I'm scanning a folder for audio files and converting them to mp3.
Works great in RUBY.
However, once the first transcoding is done, it stops the whole loop
Here's a breakdown of my code process.
def scanFolder
# lots of code above to get folder list, check for incorrect files etc..
audioFileList.each {
|getFile|
exec_command = "ffmpeg #{getFile} #{newFileName}"
exec exec_command
}
end
What's happening is that it's transcoding the first file it finds, then it stops the whole function. Is there a way to force it to continue?
The ffmpeg does run and finish correctly at the moment, so it's not breaking anything
exec replaces the current process by running the given command. Example:
2.0.0-p598 :001 > exec 'echo "hello"'
hello
shivam#bluegene:$
You can see how exec replaces the irb with system echo which then exits automatically.
Therefore try using system instead. Here the same example using system:
2.0.0-p598 :003 > system 'echo "hello"'
hello
=> true
2.0.0-p598 :004 >
You can see I am still in irb and its not exited after executing the command.
This makes your code as follows:
def scanFolder
# lots of code above to get folder list, check for incorrect files etc..
audioFileList.each {
|getFile|
exec_command = "ffmpeg #{getFile} #{newFileName}"
system exec_command
}
end
Along with shivam's answer about using system, the spawn method may also be useful here:
http://ruby-doc.org//core-2.1.5/Process.html#method-c-spawn
Related
I have a simple shell script written in ruby that runs some predefined commands and saves the output strings.
The script works well, but I need a way branch conditionally if the command fails. I've tried using the $? object but the script exits before it gets there.
#!/usr/bin/ruby
def run_command(cmd)
`#{cmd}`
if $?.success?
# continue as normal
else
# ignore this command and move on
end
end
run_command('ls')
run_command('not_a_command')
# Output:
# No such file or directory - not_a_command (Errno::ENOENT)...
I've tried $?.exitstatus or even just puts $? but it always exits before it gets there because the script is obviously running the command before hitting that line.
Is there a way to check if the command will run before actually running it in the script?
Hope that's clear, thanks for your time!
Use system (which returns true or false depending on exit code) instead of backticks (which return output string):
if system(cmd)
...
else
...
end
If you want it to run quietly without polluting your logs / output:
system(cmd, out: File::NULL, err: File::NULL)
I've written a webcrawler that pulls information into a report and would like to run it every day at 12:00pm. The script is run using:
ruby script.rb
I've tried using the whenever gem (https://github.com/javan/whenever).
My directory structure is this:
/config
schedule.rb
script.rb
In my script.rb file, I have the following:
every :day, :at => '12:00pm' do
command "ruby script.rb"
end
I've modified the time :at to take see if it runs and it doesn't.
I've also tried:
every :day, :at => '12:00pm' do
`ruby script.rb`
end
I've also looked into the "at" linux utility but it appears suited to one-time jobs. I'd like this to generate a report everyday.
Note: the script specifies where to output so I don't need to give it an output.
I've also tried creating a crontab but have encountered a problem with saving.
I use http://crontab-generator.org/ to generate the correct syntax.
Then I run:
crontab -e
Which opens vi and I copy the syntax. However, it exits with a status of 1 and if I run:
crontab -l
It says there's no jobs listed.
I've also tried running this as the super user, and it exits the same.
The error message is
/usr/bin/vi" exited with status 1
I just want a command to run at a given time, what am I missing?
Edit
Does it matter that I'm on a Mac?
Here comes a sample ruby code:
r = gets
puts r
if the script is executed standalone from console, it work fine. But if i ran it via pipeline:
echo 'testtest' | ruby test.rb
gets seem is redirected to pipeline inputs, but i need some user input.
How?
Stdin has been attached to the receiving end of the pipe by the invoking shell. If you really need interactive input you have a couple choices. You can open the tty input directly, leavng stdin bound to the pipe:
tty_input = open('/dev/tty') {|f| f.gets }
/dev/tty works under linux and OS/x, but might not work everywhere.
Alternatively, you can use a different form of redirection, process substitution, under bash to supply the (formerly piped) input as a psuedo-file passed as an argument and leave stdin bound to your terminal:
ruby test.rb <(echo 'testtest')
# test.rb
input = open(ARGV[0])
std_input = gets
input.readlines { |line| process_line(line) }
I have one simple script:
fork do
STDOUT.reopen(File.open('/tmp/log', 'w+'))
STDOUT.sync = true
exec 'bundle exec ruby script.rb'
end
script.rb:
loop do
sleep 1
puts "MESSAGE"
end
When it work, all outputs is buffering(?) and writes to /tmp/log by big pices.
It works only if I modify script:
$stdout.puts "MESSAGE"
$stdout.flush
How can I do the same without modifying script.rb ?
Thanks.
When you call exec, you create a new process, and although this process inherits the file you set as standard out, it doesn't inherit the other settings, in particular the sync setting.
In order to get unbuffered output in the new process, you need to set it in that process. If you don't want to modify script.rb one workaround could be to create another file, named somethig like sync.rb containing just:
STDOUT.sync = true
which you can then require when running your command:
exec 'bundle exec ruby -r./sync script.rb'
The new Ruby process will now require sync.rb, which simply sets sync mode on STDOUT to true before executing your script.
I used the method system to start a process. the pid of that process is being stored in a file worker.pid
however I need to generate the log of this process, how can I store the output of this process?
the process is being created with this command:
system "bundle exec rake resque:work >> ./resque.log QUEUE=* PIDFILE=#{pid_file} &"
P.S.: I am using ruby 1.8, BACKGROUND=yes won`t work.
P.S.2: platform linux
Maybe what you're looking for is IO.popen
This lets you fork off a subprocess and access it's output via an IO object
# fork off a one-off task
# and return the output as a string
ls = IO.popen("ls")
ls.read
# or return an array of lines
IO.popen("ls").readlines
# or create a continuing task
tail = IO.popen("tail -f /some/log/file.log")
loop do
puts tail.gets
end
I suggest you read the documentation,
but you can also write to the stream, and do all sorts of clever stuff.
If I'm understanding what you are trying to achieve correctly, you are looking for the Open3 class. http://www.ruby-doc.org/stdlib-1.8.7/libdoc/open3/rdoc/Open3.html