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https://github.com/wallyqs/org-converge

Literate reproducible runs using Org mode and Ruby.
https://github.com/wallyqs/org-converge

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Literate reproducible runs using Org mode and Ruby.

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# -*- mode: org; mode: auto-fill; -*-
#+STARTUP: showeverything

* Org Converge

[[https://secure.travis-ci.org/wallyqs/org-converge.png?branch=master]]

** Description

A framework to create documented reproducible runs using [[http://orgmode.org/worg/org-contrib/babel/Org Babel][Org Mode]],
borrowing several ideas of what is possible to do with tools
like =chef-solo=, =rake=, =foreman= and =capistrano=.

** Install

: gem install org-converge

** Motivation

[[http://orgmode.org/worg/org-contrib/babel/Org Babel][Org Mode]] has proven to be flexible enough to write [[http://www.jstatsoft.org/v46/i03][reproducible research papers]],
then I believe that configuring and setting up a server for
example, is something that could also be done using
the same approach, given that /converging/ the configuration
is a kind of run that one ought to be able to reproduce.

Taking the original Emacs implementation as reference,
Org Converge uses the [[https://github.com/wallyqs/org-ruby][Ruby implementation of the Org mode parser]]
to implement and enhance the functionality from Org Babel
by adding helpers to define the properties of a run while taking advantage
of what is already there in the Ruby ecosystem.

** Usage examples

Org Converge supports the following kind of runs below:

*** Parallel runs

Each one of the code blocks is run on an independent process.
This is akin to having a =Procfile= based application, where
one of the runner command would be to start a web application
and the other one to start the a worker processes.

In the following example, we are defining 2 code blocks, one
that would be run using Ruby and one more that would be run in Python.
Notice that the Python block has =:procs= set to 2, meaning that
it would spawn 2 processes for this.

#+begin_src sh
,#+TITLE: Sample parallel run
 
,#+name: infinite-worker-in-ruby
,#+begin_src ruby
$stdout.sync = true
loop { puts "working!"; sleep 1; }
,#+end_src
 
,#+name: infinite-worker-in-python
,#+begin_src python :procs 2
import sys
import time

while True:
print "working too"
sys.stdout.flush()
time.sleep(1)
,#+end_src
#+end_src

The above example can be run with the following:

: org-run procfile-example.org

Sample output of the run:

#+begin_src sh
[2014-06-07T18:05:48 +0900] infinite-worker-in-ruby -- started with pid 19648
[2014-06-07T18:05:48 +0900] infinite-worker-in-python:1 -- started with pid 19649
[2014-06-07T18:05:48 +0900] infinite-worker-in-python:2 -- started with pid 19650
[2014-06-07T18:05:48 +0900] infinite-worker-in-python:1 -- working too
[2014-06-07T18:05:48 +0900] infinite-worker-in-python:2 -- working too
[2014-06-07T18:05:48 +0900] infinite-worker-in-ruby -- working!
[2014-06-07T18:05:49 +0900] infinite-worker-in-python:1 -- working too
[2014-06-07T18:05:49 +0900] infinite-worker-in-python:2 -- working too
#+end_src

*** Sequential runs

In case the code blocks form part of a runlist that should be
ran sequentially, it is possible to do this by specifying the
~runmode=sequential~ option.

#+begin_src sh
,#+TITLE: Sample sequential run
,#+runmode: sequential
 
,#+name: first
,#+begin_src sh
echo "first"
,#+end_src
 
,#+name: second
,#+begin_src sh
echo "second"
,#+end_src
 
,#+name: third
,#+begin_src sh
echo "third"
,#+end_src
 
,#+name: fourth
,#+begin_src sh
echo "fourth"
,#+end_src
#+end_src

In order to specify that this is to be run sequentially,
we set the runmode option in the command line:

: org-run runlist-example.org --runmode=sequential

Another way of specifying this is via the Org mode file itself:

#+begin_src org
,#+TITLE: Defining the runmode as an in buffer setting
,#+runmode: sequential
#+end_src

Sample output:

#+begin_src sh
[2014-06-07T18:10:33 +0900] first -- started with pid 19845
[2014-06-07T18:10:33 +0900] first -- first
[2014-06-07T18:10:33 +0900] first -- exited with code 0
[2014-06-07T18:10:33 +0900] second -- started with pid 19846
[2014-06-07T18:10:33 +0900] second -- second
[2014-06-07T18:10:33 +0900] second -- exited with code 0
[2014-06-07T18:10:33 +0900] third -- started with pid 19847
[2014-06-07T18:10:33 +0900] third -- third
[2014-06-07T18:10:33 +0900] third -- exited with code 0
[2014-06-07T18:10:33 +0900] fourth -- started with pid 19848
[2014-06-07T18:10:33 +0900] fourth -- fourth
[2014-06-07T18:10:33 +0900] fourth -- exited with code 0
#+end_src

*** Configuration management runs

For example, using Org Babel tangling functionality we can spread
config files on a server by writing the following on a ~server.org~ file...

