Add error details for failed remote job

.github/CHANGELOG.md

@@ -31,6 +31,9 @@
 
 <h3>Improvements</h3>
 
+* Add details to the error message for failed remote jobs.
+  [(#370)](https://github.com/XanaduAI/strawberryfields/pull/370)
+
 <h3>Bug fixes</h3>
 
 <h3>Contributors</h3>

strawberryfields/api/connection.py

@@ -193,6 +193,7 @@ def get_job(self, job_id: str) -> Job:
                 id_=response.json()["id"],
                 status=JobStatus(response.json()["status"]),
                 connection=self,
+                meta=response.json()["meta"],
             )
         raise RequestFailedError(
             "Failed to get job: {}".format(self._format_error_message(response))

strawberryfields/api/job.py

@@ -73,13 +73,15 @@ class Job:
         status (strawberryfields.api.JobStatus): the job status
         connection (strawberryfields.api.Connection): the connection over which the
             job is managed
+        meta (dict[str, str]): metadata related to job execution
     """
 
-    def __init__(self, id_: str, status: JobStatus, connection):
+    def __init__(self, id_: str, status: JobStatus, connection, meta: dict = None):
         self._id = id_
         self._status = status
         self._connection = connection
         self._result = None
+        self._meta = meta or {}
 
         self.log = create_logger(__name__)
 
@@ -119,14 +121,27 @@ def result(self) -> Result:
             )
         return self._result
 
+    @property
+    def meta(self) -> dict:
+        """Returns a dictionary of metadata on job execution, such as error
+        details.
+
+        Returns:
+            dict[str, str]
+        """
+        return self._meta
+
     def refresh(self):
-        """Refreshes the status of an open or queued job,
+        """Refreshes the status and metadata of an open or queued job,
         along with the job result if the job is newly completed.
         """
         if self._status.is_final:
             self.log.warning("A %s job cannot be refreshed", self._status.value)
             return
-        self._status = JobStatus(self._connection.get_job_status(self.id))
+        job_info = self._connection.get_job(self.id)
+        self._status = JobStatus(job_info.status)
+        self._meta = job_info.meta
+        self.log.debug("Job %s metadata: %s", self.id, job_info.meta)
         if self._status == JobStatus.COMPLETED:
             self._result = self._connection.get_job_result(self.id)
 

strawberryfields/engine.py

@@ -547,8 +547,8 @@ def run(self, program: Program, *, compile_options=None, **kwargs) -> Optional[R
 
                 if job.status == "failed":
                     message = (
-                        "The remote job %s failed due to an internal "
-                        "server error. Please try again." % job.id
+                        "The remote job {} failed due to an internal "
+                        "server error. Please try again. {}".format(job.id, job.meta)
                     )
                     self.log.error(message)
 

tests/api/test_connection.py

@@ -132,16 +132,19 @@ def test_get_all_jobs_error(self, connection, monkeypatch):
 
     def test_get_job(self, connection, monkeypatch):
         """Tests a successful job request."""
-        id_, status = "123", JobStatus.COMPLETED
+        id_, status, meta = "123", JobStatus.COMPLETED, {"abc": "def"}
 
         monkeypatch.setattr(
-            requests, "get", mock_return(MockResponse(200, {"id": id_, "status": status.value})),
+            requests,
+            "get",
+            mock_return(MockResponse(200, {"id": id_, "status": status.value, "meta": meta})),
         )
 
         job = connection.get_job(id_)
 
         assert job.id == id_
         assert job.status == status.value
+        assert job.meta == meta
 
     def test_get_job_error(self, connection, monkeypatch):
         """Tests a failed job request."""
@@ -155,7 +158,9 @@ def test_get_job_status(self, connection, monkeypatch):
         id_, status = "123", JobStatus.COMPLETED
 
         monkeypatch.setattr(
-            requests, "get", mock_return(MockResponse(200, {"id": id_, "status": status.value})),
+            requests,
+            "get",
+            mock_return(MockResponse(200, {"id": id_, "status": status.value, "meta": {}})),
         )
 
         assert connection.get_job_status(id_) == status.value
@@ -238,6 +243,7 @@ def test_ping_failure(self, connection, monkeypatch):
 
         assert not connection.ping()
 
+
 class TestConnectionIntegration:
     """Integration tests for using instances of the Connection."""
 

tests/api/test_remote_engine.py

@@ -35,16 +35,17 @@ class MockServer:
     def __init__(self):
         self.request_count = 0
 
-    def get_job_status(self, _id):
+    def get_job(self, _id):
         """Returns a 'queued' job status until the number of requests exceeds a defined
         threshold, beyond which a 'complete' job status is returned.
         """
         self.request_count += 1
-        return (
+        status = (
             JobStatus.COMPLETED
             if self.request_count >= self.REQUESTS_BEFORE_COMPLETED
             else JobStatus.QUEUED
         )
+        return Job(id_="123", status=status, connection=None, meta={"foo": "bar"})
 
 
 @pytest.fixture
@@ -56,7 +57,7 @@ def job_to_complete(connection, monkeypatch):
         mock_return(Job(id_="123", status=JobStatus.OPEN, connection=connection)),
     )
     server = MockServer()
-    monkeypatch.setattr(Connection, "get_job_status", server.get_job_status)
+    monkeypatch.setattr(Connection, "get_job", server.get_job)
     monkeypatch.setattr(
         Connection,
         "get_job_result",
@@ -90,6 +91,7 @@ def test_run_async(self, connection, prog, job_to_complete):
             job.refresh()
 
         assert job.status == JobStatus.COMPLETED.value
+        assert job.meta == {"foo": "bar"}
         assert np.array_equal(job.result.samples, np.array([[1, 2], [3, 4]]))
 
         with pytest.raises(