hi team i asked a while ago, but still struggling ...
# ask-community
hi team i asked a while ago, but still struggling to make contextmanager resource work with steplauncher can you assist me with fixing the code below? tnx a lot!
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from dagster import Array, Field, Int, Noneable, String, Dict, Nothing, Permissive, op, In, Out, graph, resource
from dagster.core.definitions.no_step_launcher import no_step_launcher
from dagster.core.execution.plan.external_step import local_external_step_launcher
import tempfile
import os
from dagster import DagsterInstance, check, execute_pipeline, reconstructable
from contextlib import contextmanager
from dagster.cli.utils import get_instance_for_service

def my_resource(context):
    fd, path = tempfile.mkstemp(text=True, suffix=".txt")
    with os.fdopen(fd, "w") as f:
        f.write("Hello, world!")
        <http://context.log.info|context.log.info>(f"Yielding file {path}...")
        yield path
        <http://context.log.info|context.log.info>(f"Deleting file {path}...")

@op(required_resource_keys={"my_launcher", "my_resource"})
def my_op(context):
    assert os.path.exists(context.resources.my_resource)
    with open(context.resources.my_resource) as f:

def my_graph():

def define_my_job():
    return my_graph.to_job(name="my_job",
                           config={"resources": {"my_launcher": {"config": {"scratch_dir": "/tmp/my_launcher"}}}},
                           resource_defs={"my_launcher": local_external_step_launcher, "my_resource": my_resource},

if __name__ == "__main__":
    with get_instance_for_service("test") as instance:
        execute_pipeline(reconstructable(define_my_job), instance=instance)
what’s the error you’re hitting?
hi @yuhan my problem is that resource cleanup happens before op starts and i get assert in my_op (file doesnt exist as it was deleted in finally)
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dagster.core.errors.DagsterExecutionStepExecutionError: Error occurred while executing op "my_op"::


Stack Trace:
  File "/private/tmp/test123/lib/python3.7/site-packages/dagster/core/execution/plan/utils.py", line 47, in solid_execution_error_boundary
  File "/private/tmp/test123/lib/python3.7/site-packages/dagster/utils/__init__.py", line 406, in iterate_with_context
    next_output = next(iterator)
  File "/private/tmp/test123/lib/python3.7/site-packages/dagster/core/execution/plan/compute_generator.py", line 66, in _coerce_solid_compute_fn_to_iterator
    result = fn(context, **kwargs) if context_arg_provided else fn(**kwargs)
  File "/tmp/test.py", line 25, in my_op
    assert os.path.exists(context.resources.my_resource)
cc @chris does this error ring any bells? iirc you were looking at the resource teardown a bit