How to upload a script to SparrowHub

This is informal response to David Farrell's article How to upload a script to CPAN.

Preamble: CPAN is great. This post in no way should be treated as Sparrow VS CPAN attempt. Sparrow is just an alternative method to distribute your scripts. Ok, let's go.

So let’s say I’ve got this Perl script:

$ cat story.pl

use strict;
use warnings;
use DateTime;

my $text = 'bar';
my $dt = DateTime->now;

if ($dt->mon == 1 && $dt->day == 31) {
   $text = reverse $text;
}

print "$text\n";
exit 0;

Notice I have called my script story.pl? This is a naming convention for sparrow scripts.

Ok, let's move on.

Setup your distribution directory

All we need is to:

  • create a story check file
  • create a cpanfile to declare script dependencies
  • create a plugin meta file
  • optionally create README.md

story check file

Sparrow scripts should be accompanied by a check file. It's just a text file with some patterns to match against stdout emitted by an executed script. For example:

$ cat story.check  
regexp: (bar|rab)

Here we just require that script yields into stdout one of two lines - bar or rab. That is it.

Sometimes we don't need to check script stdout , that's ok just leave the story.check file empty:

$ echo > story.check

cpanfile

As we have an external dependency (the DateTime module) let's put it in a cpanfile:

$ cat cpanfile
requires 'DateTime'

Sparrow uses carton to run script with dependencies. That is it.

plugin meta file

In a plugin meta file one defines essential information required for script upload to SparrowHub. The structure is quite simple, there should be a JSON format file with these fields:

  • name - a plugin name
  • version - a plugin version
  • description - short plugin description
  • url - plugin web page url (optional)

In other words the sparrow meta file is the way to "convert" an existing script into sparrow plugin:

$ cat sparrow.json
{
    "name" : "bar-script",
    "version" : "0.0.1",
    "description" : "print bar or rab",
    "url" : "https://github.com/melezhik/bar-script"
}

Readme file

You might want to add some documentation to the script. Simply create a README.md file with documentation in markdown format:

$ cat README.md

# SYNOPSIS

print `bar` or `rab`

# INSTALL

    $ sparrow plg install bar-script

# USAGE

    $ sparrow plg run bar-script


# Author

[Alexey Melezhik](melezhik@gmail.com)

# Disclosure

An initial script code borrowed from David Farrell article [How to upload a script to CPAN](http://perltricks.com/article/how-to-upload-a-script-to-cpan/)

Finally we have the following project structure:

$ tree

.
├── cpanfile
├── README.md
├── sparrow.json
├── story.check
└── story.pl

0 directories, 5 files

Test script

To see that the script does what you want simply run strun inside the project root directory:

$ carton # install dependencies
$ carton exec strun


/ started

bar
ok      scenario succeeded
ok      output match /(bar|rab)/
STATUS  SUCCEED

Strun - is utility comes with Sparrow to run sparrow scripts, it is used by plugin developers.

Upload script to Sparrowhub

Provided you have an account on SparrowHub, just do this:

$ sparrow plg upload
sparrow.json file validated ...
plugin bar-script version 0.000001 upload OK

Now you can browse the script information at SparrowHub.

Run script

To run the script you need to install and run it with the sparrow client:

$ sparrow index update
$ sparrow plg install bar-script
$ sparrow plg run bar-script

sparrow-bar-script.png

Further reading

PS. Thanks to David Farrell for "giving" an idea of writing this post ( after reading his article ) and for fixing some typos and style errors in this document.

sparrow remote tasks - way to package your scripts and configurations.

Idea behind a sparrow is quite simple. You have a script, you package it as sparrow plugin and you can re-use it somewhere else.

Give me list of available plugins:

$ sparrow plg search    

type    name

public  app-cpm
public  bash
public  bitbucket-repo
public  check-tomcat-deploy
public  chemaxon-check
public  cpan-package
public  df-check
public  directory
public  docker-engine
public  file
public  foo-generic
public  foo-test
public  git-async-push
public  git-base
public  git-svn-export
public  gitprep
public  group
public  http-status
public  logdog
public  minion-check
public  module-release
public  mongodb
public  nano-setup
public  net-ping
public  nginx-check
public  nginx-example
public  outth-mysql-cookbook
public  package-generic
public  perl-app
public  perlbrew
public  proc-validate
public  ruby-test
public  sendmail
public  service
public  sph-check
public  ssh-sudo-check
public  ssh-sudo-try
public  sshd-check
public  stale-proc-check
public  svn-to-git-submodules
public  swat-nginx
public  swat-pintod
public  swat-test
public  templater
public  user
private package-generic-dev

