runtime/solvers/mzn/mzn_solver.py

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   2 #   Copyright (c) 2020 AT&T Intellectual Property
   3 #
   4 #   Licensed under the Apache License, Version 2.0 (the "License");
   5 #   you may not use this file except in compliance with the License.
   6 #   You may obtain a copy of the License at
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   8 #       http://www.apache.org/licenses/LICENSE-2.0
   9 #
  10 #   Unless required by applicable law or agreed to in writing, software
  11 #   distributed under the License is distributed on an "AS IS" BASIS,
  12 #   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13 #   See the License for the specific language governing permissions and
  14 #   limitations under the License.
  15 #
  16 # -------------------------------------------------------------------------
  17 #
  18
  19 import json
  20 from datetime import datetime
  21
  22 from pymzn import Status, minizinc, cbc, gecode, chuffed, or_tools
  23
  24 from osdf.utils.file_utils import delete_file_folder
  25
  26 error_status_map = {
  27     Status.INCOMPLETE: "incomplete",
  28     Status.COMPLETE: "complete",
  29     Status.UNSATISFIABLE: "unsatisfiable",
  30     Status.UNKNOWN: "unknown",
  31     Status.UNBOUNDED: "unbounded",
  32     Status.UNSATorUNBOUNDED: "unsat_or_unbounded",
  33     Status.ERROR: "error"
  34 }
  35
  36 solver_dict = {
  37     'cbc': cbc,
  38     'geocode': gecode,
  39     'chuffed': chuffed,
  40     'cp': chuffed,
  41     'or_tools': or_tools
  42 }
  43
  44
  45 def map_status(status):
  46     return error_status_map.get(status, "failed")
  47
  48
  49 def solve(request_json, mzn_content):
  50     req_info = request_json['requestInfo']
  51     opt_info = request_json['optimInfo']
  52     try:
  53         mzn_solution = mzn_solver(mzn_content, opt_info)
  54
  55         response = {
  56             'transactionId': req_info['transactionId'],
  57             'requestID': req_info['requestID'],
  58             'requestStatus': 'done',
  59             'statusMessage': map_status(mzn_solution.status),
  60             'solutions': mzn_solution[0] if mzn_solution else {}
  61         }
  62         return 200, json.dumps(response)
  63     except Exception as e:
  64         response = {
  65             'transactionId': req_info['transactionId'],
  66             'requestID': req_info['requestID'],
  67             'requestStatus': 'failed',
  68             'statusMessage': 'Failed due to {}'.format(e)
  69         }
  70         return 400, json.dumps(response)
  71
  72
  73 def mzn_solver(mzn_content, opt_info):
  74     args = opt_info['solverArgs']
  75     solver = get_mzn_solver(args.pop('solver'))
  76     mzn_opts = dict()
  77
  78     try:
  79         file_name = persist_opt_data(opt_info)
  80         mzn_opts.update(args)
  81         return minizinc(mzn_content, file_name, **mzn_opts, solver=solver)
  82
  83     finally:
  84         delete_file_folder(file_name)
  85
  86
  87 def persist_opt_data(opt_info):
  88
  89     if opt_info['optData'].get('json'):
  90         data_content = json.dumps(opt_info['optData']['json'])
  91         file_name = '/tmp/optim_engine_{}.json'.format(datetime.timestamp(datetime.now()))
  92     elif opt_info['optData'].get('text'):
  93         data_content = opt_info['optData']['text']
  94         file_name = '/tmp/optim_engine_{}.dzn'.format(datetime.timestamp(datetime.now()))
  95
  96     with open(file_name, "wt") as data:
  97         data.write(data_content)
  98     return file_name
  99
 100
 101 def get_mzn_solver(solver):
 102     return solver_dict.get(solver)