bash write and read simple JSON configuration data

_read_and_write_to_JSON_with_bash.md

prereqs

a recent version of bash

jq - https://stedolan.github.io/jq/

config.json

{ "service3455": "42", "service3045": "89", "service2345": "33" }

my_funcs.sh

store_config() {
    if [[ -z $1 ]] && [[ -z $2 ]] ; then
        config_json_data=$(echo '{}' | jq '.')
    else 
        config_json_data=$(echo $config_json_data | jq --arg v "$2" --arg k "$1"  '.[$k] |= $v ')
    fi
    echo $config_json_data
}

lookup_config_value() {
    echo $config_json_data | jq --arg v $1 '.[$v]'
}

output.md

write.sh
read.sh
raw data is : { "service3455": "42", "service3045": "89", "service2345": "33" }
key_1 value is 42

read.sh

#!/usr/bin/env bash

# import common functions for reading 
# and writing configuration
. my_funcs.sh

# read in configuration data from 
# configuration data file
config_json_file="config.json"
config_json_data=$(cat $config_json_file)

# output data and a queried configuration
# value
echo "raw data is : "$config_json_data
key_1="service3455"
query=$(lookup_config_value $key_1 | sed "s/\"//g")
echo "key_1 value is ${query}"

write.sh

#!/usr/bin/env bash

# import common functions for reading 
# and writing configuration
. my_funcs.sh

# set up data to be saved
key_1="service3455"
key_2="service3045"
key_3="service2345"
value_to_be_saved=42
config_json_file="config.json"

# initialise config_json_data
config_json_data=$(store_config)
# store key value data
config_json_data=$(store_config $key_1 $value_to_be_saved)
config_json_data=$(store_config $key_2 89)
config_json_data=$(store_config $key_3 33)
# save config data to a file
echo $config_json_data > $config_json_file