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Running another ruby script from a ruby script
(7 answers)
Closed 7 years ago.
I'd like to write a ruby script that then calls another ruby script.
Example, I'd like to run the "test1.rb" from my script.
The test1.rb has been simplified to just do this:
print "1"
Then get the result (-> 1).
I tried to complete this problem with backticks or another executing command (%x[#{"test1.rb"}], system("test1.rb") etc.), but it didn't work.
So any idea how I call one script that then calls another script (either relinquishing total control or forking), and get the results?
Thanks
You can simply require the file, which would load the code and execute it:
require_relative "path/test1"
For the sake of having controll over the the run code, I would advice to place your script in a method:
# In test1.rb
def exec_my_script
puts 1
end
# In your main script
require_relative "path/test1"
exec_my_script
EDIT: Ok, since this does not seem to work for your usecase, you can read the file as string and eval the string as so:
result = eval(File.read("path/test1.rb"))
# do something with result
I do NOT like this approach, because it feels kinda "hacky" and is by all means insecure and it will only work if the last thing called in your test1 script returns the result you need...
You may want to use open3
require 'open3'
cmd = 'ruby test1.rb'
#You may change the contents of cmd like you would run it from the command line; like ruby [directory]/filename
Open3.popen3(cmd) do |stdin, stdout|
var = stdout.read
puts var
end
system('ruby test1.rb') # should do the trick
You can also make test1 executable (with chmod) and add the shebang line on top of test1.
You then can call
system("./test1.rb")
Ok, the system('ruby test1.rb') and system("ruby", "test1.rb") command worked.
And now, I like to set the returning value ("1") to a variable.
How I do it? It's possible to do that with backticks?
Related
I am doing a demo command line project in Ruby. The structure is like this:
/ROOT_DIR
init.rb
/SCRIPT_DIR
(other scripts and files)
I want users to only go into the application using init.rb, but as it stands, anyone can go into the sub-folder and call other ruby scripts directly.
Questions:
What ways can above scenario be prevented?
If I was to use directory permissions, would it get reset when running the code from a Windows machine to on Linux machine?
Is there anything that can be included in Ruby files itself to prevent it from being directly called from OS command line?
You can't do this with file permissions, since the user needs to read the files; removing the read permission means you can't include it either. Removing the execute permission is useful to signal that these file aren't intended to be executed, but won't prevent people from typing ruby incl.rb.
The easiest way is probably to set a global variable in the init.rb script:
#!/usr/bin/env ruby
FROM_INIT = true
require './incl.rb'
puts 'This is init!'
And then check if this variable is defined in the included incl.rb file:
unless defined? FROM_INIT
puts 'Must be called from init.rb'
exit 0
end
puts 'This is incl!'
A second method might be checking the value of $PROGRAM_NAME in incl.rb; this stores the current program name (like argv[0] in many other languages):
unless $PROGRAM_NAME.end_with? 'init.rb'
puts 'Must be called from init.rb'
exit 0
end
I don't recommend this though, as it's not very future-proof; what if you want to rename init.rb or make a second script?
I want to run some shell scripts remotely as part of my capistrano setup. To test that functionality, I use this code:
execute <<SHELL
cat <<TEST
something
TEST
SHELL
However, that is actually running /usr/bin/env cat <<TEST; something; TEST which is obviously not going to work. How do I tell capistrano to execute the heredoc as I have written it, without converting the newlines into semicolons?
I have Capistrano Version: 3.2.1 (Rake Version: 10.3.2) and do not know ruby particularly well, so there might be something obvious I missed.
I think it might work to just specify the arguments to cat as a second, er, argument to execute:
cat_args = <<SHELL
<<TEST
something
TEST
SHELL
execute "cat", cat_args
From the code #DavidGrayson posted, it looks like only the command (the first argument to execute) is sanitized.
