PyCon 2011: IronPython Command Line
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This document discusses writing command-line tools with IronPython and Visual Studio. It describes creating a Python CLI tool in IronPython to upgrade hundreds of thousands of lines of C# code to .NET 4.0. The tool uses functions to validate the Visual Studio version in solution files, walk a file tree to find solution files, convert projects to the VS2010 format using the devenv tool, and recursively modify solution files in the tree. The run method parses arguments and executes the conversion process on the specified path, excluding any directories matching the given path.
PyCon 2011: IronPython Command Line
- 1. WRITING COMMAND-LINE TOOLS WITH IRONPYTHON AND VISUAL STUDIO Noah Gift Including PowerShell, and F#
- 2. Talk Objectives ¤ Freak you out a bit. ¤ Teach you something you didn’t know. (Not covered in any book). ¤ Be controversial. ¤ Entertain you.
- 3. Monty Hall Problem ¤ You are invited to a game show. ¤ Game show host shows you three doors. ¤ Behind two doors there is a goat, and behind one door is a $50,000 dollar sports car.
- 4. Monty Hall Problem ¤ You choose a door. ¤ Instead of opening your door. The game show host then opens up another door, to reveal a goat. ¤ Do you switch your choice?
- 5. Monty Hall Problem ¤ You always switch doors: 2/3 probability versus ½ probability. ¤ Bayes Rule shows us this: (Think Spam classification).
- 6. Monty Hall Takeaway ¤ This isn’t intuitive to most people ¤ The human brain’s intuition is often broken. ¤ What else is your brain wrong about?
- 7. Windows Is The Great Satan? ¤ Command-line is feeble ¤ People on twitter say it sucks ¤ Nothing COOL ever happens on Windows ¤ This isn’t “their” conference. ¤ What if your brain’s intuition is wrong about this too?
- 8. I Used To Hate Windows ¨ I Grew Up ¨ New Philosophy: Write Code in any language, in any environment. ¨ If it is innovative, I don’t care who made it. ¨ Sorry Stallman, we disagree.
- 9. What do most developers and admins think of when they hear Linux? ¨ Power ¨ The Shell ¨ Flexibility ¨ Command-tools ¨ Bash ¨ Man Pages ¨ SSH ¨ Awk/Sed
- 10. What Is The Unifying Theme Around This? ¨ String Output is King ¨ Tim O’Reilly in Unix ¨ Small Tools Power Tools, “A new ¨ Flexibility user by stringing together simple ¨ Geek Power. pipelines….”
- 11. The Hardest Part of Writing a *Nix Command-line tool in Python ¨ Remote Administration: ¨ Religious war in your Pyro vs SSH vs ??? company over using ¨ Dealing with *Nix tools optparse, getargs, that pass you back or argparse unstructured text.
- 12. Python/Unix Command-line Tools: The End Game ¨ Remote Object Invocation (Pyro, SSH, Fabric) ¨ Security (SSH, SSL) ¨ Automation ¨ Application API ¨ Event Management (Pyro) ¨ Transactions (Mercurial?)
- 13. How To Write A Classic IronPython CLI ¨ I needed to upgrade 100’s of thousands of lines of C# to .NET 4.0. ¨ I wrote a quick and dirty Command-line tool in IronPython.
- 14. Project Upgrader: Validate Version Step 1 def validate_vsver(slnfile): """Validates whether a .sln file has already been upgraded to VS 2010""" try: project_file = open(slnfile) for project_version_line in project_file.readlines(): if "Visual Studio 2010" in project_version_line: log.debug("Found VS 2010 project line: %s" % project_version_line) log.debug("Project file already upgraded....skipping: %s" % slnfile) return False return True finally: project_file.close()
- 15. Project Upgrader: Walk A Tree Step 2 def walk_tree(path, extension="sln", version_control_type=".svn", exclude_path=None): """Walks a tree, if there is a match to an extension, it returns a fullpath. Skips version_control_type directories, which by default is set to .svn """ for dirpath,dirname,filename in os.walk(path): #The walk should skip version control directories for dir in dirname:
- 16. Project Upgrader: Convert Project Step 3 def convert_project(filename): """Converts a project to VS2010 using deven via .NET Process Class""" p = Process() p.StartInfo.UseShellExecute = False p.StartInfo.RedirectStandardOutput = True p.StartInfo.RedirectStandardError = True p.StartInfo.FileName = """C:Program Files (x86)Microsoft Visual Studio 10.0Common7IDEdevenv.exe""" print "Stdout: %s| Stderr: %s" % (stdout, stderr) p.WaitForExit() return p.ExitCode
- 17. Project Upgrader: Convert Tree Step 4 def convert_tree(path, exclude_path): """Recursively modifies a tree of sln files, if they haven't been upgraded to VS 2010""" for file in walk_tree(path, exclude_path=exclude_path): if not validate_vsver(file): #we should pass upgrading if validate_vsver returns False continue exit_code = convert_project(file) log.info("%s, %s" % (exit_code, file))
- 18. Project Upgrader: Run method Step 4 def run(self): args, parser = self.options() if args.path: exclude = None if args.exclude: exclude = args.exclude log.info("Exclude set: %s" % exclude) log.info("%s Running VS2010 upgrade on tree: %s | excluding dirs named: %s" % (time.ctime(), args.path, exclude)) convert_tree(args.path, exclude_path=exclude) else: parser.print_help()
- 19. Python is like Kudzu ¤ Itsstrength is that it can embed itself into any project, any operating system. ¤ Not always the best tool, but often good enough.
