free rv-install from platform-specific code

[grosu]

This is not urgent.

Let's free rv-install from platform-specific code. That is, to special cases for Windows vs Linux. Java 7 allows, for example, to work with and display paths in platform-independent manner, using the Path API. If there is really code that cannot be made generic, then we would like to know it and discuss it. I am ready to bet $100 that it can be done. :)

[pdaian]

It can be done, and currently is. There is no platform specific code in RV-Install itself right now.

I'm still going to have to disagree with you on this as a long term goal though - installation is not a platform agnostic process and categorically treating it as such might limit viable solutions in some cases.

izpack, which our installer depends on as an external dependency, is not at all platform independent. It contains code to detect and behave differently on different platforms. I assert that it's therefore unwise to make our extensions to izpack core categorically platform independent.

I think we should take it on a case by case basis. For example, @traiansf asked me to add support for automatic addition to the PATH where supported in the installer. This works fundamentally different on Windows, where the PATH is handled by the registry and exposed to the command line globally with "%" and ";" delimited variables (eg %PATH%) vs. on Linux, where PATH is handled by a text file ~/.bashrc, and variables started by a single $. Java does not expose an API for this in any way, and there is no way to make this completely generic without relying on the same form of platform detection you are arguing against (and I will take you up on a bet on this... I take Bitcoin :)).

Furthermore, consider administrative permissions. The only part of our install that is currently platform specific is this single line in install-definition.xml:

        <run-privileged condition="izpack.windowsinstall|izpack.macinstall" />

On Windows and OS X, we need admin privileges to install an app by convention - the user expects all apps in Program Files or /Applications . On Linux, running non-administrative installers is quite standard and common, and installs to local directories (in HOME, or in /usr/local/bin, or /home/user/bin) are common. Do we then ask for administrative permissions on all just in case? I don't think so, because Linux users don't expect to be mandatory forced to elevate for root when installing somewhere that doesn't need it.

Anyway, my point is that I don't agree with the goal of making the entire installer platform independent. Our goal should be to make our lives easier, and if there's something we want to add in the installer that relies on a one line standard check for which platform we're on (which izpack does anyway many times anyway in its normal operation!), we shouldn't dismiss it on principle. Possibly because I'm not personally convinced it adds maintenance cost, and because I know it can be used to improve user experience.

[grosu]

As per our discussion today, let us please do NOT modify the PATH automatically! At least not for now. Our users are expected to know how to do that themselves, or may have good reasons not to do it. AspectJ does exactly the same thing as we do now: it recommends the user to add their bin to the PATH and their aspectj.rt to their CLASSPATH in their last window of their installer, but no more than recommends.

I know izPack uses platform-specific code, it would be hard not to, but I hope that we can use/configure it for our needs without having to do ourselves anything that is platform specific. If we do need to do that, then somehow izPack failed in its mission to provide a generic platform-independent installer, so we should move away from it. I think that in the long run we will want to have our own installer, developed by us completely. Like AspectJ does.

Grigore

---

From: Philip Daian [notifications@github.com]
Sent: Wednesday, July 02, 2014 12:34 PM
To: runtimeverification/rv-install
Cc: Rosu, Grigore
Subject: Re: [rv-install] free rv-install from platform-specific code (#2)

It can be done, and currently is. There is no platform specific code in RV-Install itself right now.

I'm still going to have to disagree with you on this as a long term goal though - installation is not a platform agnostic process and categorically treating it as such might limit viable solutions in some cases.

izpack, which our installer depends on as an external dependency, is not at all platform independent. It contains code to detect and behave differently on different platforms. I assert that it's therefore unwise to make our extensions to izpack core categorically platform independent.

I think we should take it on a case by case basis. For example, @traiansfhttps://github.com/traiansf asked me to add support for automatic addition to the PATH where supported in the installer. This works fundamentally different on Windows, where the PATH is handled by the registry and exposed to the command line globally with "%" and ";" delimited variables (eg %PATH%) vs. on Linux, where PATH is handled by a text file ~/.bashrc, and variables started by a single $. Java does not expose an API for this in any way, and there is no way to make this completely generic without relying on the same form of platform detection you are arguing against (and I will take you up on a bet on this... I take Bitcoin :)).

Furthermore, consider administrative permissions. The only part of our install that is currently platform specific is this single line in install-definition.xml:

    <run-privileged condition="izpack.windowsinstall|izpack.macinstall" />

On Windows and OS X, we need admin privileges to install an app by convention - the user expects all apps in Program Files or /Applications . On Linux, running non-administrative installers is quite standard and common, and installs to local directories (in HOME, or in /usr/local/bin, or /home/user/bin) are common. Do we then ask for administrative permissions on all just in case? I don't think so, because Linux users don't expect to be mandatory forced to elevate for root when installing somewhere that doesn't need it.

Anyway, my point is that I don't agree with the goal of making the entire installer platform independent. Our goal should be to make our lives easier, and if there's something we want to add in the installer that relies on a one line standard check for which platform we're on (which izpack does anyway many times anyway in its normal operation!), we shouldn't dismiss it on principle. Possibly because I'm not personally convinced it adds maintainability, and because I know it can be used to improve user experience.

—
Reply to this email directly or view it on GitHubhttps://github.com//issues/2#issuecomment-47809447.

[pdaian]

@grosu - I don't think we need our own installer. izpack 5.0 is actually quite good (we're using 4.3 as it's not out yet though), even lets you remove all mentions of izpack from it without complaining. Also I mostly agree with you that we should try to avoid platform specific code as much as possible, but I don't think we need to make it a rule. My point overall was just that there are some cases when we want to do more than what izpack provides and it remains sane to have platform specific code.

If we have our own installer we'll have a lot more code to maintain. Not that it might not be necessary at some point, but I personally don't want to code it :).