I agree with David, though, that the simpler way might be to put the data in a file, which is what the SSHKit documentation suggests:
Upload a file from a stream
on hosts do |host|
file = File.open('/config/database.yml')
io = StringIO.new(....)
upload! file, '/opt/my_project/shared/database.yml'
upload! io, '/opt/my_project/shared/io.io.io'
end
The IO streaming is useful for uploading something rather than "cat"ing it, for example
on hosts do |host|
contents = StringIO.new('ALL ALL = (ALL) NOPASSWD: ALL')
upload! contents, '/etc/sudoers.d/yolo'
end
This spares one from having to figure out the correct escaping sequences for something like "echo(:cat, '...?...', '> /etc/sudoers.d/yolo')".
This seems like it would work perfectly for your use case.
The code responsible for this sanitization can be found in SSHKit::Command#sanitize_command!, which is called by that class's initialize method. You can see the source code here:
https://github.com/capistrano/sshkit/blob/9ac8298c6a62582455b1b55b5e742fd9e948cefe/lib/sshkit/command.rb#L216-226
You might consider monkeypatching it to do nothing by adding something like this to the top of your Rakefile:
SSHKit::Command # force the class to load so we can re-open it
class SSHKit::Command
def sanitize_command!
return if some_condition
super
end
end
This is risky and could introduce problems in other places; for example there might be parts of Capistrano that assume that the command has no newlines.
You are probably better off making a shell script that contains the heredoc or putting the heredoc in a file somewhere.
Ok, so this is the solution I figured out myself, in case it's useful for someone else:
str = %x(
base64 <<TEST
some
thing
TEST
).delete("\n")
execute "echo #{str} | base64 -d | cat -"
As you can see, I'm base64 encoding my command, sending it through, then decoding it on the server side where it can be evaluated intact. This works, but it's a real ugly hack - I hope someone can come up with a better solution.
say we have a ruby file.rb like:
if __FILE__ == $0 then
if ARGV[0] == 'foo'
puts "working"
# Dir.chdir(../)
v = Someclass.new
v.do_something
end
end
it suppose to print working only if the file was triggered like ruby file.rb foo.
My question: how can that kind of stuf be tested within rspec?
My try is below. The file ran but not in the scope of rspec test:
Dir expected :chdir with (any args) once, but received it 0 times
it 'should work' do
FILE = File.expand_path('file.rb')
RUBY = File.join(Config::CONFIG['bindir'], Config::CONFIG['ruby_install_name'])
#v = Someclass.new
Someclass.should_receive(:new).and_return #v
#v.should_receive(:do_something)
`#{RUBY} #{FILE} foo`
end
Backticks runs new shell, executes command, and returns result as a string. Thats why it runs outside your scope. Backticks does not care about contents of your script: ruby, bash, or something else.
chdir, of course, applied only to this new shell, so there seems no way to check you sample script for directory changing (except of tracing system calls). Maybe some 'real' script will do something, output more, thus providing more possibilities to check it.
I'm trying to download a file using net/sftp and pass its contents as the stdin for a command-line app. I can do it by first writing the file to disk but I'd rather avoid that step.
Is there any way to control the input to a program invoked with system() in ruby?
Don't use system at all for this sort of thing, system is best for running an external command that you don't need to talk to.
Use Open3.open3 or Open3.open2 to open up some pipes to your external process then write to the stdin pipe just like writing to any other IO channel; if there is any output to deal with, then you can read it straight from the stdout pipe just like reading from any other input IO channel.
Something like this perhaps (using open as mu suggested)?
contents = "Hello, World!"
open('|echo', 'w') { puts contents }
This can also be accomplished with IO.expect
require 'pty'
require 'expect'
str = "RUBY_VERSION"
PTY.spawn("irb") do |reader, writer|
reader.expect(/0> /)
writer.puts(str)
reader.expect(/=> /)
answer = reader.gets
puts "Ruby version from irb: #{answer}"
end
This waits for the spawned process to display "0> " (the end of an irb prompt) and when it sees that prints a defined string. It then looks for the irb to return by waiting for it to display "=> " and grabs the data returned.
