create_fake_backend: tool for creating fake backend files and settings

tools/create_fake_backend.py

@@ -0,0 +1,178 @@
+#!/usr/bin/env python3
+
+# This code is part of Qiskit.
+#
+# (C) Copyright IBM 2022.
+#
+# This code is licensed under the Apache License, Version 2.0. You may
+# obtain a copy of this license in the LICENSE.txt file in the root directory
+# of this source tree or at http://www.apache.org/licenses/LICENSE-2.0.
+#
+# Any modifications or derivative works of this code must retain this
+# copyright notice, and modified files need to carry a notice indicating
+# that they have been altered from the originals.
+
+"""Utility script to create fake backends"""
+
+import argparse
+import sys
+from string import Template
+import os
+from reno.utils import get_random_string
+
+from update_fake_backends import DEFAULT_DIR
+from qiskit import IBMQ
+
+RENO_DIR = os.path.join(
+    os.path.dirname(os.path.dirname(os.path.abspath(__file__))),
+    "releasenotes",
+    "notes",
+)
+
+HEADER = """# This code is part of Qiskit.
+#
+# (C) Copyright IBM 2022.
+#
+# This code is licensed under the Apache License, Version 2.0. You may
+# obtain a copy of this license in the LICENSE.txt file in the root directory
+# of this source tree or at http://www.apache.org/licenses/LICENSE-2.0.
+#
+# Any modifications or derivative works of this code must retain this
+# copyright notice, and modified files need to carry a notice indicating
+# that they have been altered from the originals.
+"""
+
+init_py = Template(
+    """${HEADER}
+\"\"\"Fake ${capital_backend_name} device (${no_qubits} qubits)\"\"\"
+
+from .fake_${backend_name} import Fake${capital_backend_name}
+"""
+)
+
+fake_be_py = Template(
+    """${HEADER}
+
+\"\"\"
+Fake ${capital_backend_name} device (${no_qubits} qubits).
+\"\"\"
+
+import os
+from qiskit.providers.fake_provider import fake_backend
+
+
+class Fake${capital_backend_name}(fake_backend.FakeBackendV2):
+    \"\"\"A fake ${no_qubits} qubit backend.\"\"\"
+
+    dirname = os.path.dirname(__file__)
+    conf_filename = "conf_${backend_name}.json"
+    props_filename = "props_${backend_name}.json"
+    defs_filename = "defs_${backend_name}.json"
+    backend_name = "fake_${backend_name}"
+
+"""
+)
+
+reno_template = Template(
+    """---
+features:
+  - |
+    The fake backend :class:`~Fake${capital_backend_name}` was added with the information
+    from IBM Quantum `${system_name}` system.
+"""
+)
+
+
+def _insert_line_in_section(
+    line_to_insert, section, line_in_section_starts_with, backend_dir, file_to_modify
+):
+    tmp_file = os.path.join(backend_dir, "_tmp_.py")
+    with open(file_to_modify, "r") as original, open(tmp_file, "a+") as destination:
+        previous_line = ""
+        in_section = False
+        for line in original.readlines():
+            if line.startswith(section):
+                in_section = True
+            elif (
+                in_section
+                and line.startswith(line_in_section_starts_with)
+                and previous_line < line_to_insert < line
+            ):
+                in_section = False
+                destination.write(line_to_insert)
+            destination.write(line)
+    os.replace(tmp_file, file_to_modify)
+
+
+def _main():
+    parser = argparse.ArgumentParser(description="Create fake backend")
+    parser.add_argument("--dir", "-d", type=str, default=DEFAULT_DIR)
+    parser.add_argument("backend_name", type=str, default=None)
+    parser.add_argument("system_name", type=str, default=None)
+    parser.add_argument("--project", type=str, default=None)
+    parser.add_argument("--hub", type=str, default=None)
+    parser.add_argument("--group", type=str, default=None)
+    args = parser.parse_args()
+
+    backend_dir = os.path.join(args.dir, args.backend_name)
+    if os.path.isdir(backend_dir):
+        print(f"ERROR: Directory {backend_dir} already exists")
+        sys.exit(1)
+
+    provider = IBMQ.load_account()
+    if args.hub or args.group or args.project:
+        provider = IBMQ.get_provider(hub=args.hub, group=args.group, project=args.project)
+    ibmq_backend = provider.get_backend(args.system_name)
+
+    vars_ = {
+        "HEADER": HEADER,
+        "backend_name": args.backend_name,
+        "capital_backend_name": args.backend_name.capitalize(),
+        "no_qubits": len(ibmq_backend.properties().qubits),
+        "system_name": args.system_name,
+    }
+
+    # Step 1. Create the directory for the backend <backend_dir>
+    os.mkdir(backend_dir)
+
+    # Step 2. <backend_dir>/__init__.py
+    result = init_py.substitute(vars_)
+    with open(os.path.join(backend_dir, "__init__.py"), "w") as fd:
+        fd.write(result)
+
+    # Step 3. <backend_dir>/fake_<backend_name>.py
+    result = fake_be_py.substitute(vars_)
+    with open(os.path.join(backend_dir, f"fake_{args.backend_name}.py"), "w") as fd:
+        fd.write(result)
+
+    # Step 4. update <backend_dir>/../__init__.py
+    init_file = os.path.join(backend_dir, "..", "__init__.py")
+    backend_v2_line = f"from .{vars_['backend_name']} import Fake{vars_['capital_backend_name']}\n"
+    _insert_line_in_section(backend_v2_line, "# BackendV2", "from", backend_dir, init_file)
+
+    # Step 5. update <backend_dir>/../../__init__.py
+    init_file = os.path.join(backend_dir, "..", "..", "__init__.py")
+    backend_v2_line = f"    Fake{vars_['capital_backend_name']}\n"
+    _insert_line_in_section(backend_v2_line, "Fake V2 Backends", "    ", backend_dir, init_file)
+
+    # Step 6. update <backend_dir>/../../fake_provider.py
+    init_file = os.path.join(backend_dir, "..", "..", "fake_provider.py")
+    backend_v2_line = f"            Fake{vars_['capital_backend_name']}(),\n"
+    _insert_line_in_section(
+        backend_v2_line,
+        "class FakeProviderForBackend",
+        "            Fake",
+        backend_dir,
+        init_file,
+    )
+
+    # Step 7. releasenotes/notes/fake_<backend_name>-<random_string>.yaml
+    result = reno_template.substitute(vars_)
+    with open(
+        os.path.join(RENO_DIR, f"fake_{args.backend_name}-{get_random_string()}.yaml"), "w"
+    ) as fd:
+        fd.write(result)
+
+
+if __name__ == "__main__":
+    _main()