#+begin_src sh
 
Configuration for a component that shoul be run in multitenant mode:
 
,#+begin_src yaml :tangle /etc/component.yml
multitenant: false
status_port: 10004
,#+end_src
#+end_src

Then run:

: sudo org-tangle server.org

*Note:* The above tangle command is a reimplementation of the tangling functionality from Org mode using Ruby.
If you are interested in tangling from the command line without losing functionality and have available a local Emacs Org mode install,
the following project can be useful:

*** Idempotent runs

A run can have idempotency checks (similar to how the execute resource from [[http://docs.opscode.com/resource_execute.html][Chef]] works).

An example of this, would be when installing packages. In this example,
we want to install the =build-essential= package once, and skip it in following runs:

#+begin_src sh
,** Installing the dependencies
 
Need the following so that ~bundle install~ can compile
the native extensions correctly.
  
,#+name: build-essential-installed
,#+begin_src sh
dpkg -l | grep build-essential
,#+end_src
   
,#+name: build_essentials
,#+begin_src sh :unless build-essential-installed
apt-get install build-essential -y
,#+end_src
  
,#+name: bundle_install
,#+begin_src sh
cd project_path
bundle install
,#+end_src
#+end_src

Furthermore,since we are using Org mode syntax, it is possible
to reuse this setup file by including it into another Org file:

#+begin_src sh
,#+TITLE: Another setup
 
Include the code blocks from the server into this:
  
,#+include: "server.org"
 
,#+name: install_org_mode
,#+begin_src sh
apt-get install org-mode -y
,#+end_src
#+end_src
#+end_src

Since this a run that involves converging into a state,
it would be run sequentially with idempotency checks applied:

: sudo org-converge setup.org

*** Dependencies based runs

In this type of runs we use the =:after= and =:before=
header arguments to specify the prerequisites for a code block to run,
similar to some of the functioality provided by tools like =rake=
(Behind the scenes, these arguments create =Rake= tasks)

In order for this kind of run to work, it has to be specified
what is the task that we are converging to by using
the =#+final_task:= in buffer setting:

#+begin_src sh
,#+TITLE: Linked tasks example
,#+runmode: tasks
,#+final_task: final
 
,#+name: second
,#+begin_src sh :after first
for i in `seq 5 10`; do
echo $i >> out.log
done
,#+end_src
 
,#+name: first
,#+begin_src ruby
5.times { |n| File.open("out.log", "a") {|f| f.puts n } }
,#+end_src
 
,#+name: final
,#+begin_src python :after second :results output
print "Wrapping up with Python in the end"
f = open('out.log', 'a')
f.write('11')
f.close()
,#+end_src
 
,#+name: prologue
,#+begin_src sh :before first :results output
echo "init" > out.log
,#+end_src
#+end_src

: org-run chained-example.org --runmode=chained

Instead of using =--runmode= options, it is also possible to just declare in buffer
that the Org file should be run chained mode.

#+begin_src org
,#+TITLE: Defining the runmode as an in buffer setting
,#+runmode: chained
#+end_src

Sample output:

#+begin_src sh
[2014-06-07T18:14:25 +0900] Running final task: final
[2014-06-07T18:14:25 +0900] prologue -- started with pid 20035
[2014-06-07T18:14:25 +0900] prologue -- exited with code 0
[2014-06-07T18:14:25 +0900] first -- started with pid 20036
[2014-06-07T18:14:26 +0900] first -- exited with code 0
[2014-06-07T18:14:26 +0900] second -- started with pid 20038
[2014-06-07T18:14:26 +0900] second -- exited with code 0
[2014-06-07T18:14:26 +0900] final -- started with pid 20040
[2014-06-07T18:14:26 +0900] final -- Wrapping up with Python in the end
[2014-06-07T18:14:26 +0900] final -- exited with code 0
#+end_src

*** Remote runs

For any of the cases above, it is also possible to specify
whether the code blocks should be run remotely on another node.
This is done by using =:dir= in the code block header argument.

#+begin_src sh
,#+sshidentityfile: vagrant/keys/vagrant
,#+name: remote-bash-code-block
 
,#+begin_src sh :results output :dir /[email protected]#2222:/tmp
random_number=$RANDOM
for i in `seq 1 10`; do echo "[$random_number] Running script is $0 being run from `pwd`"; done
,#+end_src
#+end_src

Note that in order for the above to work, it is also needed to set identity to be used by ssh.

*** Asserted runs

In case the Org mode file has a results block which represents the expected result,
there is an ~org-spec~ command which can be useful to check whether there was a change
that no longer makes the results from the Org file valid. Example:

#+begin_src sh
,#+TITLE: Expected results example
  
,#+name: hello
,#+begin_src ruby :results output
10.times do
puts "hola"
end
,#+end_src
  
,#+RESULTS: hello
,#+begin_example
hola
hola
hola
hola
hola
hola
hola
hola
hola
hola
,#+end_example
#+end_src

We can be able to verify whether this is still correct by running:

: org-spec test.org

#+begin_src sh
Checking results from 'hello' code block: OK
#+end_src

As an example, let's say that the behavior of the original code block changed,
and now says hello 5 times instead.
In that case the output would be as follows:

#+begin_src diff
Checking results from 'hello' code block: DIFF
@@ -1,11 +1,6 @@
-hola
-hola
-hola
-hola
-hola
-hola
-hola
-hola
-hola
-hola
+hello
+hello
+hello
+hello
+hello
#+end_src

** Contributing

The project is still in very early development and a proof of concept at this moment.
But if you feel that it is interesting enough, please create a ticket to start
the discussion.