7.1 Synchronous Problem Submission¶
For the purpose of the tutorial we assume that the problem to be solved is read from a file, and the solutions will be saved to a file, i.e. we don’t go into the logic which sets up the problem and interprets the solution. See file formats for specifications of file formats.
We demonstrate synchronous optimization, see Sec. 5.1 (Synchronous Optimization). If using authentication, the access token will always be passed in the X-Mosek-Access-Token header. Assuming that an HTTP/HTTPS connection to the OptServer was established, we first submit a problem using submit. We can provide a name for easier identification of the problem in the Web GUI. The file format is passed in the Content-Type header.
# POST problem data
con.request('POST', '/api/submit?jobname=' + jobname,
probdata,
headers = dict(headers, **{"Content-Type": "application/x-mosek-{}".format(intype)}))
resp = con.getresponse()
check_status(resp)
# Recover a token identifying the job
token = resp.read().decode('ascii')
The response contains a token used to identify the job in future requests. If no errors have occurred, we use solve to request running the solver for the given job token. When requesting the solution we set the Accept header to indicate expected solution format.
# Use token to identify job
con.request('GET', '/api/solve?token=' + token,
headers = dict(headers, **{"Accept": outtype}))
resp = con.getresponse()
The request will return when optimization terminates. If there were no errors, the status codes are available in the headers and the solution in the body of the response.
## Retrieve status codes
res = resp.getheader('X-Mosek-Res-Code',None)
trm = resp.getheader('X-Mosek-Trm-Code',None)
print('\tMOSEK response: %s' % res)
print('\t trm resp: %s' % trm)
## Retrieve the solution
if resp.status == http.client.OK:
print('Solution (as plain text):\n')
print(resp.read().decode('ascii', errors = 'ignore'))
It is also possible to retrieve the log from the solver (log):
con.request('GET','/api/log?token=' + token, headers = headers)
resp = con.getresponse()
The full example is shown below.
import http.client
import sys
try:
import ssl
except:
pass
# A debug method which prints out the HTTP(S) response
# and exits in case of error
def check_status(resp):
print('\tHTTPResponse: %s / %s' % (resp.status,resp.reason))
for k,v in resp.getheaders():
print('\t%s: %s' % (k,v))
if resp.status not in [http.client.OK, http.client.NO_CONTENT]:
raise Exception('An error in connection')
# A helper method which opens a connection
def openConnection(host, port, useHttps):
if useHttps:
return http.client.HTTPSConnection(host, port, context=ssl._create_unverified_context())
else:
return http.client.HTTPConnection(host, port)
# Main code
if __name__ == '__main__':
try:
# OptServer address
host, port = sys.argv[1], int(sys.argv[2])
# Protocol (HTTP/HTTPS)
useHttps = (sys.argv[3] == "HTTPS")
# Name of file with input data
probfile = sys.argv[4]
# Input and output file type
intype, outtype = sys.argv[5], sys.argv[6]
# Jobname (for demonstration)
jobname = sys.argv[7]
# Authentication token
headers = {}
if len(sys.argv) == 9:
headers = {"X-Mosek-Access-Token": sys.argv[8]}
except:
print("Usage : python3 test_sync.py host port protocol probfile intype outtype jobname [accestoken]")
print("Example: python3 test_sync.py solve.mosek.com 38000 HTTPS lo1.mps mps text/plain SimpleTask ...")
