I have a method which check if the file exists, If the file does not exist then it should call another method which prompts the questions. Below is the sample code.
def readFile1()
flag = false
begin
#ssh.exec!("cd #{##home_dir}")
puts "\nChecking if file exists on #{#hostname}\n"
if #ssh.exec!("sh -c '[ -f "#{file_name}" ]; echo $?'").to_i == 0
flag = true
puts "File exists on #{#hostname}"
display()
else
puts "File does not exist. Please answer following questions."
prompt()
end
rescue => e
puts "readFile1 failed... #{e}"
end
return exists
end
def prompt()
puts "\nDo you want to enter the new file location? [y/n]"
ans = gets.chomp
puts "New location is #{ans}"
end
When I am calling readFile method, if the file does not exists, it prints Do you want to enter the new file location? [y/n] and does not wait for the user to enter the value but immediately prints the rescue block and quits. Below is the Output if file does not exists.
Checking if file exists on LNXAPP
File does not exist. Please answer following questions.
Do you want to enter the new file location? [y/n]
readFile1 failed... No such file or directory - LNXAPP
I want the user to enter the values for the questions but it's not happening.Need help in fixing this.
Your code is not ideal.
You should check if the file exists via:
if File.exist? location_of_your_file_goes_here
The begin/rescue is then not required, because
you already check before whether the file exists.
Also two spaces should be better than one tab,
at least when you display on a site such as here.
Reason is simple - it makes your code easier
to read for others.
You also don't need the flag variable if I am
right - try to omit it and use solely File.exist?
there.
Also you wrote:
"When I am calling readFile method"
But you have no method called readFile().
Your method is called readFile1().
I know that you probably know this too, but
you must be very specific so that the ruby
parser understands precisely what you mean,
and that what you describe with words also
matches to the code you use.
Another issue I see with your code is that
you do this:
return exists
but what is "exists" here? A variable?
A method? It has not been defined elsewhere
in your code.
Try to make your code as simple and as logical
as possible.
Related
I'm new to ruby file IO. I have a function that takes a File parameter, and I need to make sure that the file is in read-only mode.
def myfunction(file)
raise ArgumentError.new() unless file.kind_of?(File)
#Assert that file is in read-only mode
end
Any help would be appreciated!
If you don't need to raise an error, you can use reopen, I think something like:
file = file.reopen(file.path, "r")
I can't find a way to otherwise verify that there isn't a write stream, but here's a bit of a hack that will work. Although I don't like exception throwing being used in the expected path, you could use close_write:
begin
file.close_write
# you could actually raise an exception here if you want
# since getting here means the file was originally opened for writing
rescue IOError
# This error will be raised if the file was not opened for
# writing, so this is actually the path we want
end
So all you need is 'make sure make sure that the file is in read-only mode', why not just set it as readonly with FileUtils.chmod.
Or if actually you just want to test if it is readonly, use File.writeable?
You can use file.readable?, which returns true or false.
Please check this link.
This question already has answers here:
How to write to file in Ruby?
(7 answers)
Closed 7 years ago.
I want to create a temp file:
def create_file
FileUtils.mkdir_p('/var/log/my_app')
tmp_file = '/var/log/my_app/tmp_file'
File.open(tmp_file, 'w') do |file|
file.write 'test'
end
end
Here I am sure that the /var/log/my_app path exists. But after I run this method, I can't find a file named tmp_file under that path.
And there wasn't any error, too.
I think you would do better using Ruby's TempFile class and perhaps even Ruby's temp dir as suggested in this article: Quick tips for doing IO with Ruby.
I think you will find the article helpful. I believe it will make your approach easier - especially regarding deleting the file once you're done with it.
I don't see any error in your code. If you don't get any exception, the file must have been created, if this function has been executed.
I suggest that you make a test at the end of create_file:
if File.file?
puts "File has been created"
else
fail "File is not there!"
end
If you see "File has been created", but the file is still missing, something must have erased it before you had time to check its presence. If you see "File is not there!", something weird is going on and I would call an exorcist. If you don't see any message, it means that your function has not been executed.
I need to check the third parameter of a method:
def NFS(configsHash, optionsHash, backupType)
I want to use an if statement to check the path where backupType is to be saved. Something like:
If #{backupType} == "dir/file/path/name/time"
STDOUT.puts("Backup will be saved to current folder.")
else
STDOUT.puts("Putting into backup folder")
STDOUT.puts(mkdir #{backups})
But I haven't been able to get the syntax right. Any suggestions?
You can also go with this:
case backupType
when "dir/file/path/name/time"
puts("Backup will be saved to current folder.")
else
puts("Putting into backup folder")
puts(Dir.mkdir backups)
end
if backupType == "dir/file/path/name/time"
puts "Backup will be saved to current folder."
else
puts "Putting into backup folder"
Dir.mkdir "path/goes/here"
end
Notice that STDOUT has been dropped off. That is redundant. If you do STDOUT.puts.object_id and puts.object_id you will see they refer to the same things. Also, notice that it is Dir.mkdir; not just mkdir; it needs to be called on the Dir class.
Modified to be a little more idiomatic. I also dropped the puts from in from of the Dir.mkdir; as I assume that is not really what you intended.
# Assuming that backupType is a string
if backupType == "dir/file/path/name/time"
print "Backup will be saved to current folder."
else
print "Putting into backup folder"
# This part below is tricky since I don't know what the backups variable is referring to
print Dir.mkdir backups
end
#fotanus in the comments makes great suggestions on naming conventions, but to ensure consistency I've kept the names the same for the answer.
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")
On page 35, in the book "Exploring Expect", it says "The return command can be used to make a source command return. Otherwise, source returns only after executing the last command in the file."
I don't quite understand what it's getting at. I'd like to know what this means and how this is useful.
Thank you.
an example:
main script:
puts "about to source external file"
set some_var true
source something.exp
puts "done sourcing"
something.exp
puts "in something.exp"
if {$some_var} return
puts "you won't see this if some_var is true"
Basically, when the 'return' command is encountered, 'expect' will stop processing the script further, and return to the parent script (if any) that ran it using the 'source' command. It's much like 'return' in any programming language.