Checking repository and updating - python

I'm making a game using the (very) old Python library, PyGame. But that's not what I'm here to ask about.
How do I make a code that would check the repositories in a server with the latest build, check if the build is newer or the same, and if newer prompt the user to download (or deny) the update of the game, as it will be developed in multiple versions and will allow players to gradually update as we make changes.
Like Minecraft does once an update comes out and it prompts you to update... But in Python

There are 3 things you need for this:
A server where you will store all the information about the updates and versions.
It can be a web server (for Python, see flask, web.py, django, pylons, etc., or PHP or whatever) which can have a single page.
It will take the current version as input (GET/POST requests) and output the updates available (in a format that can be parsed, JSON preferably, or XML or just plain text).
These can be fetched from a database (see MySQL, postgresql, or any ORM that works with your choice of web server, sqlalchemy)
Or by checking the names of the files available on the server (if the files will be hosted on the same web server) (the names will have a pattern XXX-r24-20121224.tar.gz and you'll check the list of files with glob or something).
A piece of code that will query the server every time you start your game to check with the web server if there are updates. You can use requests or urllib2 for example.
A piece of code that will download and update your actual game.
The web server should give you a link to where the update file is
From there you will have to download it (with requests or urllib2)
Unzip it (using zipfile or tarfile) and replace your actual files with that.
Now it all depends on how your files are laid out:
If you're distributing the source code, what you could do is build it all in a package, and then you just replace the whole package.
The zipfile package and Python actually account for that, and they give you an option to only put the python files in the zip file and Python gives you an option to add said zip file to the PYTHONPATH and import directly from there.
If you're compiling it with py2exe or anything, it'll be a different issue: you might be able to only update one zip file, or replace the actual DLLs and stuff, which might be a big mess.
If it's a deb package or similar, you might want to use that to update, and ask the user to do it or something.
I hope this helps, even if it's very abstract. This had to be done :)
Now I'll give my own (biased) opinion: If you already have a website running, use that to add a single page for such a thing. Otherwise I'd recommend a free hosting that will allow you to set up a website using flask. I'd recommend that because it would be very easy to get it running in no time, plus it will allow you to use the great ORM sqlAlchemy. Also, I wouldn't bother with more than telling the user there is a new version and let them figure out where to get it. That's unless you are only distributing it in one standard way all over.

Related

Having trouble with download_app and coursebuilder

I inherited an appengine coursebuilder project a couple months ago, and we've been trying to upgrade to a more recent version of coursebuilder. In order to do this, the first step is to download local version of the course.
Whenever I run appcfg.py download_app -A $projectID -V $versionNumber ./folderToSaveTo
It downloads a different version of the course, one that looks like an old test version with old placeholder text, all links to lessons set to private, etc.
When I look at the versions of the course in the appengine dashboard, there is only a single version, so I'm not sure what it's even downloading.
Alternatively, it was suggested I use the ETL tool provided with coursebuilder to download the files instead, but that had a bunch of other issues associated with it as well. Previously I had asked the question directly on the coursebuilder forum where the ETL tool was initially suggested.
Thanks in advance for any help,
-Tyler Nolan
appcfg's download_app will only look within the default module. You should check if there are any drop-downs in the Developers Console UI which will allow you to look into whether there are other modules.
gcloud preview app modules download on the other hand, does allow you to specify modules.
Hopefully this helps you find the "real version" of your app.
It's also possible that what you download is displaying default data because it's not being viewed in a manner which is properly connected to the database, so it falls back to look like that.

How do you distribute Python scripts?

I have a server which executes Python scripts from a certain directory path. Incidently this path is a check-out from the SVN trunk version of the scripts. However, I get the feeling that this isn't the right way to provide and update scripts for a server.
Do you suggest other approaches? (compile, copy, package, ant etc.)
In the end a web server will execute some Python script with parameters. How do I do the update process?
Also, I have trouble deciding what is best to handle updated versions which only work for new projects on the server. Therefore, if I update the Python scripts, but only newly created web jobs will know how to handle that. I "delivery" to one of many directories which keep track of versions and the server picks the right one?!
EDIT: I webserver is basically an interface that runs some data analysis. That analysis is the actual scripts that take some parameters and mingle data. I don't really change the web interface. I only need to update the data scripts stored on webserver. Indeed, in some advanced version the web server should also pick the right version of my data scripts. However, at the moment I have no idea which would be the easiest way.
The canonical way of distributing Python code/functionality is by using a PyPi compliant package manager.
A list of available PyPi implementations on python.org:
http://wiki.python.org/moin/PyPiImplementations
Instructions on setting up and using EggBasket:
http://chrisarndt.de/projects/eggbasket/#installation
Instructions on installing ChiShop:
http://justcramer.com/2011/04/04/setting-up-your-own-pypi-server/
Note that for this to work you need to distribute your code as "Eggs"; you can find out how to do this here: http://peak.telecommunity.com/DevCenter/setuptools
A great blog post on the usage of eggs and the different parts in packaging: http://mxm-mad-science.blogspot.com/2008/02/python-eggs-simple-introduction.html

Is there an easy way to distribute a Flask server as an executable?

