute a sql query which would return the data in the form of a pandas dataframe. However, I'm receiving an error DagsterInvalidDefinitionError which states "Must pass the output from previous solid invocations or inputs to the composition function as inputs when invoking solids during composition.". Is it possible to pass just a regular data type (e.g string, int, etc) as a parameter to a solid instead of having it be the return type of another solid ?

Hey! What you’ve hit is certainly a confusing part of the API for new comers - we should improve the error message. The

@pipeline

decorated function is special - we just use it to build up the dependency graph of solids to define the pipeline - not resolve any “runtime” values or inputs. What you are looking to do is probably

@pipeline
def hello_world():
  execute_db2_sql() # dont fill out inputs here

execute_pipeline(hello_world, environment_dict={'solids': {'execute_db2_sql': {'inputs': {'conn_str': '<CONN>', 'sql': 'SELECT dagster FROM good_stuff''}}}})

ahhh yes. ok. while reading through the docs I saw the config files were available and was guessing that would be the appropriate solution.

yep each pipeline will have its own specific config schema

perfect. I understand now. thanks for the help alex. this tutorial looks great, I'll give that a read as well.

considering sql for example you could consider this (quite complicated) example of having a solid builder function https://github.com/dagster-io/dagster/blob/master/examples/dagster_examples/airline_demo/solids.py#L44-L131

that's what I ended up using for our prototype as well