sys.exit(1)
# Establish HTTP connection
con = openConnection(host, port, useHttps)
try:
# Read input file
with open(probfile,'rb') as probdata:
## Submit job
print('POST /api/submit')
# POST problem data
con.request('POST', '/api/submit?jobname=' + jobname,
probdata,
headers = dict(headers, **{"Content-Type": "application/x-mosek-{}".format(intype)}))
resp = con.getresponse()
check_status(resp)
# Recover a token identifying the job
token = resp.read().decode('ascii')
## Solve and wait for solution
print('GET /api/solve')
# Use token to identify job
con.request('GET', '/api/solve?token=' + token,
headers = dict(headers, **{"Accept": outtype}))
resp = con.getresponse()
check_status(resp)
## Retrieve status codes
res = resp.getheader('X-Mosek-Res-Code',None)
trm = resp.getheader('X-Mosek-Trm-Code',None)
print('\tMOSEK response: %s' % res)
print('\t trm resp: %s' % trm)
## Retrieve the solution
if resp.status == http.client.OK:
print('Solution (as plain text):\n')
print(resp.read().decode('ascii', errors = 'ignore'))
## Obtain the solver log output
print('GET /api/log')
con.request('GET','/api/log?token=' + token, headers = headers)
resp = con.getresponse()
check_status(resp)
if resp.status == http.client.OK:
print('Solver log:\n')
print(resp.read().decode('utf-8', errors = 'ignore'))
finally:
con.close()
It is also possible to simplify the logic by using the submit+solve API to submit the problem and receive the solution in one request. The remaining protocol is similar to the above so we restrict to listing the full example without further explanations.
Listing 7.6 How to submit a job and solve the problem synchronously in one request. Click
here to download.¶import http.client
import sys
try:
import ssl
except:
pass
# A debug method which prints out the HTTP(S) response
# and exits in case of error
def check_status(resp):
print('\tHTTPResponse: %s / %s' % (resp.status,resp.reason))
for k,v in resp.getheaders():
print('\t%s: %s' % (k,v))
if resp.status not in [http.client.OK, http.client.NO_CONTENT]:
raise Exception('An error in connection')
# A helper method which opens a connection
def openConnection(host, port, useHttps):
if useHttps:
return http.client.HTTPSConnection(host, port, context=ssl._create_unverified_context())
else:
return http.client.HTTPConnection(host, port)
# Main code
if __name__ == '__main__':
try:
# OptServer address
host, port = sys.argv[1], int(sys.argv[2])
# Protocol (HTTP/HTTPS)
useHttps = (sys.argv[3] == "HTTPS")
# Name of file with input data
probfile = sys.argv[4]
# Input and output file type
intype, outtype = sys.argv[5], sys.argv[6]
# Jobname (for demonstration)
jobname = sys.argv[7]
# Authentication token
headers = {}
if len(sys.argv) == 9:
headers = {"X-Mosek-Access-Token": sys.argv[8]}
except:
print("Usage : python3 test_simple_api.py host port protocol probfile intype outtype jobname [accestoken]")
print("Example: python3 test_simple_api.py solve.mosek.com 38000 HTTPS lo1.mps mps text/plain SimpleTask ...")
sys.exit(1)
# Establish HTTP connection
con = openConnection(host, port, useHttps)
try:
# Read input file
with open(probfile,'rb') as probdata:
## Submit job
print('POST /api/submit+solve')
# POST problem data
con.request('POST', '/api/submit+solve?jobname=' + jobname,
probdata,
headers = dict(headers, **{"Content-Type": "application/x-mosek-{}".format(intype),
"Accept": outtype}))
resp = con.getresponse()
check_status(resp)
# Recover a token identifying the job
token = resp.getheader('X-Mosek-Token',None)
## Retrieve status codes
res = resp.getheader('X-Mosek-Res-Code',None)
trm = resp.getheader('X-Mosek-Trm-Code',None)
print('\tMOSEK response: %s' % res)
print('\t trm resp: %s' % trm)
## Retrieve the solution
if resp.status == http.client.OK:
print('Solution (as plain text):\n')
print(resp.read().decode('ascii', errors = 'ignore'))
## Obtain the solver log output
print('GET /api/log')
con.request('GET','/api/log?token=' + token, headers = headers)
resp = con.getresponse()
check_status(resp)
if resp.status == http.client.OK:
print('Solver log:\n')
print(resp.read().decode('utf-8', errors = 'ignore'))
finally:
con.close()
