Executing shell commands from a Ruby script

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1

Anyone have any experience with executing shell commands from a Ruby script?

I want to convert this to Ruby :003:

#!/bin/bash

web_service='haproxy'
config_file='/usr/local/etc/le-renew-haproxy.ini'
domain=`grep "^\s*domains" $config_file | sed "s/^\s*domains\s*=\s*//" | sed 's/(\s*)\|,.*$//'`
http_01_port='54321'
combined_file="/etc/haproxy/certs/${domain}.pem"

le_path='/opt/letsencrypt'
exp_limit=30;

if [ ! -f $config_file ]; then
        echo "[ERROR] config file does not exist: $config_file"
        exit 1;
fi

cert_file="/etc/letsencrypt/live/$domain/fullchain.pem"
key_file="/etc/letsencrypt/live/$domain/privkey.pem"

if [ ! -f $cert_file ]; then
	echo "[ERROR] certificate file not found for domain $domain."
fi

exp=$(date -d "`openssl x509 -in $cert_file -text -noout|grep "Not After"|cut -c 25-`" +%s)
datenow=$(date -d "now" +%s)
days_exp=$(echo \( $exp - $datenow \) / 86400 |bc)

echo "Checking expiration date for $domain..."

if [ "$days_exp" -gt "$exp_limit" ] ; then
	echo "The certificate is up to date, no need for renewal ($days_exp days left)."
	exit 0;
else
	echo "The certificate for $domain is about to expire soon. Starting Let's Encrypt (HAProxy:$http_01_port) renewal script..."
	$le_path/letsencrypt-auto certonly --agree-tos --renew-by-default --config $config_file --http-01-port $http_01_port

	echo "Creating $combined_file with latest certs..."
	sudo bash -c "cat /etc/letsencrypt/live/$domain/fullchain.pem /etc/letsencrypt/live/$domain/privkey.pem > $combined_file"

	echo "Reloading $web_service"
	/usr/sbin/service $web_service reload
	echo "Renewal process finished for domain $domain"
	exit 0;
fi

(Yep, we’re finally on https://metaruby.com :slight_smile: )

2

Use backticks to execute commands, their output will come back as a string. If the file to execute isn’t found it will raise an error. For those situations you can do a rescue nil. All the grep/sed is doing is gsub. You will need to change the regex to be Ruby compatible (the ^ means something different). There are other ways to execute commands but backticks will work best for something like this.

1 Like
3

Thanks. What about when what I want to run already contains backticks? Will it be an issue?

date -d "`openssl x509 -in /etc/letsencrypt/live/site.com/fullchain.pem -text -noout|grep "Not After"|cut -c 25-`" +%s

Tried to open the same file with Ruby’s ‘openssl’ library but it says it’s not a pub or priv key. Edit: got it.

4

Use %x().

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