Update Json-Attributes in Apache-Nifi: Jolt - json

Question

I'm a newbie on Apache Nifi and have the following Problem: I would like to transform a json file as follows:
From:
{
"Property1": "x1",
"Property2": "Tag_**2ABC**",
"Property3": "x3",
"Property4": "x4"
}
to:
{
"**2ABC**_Property1": "x1",
"**2ABC**_Property3": "x3",
"**2ABC**_Property4": "x4"
},
it means: taking the value from a certain Attribute to update all other attributes.
I could find examples using JoltTransformer-Processor that works well when the update is only adding a string. But not for my case
What I've done so far: I have set each Attribute using evaluateJSONPath processor. But I just tried quite a lot of possibilities to use the update Attribute processor to do it without success. All my possible tests looked like (within UpdateAttribute):
Property1 --> ${'Property2':substring(4,6)}"_"${'Property1'}
Using Jolt:
[
{"operation": "modify-overwrite-beta",
"spec": {
"Property1": "${'Property2':substring(4,6)}_${'Property1'}"
}
}
]
Which point am I missing here? Thanks in advance!

Answer 1

I don't know about Nifi, but here is how you can do it in Jolt.
Spec
[
{
"operation": "shift",
"spec": {
// match Property2
"Property2": {
"Tag_*": { // capture the nasty "**2ABC**" part to reference later
// go back up the tree to the root
"#2": {
// match and ignore Property2
"Property2": null,
//
// match Property* and use it and the captured
// "prefix" to create the output key
// &(2,1) references the Tag_*, and pull off the "**2ABC**" part
"Property*": "&(2,1)_&"
}
}
}
}
}
]