I am writing some automation script that needs to run PowerShell commands on a remote machine using Ruby. In Ruby I have the following code:
def run_powershell(powershell_command)
puts %Q-Executing powershell #{powershell_command}-
output = system("powershell.exe #{powershell_command}")
puts "Executed powershell output #{output}"
end
I can pass in Invoke-Command based ps1 files and everything works as expected. I can see the output in the console when I run the command.
The only problem is that there is no way to find out if the command run was successful; sometimes PowerShell is clearly throwing errors (like not able to get to the machine), but the output is always true.
Is there a way to know if the command ran successfully?
system(...) will actually return a value saying if it succeeded, not the output of the call.
So you can simply say
success = system("powershell.exe #{powershell_command}")
if success then
...
end
If you want both the output and return code, you can use `backticks` and query $? for the exit status (not the same $? as linked to in the comment to the question, by the way.)
output = `powershell.exe #{powershell_command}`
success = $?.exitstatus == 0
If you want a more reliable way that will escape things better, I'd use IO::popen
output = IO::popen(["powershell.exe", powershell_command]) {|io| io.read}
success = $?.exitstatus == 0
If the problem is that powershell itself isn't exiting with an error, you should have a look at this question
There is another option, and that is running the PowerShell from cmd. Here is the (pretty hard to figure out) syntax:
def powershell_output_true?()
ps_command = "(1+1) -eq 2"
cmd_str = "powershell -Command \" " + ps_command + " \" "
cmd = shell_out(cmd_str, { :returns => [0] })
if(cmd.stdout =~ /true/i)
Chef::Log.debug "PowerShell output is true"
return true
else
Chef::Log.debug "PowerShell output is false"
return false
end
end
I am comparing the stdout to true, but you can compare it to whatever you need.
described in blog
Related
I have something like this on a Jenkinsfile (Groovy) and I want to record the stdout and the exit code in a variable in order to use the information later.
sh "ls -l"
How can I do this, especially as it seems that you cannot really run any kind of groovy code inside the Jenkinsfile?
The latest version of the pipeline sh step allows you to do the following;
// Git committer email
GIT_COMMIT_EMAIL = sh (
script: 'git --no-pager show -s --format=\'%ae\'',
returnStdout: true
).trim()
echo "Git committer email: ${GIT_COMMIT_EMAIL}"
Another feature is the returnStatus option.
// Test commit message for flags
BUILD_FULL = sh (
script: "git log -1 --pretty=%B | grep '\\[jenkins-full]'",
returnStatus: true
) == 0
echo "Build full flag: ${BUILD_FULL}"
These options where added based on this issue.
See official documentation for the sh command.
For declarative pipelines (see comments), you need to wrap code into script step:
script {
GIT_COMMIT_EMAIL = sh (
script: 'git --no-pager show -s --format=\'%ae\'',
returnStdout: true
).trim()
echo "Git committer email: ${GIT_COMMIT_EMAIL}"
}
Current Pipeline version natively supports returnStdout and returnStatus, which make it possible to get output or status from sh/bat steps.
An example:
def ret = sh(script: 'uname', returnStdout: true)
println ret
An official documentation.
quick answer is this:
sh "ls -l > commandResult"
result = readFile('commandResult').trim()
I think there exist a feature request to be able to get the result of sh step, but as far as I know, currently there is no other option.
EDIT: JENKINS-26133
EDIT2: Not quite sure since what version, but sh/bat steps now can return the std output, simply:
def output = sh returnStdout: true, script: 'ls -l'
If you want to get the stdout AND know whether the command succeeded or not, just use returnStdout and wrap it in an exception handler:
scripted pipeline
try {
// Fails with non-zero exit if dir1 does not exist
def dir1 = sh(script:'ls -la dir1', returnStdout:true).trim()
} catch (Exception ex) {
println("Unable to read dir1: ${ex}")
}
output:
[Pipeline] sh
[Test-Pipeline] Running shell script
+ ls -la dir1
ls: cannot access dir1: No such file or directory
[Pipeline] echo
unable to read dir1: hudson.AbortException: script returned exit code 2
Unfortunately hudson.AbortException is missing any useful method to obtain that exit status, so if the actual value is required you'd need to parse it out of the message (ugh!)
