1 files changed, 132 insertions, 0 deletions
diff --git a/runtime/solvers/mzn/mzn_solver.py b/runtime/solvers/mzn/mzn_solver.py
new file mode 100644
index 0000000..f3daa2b
--- /dev/null
+++ b/runtime/solvers/mzn/mzn_solver.py
@@ -0,0 +1,132 @@
+# -------------------------------------------------------------------------
+#   Copyright (c) 2020 AT&T Intellectual Property
+#
+#   Licensed under the Apache License, Version 2.0 (the "License");
+#   you may not use this file except in compliance with the License.
+#   You may obtain a copy of the License at
+#
+#       http://www.apache.org/licenses/LICENSE-2.0
+#
+#   Unless required by applicable law or agreed to in writing, software
+#   distributed under the License is distributed on an "AS IS" BASIS,
+#   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.
+#
+# -------------------------------------------------------------------------
+#
+
+from datetime import datetime
+import json
+
+from pymzn import cbc
+from pymzn import chuffed
+from pymzn import gecode
+from pymzn import minizinc
+from pymzn import or_tools
+from pymzn import Status
+
+from osdf.utils.file_utils import delete_file_folder
+
+error_status_map = {
+    Status.INCOMPLETE: "incomplete",
+    Status.COMPLETE: "complete",
+    Status.UNSATISFIABLE: "unsatisfiable",
+    Status.UNKNOWN: "unknown",
+    Status.UNBOUNDED: "unbounded",
+    Status.UNSATorUNBOUNDED: "unsat_or_unbounded",
+    Status.ERROR: "error"
+}
+
+solver_dict = {
+    'cbc': cbc,
+    'geocode': gecode,
+    'chuffed': chuffed,
+    'cp': chuffed,
+    'or_tools': or_tools
+}
+
+
+def map_status(status):
+    return error_status_map.get(status, "failed")
+
+
+def solve(request_json, mzn_content):
+    """Given the request and minizinc content.  Translates the json request to the format minizinc understands
+
+    return: returns the optimized solution.
+    """
+    req_info = request_json['requestInfo']
+    opt_info = request_json['optimInfo']
+    try:
+        mzn_solution = mzn_solver(mzn_content, opt_info)
+
+        response = {
+            'transactionId': req_info['transactionId'],
+            'requestID': req_info['requestID'],
+            'requestStatus': 'done',
+            'statusMessage': map_status(mzn_solution.status),
+            'solutions': mzn_solution[0] if mzn_solution else {}
+        }
+        return 200, json.dumps(response)
+    except Exception as e:
+        response = {
+            'transactionId': req_info['transactionId'],
+            'requestID': req_info['requestID'],
+            'requestStatus': 'failed',
+            'statusMessage': 'Failed due to {}'.format(e)
+        }
+        return 400, json.dumps(response)
+
+
+def mzn_solver(mzn_content, opt_info):
+    """Calls the minizinc optimizer.
+
+    """
+    args = opt_info['solverArgs']
+    solver = get_mzn_solver(args.pop('solver'))
+    mzn_opts = dict()
+
+    try:
+        file_name = persist_opt_data(opt_info)
+        mzn_opts.update(args)
+        return minizinc(mzn_content, file_name, **mzn_opts, solver=solver)
+
+    finally:
+        delete_file_folder(file_name)
+
+
+def persist_opt_data(opt_info):
+    """Persist the opt data, if included as part of the request.
+
+    return: file_name path of the optim_data
+            returns None if no optData is part of the request
+    """
+    file_name = None
+    if 'optData' in opt_info:
+        if opt_info['optData'].get('json'):
+            data_content = json.dumps(opt_info['optData']['json'])
+            file_name = '/tmp/optim_engine_{}.json'.format(datetime.timestamp(datetime.now()))
+            persist_data(data_content, file_name)
+        elif opt_info['optData'].get('text'):
+            data_content = opt_info['optData']['text']
+            file_name = '/tmp/optim_engine_{}.dzn'.format(datetime.timestamp(datetime.now()))
+            persist_data(data_content, file_name)
+    return file_name
+
+
+def persist_data(data_content, file_name):
+    """Save the dzn data into a file
+
+    """
+    with open(file_name, "wt") as data:
+        data.write(data_content)
+
+
+def get_mzn_solver(solver):
+    """Returns a solver type object for minizinc optimizers
+
+    solver: solver that is part of the request
+    return: solver mapped object
+    """
+    return solver_dict.get(solver)