Unable to send terminal commands using Ruby - ruby

I need to know how to send terminal commands through Ruby to execute another application. I would like to call the SIKULI script at a certain point within my Watir script to handle some steps that Watir can't.
I am not sure how to do it. I read a few of the articles here at Stack Overflow, but can't get it to work.
These are the steps to execute it manually:
jfleck-mbp:~ joe.fleck$ SIKULI_HOME=/Applications/Sikuli-IDE.app/Contents/Resources/Java
jfleck-mbp:~ joe.fleck$ java -jar $SIKULI_HOME/sikuli-script.jar '/Users/joe.fleck/Desktop/Save_File_Button.sikuli'
These are in a Ruby file I am trying to execute:
require 'rubygems'
system('SIKULI_HOME=/Applications/Sikuli-IDE.app/Contents/Resources/Java')
system ("java -jar $SIKULI_HOME/sikuli-script.jar '/Users/joe.fleck/Desktop/Save_File_Button.sikuli'")
The output I get is:
Unable to access jarfile /sikuli-script.jar
which tells me the first line in my script did not execute which allows the access.
Any suggestions would be appreciated.

I think you're getting a different shell with each system() command.
One easy way to verify, and a more maintainable approach, IMHO, would be put all the commands in a single (bash/zsh/whatever) script and run that with system().

Fix it like this:
ENV['SIKULI_HOME'] = '/Applications/Sikuli-IDE.app/Contents/Resources/Java'
system ("java -jar $SIKULI_HOME/sikuli-script.jar '/Users/joe.fleck/Desktop/Save_File_Button.sikuli'")
The issue is that when you call system, you are invoking a child process. Child processes inherit the environment from the parent processes (in this case your Ruby script). Using system to set an environment variable sets it for that child process only, the next call to system is a new child process with a fresh environment.
The solution shown above sets the environment variable in the parent process, thus it will be set for all child processes.

Related

How can I make a local Git hook run a Windows executable and wait for it to return?

I'm working in a Windows environment. I have a Git repository and am writing a custom pre-commit hook. I am much more comfortable writing a quick and dirty console application in C# than trying to figure out Perl syntax so that's the route I'm going.
My .git/hooks/precommit file looks like this:
#!/bin/sh
start MyHelperApp.exe
And this works somewhat. As you can see I have a compiled helper application in the root of the repo directory (and it is .gitignore'd), and this does indeed launch my application successfully when I call git commit. However, it doesn't wait for the process to finish nor does it seem to care what the return code of the process is. I assume this is because start is asynchronous and it returns a 0 exit code every time.
I have reason to suspect that the start process which is getting called here is not the native Windows start command, because I tried changing it to start /wait MyHelperApp.exe but this had no effect. Also trying to call MyHelperApp.exe directly gives a "command not found" error, and so does changing start to call. I suspect that start is an emulated bash command and it's running the bash version instead of the Windows version?
Anyways, my helper app does return different exit codes depending on different conditions, so it'd be great if those could be used. (Pre-commit hooks fail if a program in the script returns any exit code besides zero.) How might I go about utilizing this?
Call the executable directly, don't use start.
Also trying to call MyHelperApp.exe directly gives a "command not found" error
If the PATH variable doesn't contain a . entry, bash won't look in the current directory to find executables. Call ./MyHelperApp.exe to make it explicit that it should be run from the current directory.

Changing directory for User in Ruby script

I'm quite familiar with Dir.chdir("/xyz")
Unfortunately, this changes the directory of the process, but not actually the directory of the user. I'll make the following example to illustrate my need.
$~/: ruby my_script.rb
CHANGING TO PATH FOR USER NOT SCRIPT
$/Projects/Important/Path: pwd
$/Projects/Important/Path
See? I need the script to change the user's path. Performing system/backticks/Dir.chdir all adjust the process path, and end with the user sitting where they started, instead of the path I want them.
From what I've read exec was the way to go, since it takes over the existing process... but to no avail.
You can't, but you can do something which might be good enough. You can invoke another shell from ruby:
Dir.chdir("/xyz")
system("bash")
Running this will create a new bash process, which will start in the /xyz directory. The downside is that changing this process will bring you back to the ruby script, and assuming it ends right away - back to the bash process that started the ruby script.
Another hack that might work is to use the prompt as a hackish hook that will be called after each command. In the ruby script, you can write the new directory's path somewhere that can be read from both bash and ruby(for example a file - but not an environment variable!). In the PROMPT_COMMAND function, you check that file and cd to what's written there. Just make sure you delete that file, so you don't get automatically cded there after every command you run.

