JOLT transformation which involve linking by an attibutes value - json

Question

I need to transform the following input JSON into the format outlined here below using JOLT. The linkage is to be done by the deps.name of first array element with spec.name of the second array element. I am clueless about the linking. Thanks for your help.
Input json
[
{
"key": "Primary",
"metadata": {
"name": "35f8d9fac891"
},
"deps": [
{
"name": "e6ae6d29edf8"
}
],
"spec": {
"vattr1": "vval1",
"vattr2": "vval2"
}
},
{
"key": "Secondary",
"metadata": {
"name": "hp74z"
},
"spec": {
"name": "e6ae6d29edf8",
"nattr1": "nval1",
"nattr2": "nval2",
"deps": {
"Name": "5505da219463"
}
}
}
]
Output format expected
{
"key": "Primary",
"metadata": {
"name": "35f8d9fac891"
},
"deps": [
{
"name": {
"key": "Secondary",
"metadata": {
"name": "hp74z"
},
"spec": {
"name": "e6ae6d29edf8",
"nattr1": "nval1",
"nattr2": "nval2",
"deps": {
"Name": "5505da219463"
}
}
}
}
],
"spec": {
"vattr1": "vval1",
"vattr2": "vval2"
}
}

Answer 1

Start with this spec in order to see whether those two objects of the array to be accumulated within a new array with key a common name("e6ae6d29edf8") such as
{
"operation": "shift",
"spec": {
"*": {
"#(0)": "#(1,spec.name)",
"#": "#(1,deps[&].name)"
}
}
}
the test would fail, if those names(one from spec.name and the other from deps[].name) don't match(just try it!)
then use
{
"operation": "shift",
"spec": {
"*": {
"*": "common"
}
}
}
in order to get rid of that confusing key name("e6ae6d29edf8") by converting it to "common". Now, we get array of two objects, and need to replace the value of "deps" array with the second object. modify transformation spec is designed to do such manipulations. Then, pick only the "common" object by using a shift transformation spec.
Thus, full spec will be :
[
{
"operation": "shift",
"spec": {
"*": {
"#(0)": "#(1,spec.name)",
"#": "#(1,deps[&].name)"
}
}
},
{
"operation": "shift",
"spec": {
"*": {
"*": "common"
}
}
},
{
"operation": "modify-overwrite-beta",
"spec": {
"*": "=firstElement(#(1,&))",
"SecondaryObject": "=lastElement(#(1,common))"
}
},
{
"operation": "modify-overwrite-beta",
"spec": {
"common": {
"deps": {
"*": "=(#(3,SecondaryObject))"
}
}
}
},
{
"operation": "shift",
"spec": {
"common": {
"*": "&"
}
}
}
]
the demo on the site http://jolt-demo.appspot.com/ is
Edit(considering the case that there exists multiple objects to be embedded as commented) :
Then you can determine an attribute "name_val" in the first spec to be used as the common identifier value to be used within the upcoming specs such as
[
{
"operation": "shift",
"spec": {
"*": {
"#(0)": "#(1,spec.name)",
"#": "#(1,deps[&].name)",
"#(0,deps[&].name)": "name_val"
}
}
},
{
"operation": "shift",
"spec": {
"*": {
"*": {
"#(2,name_val)": {
"#1": "common[&2]"
}
}
}
}
},
{
"operation": "shift",
"spec": {
"common": {
"0": "c1",
"*": "c2"
}
}
},
{
"operation": "modify-overwrite-beta",
"spec": {
"c1": {
"deps": {
"*": {
"*": "=(#(4,c2))"
}
}
}
}
},
{
"operation": "shift",
"spec": {
"c1": ""
}
}
]