I'm building some simple editors with Backbone.js, and I'm hoping to be able to distribute them as apps for users to edit content in a mostly client-side way (i.e., I don't want users to have to futz with setting up stuff like MySQL or Apache).
So I was imagining a scenario like:
User downloads a .zip file
In the resulting opened folder, the user clicks index.html
That opens in a browser
Backbone app starts, stores data in localStorage
The user can then export to CSV.
Believe it or not, that would solve my problem: I want to help users edit data in a browser and then get it back out in a familiar format (CSV can be loaded into Excel, for instance).
And I’d like to do this without forcing them to configure a server. It seems like this is almost possible in the HTML5 stack. However, in at least one browser (Chrome), this doesn't work, because I get errors like this one:
XMLHttpRequest cannot load file:///users/me/project/data/Appdata.json. Origin null is not allowed by Access-Control-Allow-Origin.
(Oddly enough, I don't get that error in Firefox, and the .js or .json files load fine.)
So at this point it seems to me that there's no way around having these users use something kind of local server to serve up the Backbone interface.
So, I'm trying to figure out how to build a distributable, cross-platform executable that will allow my users to start a Flask server. (I hope to build a REST backend to a Backbone.js app.)
Is this wishful thinking? I'm assuming I can get the people in question to install Python.
Is this doable? There seem to be many ways to package up Python programs, (pyinstaller? py2exe? ...) So I thought I would ask here in case someone might know of a solution for the stack I have in mind.
TIA!
You can use Anthony Gordon McMillan’s Pyinstaller or Tuininga’s cx_Freeze
Quoting the PyInstaller website:
Features
Packaging of Python programs into standard executables, that work on
computers without Python installed.
Multiplatform: works under
Windows (32-bit and 64-bit),
Linux (32-bit and 64-bit),
Mac OS X (32-bit only, 64-bit in git, see Features/MacOsCompatibility) and
experimentally Solaris and AIX (in git).
Multiversion: works under any version of Python from 2.2 up to 2.7.
My suggestion would be to create a thin service wrapper around your code. This will allow the server to run independently of your main codebase - also allowing the user to shut down the server directly (simply right clicking the service icon and selecting "Exit").
This SO answer should help you get started.
After reading your updated question, I think something like mongoose might be more suited to your task. It is an embeddable web server that is FLOSS and has python bindings. Flask might be overkill.
Not easily. On Windows, you'd have to include Python itself. Mac and Linux usually have Python installed, but you can't be sure of what version so it's often easier to bundle your specific Python for them as well. Then you'd have to include all the dependencies that you want to run with in your package or be able to install them with pip, easy_install, etc.
You can use py2app and py2exe. This won't be cross-platform as you'll still need to make a different version for each target OS. The only way to make it cross-platform is to bundle all versions and have some cross-platform code execute the appropriate version for that platform.
If you need databases like MySQL or even SQLite things get more complicated as you'll have to include those too.

