jq - Iterate over objects in bash like an array (aws volumes) - bash

Question

I have some JSON that I have pulled from AWS and formatted with jq (the original code is at the bottom) to give me the following output:
{
"VolumeId": "vol-11111111",
"Tags": {
"Name": "volume1",
"Finish": "00:00",
"Start": "00:20",
"Period": "2"
}
}
{
"VolumeId": "vol-22222222",
"Tags": {
"Name": "volume2",
"Period": "1",
"Start": "00:00",
"Finish": "00:20"
}
}
{
"VolumeId": "vol-33333333",
"Tags": {
"Period": "1",
"Start": "00:00",
"Name": "volume3",
"Finish": "00:20"
}
}
What I now need to do is to pull the 'VolumeId', 'Period', 'Start' and 'Finish'. I would like to iterate over these objects put these into 4 bash variables of the same name in a for loop.
e.g.
VolumeId="vol-33333333"
Period="1"
Start="00:00"
Finish="00:20"
The problem is that if I put the entire JSON into a variable, it is treated as a single argument. I could use something like mapfile, however it would then turn it into too many arguments - e.g.
}
"Volumes": [
{
etc
Any help in getting this to work would be greatly appreciated. The end result is to be able to take a snapshot of the volume and use the 'Period' tag to calculate retention etc.
--
Original JSON:
{
"Volumes": [
{
"Attachments": [],
"Tags": [
{
"Value": "volume1",
"Key": "Name"
},
{
"Value": "00:00",
"Key": "Start"
},
{
"Value": "00:20",
"Key": "Finish"
},
{
"Value": "2",
"Key": "Period"
}
],
"VolumeId": "vol-11111111"
},
{
"Attachments": [],
"Tags": [
{
"Value": "volume2",
"Key": "Name"
},
{
"Value": "00:00",
"Key": "Start"
},
{
"Value": "00:20",
"Key": "Finish"
},
{
"Value": "2",
"Key": "Period"
}
],
"VolumeId": "vol-22222222"
},
{
"Attachments": [],
"Tags": [
{
"Value": "volume3",
"Key": "Name"
},
{
"Value": "00:00",
"Key": "Start"
},
{
"Value": "00:20",
"Key": "Finish"
},
{
"Value": "2",
"Key": "Period"
}
],
"VolumeId": "vol-33333333"
}
]
}
and the jq command:
jq -r '.Volumes[] | {"VolumeId": .VolumeId, "Tags": [.Tags[]] | from_entries}'

Answer 1

cat rawjsonfile |jq -r '.Volumes[]|({VolumeId}+(.Tags|from_entries))|{VolumeId,Period,Start,Finish}|to_entries[]|(.key+"="+.value)'
the rawjsonfile is your "-- Original JSON"
this result is:
VolumeId=vol-11111111
Period=2
Start=00:00
Finish=00:20
VolumeId=vol-22222222
Period=2
Start=00:00
Finish=00:20
VolumeId=vol-33333333
Period=2
Start=00:00
Finish=00:20
first unwind the array to json units
cat rawjsonfile|jq -r '.Volumes[]|({VolumeId}+(.Tags|from_entries))'
the result of first step like this:
{
"VolumeId": "vol-11111111",
"Name": "volume1",
"Start": "00:00",
"Finish": "00:20",
"Period": "2"
}
{
"VolumeId": "vol-22222222",
"Name": "volume2",
"Start": "00:00",
"Finish": "00:20",
"Period": "2"
}
{
"VolumeId": "vol-33333333",
"Name": "volume3",
"Start": "00:00",
"Finish": "00:20",
"Period": "2"
}
jq support join the json object .
second choose the fields
|{VolumeId,Period,Start,Finish}
3.make it to key-value and join them
|to_entries[]|(.key+"="+.value)