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digitalmars.D.learn - "Sourcing" a script's env into D?

reply "Nick Sabalausky" <a a.a> writes:
Due to process separation, the following won't work:

script.sh:

SOME_VAR=foobar

test.d:
import std.process;
void main()
{
    system("./script.sh");
    assert(environment["SOME_VAR"] == "foobar");
}

This, of course, is because the script is run in a totally separate process 
(AIUI). The same thing happens in Windows, too.

Is there some way to actually get the env that results from the script? I'm 
looking for solutions for both Posix and Windows.
Sep 29 2011
next sibling parent reply Graham Fawcett <fawcett uwindsor.ca> writes:
On Thu, 29 Sep 2011 13:31:13 -0400, Nick Sabalausky wrote:


 Due to process separation, the following won't work:
 
 script.sh:

 SOME_VAR=foobar
 
 test.d:
 import std.process;
 void main()
 {
     system("./script.sh");
     assert(environment["SOME_VAR"] == "foobar");
 }
 
 This, of course, is because the script is run in a totally separate
 process (AIUI). The same thing happens in Windows, too.
 
 Is there some way to actually get the env that results from the script?
 I'm looking for solutions for both Posix and Windows.


What about "export SOME_VAR=foobar"?

Best,
Graham
Sep 29 2011
parent reply "Nick Sabalausky" <a a.a> writes:
"Graham Fawcett" <fawcett uwindsor.ca> wrote in message 
news:j62ido$1n0s$1 digitalmars.com...

 On Thu, 29 Sep 2011 13:31:13 -0400, Nick Sabalausky wrote:


 Due to process separation, the following won't work:

 script.sh:

 SOME_VAR=foobar

 test.d:
 import std.process;
 void main()
 {
     system("./script.sh");
     assert(environment["SOME_VAR"] == "foobar");
 }

 This, of course, is because the script is run in a totally separate
 process (AIUI). The same thing happens in Windows, too.

 Is there some way to actually get the env that results from the script?
 I'm looking for solutions for both Posix and Windows.


 What about "export SOME_VAR=foobar"?


Still doesn't work.
Sep 29 2011
parent reply "Steven Schveighoffer" <schveiguy yahoo.com> writes:
On Thu, 29 Sep 2011 17:02:28 -0400, Nick Sabalausky <a a.a> wrote:


 "Graham Fawcett" <fawcett uwindsor.ca> wrote in message
 news:j62ido$1n0s$1 digitalmars.com...

 On Thu, 29 Sep 2011 13:31:13 -0400, Nick Sabalausky wrote:


 Due to process separation, the following won't work:

 script.sh:

 SOME_VAR=foobar

 test.d:
 import std.process;
 void main()
 {
     system("./script.sh");
     assert(environment["SOME_VAR"] == "foobar");
 }

 This, of course, is because the script is run in a totally separate
 process (AIUI). The same thing happens in Windows, too.

 Is there some way to actually get the env that results from the script?
 I'm looking for solutions for both Posix and Windows.


 What about "export SOME_VAR=foobar"?


 Still doesn't work.


This only passes the environment to children started after the export is  
done.  A child process cannot affect a parent process' environment  
directly.  Nor can a parent affect an already-running child.

-Steve
Sep 29 2011
parent Graham Fawcett <fawcett uwindsor.ca> writes:
On Thu, 29 Sep 2011 17:20:44 -0400, Steven Schveighoffer wrote:


 On Thu, 29 Sep 2011 17:02:28 -0400, Nick Sabalausky <a a.a> wrote:
 

 "Graham Fawcett" <fawcett uwindsor.ca> wrote in message
 news:j62ido$1n0s$1 digitalmars.com...

 On Thu, 29 Sep 2011 13:31:13 -0400, Nick Sabalausky wrote:


 Due to process separation, the following won't work:

 script.sh:

 SOME_VAR=foobar

 test.d:
 import std.process;
 void main()
 {
     system("./script.sh");
     assert(environment["SOME_VAR"] == "foobar");
 }

 This, of course, is because the script is run in a totally separate
 process (AIUI). The same thing happens in Windows, too.

 Is there some way to actually get the env that results from the
 script? I'm looking for solutions for both Posix and Windows.


 What about "export SOME_VAR=foobar"?


 Still doesn't work.


 
 This only passes the environment to children started after the export is
 done.  A child process cannot affect a parent process' environment
 directly.  Nor can a parent affect an already-running child.
 


Right. Sorry for the from-the-hip suggestion, I hadn't read the question 
too carefully. :)

Graham



 -Steve
Sep 30 2011
prev sibling next sibling parent reply "Steven Schveighoffer" <schveiguy yahoo.com> writes:
On Thu, 29 Sep 2011 13:31:13 -0400, Nick Sabalausky <a a.a> wrote:


 Due to process separation, the following won't work:

 script.sh:

 SOME_VAR=foobar

 test.d:
 import std.process;
 void main()
 {
     system("./script.sh");
     assert(environment["SOME_VAR"] == "foobar");
 }

 This, of course, is because the script is run in a totally separate  
 process
 (AIUI). The same thing happens in Windows, too.

 Is there some way to actually get the env that results from the script?  
 I'm
 looking for solutions for both Posix and Windows.


No.  The way it works when you "source" a script from another script is it  
uses the same process to interpret the script file, which sets the  
environment up.

