Help convert sh -> rb

Ruby
1

Hello, I am new to the forum and ruby, thank you for any help you may
have.

The goal I am trying to accomplish is converting this shell script into
a ruby script. What the script does is run the
“rds-describe-db-instances” command then pull out two variables and
input them into the JSON output. Any help would be great, thanks.

#!/bin/sh
echo "
{
“checks”: {"
rds-describe-db-instances|awk ‘$1 == “DBINSTANCE” { print $6,$9 }’|
while read S I; do
echo "
“mysql_disk_usage_$I”: {
“handlers”: [“default”,“mailer_alerts”],
“command”: “/etc/sensu/plugins/mysql-disk.rb -h$I u -p
-s$S”,
“interval”: 300,
“occurrences”: 1,
“subscribers”: [
“urls”
]
},"
done
echo “}}”

2

On Fri, May 10, 2013 at 7:51 AM, Micah H. [email protected]
wrote:

The goal I am trying to accomplish is converting this shell script into
a ruby script.

What have you written so far?

3

What have you written so far?

Haven’t worked it much yet, I’ve only got…I need to figure out how to
save the output so I can store my variables.

#!/usr/bin/env ruby
rds_describe = rds-describe-db-instances

puts "
{
“checks”: {
“mysql_disk_usage_$I”: {
“handlers”: [“default”,“mailer_alerts”],
“command”: “/etc/sensu/plugins/mysql-disk.rb -h$I u -p
-s$S”,
“interval”: 300,
“occurrences”: 1,
“subscribers”: [
“urls”
]
},
"

4

On Fri, May 10, 2013 at 3:17 PM, Micah H. [email protected] wrote:

Haven’t worked it much yet, I’ve only got…I need to figure out how to
save the output so I can store my variables.

#!/usr/bin/env ruby
rds_describe = rds-describe-db-instances

OK, so you can save the output to a file, to a DB, to a key-value
data store (e.g. Redis) – plenty of choices.

What will you be doing with the data after you store it? What is
the volume of data being generated (is performance an issue)?

5

What will you be doing with the data after you store it? What is
the volume of data being generated (is performance an issue)?

I will most likely set it up as a cronjob, but the cmd isn’t very
intensive, so that is not an issue. Now that I think about it,
out-putting to a file, and continually re-writing that file, should be
how I do this.

6

On Fri, May 10, 2013 at 5:17 PM, Micah H. [email protected] wrote:

{
},
"

Perhaps setting it up as a hash of hashes, or a class of classes might
be more useful, and then using #to_json to emit the json.

A simple hash of the above would look something like this:

check_hash =
{ “checks” =>
“mysql_disk_usage+#{i}” => {
“handlers” =>
[“default”, “mailer_alerts”],
“command” => “/etc/sensu/plugins/mysql-desk.rb -h#{i} u -p -s
{#s}”,
“interval” => 300,
“occurances” => 1,
“subscribers” => [“urls”]
}
}

then you can get the json by:

puts check_hash.to_json

which saves all the quote escaping and what-not.

Note the #{i} and #{s} in the above – these correspond to the I and S
variables in the bash script, but you’d need to get at them
differently.

Starting off, you read in the output from the command by:

rds_describe = rds-describe-db-instances

you can walk through it with something like:

rds_describe.split(“\r?\n”).each do |line|

s, i = line.split()

puts { “checks” =>
“mysql_disk_usage+#{i}” => {
“handlers” => [“default”, “mailer_alerts”],
“command” => “/etc/sensu/plugins/mysql-desk.rb -h#{i} u -p
-s {#s}”,
“interval” => 300,
“occurances” => 1,
“subscribers” => [“urls”]
}
}.to_json

end

(Note you need a require ‘json’ at the beginning of the script.)

This will basically replicate your bash script in ruby form.