Azure data factory appending to Json - json

Question

Wanted to pick your brains on something
So, in Azure data factory, I am running a set of activities which at the end of the run produce a json segment
{"name":"myName", "email":"email#somewhere.com", .. <more elements> }
This set of activities occurs in a loop - Loop Until activity.
My goal is to have a final JSON object like this:
"profiles":[
{"name":"myName", "email":"email#somewhere.com", .. <more elements> },
{"name":"myName", "email":"email#somewhere.com", .. <more elements> },
{"name":"myName", "email":"email#somewhere.com", .. <more elements> },
...
{"name":"myName", "email":"email#somewhere.com", .. <more elements> }
]
That is a concatenation of all the individual ones.
To put in perspective, each individual item is a paged data from a rest api - and all them constitute the final response. I have no control over how many are there.
I understand how to concatenate individual items using 2 variables
jsonTemp = #concat(finalJson, individualResponse)
finalJson = jsonTemp
But, I do not know how to make it all under the single roof "profiles" afterwards.

Answer 1

So this is a bit of a hacky way of doing it and happy to hear a better solution.
I'm assuming you have stored all your results in an array variable (let's call this A).
First step is to find the number of elements in this array. You can
do this using the length(..) function.
Then you go into a loop, interating a counter variable and
concatenating each of the elements of the array making sure you add
a ',' in between each element. You have to make sure you do not add
the ',' after the last element(You will need to use an IF condition
to check if your counter has reached the length of the array. At the
end of this you should have 1 string variable like this.
{"name":"myName","email":"email#somewhere.com"},{"name":"myName","email":"email#somewhere.com"},{"name":"myName","email":"email#somewhere.com"},{"name":"myName","email":"email#somewhere.com"}
Now all you need to do this this expression when you are pushing the
response anywhere.
#json(concat('{"profiles":[',<your_string_variable_here>,']}'))

Answer 2

I agree with #Anupam Chand and I am following the same process with a different Second step.
You mentioned that your object data comes from API pages and to end the until loop you have to give a condition to about the number of pages(number of iterations).
This is my pipeline:
First I have initilized a counter and used that counter each web page URL and in until condition to meet a certain number of pages. As ADF do not support self referencing variables, I have used another temporary variable to increment the counter.
To Store the objects of each iteration from web activity, I have created an array variable in pipeline.
Inside ForEach, use append variable activity to append each object to the array like below.
For my sample web activity the dynamic content will be #activity('Data from REST').output.data[0]. for you it will be like #activity('Web1').output. change it as per your requirement.
This is my Pipeline JSON:
{
"name": "pipeline3",
"properties": {
"activities": [
{
"name": "Until1",
"type": "Until",
"dependsOn": [
{
"activity": "Counter intialization",
"dependencyConditions": [
"Succeeded"
]
}
],
"userProperties": [],
"typeProperties": {
"expression": {
"value": "#equals('3', variables('counter'))",
"type": "Expression"
},
"activities": [
{
"name": "Data from REST",
"type": "WebActivity",
"dependsOn": [
{
"activity": "counter in temp variable",
"dependencyConditions": [
"Succeeded"
]
}
],
"policy": {
"timeout": "0.12:00:00",
"retry": 0,
"retryIntervalInSeconds": 30,
"secureOutput": false,
"secureInput": false
},
"userProperties": [],
"typeProperties": {
"url": {
"value": "https://reqres.in/api/users?page=#{variables('counter')}",
"type": "Expression"
},
"method": "GET"
}
},
{
"name": "counter in temp variable",
"type": "SetVariable",
"dependsOn": [],
"userProperties": [],
"typeProperties": {
"variableName": "tempCounter",
"value": {
"value": "#variables('counter')",
"type": "Expression"
}
}
},
{
"name": "Counter increment using temp",
"type": "SetVariable",
"dependsOn": [
{
"activity": "Data from REST",
"dependencyConditions": [
"Succeeded"
]
}
],
"userProperties": [],
"typeProperties": {
"variableName": "counter",
"value": {
"value": "#string(add(int(variables('tempCounter')),1))",
"type": "Expression"
}
}
},
{
"name": "Append web output to array",
"type": "AppendVariable",
"dependsOn": [
{
"activity": "Counter increment using temp",
"dependencyConditions": [
"Succeeded"
]
}
],
"userProperties": [],
"typeProperties": {
"variableName": "arr",
"value": {
"value": "#activity('Data from REST').output.data[0]",
"type": "Expression"
}
}
}
],
"timeout": "0.12:00:00"
}
},
{
"name": "Counter intialization",
"type": "SetVariable",
"dependsOn": [],
"userProperties": [],
"typeProperties": {
"variableName": "counter",
"value": {
"value": "#string('1')",
"type": "Expression"
}
}
},
{
"name": "To show res array",
"type": "SetVariable",
"dependsOn": [
{
"activity": "Until1",
"dependencyConditions": [
"Succeeded"
]
}
],
"userProperties": [],
"typeProperties": {
"variableName": "res_show",
"value": {
"value": "#variables('arr')",
"type": "Expression"
}
}
}
],
"variables": {
"arr": {
"type": "Array"
},
"counter": {
"type": "String"
},
"tempCounter": {
"type": "String"
},
"res_show": {
"type": "Array"
},
"arr_string": {
"type": "String"
}
},
"annotations": []
}
}
Result in an array variable:
You can access this array by the variable name. If you want the output to be like yours, you can use the below dynamic content.
#json(concat('{','"profile":',string(variables('res_show')),'}')))
However, if you want to store this in a variable, you have to wrap it in #string() as currently, ADF variables only supports int, string and array type only.