Example: Edit service properties

You can use the ArcGIS REST API to edit the properties of an existing service. This is demonstrated in the example below, which edits the minimum and maximum number of instances of a given service that are allowed to run per GIS server.

In the REST API, the service's edit operation requires that you pass in a JSON definition of all the service properties as you desire them to remain following the edit. The easiest way to do this is to make an initial call to the service to get its current properties, modify the properties you want, then send the modified set of properties back as a parameter to the edit operation.

In this example, the initial call is made to the service, then the JSON response is deserialized into a Python object. The script then modifies the desired properties and serializes the Python object back into JSON. This edited JSON is then passed into the edit operation.

This pattern could be followed to edit any service properties, not just the minimum and maximum number of instances.

It may be helpful to look at the JSON representation of the service using the ArcGIS Server Administrator Directory (append f=json to the service URL in the Administrator Directory). This will help you know the JSON names for the properties, such as minInstancesPerNode and maxInstancesPerNode, which were used in this example.

# Demonstrates how to modify the min and max instances for a service

# For Http calls
import httplib, urllib, json

# For system tools
import sys

# For reading passwords without echoing
import getpass


# Defines the entry point into the script
def main(argv=None):
    # Print some info
    print
    print "This tool is a sample script that resets the minimum and maximum instances allowed for a service."
    print

    # Ask for admin/publisher user name and password
    username = raw_input("Enter user name: ")
    password = getpass.getpass("Enter password: ")
    
    # Ask for server name
    serverName = raw_input("Enter Server name: ")
    serverPort = 6080

    print r"Enter the service name in the format <folder>/<name>.<type>."
    service = raw_input(r"For example USA/Chicago.MapServer: ")
    minInstances = raw_input("Enter the new minimum: ")
    maxInstances = raw_input("Enter the new maximum: ")

    # Check to make sure the minimum and maximum are numerical
    try:
        minInstancesNum = int(minInstances)
        maxInstancesNum = int(maxInstances)
    except ValueError:
        print "Numerical value not entered for minimum, maximum, or both."
        return
    
    # Check to make sure that the minimum is not greater than the maximum
    if minInstancesNum > maxInstancesNum:
        print "Maximum number of instances must be greater or equal to minimum number."
        return
    
    # Get a token
    token = getToken(username, password, serverName, serverPort)
    if token == "":
        print "Could not generate a token with the username and password provided."    
        return
    
    serviceURL = "/arcgis/admin/services/" + service
    
    # This request only needs the token and the response formatting parameter 
    params = urllib.urlencode({'token': token, 'f': 'json'})
    
    headers = {"Content-type": "application/x-www-form-urlencoded", "Accept": "text/plain"}
    
    # Connect to service to get its current JSON definition    
    httpConn = httplib.HTTPConnection(serverName, serverPort)
    httpConn.request("POST", serviceURL, params, headers)
    
    # Read response
    response = httpConn.getresponse()
    if (response.status != 200):
        httpConn.close()
        print "Could not read service information."
        return
    else:
        data = response.read()
        
        # Check that data returned is not an error object
        if not assertJsonSuccess(data):          
            print "Error when reading service information. " + str(data)
        else:
            print "Service information read successfully. Now changing properties..."

        # Deserialize response into Python object
        dataObj = json.loads(data)
        httpConn.close()

        # Edit desired properties of the service
        dataObj["minInstancesPerNode"] = minInstancesNum
        dataObj["maxInstancesPerNode"] = maxInstancesNum

        # Serialize back into JSON
        updatedSvcJson = json.dumps(dataObj)

        # Call the edit operation on the service. Pass in modified JSON.
        editSvcURL = "/arcgis/admin/services/" + service + "/edit"
        params = urllib.urlencode({'token': token, 'f': 'json', 'service': updatedSvcJson})
        httpConn.request("POST", editSvcURL, params, headers)
        
        # Read service edit response
        editResponse = httpConn.getresponse()
        if (editResponse.status != 200):
            httpConn.close()
            print "Error while executing edit."
            return
        else:
            editData = editResponse.read()
            
            # Check that data returned is not an error object
            if not assertJsonSuccess(editData):
                print "Error returned while editing service" + str(editData)        
            else:
                print "Service edited successfully."

        httpConn.close()  

        return

# A function to generate a token given username, password and the adminURL.

def getToken(username, password, serverName, serverPort):
    # Token URL is typically http://server[:port]/arcgis/admin/generateToken
    tokenURL = "/arcgis/admin/generateToken"
    
    params = urllib.urlencode({'username': username, 'password': password, 'client': 'requestip', 'f': 'json'})
    
    headers = {"Content-type": "application/x-www-form-urlencoded", "Accept": "text/plain"}
    
    # Connect to URL and post parameters
    httpConn = httplib.HTTPConnection(serverName, serverPort)
    httpConn.request("POST", tokenURL, params, headers)
    
    # Read response
    response = httpConn.getresponse()
    if (response.status != 200):
        httpConn.close()
        print "Error while fetching tokens from admin URL. Please check the URL and try again."
        return
    else:
        data = response.read()
        httpConn.close()
        
        # Check that data returned is not an error object
        if not assertJsonSuccess(data):            
            return
        
        # Extract the token from it
        token = json.loads(data)        
        return token['token']            
        

# A function that checks that the input JSON object 
#  is not an error object.
    
def assertJsonSuccess(data):
    obj = json.loads(data)
    if 'status' in obj and obj['status'] == "error":
        print "Error: JSON object returns an error. " + str(obj)
        return False
    else:
        return True
    
        
# Script start 
if __name__ == "__main__":
    sys.exit(main(sys.argv[1:]))

Feedback on this topic?