How add values in JSON to get a cumulative total using Dataweave - mule

Question

I have a json object that has the memory, cpu and number of replicas for each API in the system.
I need to calculate the total CPU and Memory where the CPU / Memory for each API is cpu * number fo replicas. Take a look at the following input JSON
var payload = [
{
"id": "5a9b06b3-ed2c-4382-cf41427b6f56",
"name": "api-1",
"cpuReserved": 0.2,
"cpuLimit": 0.5,
"memReserved": 2,
"memLimit": 2,
"replicas": 1,
"status": "RUNNING"
},
{
"id": "79a90d5e-d042-9a6c-61cbe1341d04",
"name": "api-2",
"cpuReserved": 0.2,
"cpuLimit": 1,
"memReserved": 2,
"memLimit": 2,
"replicas": 2,
"status": "RUNNING"
},
{
"id": "15d0e51f-198c-948c-c4c864a5dd72",
"name": "api-3",
"cpuReserved": 0.2,
"cpuLimit": 0.5,
"memReserved": 2,
"memLimit": 2,
"replicas": 1,
"status": "RUNNING"
}
]
The output required is something like this:
"report": {
"count": 3,
"totalCPULimit": 3,
"totalCPUReserved": 0.8,
"totalMemReserved": 8,
"totalMemLimit": 8
}
Note: out of the 3 APIS in the input; 1 API has 2 replicas while the other 2 APIs have 1 replica each.
How can I generate this output using Dataweave in MuleSoft 4?

Answer 1

Pretty crude though it can get you to the desired:
%dw 2.0
output application/json
var totals = payload map {
a: $.cpuLimit * $.replicas,
b: $.cpuReserved * $.replicas,
c: $.memReserved * $.replicas,
d: $.memLimit *$.replicas
}
---
"report": {
"count": sizeOf(payload),
"totalCPULimit": sum(totals.a),
"totalCPUReserved": sum(totals.b),
"totalMemReserved": sum(totals.c),
"totalMemLimit": sum(totals.d),
}

Answer 2

I found another way of doing it deriving from an XML transformation code
%dw 2.0
output application/json
---
"report": {
"count": sizeOf(payload) as String,
"totalCPULimit": sum(payload map($.cpuLimit * $.replicas)),
"totalCPUReserved": sum(payload map($.cpuReserved * $.replicas)),
"totalMemReserved": sum(payload map($.memReserved * $.replicas)),
"totalMemLimit": sum(payload map($.memLimit * $.replicas)),
}
]