Accessing licenses and extensions in Python
Whenever a tool is executed in a script, an ArcGIS Desktop license is required. Tools from ArcGIS extensions, such as ArcGIS Spatial Analyst, require an additional license for that extension. If the necessary licenses are not available, a tool fails and returns error messages. For example, if you install with an ArcView license, and you attempt to execute a tool set for an ArcEditor or ArcInfo license, the tool will fail.
When using an ArcView or ArcEditor license, a script should set the product to ArcView or ArcEditor. Likewise, when using an Engine or EngineGeoDB license, a script should set the product to Engine or EngineGeoDB. If a license is not explicitly set, the license will be initialized based on the highest available license level the first time an ArcPy tool, function, or class is accessed.
Every tool checks to ensure it has the appropriate license. If it doesn't have what's required, it fails. To guard against the situation of executing part way through and failing, you can perform a check at the top of your script and fail immediately.
Tip:The setting of the product and extensions is only necessary within stand-alone scripts. If you are running tools from the Python window or using script tools, the product is already set from within the application, and the active extensions are based on the Extensions dialog box.
Desktop, Engine/Server licenses
Product modules are imported prior to the import of arcpy to define the desktop license used by a script. The CheckProduct function can be used to the check the availability of desktop licenses, while the ProductInfo function reports what the current product license is.
Legacy:The product level should be set by importing the appropriate product module (arcinfo, arceditor, arcview, arcserver, arcenginegeodb, arcengine) prior to importing arcpy. The SetProduct function is a legacy function and cannot set the product once arcpy has been imported.
Extension licenses
Licenses for extensions can be retrieved from a license manager and returned once they are no longer needed. CheckExtension is used to see if a license is available to be checked out for a specific type of extension, while CheckOutExtension actually retrieves the license. Once the extension license has been retrieved by the script, extension tools can be executed. Once a script is done using tools from a particular extension, the CheckInExtension function should be used to return the license to the license manager so other applications can use it. All checked-out extension licenses and set product licenses are returned to the license manager when a script completes.
The following example executes some ArcGIS 3D Analyst tools and sets the desktop product license to ArcView, since an ArcInfo license is not required to execute tools from an extension. The script will fail if the ArcView license is not explicitly set and no ArcInfo license is available, since a desktop license is required to execute extension tools.
class LicenseError(Exception):
pass
# Set desktop license used to ArcView
#
import arcview
import arcpy
from arcpy import env
try:
if arcpy.CheckExtension("3D") == "Available":
arcpy.CheckOutExtension("3D")
else:
# Raise a custom exception
#
raise LicenseError
env.workspace = "D:/GrosMorne"
arcpy.HillShade_3d("WesternBrook", "westbrook_hill", 300)
arcpy.Aspect_3d("WesternBrook", "westbrook_aspect")
except LicenseError:
print "3D Analyst license is unavailable"
except:
print arcpy.GetMessages(2)
finally:
# Check in the 3D Analyst extension
#
arcpy.CheckInExtension("3D")
In the above example, the 3D Analyst extension is checked in under a finally clause, ensuring that the extension is always checked back in, whether an exception has occurred or not.
A returned value of Failed, Unavailable or NotLicensed indicates that the extension could not be successfully checked out.
Below are the extension names and their extension code names:
|
Extension |
Extension Code |
|---|---|
|
3D Analyst |
3D |
|
ArcGIS Schematics |
Schematics |
|
ArcScan |
ArcScan |
|
Business Analyst |
Business |
|
Data Interoperability |
DataInteroperability |
|
Geostatistical Analyst |
GeoStats |
|
ArcGIS Workflow Manager |
JTX |
|
Network Analyst |
Network |
|
Esri Aeronautical Solution |
Aeronautical |
|
Esri Defense Mapping |
Defense |
|
Esri Production Mapping |
Foundation |
|
ArcGIS Data Reviewer |
Datareviewer |
|
Esri Nautical Solution |
Nautical |
|
Spatial Analyst |
Spatial |
|
StreetMap |
StreetMap |
|
Tracking Analyst |
Tracking |
Product code names
|
Product Codes |
|---|
|
ArcInfo |
|
ArcEditor |
|
ArcView |
|
Engine |
|
EngineGeoDB |
|
ArcServer |
Licensing functions
|
Function |
Explanation | ||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
CheckExtension(extension) |
Checks to see if a license is available to be checked out for a specific type of extension.
|
||||||||||||||||
|
CheckInExtension(extension) |
Returns the license so other applications can use it.
|
||||||||||||||||
|
CheckOutExtension(extension) |
Retrieves the license.
|
||||||||||||||||
|
CheckProduct(code) |
Checks to see if the requested license is available.
|
||||||||||||||||
|
ProductInfo() |
Returns the current product license.
|
||||||||||||||||
|
SetProduct(code) |
Defines the desktop license.
|