How to read yaml file into bash associative array? - bash

Question

I want to read into bash associative array the content of one yaml file, which is a simple key value mapping.
Example map.yaml
---
a: "2"
b: "3"
api_key: "somekey:thatcancontainany#chara$$ter"
the key can contain any characters excluding space
the value can contain any characters without limitations $!:=#etc
What will always be constant is the separator between key and value is :
the script proceses.sh
#!/usr/bin/env bash
declare -A map
# how to read here into map variable, from map.yml file
#map=populatesomehowfrommap.yaml
for key in "${!map[#]}"
do
echo "key : $key"
echo "value: ${map[$key]}"
done
I tried to play around with yq tool, similar to json tool jq but did not have success yet.

Answer 1

With the following limitations:
simple YAML key: "value" in single lines
keys cannot contain :
values are always wrapped in "
#!/usr/bin/env bash
declare -A map
regex='^([^:]+):[[:space:]]+"(.*)"[[:space:]]*$'
while IFS='' read -r line
do
if [[ $line =~ $regex ]]
then
printf -v map["${BASH_REMATCH[1]}"] '%b' "${BASH_REMATCH[2]}"
else
echo "skipping: $line" 1>&2
fi
done < map.yaml
Update
Here's a robust solution using yq, which would be simpler if the builtin #tsv filter implemented the lossless TSV escaping rules instead of the CSV ones.
#!/usr/bin/env bash
declare -A map
while IFS=$'\t' read key value
do
printf -v map["$key"] '%b' "$value"
done < <(
yq e '
to_entries | .[] |
[
(.key | sub("\\","\\") | sub("\n","\n") | sub("\r","\r") | sub("\t","\t")),
(.value | sub("\\","\\") | sub("\n","\n") | sub("\r","\r") | sub("\t","\t"))
] |
join(" ")
' map.yaml
)
note: the join needs a literal Tab

Answer 2

One way, is by letting yq output each key/value pair on a single line, in the following syntax:
key#value
Then we can use bash's IFS to split those values.
The # is just an example and can be replaced with any single char
This works, but please note the following limitations:
It does not expect nested values, only a flat list`
The field seperator (# in the example) does not exist in the YAML key/value's
#!/bin/bash
declare -A arr
while IFS="#" read -r key value
do
arr[$key]="$value"
done < <(yq e 'to_entries | .[] | (.key + "#" + .value)' input.yaml)
for key in "${!arr[#]}"
do
echo "key : $key"
echo "value: ${arr[$key]}"
done
$ cat input.yaml
---
a: "bar"
b: "foo"
$
$
$ ./script.sh
key : a
value: bar
key : b
value: foo
$

Answer 3

I used #Fravadona s answer so will mark it as answer
After some modification to my use case, what worked for me looks like:
DEFS_PATH="definitions"
declare -A ssmMap
for file in ${DEFS_PATH}/*
do
filename=$(basename -- "$file")
projectName="${filename%.*}"
regex='^([^:]+):[[:space:]]*"(.*)"[[:space:]]*$'
while IFS='' read -r line
do
if [[ $line =~ $regex ]]
then
value="${BASH_REMATCH[2]}"
value=${value//"{{ ssm_env }}"/$INFRA_ENV}
value=${value//"{{ ssm_reg }}"/$SSM_REGION}
value=${value//"{{ projectName }}"/$projectName}
printf -v ssmMap["${BASH_REMATCH[1]}"] '%b' "$value"
else
echo "skipping: $line" 1>&2
fi
done < "$file"
done
Basically in real use case I have one folder where yaml definitions are located. I iterate over all of them to form the associative array ssmMap