I want to be able to read a currently open file. The test.rb is sending its output to test.log which I want to be able to read and ultimately send via email.
I am running this using cron:
*/5 * * * /tmp/test.rb > /tmp/log/test.log 2>&1
I have something like this in test.rb:
#!/usr/bin/ruby
def read_file(file_name)
file = File.open(file_name, "r")
data = file.read
file.close
return data
end
puts "Start"
puts read_file("/tmp/log/test.log")
puts "End"
When I run this code, it only gives me this output:
Start
End
I would expect the output to be something like this:
Start
Start (from the reading of the test.log since it should have the word start already)
End
Ok, you're trying to do several things at once, and I suspect you didn't systematically test before moving from one step to the next.
First we're going to clean up your code:
def read_file(file_name)
file = File.open(file_name, "r")
data = file.read
file.close
return data
end
puts "Start"
puts read_file("/tmp/log/test.log")
puts "End"
can be replaced with:
puts "Start"
puts File.read("./test.log")
puts "End"
It's plain and simple; There's no need for a method or anything complicated... yet.
Note that for ease of testing I'm working with a file in the current directory. To put some content in it I'll simply do:
echo "foo" > ./test.log
Running the test code gives me...
Greg:Desktop greg$ ruby test.rb
Start
foo
End
so I know the code is reading and printing correctly.
Now we can test what would go into the crontab, before we deal with its madness:
Greg:Desktop greg$ ruby test.rb > ./test.log
Greg:Desktop greg$
Hmm. No output. Something is broken with that. We knew there was content in the file previously, so what happened?
Greg:Desktop greg$ cat ./test.log
Start
End
Cat'ing the file shows it has the "Start" and "End" output of the code, but the part that should have been read and output is now missing.
What happening is that the shell truncated "test.log" just before it passed control to Ruby, which then opened and executed the code, which opened the now empty file to print it. In other words, you're asking the shell to truncate (empty) it just before you read it.
The fix is to read from a different file than you're going to write to, if you're trying to do something with the contents of it. If you're not trying to do something with its contents then there's no point in reading it with Ruby just to write it to a different file: We have cp and/or mv to do those things for us witout Ruby being involved. So, this makes more sense if we're going to do something with the contents:
ruby test.rb > ./test.log.out
I'll reset the file contents using echo "foo" > ./test.log, and cat'ing it showed 'foo', so I'm ready to try the redirection test again:
Greg:Desktop greg$ ruby test.rb > ./test.log.out
Greg:Desktop greg$ cat test.log.out
Start
foo
End
That time it worked. Trying it again has the same result, so I won't show the results here.
If you're going to email the file you could add that code at this point. Replacing the puts in the puts File.read('./test.log') line with an assignment to a variable will store the file's content:
contents = File.read('./test.log')
Then you can use contents as the body of a email. (And, rather than use Ruby for all of this I'd probably do it using mail or mailx or pipe it directly to sendmail, using the command-line and shell, but that's your call.)
At this point things are in a good position to add the command to crontab, using the same command as used on the command-line. Because it's running in cron, and errors can happen that we'd want to know about, we'd add the 2>&1 redirect to capture STDERR also, just as you did before. Just remember that you can NOT write to the same file you're going to read from or you'll have an empty file to read.
That's enough to get your app working.
class FileLineRead
File.open("file_line_read.txt") do |file|
file.each do |line|
phone_number = line.gsub(/\n/,'')
user = User.find_by_phone_number(line)
user.destroy unless user.nil?
end
end
end
open file
read line
DB Select
DB Update
In the cron job you have already opened and cleared test.log (via redirection) before you have read it in the Ruby script.
Why not do both the read and write in Ruby?
It may be a permissions issue or the file may not exist.
f = File.open("test","r")
puts f.read()
f.close()
The above will read the file test. If the file exists in the current directory
The problem is, as I can see, already solved by Slomojo. I'll only add:
to read and print a text file in Ruby, just:
puts File.read("/tmp/log/test.log")