How Secure is using execFile for Bash Scripts?

I have a node.js app which is using the child_process.execFile command to run a command-line utility.
I'm worried that it would be possible for a user to run commands locally (a rm / -rf horror scenario comes to mind).
How secure is using execFile for Bash scripts? Any tips to ensure that flags I pass to execFile are escaped by the unix box hosting the server?
Edit
To be more precise, I'm more wondering if the arguments being sent to the file could be interpreted as a command and executed.
The other concern is inside the bash script itself, which is technically outside the scope of this question.
Using child_process.execFile by itself is perfectly safe as long as the user doesn't get to specify the command name.
It does not run the command in a shell (like child_process.exec does), so there is no need to escape anything.
child_process.execFile will execute commands with the user id of the node process, so it can do anything that user could do, which includes removing all the server files.
Not a good idea to let user pass in command as you seem to be implying by your question.
You could consider running the script in a sandbox by using chroot, and limiting the commands and what resides on the available file system, but this could get complet in a hurry.
The command you pass will get executed directly via some flavor of exec, so unless what you trying to execute is a script, it does not need to be escaped in any way.

Pass variable from Jenkins to Ruby script (Jenkins newbie)

I've pulled a few scripts into Jenkins for a proof of concept and think I'd like to move that direction for all of our scripts. Right now I keep an environment.rb file with my code (watir-webdriver, cucumber) which tells the script which environment we're testing and which browser to use (global variables). Jenkins fires off the script using rake.
I'd love to let the user choose the environment and browser through Jenkins 'choice' variable or similar, and then pass that to the script. While I see the framework in that for Jenkins and set up a choice list for environment, I'm having trouble determining what the next step is.
I could write to environment.rb, I could pass a variable to rake - I have many options for how to pass the information, I just need some assistance finding the first step to find the Jenkins way of accomplishing them. Google results and previous Stack questions weren't what I was looking for.
Thanks
Sure. Give the user either a text entry field a dropdown after telling Jenkins that this is a parameterized build. You'll give them a name, something like BuildEnvironment. Then when you call the build, you can pass these from the environment variables. For example, if you were using ANT, you'd add a line to the parameters that said environment = ${MyEnvironment} Jenkins will then pass the value along for your build tool to use.
There is a way to pass Jenkins Environment Variable to Ruby script. Please see the following example:
workspace_path = `echo $WORKSPACE`.strip # note the use of backticks
puts workspace_path
In the "echo $WORKSPACE".strip # the code work only if you replace quotes with backticks
This code example works in Jenkins on a Linux system.

run command in parent shell from ruby

I'm trying to change the directory of the shell I start the ruby script form via the ruby script itself...
My point is to build a little program to manage favorites directories and easily change among them.
Here's what I did
#!/usr/bin/ruby
Dir.chdir("/Users/luca/mydir")
and than tried executing it in many ways...
my_script (this doesn't change the directory)
. my_script (this is interpreted as bash)
. $(ruby my_script) (this is interpreted as bash too!)
any idea?
Cannot be done. Child processes cannot modify their parents environment (including the current working directory of the parent). The . (also known as source) trick only works with shell scripts because you are telling the shell to run that code in the current process (rather than spawning a subprocess to run it). Just for fun try putting exit in a file you run this way (spoiler: you will get logged out).
If you wish to have the illusion of this working you need to create shell functions that call your Ruby script and have the shell function do the actual cd. Since the functions run in the current process, they can change the directory. For instance, given this ruby script (named temp.rb):
#!/usr/bin/ruby
print "/tmp";
You could write this BASH function (in, say, you ~/.profile):
function gotmp {
cd $(~/bin/temp.rb)
}
And then you could say gotmp at the commandline and have the directory be changed.
#!/usr/bin/env ruby
`../your_script`
Like this?
Or start your script in the directory you want it to do something.
Maybe I don't get your question. Provide some more details.

Resources