Contrary to the Javadoc https://javadoc.jenkins-ci.org/hudson/AbortException.html the build is not failed when this exception is caught. It fails when it's not caught!
Update:
If you also want the STDERR output from the shell command, Jenkins unfortunately fails to properly support that common use-case. A 2017 ticket JENKINS-44930 is stuck in a state of opinionated ping-pong whilst making no progress towards a solution - please consider adding your upvote to it.
As to a solution now, there could be a couple of possible approaches:
a) Redirect STDERR to STDOUT 2>&1
- but it's then up to you to parse that out of the main output though, and you won't get the output if the command failed - because you're in the exception handler.
b) redirect STDERR to a temporary file (the name of which you prepare earlier) 2>filename (but remember to clean up the file afterwards) - ie. main code becomes:
def stderrfile = 'stderr.out'
try {
def dir1 = sh(script:"ls -la dir1 2>${stderrfile}", returnStdout:true).trim()
} catch (Exception ex) {
def errmsg = readFile(stderrfile)
println("Unable to read dir1: ${ex} - ${errmsg}")
}
c) Go the other way, set returnStatus=true instead, dispense with the exception handler and always capture output to a file, ie:
def outfile = 'stdout.out'
def status = sh(script:"ls -la dir1 >${outfile} 2>&1", returnStatus:true)
def output = readFile(outfile).trim()
if (status == 0) {
// output is directory listing from stdout
} else {
// output is error message from stderr
}
Caveat: the above code is Unix/Linux-specific - Windows requires completely different shell commands.
this is a sample case, which will make sense I believe!
node('master'){
stage('stage1'){
def commit = sh (returnStdout: true, script: '''echo hi
echo bye | grep -o "e"
date
echo lol''').split()
echo "${commit[-1]} "
}
}
For those who need to use the output in subsequent shell commands, rather than groovy, something like this example could be done:
stage('Show Files') {
environment {
MY_FILES = sh(script: 'cd mydir && ls -l', returnStdout: true)
}
steps {
sh '''
echo "$MY_FILES"
'''
}
}
I found the examples on code maven to be quite useful.
All the above method will work. but to use the var as env variable inside your code you need to export the var first.
script{
sh " 'shell command here' > command"
command_var = readFile('command').trim()
sh "export command_var=$command_var"
}
replace the shell command with the command of your choice. Now if you are using python code you can just specify os.getenv("command_var") that will return the output of the shell command executed previously.
How to read the shell variable in groovy / how to assign shell return value to groovy variable.
Requirement : Open a text file read the lines using shell and store the value in groovy and get the parameter for each line .
Here , is delimiter
Ex: releaseModule.txt
./APP_TSBASE/app/team/i-home/deployments/ip-cc.war/cs_workflowReport.jar,configurable-wf-report,94,23crb1,artifact
./APP_TSBASE/app/team/i-home/deployments/ip.war/cs_workflowReport.jar,configurable-temppweb-report,394,rvu3crb1,artifact
========================
Here want to get module name 2nd Parameter (configurable-wf-report) , build no 3rd Parameter (94), commit id 4th (23crb1)
def module = sh(script: """awk -F',' '{ print \$2 "," \$3 "," \$4 }' releaseModules.txt | sort -u """, returnStdout: true).trim()
echo module
List lines = module.split( '\n' ).findAll { !it.startsWith( ',' ) }
def buildid
def Modname
lines.each {
List det1 = it.split(',')
buildid=det1[1].trim()
Modname = det1[0].trim()
tag= det1[2].trim()
echo Modname
echo buildid
echo tag
}
If you don't have a single sh command but a block of sh commands, returnstdout wont work then.
I had a similar issue where I applied something which is not a clean way of doing this but eventually it worked and served the purpose.
Solution -
In the shell block , echo the value and add it into some file.
Outside the shell block and inside the script block , read this file ,trim it and assign it to any local/params/environment variable.
example -
steps {
script {
sh '''
echo $PATH>path.txt
// I am using '>' because I want to create a new file every time to get the newest value of PATH
'''
path = readFile(file: 'path.txt')
path = path.trim() //local groovy variable assignment
//One can assign these values to env and params as below -
env.PATH = path //if you want to assign it to env var
params.PATH = path //if you want to assign it to params var
}
}
Easiest way is use this way
my_var=`echo 2`
echo $my_var
output
: 2
note that is not simple single quote is back quote ( ` ).
