Azure Policy - GitHub Actions - Authoring Custom Policies - azure

Question

I'm working on testing out using GitHub and GitHub Actions to do policy as code for Azure. I have been successful in following the tutorials that Microsoft has where you export the policy you want to manage to GitHub from the Azure portal. This works fine and I'm able to edit and run the workflows to update Azure with changes to policies.
What I'd like to know is, can you create NEW policies in GitHub and push them to Azure? It seems that you need to first export a custom policy from Azure into GitHub, then you can manage that policy. I say this because when I create a new policy and a workflow for that policy I get the following error in GitHub from the workflow:
> Did not find any policies to create/update. No policy files match the
> given patterns or no changes were detected.
The policy I have in the folder is called "policy.json"
I also see:
Error occured while reading policy in path :
policies/global_tagging_policy. Error : Error: Path :
policies/global_tagging_policy. Property id is missing from the policy
definition. Please add id to the definition file.
That leads me to believe I need an ID prior to being able to push a policy, that says to me that Azure must have assigned one... I can't just make one up.
This is the policy I'm trying to push - just a tagging policy for testing, I don't have an ID in there, I read that you don't need to add one... that Azure would do it for you. Am I wrong?:
{
"properties": {
"displayName": "test-policy",
"description": "this is a test policy",
"mode": "indexed",
"parameters": {
"tagName": {
"type": "String",
"metadata": {
"displayName": "Tag Name",
"description": "Name of the tag, such as 'environment'"
}
},
"tagValue": {
"type": "String",
"metadata": {
"displayName": "Tag Value",
"description": "Value of the tag, such as 'production'"
}
}
}
},
"policyRule": {
"if": {
"allOf": [
{
"field": "type",
"equals": "Microsoft.Resources/subscriptions/resourceGroups"
},
{
"field": "[concat('tags[', parameters('tagName'), ']')]",
"exists": "false"
}
]
},
"then": {
"effect": "modify",
"details": {
"roleDefinitionIds": [
"/providers/microsoft.authorization/roleDefinitions/b24988ac-6180-42a0-ab88-20f7382dd24c"
],
"operations": [
{
"operation": "add",
"field": "[concat('tags[', parameters('tagName'), ']')]",
"value": "[parameters('tagValue')]"
}
]
}
}
}
}

Answer 1

This tripped me up too so I did some exploring of the APIs and files. I've written about this in greater detail here.
To create a custom Policy, Initiative or Assignment file using GitHub Actions you'll need to generate an id, name & type at the root of the JSON.
The name property needs to be unique at the scope you assign it, I use GUIDs for this but you don't have to. Bear in mind if you define/assign at the Management Group scope then the name needs to be 24 characters or less.
The type denotes the type of file, the options are:
Microsoft.Authorization/policyDefinitions --> Policies
Microsoft.Authorization/policySetDefinitions --> Initiatives
Microsoft.Authorization/policyAssignments --> Assignments
The id is a bit more complex, and is a concatenation of the name and type values with other values mixed in.
The prefix depends on the scope which you want to define your Policy/Initiative/Assignment.
For Management Groups it would be:
/providers/Microsoft.Management/managementGroups/00000000-0000-0000-0000-000000000000
Subscriptions would be:
/subscrptions/00000000-0000-0000-0000-000000000000
Resource Groups:
/subscriptions/00000000-0000-0000-0000-000000000000/resourceGroups/myResourceGroup
This is followed by: providers in all cases
Next is the type value, so whatever you've used for that use again here.
Finally the last segment of the id is the same value you've used for the name property.
In one line that is
/{scope}/providers/{type}/{name}
So as an example:
Policy Definition scoped at a Management Group
{
"id": "/providers/Microsoft.Management/managementGroups/00000000-0000-0000-0000-000000000000/providers/Microsoft.Authorization/policyDefinitions/5f44e572-5d2d-4edf-9d61",
"name": "5f44e572-5d2d-4edf-9d61",
"type": "Microsoft.Authorization/policyDefinitions",
"properties":{}
}
Policy Definition scoped at a Subscription
{
"id": "/subscriptions/00000000-0000-0000-0000-000000000000/providers/Microsoft.Authorization/policyDefinitions/8e4a8c58-1938-4467-8698",
"name": "8e4a8c58-1938-4467-8698",
"type": "Microsoft.Authorization/policyDefinitions",
"properties":{}
}
Initiative scoped at a Management Group
{
"id": "/providers/Microsoft.Management/managementGroups/00000000-0000-0000-0000-000000000000/providers/Microsoft.Authorization/policySetDefinitions/be09f23f-0252-4d8a-a805",
"name": "5f44e572-5d2d-4edf-9d61",
"type": "Microsoft.Authorization/policySetDefinitions",
"properties":{}
}
Initiative scoped at a Subscription
{
"id": "/subscriptions/00000000-0000-0000-0000-000000000000/providers/Microsoft.Authorization/policySetDefinitions/8e4a8c58-1938-4467-8698",
"name": "8e4a8c58-1938-4467-8698",
"type": "Microsoft.Authorization/policySetDefinitions",
"properties":{}
}