JQ: How do I replace keys and values based on regex match? - json

Question

I have two questions:
How can I use jq to search for "name" fields that start with an underscore (like _RDS_PASSWORD) and remove the leading underscore (so it becomes RDS_PASSWORD)
How can I use jq for "name" fields that start with an underscore (like _RDS_PASSWORD) and pass the value of the value cGFzc3dvcmQK to be decoded via base64? (ex: "cGFzc3dvcmQK" | base64 --decode)
Input:
[
{
"name": "RDS_DB_NAME",
"value": "rds_db_name"
},
{
"name": "RDS_HOSTNAME",
"value": "rds_hostname"
},
{
"name": "RDS_PORT",
"value": "1234"
},
{
"name": "RDS_USERNAME",
"value": "rds_username"
},
{
"name": "_RDS_PASSWORD",
"value": "cGFzc3dvcmQK"
}
]
Desired output:
[
{
"name": "RDS_DB_NAME",
"value": "rds_db_name"
},
{
"name": "RDS_HOSTNAME",
"value": "rds_hostname"
},
{
"name": "RDS_PORT",
"value": "1234"
},
{
"name": "RDS_USERNAME",
"value": "rds_username"
},
{
"name": "RDS_PASSWORD",
"value": "password"
}
]

Answer 1

Q1
walk( if type=="object" and has("name") and .name[0:1] == "_"
then .name |= .[1:]
else .
end)
If your jq does not have walk/1 then you can either upgrade to a more recent version of jq than 1.5, or include its def, which can be found at https://github.com/stedolan/jq/blob/master/src/builtin.jq
Q2
.. | objects | select(has("name") and .name[0:1] == "_") | .value
If you are certain that the encoded string was a UTF-8 string, you could use jq's #base64d; otherwise, invoke jq with the -r option and pipe the results to a decoder as you indicated you planned to do.