Exemple : interrogation des journaux ArcGIS Server

Cet exemple illustre la lecture, par programmation, des journaux ArcGIS Server et des statistiques de rapport relatives aux cartes de type image tracées par un service de carte donné. Pour tester cet exemple, procédez comme suit :

1. Définissez le niveau de consignation d'ArcGIS Server sur FIN.
2. Publiez un nouveau service de carte (sans définir de cache de tuile).
3. Utilisez ArcMap ou le répertoire de services pour effectuer des déplacements et des zooms sur votre nouveau service de carte.
4. Exécutez le script, en saisissant le nom du serveur et les informations d’identification lorsque vous y êtes invité, ainsi que le nom du service de carte.

Vous recevez alors un rapport indiquant la longueur de chaque affichage de carte, ainsi que la longueur moyenne d'un affichage.

Notez que les journaux sont renvoyés au format JSON, lequel peut être désérialisé dans un objet Python à l'aide de la fonction json.loads(). Vous pourrez ensuite itérer l'objet et lire ou signaler les éléments de votre choix.

# Queries the logs to find the average draw time for a given map 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 queries the ArcGIS Server logs."
    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

    # Ask for map service name
    mapService = raw_input("Enter map service name, using a forward slash / to denote a folder: ")
    if mapService.endswith(".MapServer"):
        pass
    else:
        mapService += ".MapServer"
    
    # Get a token
    token = getToken(username, password, serverName, serverPort)
    if token == "":
        print "Could not generate a token with the username and password provided."
        return
    
    # Construct URL to query the logs
    logQueryURL = "/arcgis/admin/logs/query"
    logFilter = "{'services': ['" + mapService + "']}"
    
    # Supply the log level, filter, token, and return format
    params = urllib.urlencode({'level': 'FINE', 'filter': logFilter, 'token': token, '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", logQueryURL, params, headers)
    
    # Read response
    response = httpConn.getresponse()
    if (response.status != 200):
        httpConn.close()
        print "Error while querying logs."
        return
    else:
        data = response.read()

        # Check that data returned is not an error object
        if not assertJsonSuccess(data):          
            print "Error returned by operation. " + data
        else:
            print "Operation completed successfully!"

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

        # Need these variables to calculate average draw time for an ExportMapImage call
        mapDraws = 0
        totalDrawTime = 0 
        
        # Iterate over messages        
        for item in dataObj["logMessages"]:
                       
            if item["message"] == "End ExportMapImage":
                print "Server drew map in " + item["elapsed"] + " seconds."
                mapDraws +=1
                totalDrawTime += float(item["elapsed"])

        print "Total number of draws found in logs: " + str(mapDraws)

        if mapDraws == 0:
            return
        
        print "Average draw time: " + str(1.0*(totalDrawTime / mapDraws)) + " seconds."      
            
        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"
    
    # URL-encode the token parameters
    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 toke 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:]))