Having getopts in a seperate function in a bash script - bash

Question

I have written the following shell script to parse arguments and print. Its not working as intended. I am sure that I am not passing correct argument to the function thats evaluating the optional params. Can some one please help is correcting it
#! /bin/sh
MAX_NO_OF_DATABASE=500;
MAX_NO_OF_CONCURRENT_REQUEST=500;
MAX_NO_OF_REQUEST=500;
function showUsage(){
echo "Sample Usage : ./benchmarking.sh <CORE_URL> <SYNC_SERVER_URL> [-d MAX_NO_OF_DATABASE] [-c MAX_NO_OF_CONCURRENT_REQUEST] [-n MAX_NO_OF_REQUEST]";
exit;
}
function readArguements(){
# Check for core url
if [ -z $1 ]; then
echo "CORE_URL is not specified"
showUsage
fi
# Check for sync server url
if [ -z $2 ]; then
echo "SYNC_SERVER_URL is not specified"
showUsage
fi
}
function readOptionalArguements(){
# Check for the optional parameters
while getopts dcn: opt
do
case $opt in
d) MAX_NO_OF_DATABASE="$OPTARG";;
c) MAX_NO_OF_CONCURRENT_REQUEST="$OPTARG";;
n) MAX_NO_OF_REQUEST="$OPTARG";;
esac
done
}
readArguements $*
readOptionalArguements $*
echo "$1 $2 $MAX_NO_OF_DATABASE $MAX_NO_OF_CONCURRENT_REQUEST $MAX_NO_OF_REQUEST"
When I run it ./benchmarker.sh core_url sync_url -d 500 -c 100 -n 200
It prints as
core_url sync_url 500 500 500
I had debugging on and I could see that it does not evaluate the switch block. Am I passing the correct arguments to readOptionalArguements

Answer 1

You should set the string to d:c:n:, because all three options take parameters.
Read carefully what man bash says about getopts:
When the end of options is encountered, getopts exits with a return
value greater than zero. OPTIND is set to the index of the first non-
option argument, and name is set to ?.
Therefore, you have to process the first two non-option parameters before processing the options.
core_url=$1
sync_server=$2
shift 2
readArguements "$#"
readOptionalArguements "$#"
Also, if you are using bash, do not write #!/bin/sh in the shebang line.

Answer 2

getopts stops on the first non-option argument, so you need to shift-out those non-option arguments before using them in getopts.
So for example:
function readOptionalArguements(){
# skip two mandatory arguments
shift 2
# Check for the optional parameters
while getopts d:c:n: opt
do
case $opt in
d) MAX_NO_OF_DATABASE="$OPTARG";;
c) MAX_NO_OF_CONCURRENT_REQUEST="$OPTARG";;
n) MAX_NO_OF_REQUEST="$OPTARG";;
esac
done
}
Also, you should declare a local OPTIND to keep that variable safe in case you call the function multiple times.

Answer 3

I believe, the problem may be in the readOptionalArguments method (btw, this is misspelled in your question). The following seems to work for me (in bash)
function readOptionalArguements() {
# Check for the optional parameters
while getopt "d:c:n:" $*
do
echo "opt: <$1>";
case $1 in
-d) shift; MAX_NO_OF_DATABASE="$1"; shift;;
-c) shift; MAX_NO_OF_CONCURRENT_REQUEST="$1"; shift;;
-n) shift; MAX_NO_OF_REQUEST="$1"; shift;;
--) break;;
*) break;;
esac
done
}