Wait for previous jobs if limit is reached

CHANGELOG.md

@@ -36,6 +36,8 @@ Changed
 -   Classical algorithms renamed, former names deprecated (#851)
 -   Chemistry process algorithm result returns result object, lines, dict return deprecated (#861)
 -   Measurement error mitigation supports different output orders on same qubits (#865)
+-   If ibmq-provider is used and job limit is reached, `run_circuit` now waits for a previous job
+    to finish before submitting the next one. (#906)
 
 Removed
 -------

qiskit/aqua/utils/run_circuits.py

@@ -26,11 +26,13 @@
 from qiskit.providers.jobstatus import JOB_FINAL_STATES
 from qiskit.providers.basicaer import BasicAerJob
 from qiskit.qobj import QasmQobj
+from qiskit.exceptions import QiskitError
 from qiskit.aqua.aqua_error import AquaError
 from qiskit.aqua.utils.backend_utils import (is_aer_provider,
                                              is_basicaer_provider,
                                              is_simulator_backend,
-                                             is_local_backend)
+                                             is_local_backend,
+                                             is_ibmq_provider)
 
 MAX_CIRCUITS_PER_JOB = os.environ.get('QISKIT_AQUA_MAX_CIRCUITS_PER_JOB', None)
 MAX_GATES_PER_JOB = os.environ.get('QISKIT_AQUA_MAX_GATES_PER_JOB', None)
@@ -134,15 +136,24 @@ def _maybe_split_qobj_by_gates(qobjs, qobj):
 def _safe_submit_qobj(qobj, backend, backend_options, noise_config, skip_qobj_validation):
     # assure get job ids
     while True:
-        job = run_on_backend(backend, qobj, backend_options=backend_options,
-                             noise_config=noise_config,
-                             skip_qobj_validation=skip_qobj_validation)
         try:
+            job = run_on_backend(backend, qobj, backend_options=backend_options,
+                                 noise_config=noise_config,
+                                 skip_qobj_validation=skip_qobj_validation)
             job_id = job.job_id()
             break
-        except JobError as ex:
-            logger.warning("FAILURE: Can not get job id, Resubmit the qobj to get job id."
+        except QiskitError as ex:
+            logger.warning("FAILURE: Can not get job id, Resubmit the qobj to get job id. "
                            "Terra job error: %s ", ex)
+            if is_ibmq_provider(backend) and 'Error code: 3458' in str(ex):
+                # TODO Use IBMQBackendJobLimitError when new IBM Q provider is released.
+                oldest_running = backend.jobs(limit=1, descending=False,
+                                              status=['QUEUED', 'VALIDATING', 'RUNNING'])
+                if oldest_running:
+                    oldest_running = oldest_running[0]
+                    logger.warning("Job limit reached, waiting for job %s to finish "
+                                   "before submitting the next one.", oldest_running.job_id())
+                    oldest_running.wait_for_final_state(timeout=300)
         except Exception as ex:  # pylint: disable=broad-except
             logger.warning("FAILURE: Can not get job id, Resubmit the qobj to get job id."
                            "Error: %s ", ex)

requirements.txt

@@ -1,4 +1,4 @@
-qiskit-terra>=0.11.0
+qiskit-terra>=0.13.0
 qiskit-ignis>=0.2.0
 scipy>=1.0
 sympy>=1.3

setup.py

@@ -26,7 +26,7 @@
  Qiskit Finance, Qiskit Machine Learning and Qiskit Optimization to experiment with real-world applications to quantum computing."""
 
 requirements = [
-    "qiskit-terra>=0.11.0",
+    "qiskit-terra>=0.13.0",
     "qiskit-ignis>=0.2.0",
     "scipy>=1.0",
     "sympy>=1.3",