Wing IDE with Zope

"The best solution for debugging Zope and Plone" -- Joel Burton, Member, Plone Team, Jul 2005

Wing IDE can be used to develop and debug Python code running under Zope2 or Zope3, including Products, External Methods, file system-based Scripts and Zope itself. It is also useful for Zope-based frameworks like Plone (see Plone Quickstart).

Wing provides auto-completion, call tips, and other features that help to write, navigate, and understand Zope code. Wing's debugger can work with Zope's code reloading features to achieve a very short edit/debug cycle.

Note: This guide is for Zope2 users. If you are using Zope3, please try z3wingdbg by Martijn Pieters or refer to Debugging Externally Launched Code in the users manual top set up Zope3 debugging manually.

Limitations: Wing IDE cannot debug DTML, Page Templates, ZCML, or Python code that is not stored on the file system.

Security Warning: We advise against using the WingDBG product on production web servers. Any user connected to the Wing IDE debugger will (unavoidably) have extensive access to files and data on the system.

Quick Start on a Single Host

To use Wing IDE with Zope running on the same host as the IDE:

· Install Zope -- You can obtain Zope from zope.org. Version 2.5.1 or newer will work with Wing.

· Install Wing IDE -- You will need Wing IDE 2.1 or later. See Installing for details.

· Configure Wing IDE -- Start Wing, create or open the project you wish to use (from the Project menu). Then use the Extensions tab in Project Properties to enable Zope2/Plone support and to specify the Zope2 Instance Home to use with the project. Wing will find your Zope installation by reading the file etc/zope.conf in the provided Zope instance. Once you press Apply or OK in the Project Properties dialog, Wing will ask to install the WingDBG product and will offer to add files from your Zope installation to the project.

· Configure the WingDBG Product -- Start or restart Zope and log into http://localhost:8080/manage (assuming default Zope configuration). The Wing Debugging Service will be created automatically on startup; you can find it under the Control Panel of your server.

Starting the Debugger

Proceed to the Wing Debugger Service by navigating to the Control Panel, then selecting the 'Wing Debugging Service'. Click in the "Start" button. The Wing IDE status area should display "Debugger: Debug process running".

Note that you can configure WingDBG to start and connect to the IDE automatically when Zope is started from the Advanced configuration tab.

Problems? See the Trouble-Shooting Guide below.

Test Drive Wing IDE

Once you've started the debugger successfully, here are some things to try:

Run to a Breakpoint -- Open up your Zope code in Wing IDE and set a breakpoint on a line that will be reached as the result of a browser page load. Then load that page in your web browser using the port number displayed by the Zope Management Interface after you started the debugger. By default, this is 50080, so your URL would look something like this:

http://localhost:50080/Rest/Of/Usual/Url

Explore the Debugger Tools -- Take a look at these tools available from the Tools menu:

· Stack Data -- displays the stack, allows selecting current stack frame, and shows the locals and globals for that frame.

· Debug Probe -- lets you interact with your paused debug process using a Python shell prompt

· Watch -- watches values selected from other value views (by right-clicking and selecting one of the Watch items) and allows entering expressions to evaluate in the current stack frame

· Modules -- browses data for all modules in sys.modules

· Exceptions -- displays exceptions that occur in the debug process

· Debug I/O -- displays debug process output and processes keyboard input to the debug process, if any

Continue the Page Load -- When done, select Debug / Continue from the Debug menu or toolbar.

Try Pause -- From Wing, you can pause the Zope process by pressing the Pause icon in the toolbar or using Pause from the Debug menu. This is a good way to interrupt a lengthy computation to see what's going on. When done between page loads, it pauses Zope in its network service code.

Other Features -- Notice that Wing IDE's editor contains a source index and presents you with an auto-completer when you're editing source code. The Source Assistant will display context appropriate call tips and documentation. Control-click on a source symbol to jump to its point of definition (or use Goto Selected Symbol in the Source menu). Bring up the Source Browser from the Tools menu to look at the module and class structure of your code.