This plugin makes a trivial nano.rc file configuration:

$ sparrow plg install nano-setup

Project is just a container for plugins to group them logically:

$ sparrow project create utils

Task is a plugin with parameters, in other words task bind plugin with parameters to project:

$ sparrow task add utils nano-rc nano-setup
$ sparrow task ini utils nano-rc
   tabsize 2

Now let's run our task:

$ sparrow task run utils nano-rc

<nano-rc>

/ started

rc file generated from template
rc file updated
ok      scenario succeeded
ok      [b] output match 'rc file generated from template'
ok      [b] output match 'rc file updated'
STATUS  SUCCEED

You can even override task parameters via command line:

 $ sparrow task run utils nano-rc --param tabsize=4

So sparrow plugins are packed scripts, but I want to package my configuration ...

A task initialization process could be the same if we want to reuse not only scripts but configuration. Every time I ssh on new server I want to apply the same nano.rc as it good for me. Here are remote sparrow tasks:

$ sparrow remote task upload utils/nano-rc 'my nano.rc setup'
task updated
task ini data updated OK

I have just uploaded a nano-rc task and it's configuration to my SparrowHub account. Now having this I could ssh to another server and re-apply my task:

$ ssh some-server
$ sparrow remote task run  utils/nano-rc


task meta data saved to /home/vagrant/sparrow/cache/meta/utils/nano-rc.json ...
public@nano-setup is uptodate (0.1.0)
project utils already exists - nothing to do here ...
task utils/nano-rc already exists, update task parameters
task - set plugin to public@nano-setup
task utils/nano-rc successfully created
loaded test suite ini from /home/vagrant/sparrow/cache/meta/utils/nano-rc.ini OK

<nano-rc>

/ started

rc file generated from template
rc file updated
ok      scenario succeeded
ok      [b] output match 'rc file generated from template'
ok      [b] output match 'rc file updated'
STATUS  SUCCEED

Pretty handy, huh?

Once remote task gets run for the first time , later you can run it as local sparrow task :

 $ sparrow task run utils nano-rc

Ok, if I find my task quite common I even can share it with others:

$ sparrow remote task share  utils/nano-rc
task nano-rc shared OK
now everyone could see it!

Everyone now can run my task:

$ sparrow remote task run melezhik@utils/nano-rc

The list of available remote tasks could be fetched like this:

$ sparrow remote task public-list 

2016-10-24 12:59:06 melezhik@packages/toplist | install my favorite packages
2016-10-24 12:58:22 melezhik@utils/nano-rc | my nano.rc setup

The list of private remote tasks related to your account is taken as:

$ sparrow remote task list

You may take other actions on your remote tasks:

$ sparrow remote task hide app/secure # to hide task from others ( make it private )
$ sparrow remote task remove app/secure # to remove task

Further steps

Follow sparrow docs on remote tasks API. Or create useful task and share with others!

At the end of my post is a simple but illuminative example of remote task to install my favorite packages:

$ sparrow project create packages
$ sparrow task add packages toplist package-generic
$ sparrow task ini packages toplist
    list       nano mc ncdu telnet tree 

$ sparrow remote task upload packages/toplist 'installs my favorite packages'

Regards

Alexey Melezhik

SparrowHub Plugins Request

A quick search at github on something like Perl/Bash scripts gives me a lot of results.

As developers we more think about modules and libraries when talk about software reuse. But in our day-to-day life scripts still take a vital part. Scripts like little, but useful commands to get our job done. This is why people from many programming languages/environments tend to create a places for such a tools called repositories, so other could easily find, install and run scripts or utilities. To list a few:

Well. A SparrowHub is a attempt to make a such effort in Perl communities to create a repository of useful automation scripts. Sparrow is Perl friendly in many ways:

  • it is written on Perl
  • it gets installed as CPAN module
  • it respects carton/cpanfile dependency management for your scripts
  • it supports Config::General format for script configuration ( among JSON, YAML and command line parameters )

Well let me now turn to the essential point of my post.

I know there are a plenty of cool software written by Perl community we know as CPAN, and many, many Perl modules get shipped with some useful scripts, even more some module's are only public interface - some command line scripts. So why not to upload such a script into a repository so other could use it? I know not all the cases are good fit, but let me outline some criteria if your script could be a good candidate to be uploaded as sparrow plugin:

  • you have some command line tools based on existed Perl/CPAN/Bash scripts and want to share it somehow with others or even keep it for yourself so to repeat script installation / execution process in the same way every time you setup a new server.