How to remotely update Python applications

What is the best method to push changes to a program written in Python? I have a piece of software that is written in Python that will regularly be updated. What would be the best way to do this? All the machines will have Windows 7.
Also, excuse the ambiguity of my question. This will be my first time having to implement an updating procedure. Feel free to mention specifics you would like me ot add.
If you're not already packaging your program with InnoSetup, I strongly recommend you switch to it, because it has facilities to make this sort of thing easier. You can specify any special situations, such as files that should not be updated if they already exist (i.e. if you have any internal configuration files or things like that), in the InnoSetup script.
Next, to allow the client machine to find out about new versions of your app, keep a very small file on your public web server that has the version number of the current release and the URL to the latest version's installer exe. For this file to be useful, whenever you release a newer version of your program you must update this file, as well as the version number in the InnoSetup script, and also some kind of APP_VERSION constant in your program.
Then, you'll need to handle these parts of the updater yourself:
Detecting when a newer version is available by retrieving the current-version file from your web server over HTTP, and comparing the version number there to the app's own APP_VERSION. Make sure to do this query in a way that fails gracefully if the client machine doesn't have Internet access, and that doesn't block the GUI while it is doing the request (in case there's a network issue that forces the query to wait a long while for a timeout).
If a newer version is available, asking the user if they want to update, and if they say yes downloading an updated installer to the TEMP directory. Depending on what GUI toolkit you are using, there are various mechanisms for displaying a progress dialog during the download; this is a good idea since the installer is likely to be at least an MB.
Closing your app, running a special update script in the background, then starting up the app again.
The update script will wait for the original process to die completely (easiest way to do this is to pass in the original process's PID as a command line argument and have the update script send a query signal 0 to that process every second or so until it goes away.) It can then run the installer silently in the background, perhaps while displaying a "Please Wait..." dialog to the user. Once the installer is done and reports success in its return code, the updater can restart your program.
Depending on how big your app is, this is more wasteful of bandwidth than the method using git or another SCM. Every update with this approach would involve downloading the entire installer for the latest version of the app, whereas an SCM would only download the files that have changed. However, it has the advantage that it requires no special server facilities except a regular web server, and no special installation of the SCM client on the user's computer.
Plus, InnoSetup is just generally cool. :-)
I would suggest using a source control program such as git or subversion. Also, if you are okay with everyone seeing the code, you can post the code on github, where anyone can pull from it. You could make it private, but you would have to pay for it and all the users would also have create a github account and set it up with their git install.
If you use a source control program, the other people will have to pull the edits manually by running a command, but you could make a script pr batch file that does this and have it run at start up or at regular intervals.
Just to be clear, if you want to do this, you will have to put the code on a server with and SSH support and set up git. If you don't want to go through all of the server set up, I would reccomend github.
git- http://git-scm.com/ (For windows version, go to downloads and select msysGit)
github - https://github.com/
For those of you that would be looking into something a little less dated, I was just looking at how to create python applications that can be updated remotely (though not limited to Windows like OP).
It seems like esky as been a solution for a while. Though it's been deprecated since 2018.
The latest and most up to date solution seem to be a combination of pyinstaller and pyupdater. Note that I don't have personal experience with it, I'm looking for a friend.
It seems to support windows, linux and Mac though and both python 2 and 3 so definitely worth having a look.
The basic principles of application updates are described well by DSimon's answer.
However, update security is a different matter altogether: You don't want your clients to end up installing malicious files.
PyUpdater, as suggested in jlengrand's answer, does provide some secure update functionality, but, unfortunately, PyUpdater 4.0 is broken and there has not been a new release in over half a year (now Aug 2022).
There's also python-tuf, which is the reference implementation of The Update Framework (TUF).
TUF (python-tuf) does everything humanly possible to ensure your update files are distributed securely. However, it does not handle application-specific things like checking for new application versions and installation on the client side.

Python: tool to keep track of deployments

I'm looking for a tool to keep track of "what's running where". We have a bunch of servers, and on each of those a bunch of projects. These projects may be running on a specific version (hg tag/commit nr) and have their requirements at specific versions as well.
Fabric looks like a great start to do the actual deployments by automating the ssh part. However, once a deployment is done there is no overview of what was done.
Before reinventing the wheel I'd like to check here on SO as well (I did my best w/ Google but could be looking for the wrong keywords). Is there any such tool already?
(In practice I'm deploying Django projects, but I'm not sure that's relevant for the question; anything that keeps track of pip/virtualenv installs or server state in general should be fine)
many thanks,
Klaas
==========
EDIT FOR TEMP. SOLUTION
==========
For now, we've chosen to simply store this information in a simple key-value store (in our case: the filesystem) that we take great care to back up (in our case: using a DCVS). We keep track of this store with the same deployment tool that we use to do the actual deploys (in our case: fabric)
Passwords are stored inside a TrueCrypt volume that's stored inside our key-value store.
==========
I will still gladly accept any answer when some kind of Open Source solution to this problem pops up somewhere. I might share (part of) our solution somewhere myself in the near future.
pip freeze gives you a listing of all installed packages. Bonus: if you redirect the output to a file, you can use it as part of your deployment process to install all those packages (pip can programmatically install all packages from the file).
I see you're already using virtualenv. Good. You can run pip freeze -E myvirtualenv > myproject.reqs to generate a dependency file that doubles as a status report of the Python environment.
Perhaps you want something like Opscode Chef.
In their own words:
Chef works by allowing you to write
recipes that describe how you want a
part of your server (such as Apache,
MySQL, or Hadoop) to be configured.
These recipes describe a series of
resources that should be in a
particular state - for example,
packages that should be installed,
services that should be running, or
files that should be written. We then
make sure that each resource is
properly configured, only taking
corrective action when it's
neccessary. The result is a safe,
flexible mechanism for making sure
your servers are always running
exactly how you want them to be.
EDIT: Note Chef is not a Python tool, it is a general purpose tool, written in Ruby (it seems). But it is capable of supporting various "cookbooks", including one for installing/maintaining Python apps.

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