[cirqflow] Convenience method for loading results (quantumlib#4720)

Add cg.ExecutableGroupResultFilesystemRecord.from_json(run_id)

cirq-google/cirq_google/workflow/io.py

@@ -44,6 +44,23 @@ class ExecutableGroupResultFilesystemRecord:
 
     run_id: str
 
+    @classmethod
+    def from_json(
+        cls, *, run_id: str, base_data_dir: str = "."
+    ) -> 'ExecutableGroupResultFilesystemRecord':
+        fn = f'{base_data_dir}/{run_id}/ExecutableGroupResultFilesystemRecord.json.gz'
+        egr_record = cirq.read_json_gzip(fn)
+        if not isinstance(egr_record, cls):
+            raise ValueError(
+                f"The file located at {fn} is not an `ExecutableGroupFilesystemRecord`."
+            )
+        if egr_record.run_id != run_id:
+            raise ValueError(
+                f"The loaded run_id {run_id} does not match the provided run_id {run_id}"
+            )
+
+        return egr_record
+
     def load(self, *, base_data_dir: str = ".") -> 'cg.ExecutableGroupResult':
         """Using the filename references in this dataclass, load a `cg.ExecutableGroupResult`
         from its constituent parts.

cirq-google/cirq_google/workflow/io_test.py

@@ -11,6 +11,9 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+import os
+
+import pytest
 
 import cirq
 import cirq_google as cg
@@ -47,6 +50,46 @@ def test_egr_filesystem_record_repr():
     cg_assert_equivalent_repr(egr_fs_record)
 
 
+def test_egr_filesystem_record_from_json(tmpdir):
+    run_id = 'my-run-id'
+    egr_fs_record = cg.ExecutableGroupResultFilesystemRecord(
+        runtime_configuration_path='RuntimeConfiguration.json.gz',
+        shared_runtime_info_path='SharedRuntimeInfo.jzon.gz',
+        executable_result_paths=[
+            'ExecutableResult.1.json.gz',
+            'ExecutableResult.2.json.gz',
+        ],
+        run_id=run_id,
+    )
+
+    # Test 1: normal
+    os.makedirs(f'{tmpdir}/{run_id}')
+    cirq.to_json_gzip(
+        egr_fs_record, f'{tmpdir}/{run_id}/ExecutableGroupResultFilesystemRecord.json.gz'
+    )
+    egr_fs_record2 = cg.ExecutableGroupResultFilesystemRecord.from_json(
+        run_id=run_id, base_data_dir=tmpdir
+    )
+    assert egr_fs_record == egr_fs_record2
+
+    # Test 2: bad object type
+    cirq.to_json_gzip(
+        cirq.Circuit(), f'{tmpdir}/{run_id}/ExecutableGroupResultFilesystemRecord.json.gz'
+    )
+    with pytest.raises(ValueError, match=r'.*not an `ExecutableGroupFilesystemRecord`.'):
+        cg.ExecutableGroupResultFilesystemRecord.from_json(run_id=run_id, base_data_dir=tmpdir)
+
+    # Test 3: Mismatched run id
+    os.makedirs(f'{tmpdir}/questionable_run_id')
+    cirq.to_json_gzip(
+        egr_fs_record, f'{tmpdir}/questionable_run_id/ExecutableGroupResultFilesystemRecord.json.gz'
+    )
+    with pytest.raises(ValueError, match=r'.*does not match the provided run_id'):
+        cg.ExecutableGroupResultFilesystemRecord.from_json(
+            run_id='questionable_run_id', base_data_dir=tmpdir
+        )
+
+
 def test_filesystem_saver(tmpdir, patch_cirq_default_resolvers):
     assert patch_cirq_default_resolvers
     run_id = 'asdf'
@@ -56,11 +99,13 @@ def test_filesystem_saver(tmpdir, patch_cirq_default_resolvers):
     shared_rt_info = cg.SharedRuntimeInfo(run_id=run_id)
     fs_saver.initialize(rt_config, shared_rt_info=shared_rt_info)
 
+    # Test 1: assert fs_saver.initialize() has worked.
     rt_config2 = cirq.read_json_gzip(f'{tmpdir}/{run_id}/QuantumRuntimeConfiguration.json.gz')
     shared_rt_info2 = cirq.read_json_gzip(f'{tmpdir}/{run_id}/SharedRuntimeInfo.json.gz')
     assert rt_config == rt_config2
     assert shared_rt_info == shared_rt_info2
 
+    # Test 2: assert `consume_result()` works.
     # you shouldn't actually mutate run_id in the shared runtime info, but we want to test
     # updating the shared rt info object:
     shared_rt_info.run_id = 'updated_run_id'
@@ -76,6 +121,7 @@ def test_filesystem_saver(tmpdir, patch_cirq_default_resolvers):
     assert shared_rt_info == shared_rt_info3
     assert exe_result == exe_result3
 
+    # Test 3: assert loading egr_record works.
     egr_record: cg.ExecutableGroupResultFilesystemRecord = cirq.read_json_gzip(
         f'{fs_saver.data_dir}/ExecutableGroupResultFilesystemRecord.json.gz'
     )

cirq-google/cirq_google/workflow/quantum_runtime_test.py

@@ -182,10 +182,14 @@ def test_execute(tmpdir, run_id_in, patch_cirq_default_resolvers):
         f'{tmpdir}/{run_id}/ExecutableGroupResultFilesystemRecord.json.gz'
     )
     exegroup_result: cg.ExecutableGroupResult = egr_record.load(base_data_dir=tmpdir)
+    helper_loaded_result = cg.ExecutableGroupResultFilesystemRecord.from_json(
+        run_id=run_id, base_data_dir=tmpdir
+    ).load(base_data_dir=tmpdir)
 
     # TODO(gh-4699): Don't null-out device once it's serializable.
     assert isinstance(returned_exegroup_result.shared_runtime_info.device, cg.SerializableDevice)
     returned_exegroup_result.shared_runtime_info.device = None
 
     assert returned_exegroup_result == exegroup_result
     assert manual_exegroup_result == exegroup_result
+    assert helper_loaded_result == exegroup_result