  • script takes a lot of input parameters or parameters with the structure is hard to be expressed in command line manner ( Hashes, Lists, Groups, so on ).

  • you need to add some middle-ware steps to your script logic , but don't want to add this into scripts source code.

  • you need to build a more complex tool based on your low level script/utility.

  • script possibly gets run often and / or on multiple servers.

  • script requires some extra checks so one could run it safely.

  • script is a generic tool acting differently depending on input parameters.

So if this sounds like about your scripts, you may start playing with SparrowHub. After all it's just distribution platform, having minimal impact at your script code:

  • You write/already have a script ( plus some dependencies software like CPAN module )
  • You upload script / or script based tool to SparrowHub as sparrow plugin
  • Others may find, install and run your script ( via SparrowHub ).

If this sounds interesting there are simple `how to contribute' steps:

  • Get registered at SparrowHub
  • Convert your script into sparrow plugin
  • Upload new sparrow plugin

In case you still have a questions or need help on converting your scripts into sparrow plugin, please:

Finally, if you feel like you have no time to dive into new things and study docs, but you are still interested in the subject, just let me know ( creating an issue at sparrow/github ) about script you wish add sparrowhub to and I will try to do it soon.

Regards.

Alexey Melezhik

Monitoring minion workers/tasks using Sparrow

Hi! This is small post concerning sparrow plugin to monitor minion workers. I had some post on this recently, but now I have made some improvements at existed plugin, so I am writing a new one ...

On my production server I use Minion to send emails to my clients. For some reasons there are faults on executing minion tasks or even minion workers get stopped sometimes for reasons unknown. As sending emails is a vital part of the service registration system I need to know if everything goes bad with my email system. Here is minon-check sparrow plugin to risqué.

Install sparrow

$ cpanm Sparrow

Install sparrow plugin

$ sparrow index update # get latest plugins index from Sparrowhub
$ sparrow plg install minion-check # install plugin

Set plugin up

$ sparrow project create webapp # create a projects to hold web applications tasks
$ sparrow task add webapp minion-health minion-check # this is 
# minion health task which is "tied" to minion-check plugin

$ EDITOR=nano  sparrow task ini webapp minion-health # set task parameters. 
# on my server this will be:

# I use carton install, so:
command = cd /path/to/your/mojo/app && carton exec ./app.pl minion

# sets worker footprint to lookup at processes list
worker_cmd = minion worker

A few comments on plugin setup here:

  • A command parameter define a system command to handle your minion jobs/tasks , An app.pl is Mojolicious application to run my web application, so I set my minion command as mojolicious command.

  • A worker_cmd parameter is just a string to look up inside a process list, to identify that minion worker is alive. A simple stings minion worker works for me.

Let's run a task and see the output:

$ sparrow task run webapp minion-health


<minion-tasks>

/modules/check-worker/ started

look up {{{minion worker}}} at proccess list ...
web-app       2748  0.3  3.4 202704 35216 pts/0    S    23:17   0:00 perl ./app.pl minion worker -m production -I 15 -j 2
done
ok      scenario succeeded
ok      output match 'done'

/modules/last-task/ started

Q=0
ok      scenario succeeded
ok      output match /Q=(1|0)/

/ started

no failed tasks found
ok      0 failed jobs found
STATUS  SUCCEED

So what sparrow plugin minion-check does?

  • check if your minion worker(s) is running.

  • check if you have no tasks marked as FAILED for the given period of time. ( I do not set it up explicitly here, but for default it uses 10 minutes interval , for details follow minion-check documentation ).

Finally I setup cron job to run a sparrow plugin every 10 minutes:

$ sparrow task run webapp minion-health --cron

A --cron flag makes sparrow client silent unless any errors happen during execution.


Regards.

Alexey Melezhik

Sparrowdo automation. Part 6. Sparrowdo modules - getting a bigger things using light primitives.

This is what have been seen before:

Well, while keep writing a sparrowdo tutorial the tool keep growing too. Let me introduce something new and excited about sparrowdo automation - how one can easily create a higher level entities using so called sparrowdo modules.

Sparrowdo modules ...

So far we have talked about some sparrowdo primitives. They are light, they are small and they relate to a small specific tasks, under the hood they are just sparrow plugins with parameters - sparrowdo tasks.

Well, here is the list to recall a few:

  • System packages - package-generic plugin
  • CPAN packages - cpan-package plugin
  • Users and groups - are user and group plugins
  • Linux Services are represented by service plugin
  • And more and more and more ...