Setting Up Auto-Refresh

When you edit and save Zope External Methods or Scripts, your changes will automatically be loaded into Zope with each new browser page load.

By default, Zope Products are not automatically reloaded, but it is possible to configure them to do so. This can make debugging much faster and easier.

Take the following steps to take advantage of this feature:

· Place a file called refresh.txt in your Product's source directory (for example, Products/MyProductName inside your Zope installation). This file tells Zope to allow refresh for this product.

· Open the Zope Management Interface.

· Expand the Control Panel and Products tabs on the upper left.

· Click on your product.

· Select the Refresh tab.

· Check the "Auto refresh mode" check box and press "Change".

· Make an edit to your product source, and you should see the changes you made take effect in the next browser page load.

Limitations: Zope may not refresh code if you use import statements within functions or methods. Also, code that manages to retain references to old code objects after a refresh (for example, by holding the references in a C/C++ extension module) will not perform as expected.

If you do run into a case where auto-reload causes problems, you will need to restart Zope from the Zope Managemetn Interface's Control Panel or from the command line. Note that pressing the Stop button in Wing only disconnects from the debug process and does not terminate Zope.

Setting up Remote Debugging

Configuring Wing for remote debugging can be complicated, so we recommend using X Windows (Linux/Unix) or Remote Desktop (Windows) to run Wing IDE on the same machine as Zope but display it remotely.

When this is not possible, you can set up Wing to debug Zope running on another machine, as described below:

· Set up File Sharing -- You will need some mechanism for sharing files between the Zope host and the Wing IDE host. Windows file sharing, Samba, NFS, and ftp or rsync mirroring are all options. For secure file sharing via SSH on Linux, try sshfs.

· Install Wing on Server -- You will also need to install Wing on the host where Zope is running, if it is not already there. No license is needed for this installation, unless you plan to also run the IDE there. If there is no binary distribution of Wing available for the operating system where Zope is running, you can instead install only the debugger libraries as outlined in Compiling the Wing IDE Debugger from Source.

· Basic Configuration -- Follow the instructions for Single-Host Debugging above first if you have not already done so. Then return here for additional setup instructions.

· Configure Allowed Hosts -- You will need to add the IP address of the Zope host to the Allowed Hosts preference in Wing. Otherwise Wing will not accept your debug connections.

· Configure File Mapping -- Next, set up a mapping between the location of the Zope installation on your Zope host and the point where it is accessible on you Wing IDE host. For example, if your Zope host is 192.168.1.1 Zope is installed in /home/myuser/Zope on that machine, and /home/myuser is mounted on your Wing IDE host as e:, you would add a Location Map preference setting that maps 192.168.1.1 to a list containing /home/myuser/Zope and file:e:/Zope. For more information on this, see File Location Maps and Location Map Examples in the Wing IDE manual.

· Modify WingDBG Configuration -- When debugging remotely, the value given to WingDBG for the Wing Home Directory must be the location where Wing is installed on the Zope host (the default value will usually need to be changed).

· Check Project Configuration -- Similarly, the paths identified in Project Properties should be those on the host where Wing IDE is running, not the paths on the Zope host.

Trouble Shooting Guide

You can obtain additional verbose output from Wing IDE and the debug process as follows:

· Go into the Wing Debugging Service in the Zope Management Interface and set Log file under the Configure tab. Using will cause logging information to be printed to the console from which Zope was started. Alternatively, set this to the full path of a log file. This file must already exist for logging to occur.

· Restart Zope and Wing and try to initiate debug.

· Inspect the contents of the log. If you are running Zope and Wing IDE on two separate hosts, you should also inspect the error-log file on the Wing IDE host (located in the User Settings Directory). It contains additional logging information from the Wing IDE process.

For additional help, send these errors logs to support at wingware.com.