convert yaml array to string representation to export as environment variable with yq

Question

I use yq to add environment vars from yaml files.

example.yaml:

var0: string0
var1: string1
ary0: ['aryval0', 'aryval1', 'aryval2']

code:

while read -r key val; do

    eval "export $key=${val}"
    
done < <(yq '.[] | key + " " + .' example.yaml)

error:

!!seq (ary0) cannot be added to a !!str ()

desired outcome:

The same yaml file gets read into bash, environment variables, ansible and php at different times for different purposes.

I need to catch array entries when reading the yaml file and convert those array entries into a string representation to export as an environment variable, but I don't know the syntax or methods to do this in yq.

array declaration and values; I don't know how to get the environment variable example to work:

ansible/yaml: ary0: ['aryval0', 'aryval1', 'aryval2'] 
bash: ary0=('aryval0', 'aryval1', 'aryval2') 
php: $ary0 = array('aryval0', 'aryval1', 'aryval2'); 
environment variable: ary0="aryval0:aryval1:aryval2"

Thanks!

Answer 1

You can do it in a yq script file like this:

bash.yq

.[] |(
    ( select(kind == "scalar") | key + "='" + . + "'"),
    ( select(kind == "seq") | key + "=(" + (map("'" + . + "'") | join(",")) + ")")
)

Then run it with yq like:

yq --from-file=bash.yq example.yaml

To get:

var0='string0'
var1='string1'
ary0=('aryval0','aryval1','aryval2')

Explanation:

• .[] matches all top level elements
• Then we're going to have a string expression for each of the different types that will product the bash syntax, and use the union operator , to join them together
• Scalars, we just need the key and quoted value: ( select(kind == "scalar") | key + "='" + . + "'")
• Sequences (or arrays) are trickier, we need to quote each value and join them with ,: map("'" + . + "'") | join(",")

Disclaimer: I wrote yq

Answer 2

I have a solution, but with this yq (https://kislyuk.github.io/yq/)

#!/usr/bin/env bash

file=example.yaml

eval "$(yq -r 'map_values(scalars)|to_entries[]|"export \(.key)=\(.value|@sh)"' $file)"
declare -p var0
for key in $(yq -r 'map_values(arrays)|keys[]' $file); do
    mapfile -d "" $key < <(yq --raw-output0 --arg key "$key" '.[$key][]' $file)
    declare -p $key
done