And so on, you can see all of them here, on sparrowhub site - https://sparrowhub.org/search. Most of sparrow plugins are just black boxes to solve a specific task. More or less plugins are just primitives.

Take a look at chef resources or ansible modules - they are probably of the same nature.

Now let's me introduce a sparrowdo module - a container for sparrow plugins.

Consider a quite common task. Installing Nginx web server. Having looked at sparrow toolkit we have all necessary bricks to "build" a running Nginx server:

  • Package-generic plugin to install nginx package
  • Service plugin to enable and run nginx service

Let's write code then:

use v6;

unit module Sparrowdo::Nginx;

use Sparrowdo;

our sub tasks (%args) {

  task_run  %(
    task => 'install nginx',
    plugin => 'package-generic',
    parameters => %( list => 'nginx' )
  );

  task_run  %(
    task => 'enable nginx',
    plugin => 'service',
    parameters => %( service => 'nginx', action => 'enable' )
  );

  task_run  %(
    task => 'start nginx',
    plugin => 'service',
    parameters => %( service => 'nginx', action => 'start' )
  );


}

Ok. The code is quite simple, I just want to add some vital comments here.

  • Sparrowdo modules are plain Perl6 modules.

  • You need to load Sparrowdo module to export some sparrowdo API functions, like task_run or others.

  • You have to define at least a tasks(%args) function gets called when someone else use your modules, see how later

  • You optionally may handle some arguments get passed into your module, see tasks function signature.

  • And finally sparrowdo module is just a container for some sparrowdo tasks get called sequentially .

Ok. Now lets use our new sparrowdo module.

First step we need to ensure that module installed at the server where from we are going to run a sparrowdo tasks:

$ panda install Sparrowdo::Nginx

Ok when we are ready with module install we have two ways here.

  1. running module as is

  2. using module inside sparrowdo scenario.

Running module as is

This is the simplest way. This is very similar to running ansible modules:

sparrowdo --host=127.0.0.1 --module_run=Nginx

install nginx server

Running module via sparrowfile

Of course one can just use sparrowdo module using sparrowdo API

$ cat sparrowfile

run_module 'Nginx';

Sparrowdo uses a convention about modules names, it cut a Sparrowdo:: prefix from module name when run it via run_module function. So the rule is simple:

| Module Perl6 Name | Run_module $name parameter |
+-------------------+----------------------------+
| Sparrow::Foo::Bar | 'Foo::Bar'                 |

A current version of Sparrowdo::Nginx ignore an arguments, one day it would be possible to call 'Nginx' module with parameters:

run_module 'Nginx', %( port => 81 );

Little helpers for developers life

Sparrowdo provides some essentials helpers to simplify some developers tasks.

Guessing a target OS

It's very usual when we need to know a target server OS name to make a right decision about server configuration. Let me show you. Recall Nginx module, for centos we need install a repository so nginx package is not here by default:

our sub tasks (%args) {

  if target_os() ~~ m/centos/ {

    task_run  %(
      task => 'install epel-release',
      plugin => 'package-generic',
      parameters => %( list => 'epel-release' )
    );

  }

Passing a sparrowdo command line parameters

Remember a post on installing CPAN packages on the servers with http proxy restrictions?

Consider this sparrwodo module to install CPAN modules:

use v6;

unit module Sparrowdo::CpanInstall;

use Sparrowdo;

our sub tasks (%args) {

  task_run  %(
    task => 'install cpan modules',
    plugin => 'cpan-package',
    parameters => %( 
      list => %args<list>,
      http_proxy => input_params('HttpProxy'), 
      https_proxy => input_params('HttpsProxy'), 
    )
  );

}

And sparrowfile:

module_run 'CpanInstall' %(
  list => 'DBI Moose Mojolicious'
);

And finally sparrowdo scenario run:

$ sparrwodo --host=<$some-host> --http_proxy=<$http_proxy>  --https_proxy=<$https_proxy>

An input_params($param_name) function will pass all the sparrowdo client parameters back to Sparrowdo::CpanInstall module.

Conclusion

Sparrowdo modules are high level members of sparrowdo echo system. What is good they are just Perl6 modules. Anybody who codes at Perl6 could easily start a new ones ( a basic knowledge of existed sparrow plugins is required though ).

Here is a short list of my ones:

https://modules.perl6.org/#q=Sparrowdo%3A%3A

Will be happy to see a new members of Sparrowdo::* family at Perl6 modules repository.

Regards and have a good weekend.


Alexey Melezhik