I have a bunch of system calls in ruby such as the following and I want to check their exit codes simultaneously so that my script exits out if that command fails.
system("VBoxManage createvm --name test1")
system("ruby test.rb")
I want something like
system("VBoxManage createvm --name test1", 0) <-- where the second parameter checks the exit code and confirms that that system call was successful, and if not, it'll raise an error or do something of that sort.
Is that possible at all?
I've tried something along the lines of this and that didn't work either.
system("ruby test.rb")
system("echo $?")
or
`ruby test.rb`
exit_code = `echo $?`
if exit_code != 0
raise 'Exit code is not zero'
end
From the documentation:
system returns true if the command gives zero exit status, false for
non zero exit status. Returns nil if command execution fails.
system("unknown command") #=> nil
system("echo foo") #=> true
system("echo foo | grep bar") #=> false
Furthermore
An error status is available in $?.
system("VBoxManage createvm --invalid-option")
$? #=> #<Process::Status: pid 9926 exit 2>
$?.exitstatus #=> 2
For me, I preferred use `` to call the shell commands and check $? to get process status. The $? is a process status object, you can get the command's process information from this object, including: status code, execution status, pid, etc.
Some useful methods of the $? object:
$?.exitstatus => return error code
$?.success? => return true if error code is 0, otherwise false
$?.pid => created process pid
system returns false if the command has an non-zero exit code, or nil if there is no command.
Therefore
system( "foo" ) or exit
or
system( "foo" ) or raise "Something went wrong with foo"
should work, and are reasonably concise.
You're not capturing the result of your system call, which is where the result code is returned:
exit_code = system("ruby test.rb")
Remember each system call or equivalent, which includes the backtick-method, spawns a new shell, so it's not possible to capture the result of a previous shell's environment. In this case exit_code is true if everything worked out, nil otherwise.
The popen3 command provides more low-level detail.
One way to do this is to chain them using and or &&:
system("VBoxManage createvm --name test1") and system("ruby test.rb")
The second call won't be run if the first fails.
You can wrap those in an if () to give you some flow-control:
if (
system("VBoxManage createvm --name test1") &&
system("ruby test.rb")
)
# do something
else
# do something with $?
end
Ruby 2.6 added option to raise exception in Kernel#system:
system("command", exception: true)
I want something like
system("VBoxManage createvm --name test1", 0) <-- where the second parameter checks the exit code and confirms that that system call was successful, and if not, it'll raise an error or do something of that sort.
You can add exception: true to your system call to have an error raised on non 0 exit codes.
For example, consider this small wrapper around system which prints the command (similar to bash -x, fails if there's a non 0 exit code (like bash -e) and returns the actual exit code:
def sys(cmd, *args, **kwargs)
puts("\e[1m\e[33m#{cmd} #{args}\e[0m\e[22m")
system(cmd, *args, exception: true, **kwargs)
return $?.exitstatus
end
To be called like: sys("hg", "update")
If you want to call a program that uses a different convention for exit codes, you can suppress raising the exception:
sys("robocopy", src, dst, "/COPYALL", "/E", "/R:0", "/DCOPY:T", exception: false)
You can also suppress stdout and stderr for noisy programs:
sys("hg", "update", "default", :out => File::NULL, :err => File::NULL)
How can I check the return value (true/false) of bash command in an if statement in Ruby. I want something like this to work,
if ("/usr/bin/fs wscell > /dev/null 2>&1")
has_afs = "true"
else
has_afs = "false"
end
It complains with the following error meaning, it will always return true.
(irb):5: warning: string literal in condition
What's the correct syntax ?
UPDATE :
/usr/bin/fs wscell
looks for afs installed and running condition. It will throw a string like this,
This workstation belongs to cell <afs_server_name>
If afs is not running, the command exits with status 1
You want backticks rather than double-quotes. To check a program's output:
has_afs = `/usr/bin/fs wscell > /dev/null 2>&1` == SOMETHING ? 'true' : 'false'
Where SOMETHING is filled in with what you're looking for.
