Replace first match after a match with sed - bash

Question

what I want to achieve is to find an string in file and go on finding first occurrence of another match and replace that with some value.
Ex: string = {Name: name;Address:someadd;var1:var1;var2:var2},{Name: differntName;Address:someadd;var1:var1;var2:var2}
Now what i need to do is to find Name: name and then find first occurrence of "var2:var2" after "Name: name" and replace it with "var2:newvarvalue"
Please note that i need to complete this task with sed in bash scripting.
Thanks in advance.
Edit : i am trying to modify .yaml docker compose file

Answer 1

Here is a terrible solution using sed :
split on ,, one part per line :
sed 's/,/\n/g'
replace var2:var2 by var2:newvarvalue if on the same line as Name: name :
sed '/Name: name/s/var2:var2/var2:newvarvalue/'
or
sed -E 's/(Name: name.*)var2:var2/\1var2:newvarvalue/'
It's terrible because any extra comma or linefeed might break the whole thing.

Answer 2

var='{Name: name;Address:somea,dd;var1:var1;var2:var2},{Name: differntName;Address:someadd;var1:var1;var2:var2}'
NEW_VAL='new_value'
IFS=$'\n'
OBJECTS=("$(echo "${var}" | sed -nE 's/[^{]*(\{[^}]+\})/\1\n/gp')")
for obj in "${OBJECTS[#]}"; do
echo "${obj}" | sed -E 's/(.*var2:)(var2)(.*)/\1'"${NEW_VAL}"'\3/'
done
Output:
{Name: name;Address:somea,dd;var1:var1;var2:new_value}
{Name: differntName;Address:someadd;var1:var1;var2:new_value}
This solution accounts for a comma in the object (as exemplified in the first object) by extracting each and setting the delimiter to a newline.