How update collections using Azure functions - azure

Question

I want to create the azure Function which is bind to cosmos DB.
Whenever some insertion happens in "A" collection I want to update "B" collection.
"B" collection has stored procedure which I want to call after the insertion in collection "A".
I am new to Azure and cosmos-DB.
Suggest me what need to be done to accomplish the requirement.
So far I have created Azure Function
Also Updated the function.json with below code.
{
"bindings": [
{
"type": "cosmosDBTrigger",
"name": "input",
"direction": "in",
"leaseCollectionName": "leases",
"connectionStringSetting": "cdb-swm-dev-001_DOCUMENTDB",
"databaseName": "admin",
"collectionName": "aomsorders",
"createLeaseCollectionIfNotExists": true
},
{
"type": "documentDB",
"name": "inputDocument",
"databaseName": "admin",
"collectionName": "aomsorders",
"connection": "cdb-swm-dev-001_DOCUMENTDB",
"direction": "in"
},
{
"type": "documentDB",
"name": "outputDocument",
"databaseName": "admin",
"collectionName": "test",
"createIfNotExists": true,
"connection": "cdb-swm-dev-001_DOCUMENTDB",
"direction": "out"
}
],
"disabled": false
}
Also Updated the Integrate Part as below
Any Suggestion will be appreciable.

Answer 1

I find your question not very specific, but broadly you have at least two options:
Insert to both collections from the same Azure Function
Insert to the collection 1 from the first Azure Function, then have a second Azure Function with Cosmos DB trigger listening to the changes of collection 1 and updating collection 2
I'm sure there are other options too.

Answer 2

Here is an example of an Azure Function that gets triggered by a CosmosDBTrigger and then it uses a DocumentDB Output Binding to write to a second collection:
function.json
{
"bindings": [
{
"type": "cosmosDBTrigger",
"name": "input",
"direction": "in",
"databaseName": "your-database",
"collectionName": "your-collection1",
"connectionStringSetting": "name-of-connectionstring-setting-for-collection1",
"leaseCollectionName": "your-lease-collection"
},
{
"type": "documentDB",
"direction": "out",
"name": "docsToSave",
"databaseName": "your-database2",
"collectionName": "your-collection2",
"connection": "name-of-connectionstring-setting-for-collection2",
"createIfNotExists": false
}
]
}
run.csx (C#)
#r "Microsoft.Azure.Documents.Client"
using Microsoft.Azure.Documents;
using System.Collections.Generic;
using System;
public static async Task Run(IReadOnlyList<Document> input, IAsyncCollector<Document> docsToSave)
{
foreach(var doc in input){
// Do something here, process the document or do your compute
// Here I am saving the same document to the second collection but you could send a new document created within the processing logic or send the same document modified by some logic
await docsToSave.AddAsync(doc);
}
}
index.js (NodeJS)
module.exports = function(context, input) {
if(!!input && input.length > 0){
context.bindings.docsToSave = [];
for(var i = 0, len=input.length; i<len;i++){
var doc = input[i];
// Do something here with the doc or create a new one
context.bindings.docsToSave.push(doc);
}
}
context.done();
}