You should probably use system() or Backticks and then check the exit status of the command ($?.exitstatus):
Heres a good quicktip read: http://rubyquicktips.com/post/5862861056/execute-shell-commands)
UPDATE:
system("/usr/bin/fs wscell > /dev/null 2>&1") # Returns false if command failed
has_afs = $?.exitstatus != 1 # Check if afs is running
Hey so I have a bash command that echos a string based on reading some file. Say for simplicity it is like this
for line in `cat file`
do
if [ "$line" == "IwantThisLine" ]
then
echo "True"
fi
done
And I have it saved as its own individual script. Its called readRef.sh. So now I want to call it in matlab and store whatever it outputs in a variable! I am not entirely sure on how to do that, I seem to get an error when using evalc() on a system(). But it could be just me messing up quotations.
I tried something like
evalc(system(['./readRef.sh ' bamfile']))
The "bamfile" is a variable that is just a string to the path of a bamfile.
I get this error.
>> tes = evalc(system(['./readRef.sh ' smplBamFile]))
hg18
??? Undefined function or method 'evalc' for input arguments of type 'double'.
Coincidentally it does spit out "hg18" which is what I want to set the matlab variable to be.
Oh, I see. I don't think you need evalc at all. Reading the system docs you can just do:
[status, result] = system('echo True; echo "I got a loverly bunch of coconuts"')
And result will be
True
I got a loverly bunch of coconuts
So just do:
[status, result] = system(['./readRef.sh ' smplBamFile])
The reason evalc isn't working is that it requires its input to be a Matlab expression in a string, but you are passing it the result of system.
You could try:
evalc("system(['./readRef.sh ' smplBamFile])")
See how I'm passing in the system(...) as a string?
The reason you get this error is because system(...) returns the return-code of the command it ran, not its output. To capture its output, use
[~, output] = system(...)
tes = evalc(output);
I'm trying to get a script that works both in a native windows shell and a cygwin shell (via ssh) that prompts for and reads a password entered by the user. So far, I have tried the following methods:
using Term::ReadKey and setting ReadMode to 'noecho'
RESULT: returns an error GetConsoleMode failed and quits
using Term::ReadPassword::Win32
RESULT: hangs and never offers a prompt or reads input
using IO::Prompt
RESULT: returns an error Cannot write to terminal and quits
using Term::InKey
RESULT: returns an error Not implemented on MSWin32: The handle is invalid and quits
All of these work in a native Windows shell (command prompt or power shell), but none of them work when I'm in an ssh session to the server.
Really, that's what I'm most interested in, getting it to work in the remote ssh session.
I'm getting ssh via cygwin installed on the Windows server (2003 R2). I'm using strawberry perl and not the cygwin perl (cygwin perl breaks other perl scripts I need to run natively in Windows, not via ssh).
My best guess is that cygwin+Windows is screwing with strawberry perl enough that it can't tell what kind of environment it is in. I'm looking into alternative sshd+Windows solutions to explore this.
These are all the methods I've been able to find in my searching. Does anybody else have any other methods for hiding user input they can suggest?
use Term::ReadKey;
print "Please enter your artifactory user name:";
$username = <STDIN>;
chomp($username);
ReadMode('noecho'); # don't echo
print "Please enter your artifactory password:";
$password = <STDIN>;
chomp($password);
ReadMode(0); #back to normal
print "\n\n";
I would try outputting the environment variables (%ENV) during the sessions that work, and then again during the sessions that don't. I find that, when dealing with terminal IO, you have to carefully tweak the "TERM" variable based on things like the $^O variable and $ENV{SESSIONNAME} (in Windows).
how about Term::ReadKey's ReadMode(4)? i've just used this in a personal project, having found the answer here
works on cygwin / win7, can't vouch for native windows shell however.
use strict;
use warnings;
use Term::ReadKey;
sub get_input {
my $key = 0;
my $user_input = "";
# disable control keys and start reading keys until enter key is pressed (ascii 10)
ReadMode(4);
while (ord($key = ReadKey(0)) != 10)
{
if (ord($key) == 127 || ord($key) == 8) {
# backspace / del was pressed. remove last char and move cursor back one space.
chop ($user_input);
print "\b \b";
} elsif (ord($key) < 32) {
# control characters, do nothing
} else {
$user_input = $user_input . $key;
print "*";
}
}
ReadMode(0);
return $user_input;
}
# variables
my $password = "";
my $username = "";
print "\nPlease input your username: ";
$username = get_input();
print "\nHi, $username\n";
print "\nPlease input your password: ";
$password = get_input();