- 20. Who Is The Target Audience For Command-line Tools? ¤ Systems Administrators ¤ Power Users ¤ Developers ¤ Systems Integrators/OEM ¤ Young Geeky Stallman
- 21. What Does It Really Mean To Write A Command-line tool on Linux ¤ You have an executable that runs in the context of, most likely, Bash. ¤ You output a string, which you can then pipeline into our Unix tools, sed, awk, grep. ¤ If your nice you create –help
- 22. What Does It Really Mean To Write A Command-line tool on Modern Windows ¤ Itis going to run inside of PowerShell. PowerShell is your bash. ¤ You have a unified interface to .NET and every possible high level automation API you can think of. ¤ PowerShell tools expect OBJECTS not strings.
- 23. PowerShell is Secure By Default ¤ Default File Association is Notepad or ISE. ¤ Remoting is disabled. ¤ No execution of scripts. ¤ Script Signing
- 24. Learning To Properly Write IronPython Command-Line Tools: “A two minute affair” ¤ Actually no, not even close. ¤ Forget “most” of what you know from linux. ¤ PowerShell changes everything.
- 25. PowerShell Object Passing Changes How Shells Work ¤ Fundamental change to understand ¤ You need to understand this to write command-line tools on Windows ¤ Game changer
- 26. We’re not in a flyover state anymore ¤ String output is lame! ¤ PowerShell wants objects ¤ What to do…what to do…
- 27. Fight the ecosystem and you will die ¤ Command-line tools should run in PowerShell not cmd.exe. ¤ The bash/linux CPython way, won’t cut it here. ¤ You must think the way .NET thinks. ¤ Everything takes and returns an Object.
- 28. PowerShell Endgame: We did EVERYTHING for you. ¤ Encrypted, paranoid secure, transactional, asynchronous remoting of serialized objects ¤ High level automation API to everything. ¤ Ignore at your own peril.
- 29. Writing a PowerShell Module In IronPython: The “real” way to write Command-line tools? ¨ Create a New Visual Studio Project ¨ Thinks Objects ¨ Use PowerShell SDK ¨ Write a Binary Module
- 30. Installing the PowerShell SDK ¤ Download the SDK ¤ Add a reference to the DLL in your Visual Studio Project ¤ C:ProgramFiles (x86)Reference AssembliesMicrosoftWindowsPowerShell v1.0System.Management.Automation
- 31. Finding and Loading PowerShell Modules ¨ Get-Module –all ¨ When you create a .dll in IronPython, could then simply integrate it into the PowerShell workflow.
- 32. What is a Binary Module? ¤ A .NET assembly compiled against PowerShell libraries. ¨ For IronPython folks, this is one way to integrate into PowerShell ¨ In a lot of documentation it will refer to C# code. ¨ You can also write a PowerShell, non-compiled, module.
- 33. Creating a Binary Module For Powershell in IronPython ¤ http://stackoverflow.com/questions/2094694/launch- powershell-under-net-4 ¤ You need to tweak some registry settings to support .NET 4.0 in PowerShell.
- 34. Creating a Binary Module For Powershell in IronPython: Continued ¤ Should follow C# example code for best implementation advice. ¤ Note, Argparse, Optparse, etc, aren’t used. They don’t make sense. ¤ These are objects being passed into other cmdlets, and methods are being called on those objects.
- 35. IronPython PowerShell Module Hello World Visual Studio import clr Project: clr.AddReference('System.Management.Automation') print 'Hello World' Step 1
- 36. IronPython PowerShell Module Hello World Visual Studio ¨ Build the project to create a .dll Project: ¨ In PowerShell Import Module Step 2 ¨ Import-Module MyModule.dll ¨ You can know interact with it from inside of .Net. Is this a commandline tool???
- 37. Setting Up A PowerShell Profile For IronPython ¨ Just like in Bash or ZSH, aliases are your friend. ¨ Edit your $profile with the ISE, and add interactive IronPython to it.
- 38. Creating Standalone IronPython executables ¨ Make sure you can pass objects in and out of them. ¨ Use the IronPython on codeplex: Pyc-Python Command-line compiler
- 39. F#: The Elephant in the Room ¤ Type inference ¤ Immutable data structures ¤ Run as script or compiled ¤ Tail recursion ¤ Fully integrated with Visual Studio ¤ Sexier then Python?
- 40. F# and Python: A Sexy Beast ¤ Mixing .dll files written in F# into IronPython modules, loaded into Powershell. ¤ Calling IronPython/CPython from inside of F# ¤ “A statically typed Python…” (Note, this will come up..just preparing you…)
- 41. Credit Some Excellent Books That Reference PowerShell ¤ PowerShell in Action, Manning (The Bible) ¤ PowerShell Cookbook, O’Reilly ¤ IronPython in Action, Manning
- 42. Conclusion ¤ PowerShell isn’t a competing language, it IS THE ECOSYSTEM. ¤ Windows Systems Admins are using PowerShell for everything ¤ Get your head wrapped around object based pipelines. ¤ Why doesn’t Linux have this?
- 43. Questions? Code: https://bitbucket.org/noahgift/pycon2011- ironpython-cli