Shell Function to get value of a property from YAML file - shell

Question

I am trying to create a unix shell/bash function to get a specific value from a YAML file.
I don't want to use Python/Ruby or other scripting languages or do not want to install any packages that are not natively available in bash.
The function should take the property name name and yaml file name as input and return the value of the property.
Sample YAML is given below.
---
Action: start
Version: 642
Domains:
Domain:
Name: SanityTest
AppSpaces:
AppSpace:
Name: SanityAppSpace
AppNodes:
AppNode:
Name: SanityAppnode
Applications:
Application:
Name: InstagramTest.application
Version: "1.0"
AppNode:
Name: SanityAppnode_1
Applications:
Application:
Name: InstagramTest.application
Version: "1.0"
I am looking for some function that works like:
DomainName=getValue Domains_Domain[1]_Name /path/my_yaml.yml
AppSpaceName=getValue Domains_Domain[$DomainName]_AppSpaces_AppSpace[1]_Name /path/my_yaml.yml
AppNodeName=getValue Domains_Domain[$DomainName]_AppSpaces_AppSpace[$AppSpaceName]_AppNodes_AppNode[1]_Name /path/my_yaml.yml
AppName=getValue Domains_Domain[$DomainName]_AppSpaces_AppSpace[$AppSpaceName]_AppNodes_AppNode[$AppNodeName]_Applications_Application[1]_Name /path/my_yaml.yml
AppVersion=getValue Domains_Domain[$DomainName]_AppSpaces_AppSpace[$AppSpaceName]_AppNodes_AppNode[$AppNodeName]_Applications_Application[$AppName]_Version /path/my_yaml.yml
I came up with the below code so far, but it is not working as expected. Appreciate any help. Please advise if my approach is wrong and if there is better way.
function getValue {
local ymlFile=$2
local Property=$1
IFS='_' read -r -a props_tokens <<< "${Property}"
local props_index=0
echo "${props_tokens[props_index]}"
CheckingFor="Domains"
currEntity_Index=0
while IFS= read -r line; do
curr_prop="${props_tokens[props_index]}"
curr_prop_Index=0
IFS=':' read -r -a curr_line_props <<< "${line}"
curr_line_prop = ${curr_line_props[0]}
if [ "${props_tokens[props_index]}" == *"["*"]"* ]
then
IFS='[' read -r -a prop_tokens <<< "${props_tokens[props_index]}"
curr_prop=${prop_tokens[0]}
curr_prop_Index=${prop_tokens[1]::-1}
echo "Index processed"
echo $curr_prop
echo $curr_prop_Index
else echo "No Index for this property"
fi
if [ "$curr_line_prop" != "$CheckingFor" ]
then continue
fi
if [ "|Action|Name|Version|" == *"$curr_prop"* ]
then
return curr_line_props[1]
fi
if [ "$curr_prop" == "$CheckingFor" ]
then
if [ "|Domains|AppSpaces|AppNodes|Applications|" == *"$curr_prop"* ]
then
props_index++
case $CheckingFor in
Domains)
CheckingFor="Domain";;
Domain)
CheckingFor="AppSpaces";;
AppSpaces)
CheckingFor="AppSpace";;
AppSpace)
CheckingFor="AppNodes";;
AppNodes)
CheckingFor="AppNode";;
AppNode)
CheckingFor="Applications";;
Applications)
CheckingFor="Application";;
*) echo "$curr_prop - not switched";;
esac
continue
else
if [ "$curr_prop_Index" == 0 ]
then
case $CheckingFor in
Domains)
CheckingFor="Domain";;
Domain)
CheckingFor="AppSpaces";;
AppSpaces)
CheckingFor="AppSpace";;
AppSpace)
CheckingFor="AppNodes";;
AppNodes)
CheckingFor="AppNode";;
AppNode)
CheckingFor="Applications";;
Applications)
CheckingFor="Application";;
*) echo "$curr_prop - not switched";;
esac
props_index++
continue
else
Integer_regex='^[0-9]+$'
if [[ $curr_prop_Index =~ $Integer_regex ]]
then
# Iterate until we get to the nth Item
currEntity_Index++
if [ $currEntity_Index == $curr_prop_Index ]
then
case $CheckingFor in
Domains)
CheckingFor="Domain";;
Domain)
CheckingFor="AppSpaces";;
AppSpaces)
CheckingFor="AppSpace";;
AppSpace)
CheckingFor="AppNodes";;
AppNodes)
CheckingFor="AppNode";;
AppNode)
CheckingFor="Applications";;
Applications)
CheckingFor="Application";;
*) echo "$curr_prop - not switched";;
esac
currEntity_Index=0
else
fi
props_index++
continue
else
# Iterate until the name of the entity match and continue with next property token
# How to handle if the search sipllied into next object?
fi
fi
fi
else
props_index++
continue
fi
done < $ymlFile
return "${props_tokens[props_index]}"
}