I have a very simple pipeline, adapted from the

deploy_docker

example that fails (see: https://github.com/jeremyadamsfisher/dagster-sensor-min-failing)

from dagster import pipeline, repository, schedule, solid, sensor, SkipReason


@solid
def hello(_):
    return 1


@pipeline
def my_pipeline():
    hello()


@schedule(cron_schedule="* * * * *", pipeline_name="my_pipeline", execution_timezone="US/Central")
def my_schedule(_context):
    return {}


@sensor(pipeline_name="my_pipeline")
def always_skips(_context):
    yield SkipReason("I always skip!")


@repository
def deploy_docker_repository():
    return [my_pipeline, my_schedule, always_skips]

This is the traceback:

docker_example_daemon        | 2021-04-03 19:36:56 - SensorDaemon - INFO - Checking for new runs for sensor: always_skips
docker_example_daemon        | 2021-04-03 19:36:56 - SensorDaemon - ERROR - Error launching sensor run: json.decoder.JSONDecodeError: Expecting value: line 1 column 1 (char 0)
docker_example_daemon        | 
docker_example_daemon        | Stack Trace:
docker_example_daemon        |   File "/usr/local/lib/python3.7/site-packages/dagster/daemon/sensor.py", line 230, in execute_sensor_iteration
docker_example_daemon        |     sensor_debug_crash_flags,
docker_example_daemon        |   File "/usr/local/lib/python3.7/site-packages/dagster/daemon/sensor.py", line 264, in _evaluate_sensor
docker_example_daemon        |     job_state.job_specific_data.last_run_key if job_state.job_specific_data else None,
docker_example_daemon        |   File "/usr/local/lib/python3.7/site-packages/dagster/core/host_representation/repository_location.py", line 448, in get_external_sensor_execution_data
docker_example_daemon        |     last_run_key,
docker_example_daemon        |   File "/usr/local/lib/python3.7/site-packages/dagster/api/snapshot_sensor.py", line 41, in sync_get_external_sensor_execution_data_grpc
docker_example_daemon        |     last_run_key=last_run_key,
docker_example_daemon        |   File "/usr/local/lib/python3.7/site-packages/dagster/grpc/client.py", line 291, in external_sensor_execution
docker_example_daemon        |     res.serialized_external_sensor_execution_data_or_external_sensor_execution_error
docker_example_daemon        |   File "/usr/local/lib/python3.7/site-packages/dagster/serdes/serdes.py", line 236, in deserialize_json_to_dagster_namedtuple
docker_example_daemon        |     check.str_param(json_str, "json_str"), whitelist_map=_WHITELIST_MAP
docker_example_daemon        |   File "/usr/local/lib/python3.7/site-packages/dagster/serdes/serdes.py", line 246, in _deserialize_json_to_dagster_namedtuple
docker_example_daemon        |     return _unpack_value(seven.json.loads(json_str), whitelist_map=whitelist_map)
docker_example_daemon        |   File "/usr/local/lib/python3.7/json/__init__.py", line 361, in loads
docker_example_daemon        |     return cls(**kw).decode(s)
docker_example_daemon        |   File "/usr/local/lib/python3.7/json/decoder.py", line 337, in decode
docker_example_daemon        |     obj, end = self.raw_decode(s, idx=_w(s, 0).end())
docker_example_daemon        |   File "/usr/local/lib/python3.7/json/decoder.py", line 355, in raw_decode
docker_example_daemon        |     raise JSONDecodeError("Expecting value", s, err.value) from None

Am I missing something or should I file a github issue?

hi - my best guess here is that your two containers could be using different versions of dagster and you're running into a version mismatch issue. If you built Dockerfile_pipelines after our most recent release without rebuilding Dockerfile_dagster , I could imagine seeing this error. Could you try rebuilding both containers and skipping the docker cache?

Issue persists after rebuilding both from scratch

Huh, strange - I just tried checking out your code and I'm not running into the problem

Weird!

I can reproduce that error by forcing Dockerfile_dagster to 0.11.2 and Dockerfile_pipelines to 0.11.3 though

Yes, this seems to be the issue