Ich bin recht faul. Aus diesem Grund lass ich mir die Zertifikate einmal im Monat neu generieren. Um die Infrastruktur nicht zu sehr zu belasten, habe ich mir einen anderen Tag, als den Ersten im Monat ausgesucht. Das gleiche gilt für die Uhrzeit.
Given is the fact that you have some processes (like cronjobs) executed via an webserver like apache. Furthermore you have installed and enables apache server status.
To add some re usability benefits, we should divide and conquer the problems into either shell scripts or shell functions. Side note, if I am writing about shell, I am in the bash environment.
What are the problems we want to tackle down?:
find the correct environment
check all available webservers if a process is not running
specify which process should not run and start it if possible
We can put the first two problems into shell functions like the following ones. I am referencing to some self written shell functions. The reference is indicated by the "net_bazzline_" prefix.
#!/bin/bash
#find the correct environment
if net_bazzline_string_contains $HOSTNAME 'production';
NET_BAZZLINE_IS_PRODUCTION_ENVIRONMENT=1
else
NET_BAZZLINE_IS_PRODUCTION_ENVIRONMENT=0
fi
And the mighty check.
#!/bin/bash
#check all available webservers if a process is not running
####
# @param string <process name>
# @return int (0 if at least one process was found)
####
function local_is_there_at_least_one_apache_process_running()
{
if [[ $# -lt 1 ]]; then
echo 'invalid number of arguments'
echo ' local_is_there_at_least_one_apache_process_running <process name>'
return 1
fi
if [[ $NET_BAZZLINE_IS_PRODUCTION_ENVIRONMENT -eq 1 ]]; then
LOCAL_ENVIRONMENT='production'
else
LOCAL_ENVIRONMENT='staging'
fi
#variables are prefixed with LOCAL_ to prevent overwriting system variables
LOCAL_PROCESS_NAME="$1"
#declare the array with all available host names
declare -a LOCAL_HOSTNAMES=("webserver01" "webserver02" "webserver03");
for LOCAL_HOSTNAME in ${LOCAL_HOSTNAMES[@]}; do
APACHE_STATUS_URL="http://$LOCAL_HOSTNAME.my.domain/server-status"
OUTPUT=$(curl -s $APACHE_STATUS_URL | grep -i $LOCAL_PROCESS_NAME)
EXIT_CODE_OF_LAST_PROCESS="$?"
if [[ $EXIT_CODE_OF_LAST_PROCESS == "0" ]]; then
echo "$LOCAL_PROCESS_NAME found on $LOCAL_HOSTNAME"
return 0
fi
done;
return 1
}
And here is an example how to use it.
#!/bin/bash
#specify which process should not run and start it if possible
source /path/to/your/bash/functions
LOCAL_PROCESS_NAME="my_process"
local_is_there_at_least_one_apache_process_running $LOCAL_PROCESS_NAME
EXIT_CODE_OF_LAST_PROCESS="$?"
if [[ $EXIT_CODE_OF_LAST_PROCESS == "0" ]]; then
echo "$LOCAL_PROCESS_NAME still running"
exit 0;
else
#execute your process
echo 'started at: '$(date +'%Y-%m-%d %H:%M:%S');
curl "my.domain/$LOCAL_PROCESS_NAME"
echo 'started at: '$(date +'%Y-%m-%d %H:%M:%S');
fi
You can put this into a loop by calling it via the cronjob environment or use watch if you only need it from time to time:
The following script provides a solution to compare two big xml files. I tried to compare a lot of xml files with a size of greater 500 megabytes with different tools. Each tool was eating up my memory and swap and finally crashed.
All i want to have is "show me what is in file one and not in file two and vice versa". I've reached this goal by using a property my xml files have. Each file as nodes. Each node has a unique identifier inside. I cutting out the unique identifier tag and putting this tag, line by line, into a file. After that, i'm sorting this unique identifiers. Finally i am using diff. To create a more useful output, i'm separating the "what is only in file one" into a own file (and the same for file two).
Happy using and if you find errors, i'm ready to fix them :-).
#!/bin/bash
####
# script to compare two xml files by (unique) tag
####
# @author stev leibelt
# @since 2013-03-13
####
if [[ $# -eq 3 ]]; then
XML_FILE_ONE="$1"
XML_FILE_TWO="$2"
XML_TAG="$3"
if [[ -f "$XML_FILE_ONE"
&& -f "$XML_FILE_TWO"
&& ! -z "$XML_TAG" ]]; then
#retrieving xml_tags per file
#reduce xmls by lines containing the tag
sed -n -e 's/.*<'$XML_TAG'>\(.*\)<\/'$XML_TAG'>.*/\1/p' $XML_FILE_ONE > $XML_FILE_ONE'.sed'
sed -n -e 's/.*<'$XML_TAG'>\(.*\)<\/'$XML_TAG'>.*/\1/p' $XML_FILE_TWO > $XML_FILE_TWO'.sed'
#sort and uniq the sed'ed files
sort $XML_FILE_ONE'.sed' | uniq > $XML_FILE_ONE'.sort'
sort $XML_FILE_TWO'.sed' | uniq > $XML_FILE_TWO'.sort'
#output the differences
diff $XML_FILE_ONE'.sort' $XML_FILE_TWO'.sort' > 'xml_diff_by_tag.diff'
#diff --side-by-side $XML_FILE_ONE'.sort' $XML_FILE_TWO'.sort' > 'xml_diff_by_tag.diff'
#comm -3 $XML_FILE_ONE'.sort' $XML_FILE_TWO'.sort' > 'xml_diff_by_tag.comm'
#show only differences per file
sed -n -e 's/^<\ \(.*\)/\1/p' 'xml_diff_by_tag.diff' > $XML_FILE_ONE'.diff.uniq'
sed -n -e 's/^>\ \(.*\)/\1/p' 'xml_diff_by_tag.diff' > $XML_FILE_TWO'.diff.uniq'
#sed -n -e 's/^<\(.*\)/<\1/p' 'xml_diff_by_tag.comm' > $XML_FILE_ONE'.comm.uniq'
#sed -n -e 's/\t<\(.*\)/<\1/p' 'xml_diff_by_tag.comm' > $XML_FILE_TWO'.comm.uniq'
#removing unused files
rm -fr $XML_FILE_ONE'.sed' $XML_FILE_TWO'.sed' $XML_FILE_ONE'.sort' $XML_FILE_TWO'.sort'
else
echo 'Invalid arguments provided'
echo 'try '$0' $xmlFileOne $xmlFileTwo $comparingTag'
fi
else
echo 'Invalid number of arguments provided'
echo 'try '$0' $xmlFileOne $xmlFileTwo $comparingTag'
fi
Since we are dealing more with usb devices, the good old optical burning is not used that often. I created a simple function with an alias of "burn" to write a iso file as quick as possible to my optical storage device.
####
# burns given iso file
#
# @author stev leibelt
# @since 2013-02-12
####
function net_bazzline_burn ()
{
if [[ $# -lt 1 ]]; then
echo 'No valid argument supplied.'
echo 'Try net_bazzline_burn $isoFile [$opticalDevice]'
exit 1
fi
if [[ $# -eq 1 ]]; then
sudo wodim -v dev=/dev/cdrom "$1"
else
sudo wodim -v dev=/dev/"$2" "$1"
fi
}
This is available to my shell function on github.com.