Since a D program cannot interpret shell script, all you can do is read  
the environment from the script (have it output the environment) and read  
it in:


SOME_VAR=foobar


export SOME_VAR


env

test.d:
import std.process:
void main()
{
    processEnv(system("./script.sh")); // need to write the processEnv  
function which processes the output from env.
}

I don't know what your real test case looks like, so I can't really  
comment on the approach.  If it's simply loading file-defined environment  
variables, there are better ways (as I'm sure you're aware).

-Steve
Sep 29 2011
parent "Nick Sabalausky" <a a.a> writes:
"Steven Schveighoffer" <schveiguy yahoo.com> wrote in message 
news:op.v2k6axvveav7ka localhost.localdomain...

 On Thu, 29 Sep 2011 13:31:13 -0400, Nick Sabalausky <a a.a> wrote:


 Due to process separation, the following won't work:

 script.sh:

 SOME_VAR=foobar

 test.d:
 import std.process;
 void main()
 {
     system("./script.sh");
     assert(environment["SOME_VAR"] == "foobar");
 }

 This, of course, is because the script is run in a totally separate 
 process
 (AIUI). The same thing happens in Windows, too.

 Is there some way to actually get the env that results from the script? 
 I'm
 looking for solutions for both Posix and Windows.


 No.  The way it works when you "source" a script from another script is it 
 uses the same process to interpret the script file, which sets the 
 environment up.


Right, that's why I wasn't surpeised about the above not working and put 
"Sourcing" in quotes. I was just wondering if there was some way to get the 
environment from the end of that process into the current process.


 Since a D program cannot interpret shell script, all you can do is read 
 the environment from the script (have it output the environment) and read 
 it in:


 SOME_VAR=foobar


 export SOME_VAR


 env

 test.d:
 import std.process:
 void main()
 {
    processEnv(system("./script.sh")); // need to write the processEnv 
 function which processes the output from env.
 }


Good idea, that could work.


 I don't know what your real test case looks like, so I can't really 
 comment on the approach.  If it's simply loading file-defined environment 
 variables, there are better ways (as I'm sure you're aware).


Yea, I'm not even sure what approach I'll end up taking. Hell, I'm probably 
over-engineering it all anyway. FWIW, the scenario is like this:

I was making a shell script for one of my open source projects to help 
automate doing releases. The script is supposed to connect to a file server 
(generally via sshfs, which is freaking awesome, btw), update some stuff, 
and disconnect.

I figured there was no reason not to make the script public, but also that 
it would make sence for various reasons to make the connect/disconnect 
configurable (and not included). So the way I did it was it to have the 
script call the optional (and user-written) serverConnect and 
serverDisconnect scripts. The script also needed to know the path to the 
specific destination in the server, so I had the serverConnect set that path 
as an environment var (or the user could just set the env var elsewhere, 
wherever/however they wanted). So my script just sources the serverConnect 
script:

http://www.dsource.org/projects/goldie/browser/trunk/updateServerDocs?rev=449

Then I decided to convert the script to D (partly because my script-fu isn't 
all that great). Obviously now the env var solution won't work anymore, at 
least not quite as easily, so I'm thinking about what to do.

I was about to just change it from an env var to a cmd line param, but I'm 
thinking now my whole connect/disconnect system (proud of it as I was) is 
totally backwards and over-engineered.  I should just assume the computer's 
already connected, take the target path as a cmd line param, and let the 
user just wrap the whole damn thing in one "connect, run the tool, 
disconnect" script however they wish. That seems to make the most sense.
Sep 29 2011
prev sibling parent reply Jacob Carlborg <doob me.com> writes:
On 2011-09-29 19:31, Nick Sabalausky wrote:

 Due to process separation, the following won't work:

 script.sh:

 SOME_VAR=foobar

 test.d:
 import std.process;
 void main()
 {
      system("./script.sh");
      assert(environment["SOME_VAR"] == "foobar");
 }

 This, of course, is because the script is run in a totally separate process
 (AIUI). The same thing happens in Windows, too.

 Is there some way to actually get the env that results from the script? I'm
 looking for solutions for both Posix and Windows.


Either you do it how it works in DVM or have the script write out a file 
that the parent process reads.

-- 
/Jacob Carlborg
Sep 29 2011
parent "Regan Heath" <regan netmail.co.nz> writes:
On Fri, 30 Sep 2011 07:18:34 +0100, Jacob Carlborg <doob me.com> wrote:


 On 2011-09-29 19:31, Nick Sabalausky wrote:

 Due to process separation, the following won't work:

 script.sh:

 SOME_VAR=foobar

 test.d:
 import std.process;
 void main()
 {
      system("./script.sh");
      assert(environment["SOME_VAR"] == "foobar");
 }

 This, of course, is because the script is run in a totally separate  
 process
 (AIUI). The same thing happens in Windows, too.

 Is there some way to actually get the env that results from the script?  
 I'm
 looking for solutions for both Posix and Windows.


 Either you do it how it works in DVM or have the script write out a file  
 that the parent process reads.


On windows you can use:

set>file.txt

this will output the whole environment into file.txt in the form:

label=value

So, add that line to the end of script.cmd|bat|sh and then have the D  
program read it .. using std.getopt perhaps?

R

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Sep 30 2011