Get CosmosDb Primary Connection String in ARM template

Question

I have an ARM template which sources the primaryMasterKey of a cosmosDb as follows:

{ "properties": { "enabled": true, "siteConfig": { "appSettings": [ { "name": "MongoDb:CnnDetails", "value": "[listKeys(resourceId('Microsoft.DocumentDB/databaseAccounts', variables('cosmosdb_full')), '2015-04-08').primaryMasterKey]" } }

How to I modify it to get the actual connection string instead?

I've tried couple of things:

1. changed the word primaryMasterKey to primaryConnectionString. This gives an error saying:

'The language expression property 'primaryConnectionString' doesn't exist, available properties are 'primaryMasterKey, secondaryMasterKey, primaryReadonlyMasterKey, secondaryReadonlyMasterKey'

2. changed the work listKeys to listConnectionStrings. This is red underlined in my visual studio, but seems to work when put through azure devops

'The language expression property 'primaryConnectionString' doesn't exist, available properties are 'connectionStrings'

3. I went to https://learn.microsoft.com/en-us/rest/api/cosmos-db-resource-provider/databaseaccounts/listconnectionstrings#code-try-0 to try it out. ListKeys returns a structure like this:

   { "primaryMasterKey": "[REDACTED]", "secondaryMasterKey": "[REDACTED]", "primaryReadonlyMasterKey": "[REDACTED]", "secondaryReadonlyMasterKey": "[REDACTED]" }

so I get why the .primaryMasterKey worked. But ListConnectionStrings returns:

{
  "connectionStrings": [
{
  "connectionString": "mongodb://[REDACTED]:10255/?ssl=true&replicaSet=globaldb",
  "description": "Primary MongoDB Connection String"
},
{
  "connectionString": "mongodb://[REDACTED]:10255/?ssl=true&replicaSet=globaldb",
  "description": "Secondary MongoDB Connection String"
},
{
  "connectionString": "mongodb://[REDACTED]:10255/?ssl=true&replicaSet=globaldb",
  "description": "Primary Read-Only MongoDB Connection String"
},
{
  "connectionString": "mongodb://[REDACTED]:10255/?ssl=true&replicaSet=globaldb",
  "description": "Secondary Read-Only MongoDB Connection String"
}
]
}

Not sure how to "index into it"?

Any clues gratefully received.

Answer 1

like you normally would in almost any language:

ListConnectionStrings.connectionStrings[index].connectionString

index starts at 0.

you have a more "native" way of doing this:

first(ListConnectionStrings.connectionStrings).connectionString

but only available functions are first and last