Azure Functions (PowerShell): How to use table input binding? - powershell

Question

I have a very simple input binding in my powershell function.
# Input bindings are passed in via param block.
param($Request, $table, $TriggerMetadata)
I am kind of a beginner in Powershell, though I had plenty of experience in other languages back then.
I do understand the Azure Table Datamodel in general
Can someone please explain the structure of the binding in terms of Powershell? Is it a Hashtable, Dictionary, array of entities, of properties? What (exactly) is an entity or a property? (again in terms of Powershell-Objects)
Actually I simply want to lookup an entity that has only one property by PartitionKey and RowKey in the most simple way!
$value = $table['mykey']
Thanks alot!

Answer 1

What (exactly) is an entity or a property? (again in terms of Powershell-Objects)
As far as I know,
An Entity in the Azure Table Storage is a set of properties such as database row (Eg, key-value pair).
Every entity has a Composite Primary Key (combination of Partition Key and Row Key) and also a timestamp.
Partition is a column in every entity.
Azure Table Storage does not enforce any schema structure of all the entities that are collectively making up the table.
Every entity will have different types of partitions/columns.
Partition Key:
A Partition key is used to partition a table to support load balancing. It's used to specify which partition an object belongs to.
Row Key: A Row Key is used to uniquely identify an entity (record) in a given partition.
And I believe you have to work upon the entity that has one property (1 Partition-Row Key) which is the format of:
$inputCloudTable = $storageTable.CloudTable
Here is the MS Doc that provides example of Working on the Entities as a PowerShell Objects.

Answer 2

I solved it with plain old Powershell - for debugging purposes I used "ConvertTo-JSON" to inspect the binding object.
I also added a binding that refines to the respective partion upfront in the function.json by simply adding the partitionkey property to the binding. It filters the entities accordingly upfront.
Then it is straightforward to work with the binding (when you're able to use Powershell properly):
#select entity by property (here RowKey is used as primary Key) using "Where-Object" (alias "?")
$entity = $binding | ?{ $_.RowKey -eq $id }
#get an arbitrary property from the azure table entity
$property = $entity.someproperty
So as expected, no AzTable module / cmdlet neded !

Answer 3

You can add PartitionKey and RowKey to the binding input so that you can filter without having to return all results.
https://learn.microsoft.com/en-us/azure/azure-functions/functions-bindings-storage-table-input?tabs=in-process%2Ctable-api&pivots=programming-language-powershell
{
"name": "PersonEntity",
"type": "table",
"tableName": "Person",
"partitionKey": "Test",
"rowKey": "{queueTrigger}",
"connection": "MyStorageConnectionAppSetting",
"direction": "in"
}
There is also an oData filter option within the binding which isn't included in the documentation examples.
{
"name": "PersonEntity",
"type": "table",
"tableName": "Person",
"filter": "(age ge '{myNum}')",
"connection": "MyStorageConnectionAppSetting",
"direction": "in"
}
You also don't need to use the queue binding if you need HTTP input.
{
"bindings": [
{
"authLevel": "function",
"type": "httpTrigger",
"direction": "in",
"name": "Request",
"methods": [
"get"
],
"route": "route/{FirstName}"
},
{
"name": "PersonEntity",
"type": "table",
"tableName": "Person",
"partitionKey": "{FirstName}",
"connection": "MyStorageConnectionAppSetting",
"direction": "in"
},
{
"type": "http",
"direction": "out",
"name": "Response"
}
]
}